Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

888 results found
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Giant breast masses

Many patients, particularly in developing countries, can present late with giant breast masses. They may be single or multiple and either benign or malignant. Many of these conditions are indistinguishable on physical examination alone. Some of these lesions require mastectomy while others can b...
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Giant cell tumor of bone

Giant cell tumors of bone, also known as osteoclastomas, are relatively common bone tumors and are usually benign. They typically arise from the metaphysis of long bones, extend into the epiphysis adjacent to the joint surface, and have a narrow zone of transition. Epidemiology Giant cell tumo...
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Gliosarcoma

Gliosarcomas are a variant of glioblastoma (along with epithelioid glioblastoma and giant cell glioblastoma) recognized in the current (2016) WHO classification of CNS tumors 9. They are highly malignant (WHO grade IV) primary intra-axial neoplasms with both glial and mesenchymal elements. Term...
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Gynecologic Imaging-Reporting and Data System (GI-RADS)

The Gynecologic Imaging-Reporting and Data System (GI-RADS) is a reporting system that was created for reporting the findings in adnexal masses based on transvaginal ultrasonography. Classification Findings are classified into five categories 1: GI-RADS 1 normal ovaries identified and no adn...
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Hemangioblastoma (central nervous system)

Hemangioblastomas are tumors of vascular origin and occur both sporadically and in patients with von Hippel Lindau (vHL). They are WHO grade I tumors that can occur in the central nervous system or elsewhere in the body, including kidneys, liver, and pancreas. These tumors generally present on ...
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Hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) (encompasses bone marrow transplantation (BMT)) is a relatively common procedure used to treat a wide spectrum of conditions 1,2: lymphoproliferative disorders, e.g. multiple myeloma (most common indication), lymphoma,  leukemia solid tumors, e.g...
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Hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a non-malignant but often-fatal disorder of immune dysregulation affecting multiple organs. It is also known as macrophage activation syndrome when occurring in the setting of a rheumatologic disorder. Epidemiology It typically affects infants and yo...
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Hemorrhage exclusion sign (prostate)

The hemorrhage exclusion sign can be a useful MRI finding following prostate biopsy. Pathology The normal prostate produces high concentrations of citrate, which among other properties, acts as an anticoagulant 1. As tumor cells are dysfunctional, they will produce lower levels of citrate than...
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Hemorrhagic intracranial metastases (mnemonic)

A mnemonic for primary malignancies responsible for hemorrhagic intracranial metastases is: MR CT BB MR CT HBO Mnemonic MR CT BB M: melanoma R: renal cell carcinoma C: choriocarcinoma T: thyroid carcinoma, teratoma B: bronchogenic carcinoma B: breast carcinoma   MR CT HBO M: melano...
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Haemosiderotic fibrolipomatous tumor

Haemosiderotic fibrolipomatous tumors or haemosiderotic fibrohistiocytic lipomatous lesions are locally aggressive soft tissue tumors of uncertain differentiation. Epidemiology Haemosiderotic fibrolipomatous tumors are rare with an estimated incidence of less than 0.2% of all benign lipomatous...
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Halo sign (osseous)

The Halo sign in bone imaging refers to the presence of a hyperintense rim around an osseous lesion on T2-weighted MRI, which is an indicator of a metastatic lesion 1.
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Hamartoma

A hamartoma (plural: hamartomas or hamartomata) is a benign tumor-like malformation that consists of a collection of architecturally disorganized cells located in an area of the body where the cells are normally found. It is often due to abnormal development. In radiology, hamartomas often mimi...
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Hand-foot syndrome (chemotherapy)

Hand-foot syndrome, also known as palmar-plantar erythrodysaesthesia or Burgdorf reaction, is a benign, aseptic, self-limiting complication of many chemotherapeutic agents characterized by a widespread erythema, edema and ulceration of the hands and feet.  Causative drugs Many chemotherapeutic...
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Hartmann procedure

Hartmann procedure (HP) (or proctosigmoidectomy) is an operation in which the sigmoid colon is resected and the distal colon brought out as a colostomy in the left iliac fossa. The remnant rectum stump is sewn shut. It is a quick and straightforward intervention and currently finds most favor in...
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Head and neck cancer therapy response interpretation (Hopkins criteria)

The head and neck cancer therapy response interpretation (Hopkins criteria) is a qualitative system of interpretation for therapy response assessment using PET-CT. Background Widely used options for therapy response assessment are clinical examination, histopathology, CT and MR imaging, howeve...
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Head and neck squamous cell carcinoma (overview)

Head and neck squamous cell carcinomas (SCC) are common, being the sixth most common cancer. They can have a cutaneous or mucosal origin. As such there is a wide array of clinical and radiographic manifestations, and are separated into: squamous cell carcinoma of the skin of the head and neck ...
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Head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCC) are the most common histologic type of head and neck cancer. While the term may include any squamous cell carcinoma of the head and neck, common usage focuses on those of mucosal origin, i.e., squamous cell carcinoma of the upper aerodigestive tract...
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Heavy charged particle therapy

Heavy charged particle therapy (also known as heavy ion radiotherapy) is a type of particle therapy that uses ionized atoms (e.g. neon, argon, silicon, carbon etc.). Currently carbon ions are most commonly employed, termed carbon ion radiotherapy (CIRT). It is a technically-demanding technique ...
Article

Hepar lobatum carcinomatosum

Hepar lobatum carcinomatous, also known as pseudocirrhosis of the liver, is a rare form of metastatic liver disease. It is most often secondary to invasive ductal and lobular breast cancer. It was, however, first described in tertiary syphilis. The exact pathogenesis is unclear, and both direct ...
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Hepatic carcinosarcoma

Hepatic carcinosarcoma is a very rare tumor that is defined by mixed histological features.  Terminology This tumor has also been referred to as malignant mixed tumor, spindle cell carcinoma, pseudosarcoma or sarcomatoid carcinoma 1,2.  Pathology Hepatic carcinocarcinoma contain a mixture of...
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Hepatic epithelioid hemangioendothelioma

Hepatic epithelioid hemangioendothelioma (HEHE) is a rare, low to intermediate grade malignant hepatic vascular tumor. Epidemiology There may be a greater female incidence (with reported male-to-female ratio, 3:2), with peak incidence thought to be around 30-40 years old. Pathology Histologi...
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Hepatic metastases

Hepatic metastases are 18-40 times more common than primary liver tumors 6. Ultrasound, CT, and MRI are all useful for detection of hepatic metastases and evaluation across multiple post-contrast CT series, or MRI pulse sequences are necessary.  Epidemiology The demographics of patients with l...
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Hepatoblastoma (staging)

As expected there are a number of different staging systems for hepatoblastoma. Staging PRETEXT grouping system of pediatric liver tumors not specific to hepatoblastoma; used in all pediatric liver tumors Intergroup staging system specific for hepatoblastoma (see below) Intergroup staging ...
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Hepatomegaly

Hepatomegaly refers to an increase in size or enlargement of the liver.  Pathology Etiology Hepatomegaly can result from a vast range of pathology including, but not limited to, the following: malignancy/cellular infiltrate multiple metastases lymphoma(s) leukemia(s) hepatocellular carci...
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Hepatosplenomegaly

Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly). Pathology Etiology Infection Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive! vira...
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HER-2 mutations in lung cancer

Human epidermal growth factor receptor 2 (HER-2) mutations may be detected in approximately 3% of lung adenocarcinomas 1. Radiographic features CT Early studies have suggested HER2-mutant tumors exhibit more aggressive features in general and tend to: exhibit a locally-invasive behavior comp...
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Hereditary cancer syndromes

Hereditary cancer syndromes contribute to only 5% of all cancers but are important to recognize due to the long-term surveillance and follow up required for these patients. Autosomal recessive ataxia telangiectasia Fanconi anemia MUTYH-associated polyposis Autosomal dominant familial adeno...
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Hereditary renal cancer syndromes

Despite the vast majority of renal cancers being sporadic, there are a number of hereditary renal cancer syndromes: von Hippel Lindau syndrome: predominantly clear cell type tuberous sclerosis: predominantly clear cell type (also associated with angiomyolipoma) hereditary paraganglioma-pheoch...
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Hickman catheter

Hickman catheters (or Hickman lines) are a type of tunnelled central venous access line. Indications chemotherapy administration 2 parenteral nutrition 2 long-term parenteral antibiotic administration 2 Complications Insertion arrhythmia (most common) 1 arterial injury kinking pneumoth...
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High-grade appendiceal mucinous neoplasms

High-grade appendiceal mucinous neoplasms (HAMN) are rare mucinous tumors of the appendix showing high-grade cytologic atypia, cf. low-grade appendiceal mucinous neoplasms (LAMN). The distinction between both LAMN and HAMN is done on histological grounds and these tumors look the same on imaging...
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High-grade surface osteosarcoma

High-grade surface osteosarcomas are very rare and high-grade malignant osteoid forming tumors emerging from the bony surfaces similar to parosteal and periosteal osteosarcomas. Epidemiology High-grade surface osteosarcomas are very rare and constitute <1% of all osteosarcomas. There seems to ...
Article

Histiocytic sarcoma

Histiocytic sarcoma is a rare malignant hematopoietic neoplasm that has been reported in association with other hematological malignancies (particularly B and T cell lymphomas). Pathology It comprises of tumor cells derived from the monocyte/macrophage lineage. Location It usually occurs in ...
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HIV associated neoplasms

HIV-associated neoplasms are numerous and can be broadly divided into two groups: AIDS-defining malignancies associated but not AIDS defining malignancies AIDS-defining malignancies The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4: Ka...
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Hodgkin lymphoma

Hodgkin lymphoma or Hodgkin disease (HD) is a type of lymphoma and accounts for ~1% of all cancers. Hodgkin disease spreads contiguously and predictably along lymphatic pathways and is curable in ~90% of cases, depending on its stage and sub-type. Epidemiology There is a bimodal distribution i...
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Hodgkin lymphoma (pulmonary manifestations)

Pulmonary manifestations of Hodgkin lymphoma are relatively rare, present in  5-12% of patients at the time of diagnosis. It is relatively more common with the nodular sclerosing subtype. Pulmonary involvement usually indicates stage IV disease.  Radiographic features Bilateral involvement is ...
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How you can help build Radiopaedia.org

Contributing to Radiopaedia.org does not need to be a massive commitment. Even a few minutes here and there can make a real difference. This page is a great place to start if you want to get involved. There are many ways to do this: create your own case library and make your existing cases comp...
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Hybrid nerve sheath tumor

Hybrid nerve sheath tumors or hybrid peripheral nerve sheath tumors (HPNST) are benign peripheral nerve sheath tumors displaying combined morphological characteristics of more than one of the conventional tumor types as schwannoma neurofibroma or perineurioma. Recognized combinations are: schwa...
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Hyperechoic liver lesions

A hyperechoic liver lesion on ultrasound can arise from a number of entities, both benign and malignant. A benign hepatic hemangioma is the most common entity encountered, but in patients with atypical findings or risk for malignancy, other entities must be considered. Benign hepatic hemangiom...
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Hyperparathyroidism-jaw tumor syndrome

Hyperparathyroidism-jaw tumor syndrome is an extremely rare condition where a gene mutation results in hyperparathyroidism in association with both benign and malignant tumors, most notably, tumors in the mandible or maxilla 2. Epidemiology Approximately 200 cases have been reported in the med...
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Hyperthermic intraperitoneal chemotherapy

Hyperthermic intraperitoneal chemotherapy (often abbreviated as HIPEC) is a form of chemotherapy used for the treatment of peritoneal involvement with malignancy.  It usually involves the instillation of heated (to around 41–43°C) chemotherapy agents directly into the abdominopelvic cavity imme...
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Hypertrophic osteoarthropathy

Hypertrophic osteoarthropathy (HPOA) is a syndrome characterized by periosteal reaction of the long bones without underlying bone lesion. There are a broad range of manifestations, although typically there is symmetrical involvement of the appendicular skeleton. Accompanying abnormal soft tissue...
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Hypervascular metastases

There are several tumors which are noted to cause hypervascular metastases. The list of differential diagnoses includes: renal cell carcinoma (RCC) breast cancer: homogeneously hypervascular liver metastases from breast are considered rare 3 lung cancer neuroendocrine tumors carcinoid tumor...
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Hypervascular metastases (mnemonic)

A useful mnemonic for remembering the tumors which cause hypervascular metastases is: MR CT PET Mnemonic M: melanoma R: renal cell carcinoma C: choriocarcinoma T: thyroid carcinoma PET: (pancreatic) neuroendocrine tumor
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Hypopharyngeal carcinoma (staging)

Hypopharyngeal carcinoma staging refers to TNM staging of carcinomas originating in the hypopharynx. This system most commonly applies to squamous cell carcinomas but can also apply to rarer epithelial malignancies in the region. The following article reflects the 8th edition published by the Am...
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Hypopharyngeal squamous cell carcinoma

Squamous cell carcinoma (SCC) of the hypopharynx is relatively uncommon, carries the worst prognosis of any head and neck squamous cell carcinoma (HNSCC), and is a challenge to diagnose and treat.  Hypopharyngeal carcinoma is relatively uncommon representing only 10% of all proximal aerodigesti...
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Hypothalamic lesions

Hypothalamic lesions are numerous representing some entities that are unique to the hypothalamus, as well as many lesions that can be seen elsewhere within the brain. Additionally, due to its proximity to the optic chiasm, third ventricle and pituitary region, many lesions of these locations can...
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Immature ovarian teratoma

Immature ovarian teratomas are uncommon ovarian germ cell tumors. They differ from mature ovarian teratomas (dermoid cysts) both histologically by the presence of immature tissue, and clinically by their more malignant behavior. Epidemiology They are considerably less common than mature ovaria...
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Immune checkpoint inhibitor therapy

Immune checkpoint inhibitor therapy is a relatively new treatment for certain cancers which result in immune system-mediated destruction of tumor cells. Immune checkpoint inhibitors act through a unique mechanism of action when compared with those of conventional chemotherapeutic agents. They t...
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Immune checkpoint inhibitor therapy related pneumonitis

Immune checkpoint inhibitor therapy-related pneumonitis is one of the complications that can occur in the setting of immune checkpoint inhibitor therapy. Radiographic features CT Variable and several distinct radiographic patterns of pneumonitis have been described which include 1:  organizi...
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Incidentaloma

An incidentaloma is a radiological neologism to denote a lesion found incidentally and of dubious clinical significance. Although it can refer to any incidental lesion (e.g. pituitary 3, thyroid 4), it is most often used to denote an incidental adrenal lesion, which is commonly an adrenal adenom...
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Indocyanine green lymphangiography

Indocyanine green (ICG) lymphangiography is an emerging imaging technique used to visualize lymphatic vessels and map their course as they drain to sentinel lymph nodes.  History Indocyanine green is a fluorescent dye discovered by researchers at Kodak working on near-infrared photography in 1...
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Infantile fibrosarcoma

Infantile fibrosarcomas are locally aggressive rarely metastasizing fibroblastic tumors found in the pediatric population. Terminology Other acceptable terms include congenital fibrosarcoma, infantile fibrosarcoma-like tumor, cellular congenital mesoblastic nephroma 1. Epidemiology Infantile...
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Infantile fibrosarcoma of the lung

Infantile fibrosarcoma of the lung, also known as primary bronchopulmonary fibrosarcoma, is a very rare spindle-cell tumor. Epidemiology More than 80% of cases are reported to occur within the 1st year of life. There is a slight predominance in male infants 1,2. Clinical presentation Patient...
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Inferior vena cava leiomyosarcoma

Inferior vena cava leiomyosarcomas are the most common type of retroperitoneal leiomyosarcoma and most common primary malignancy of the inferior vena cava. Epidemiology Three-quarters of cases occur in women, usually aged 40-60 years 2. Clinical presentation When symptomatic, patients most c...
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Inferior vena caval thrombosis

Inferior vena caval thrombosis is an essential diagnosis while evaluating any neoplastic lesion, or portal hypertension. It is also important to differentiate bland thrombus from tumor thrombus. Clinical features A patient can present with many features which include bilateral pedal edema Bu...
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Inflammatory carcinoma of the breast

Inflammatory carcinoma of the breast, also referred to as inflammatory breast cancer, is a relatively uncommon but aggressive form of invasive breast carcinoma with a characteristic clinical presentation and unique radiographic appearances.  Epidemiology   Inflammatory carcinomas account for 1...
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Inflammatory myofibroblastic tumor of the spleen

Inflammatory myofibroblastic tumors of the spleen are rare spindle cells tumors of indeterminate clinical behavior. Please refer to the article on inflammatory myofibroblastic tumors for a broad discussion on the subject.  Radiographic features Ultrasound They usually present as a well define...
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Inguinal lymph nodes

The inguinal lymph nodes (often shortened to the inguinal nodes) are a major group of lymph nodes in the lymphatic system. They are the major drainage pathway of the lower limbs, genitals, dorsal perineum and the inferior most aspect of the anterior abdominal wall. Inguinal lymph nodes larger th...
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Intensity-modulated radiation therapy

Intensity-modulated radiation therapy (IMRT) is a type of conformal radiation therapy where not only the shape but also the intensity profile (i.e. fluence) of each beam is varied, therefore, superior to the 3D-CRT.  Early implementations involved building up a fluence profile by summing smalle...
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Intermuscular lipoma

Intermuscular lipomas are lipomas located deep between muscles. Terminology Intermuscular lipomas are sometimes called ‘infiltrating lipoma’ since they can involve both the intramuscular and the tissue between muscles 1. Epidemiology Intermuscular lipomas are much less common than superficia...
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Internal iliac lymph nodes

The internal iliac lymph nodes (often shortened to internal iliac nodes) are the lymph nodes found adjacent to the internal iliac artery and its branches and drain the regions supplied by these vessels. This encompasses a large area from the genitalia anteriorly, the psoas muscle posteriorly and...
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International Myeloma Working Group response criteria

The International Myeloma Working Group response criteria are consensus definitions used to assess response to treatment of multiple myeloma. With the latest version published in 2016, the criteria have been widely adopted for classifying responses in clinical trials and in routine practice 1. I...
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Intracranial epidermoid cyst

Intracranial epidermoid cysts are uncommon congenital lesions which account for about 1% of all intracranial tumors. They result from inclusion of ectodermal elements during neural tube closure, and typically present in middle age due to mass effect on adjacent structures. Their content, derived...
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Intracranial metastatic melanoma

Intracranial metastatic melanoma is the third most common brain metastasis.  For a broad discussion about the primary tumor or brain metastasis in general, please refer to the articles: malignant melanoma cerebral metastases Epidemiology A population-based study of 169,444 cancer patients f...
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Intracranial tumors with calcification

A variety of intracranial tumors exhibit different forms of calcification. Some lesions commonly show calcification while in some tumors, calcification is seen only in few number of cases. In this article these tumors are classified on the basis of frequency of calcification. Commonly calcified...
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Intraductal papillary mucinous neoplasm

Intraductal papillary mucinous neoplasms or tumors (IPMNs or IMPTs) are epithelial pancreatic cystic tumors of mucin-producing cells that arise from the pancreatic ducts. They are most commonly seen in elderly patients.  On imaging, particularly MRCP, they are characterized by single or multipl...
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Intradural extramedullary metastases

Intradural extramedullary metastases are rare and only account for approximately 5% of spinal metastases. Please review leptomeningeal metastases (brain) for a general discussion focused on the brain's subarachnoid space involvement. Epidemiology The age at presentation depends on tumor type....
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Intradural extramedullary spinal tumors (mnemonic)

Useful mnemonics to remember the differential diagnoses for intradural extramedullary spinal neoplasms include the following: No More Spinal Masses MNM Mnemonics No More Spinal Masses N: neurofibroma M: meningioma S: schwannoma M: metastasis MnM This simplified mnemonic, as in M&M cand...
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Intrahepatic cholangiocarcinoma (staging)

Intrahepatic cholangiocarcinoma staging is conducted most commonly in accordance with the TNM staging classification of the American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC). As of 2018, the staging criteria are in their 8th edition and reflected below 1. Th...
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Intramedullary spinal masses (mnemonic)

A useful mnemonic to remember the differential diagnoses of intramedullary spinal masses is: I HEAL Mnemonic I: infarction H: hemangioblastoma E: ependymoma A: astrocytoma L: lipoma
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Intramedullary spinal metastasis

Intramedullary spinal metastases are rare, occurring in ~1% of autopsied cancer patients, and are less common than leptomeningeal metastases. Intramedullary lesions may result from: growth along the Virchow-Robin spaces hematogenous dissemination direct extension from leptomeninges Epidemio...
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Intramuscular angioma

Intramuscular angiomas or intramuscular hemangiomas are benign vascular soft tissue tumors consisting of benign vascular channels within the skeletal muscle. Terminology The term 'intramuscular-infiltrating angiolipoma' is now discouraged. Epidemiology Intramuscular angiomas are uncommon and...
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Intramuscular lipoma

Intramuscular lipomas are deep-seated lipomas located within a muscle. Terminology Intramuscular lipomas share the term ‘infiltrating lipoma’ with intermuscular lipomas. Epidemiology Intramuscular lipomas account for about 1% of all lipomas and occur in all age groups with the most occurring...
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Intraosseous meningioma

Intraosseous meningioma, also referred to as primary intraosseous meningioma, is a rare subtype of meningioma that accounts for less than 1% of all osseous tumors. They are the most common type of primary extradural meningiomas 6. Terminology It is important to note that it has been argued by ...
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Intraventricular masses (an approach)

The ventricular system of the brain plays host to a variety of unique tumors, as well as tumors that are more frequently seen elsewhere (e.g. meningiomas). Besides, some intra-axial (parenchymal) masses can be mostly exophytic and thus appear mostly intraventricular. A systematic approach taking...
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Intraventricular meningioma

Intraventricular meningiomas, although are rare intracranial tumors, are a common type of intraventricular neoplasm in adults. They account for less than 3% of all meningiomas.  On imaging, they classically present as vividly enhancing solid mass at the trigone of the lateral ventricles. Epide...
Article

Intraventricular neoplasms and lesions

Intraventricular neoplasms are rare and arise from periventricular structures such as the walls of the ventricular system, the septum pellucidum and the choroid plexus. Many tumor types arise from or can bulge into the ventricular system, although there are certain lesions that are relatively re...
Article

Invasive ductal carcinoma

Invasive ductal carcinoma not otherwise specified, also known as invasive carcinoma of no special type, is the most common type of breast cancer. It is an infiltrating, malignant and abnormal proliferation of neoplastic cells in the breast tissues. Terminology The latest (4th) edition of the W...
Article

Invasive lobular carcinoma of the breast

Invasive lobular carcinoma is the most common special type of invasive breast cancer after invasive breast carcinoma of no special type (invasive ductal carcinoma not otherwise specified). Epidemiology They represent 5-10% of all breast cancer. Associations There is a greater rate of contral...
Article

Inverted papilloma

Inverted papillomas are a type of Schneiderian papilloma, representing an uncommon sinonasal tumor that mostly affects middle-aged men. On imaging, they classically demonstrate a convoluted cerebriform pattern seen on both T2 and contrast-enhanced T1 weighted MRI images. Terminology  The term ...
Article

Investigation of hemoptysis (summary)

This is a basic article for medical students and other non-radiologists. Hemoptysis is the coughing up of frank blood or blood-stained mucus/pus from the lungs and it is an important indicator of pathology. Careful assessment of history, clinical examination and investigations will help elicit ...
Article

Iodine-131

Iodine-131​ (131I or I-131) is a radioisotope of iodine, which is used in the diagnosis and treatment of thyroid lesions. It is one of the oldest radiotracers used in nuclear medicine, in use for over 50 years. It is predominately used in thyroid ablation therapy, for patients post-thyroidectomy...
Article

Ischemic colitis

Ischemic colitis refers to inflammation of the colon secondary to vascular insufficiency and ischemia. It is sometimes considered under the same spectrum as intestinal ischemia. The severity and consequences of the disease are highly variable. Epidemiology Ischemic bowel is typically a disease...
Article

Ischemic fasciitis

Ischemic fasciitis refers to a reactive pseudosarcomatous fibroblastic or myofibroblastic proliferation associated with physical constraints. Terminology Terms that are no longer recommended for use include ‘pseudosarcomatous fibromatosis’ and ‘atypical decubital fibroplasia’. Epidemiology M...
Article

Ishikawa classification of venous involvement by pancreatic ductal adenocarcinoma

Ishikawa classification system describes the degree of involvement of adjacent portal vein and SMV by pancreatic ductal adenocarcinoma based on caliber of the vein: type I: normal  type II: smooth shift/displacement with normal caliber   type III: unilateral narrowing  type IV: bilateral nar...
Article

ISSVA classification of vascular anomalies

The ISSVA classification of vascular anomalies encompasses all vascular malformations and tumors in a framework of internationally consistent nomenclature.  ISSVA is the International Society for the Study of Vascular Anomalies. It is based on the initial classification published by Mulliken and...
Article

Ivory vertebra

The ivory vertebra (also known as ivory vertebra sign) sign refers to the diffuse and homogeneous increase in opacity of a vertebral body that otherwise retains its size and contours, and with no change in the opacity and size of adjacent intervertebral discs. Pathology Etiology The cause for...
Article

Janus Kinase

Janus kinases or JAKs are cytoplasmic tyrosine kinases which link cytokine signaling from membrane receptors to signal transducers and activators of transcription (STAT) transcription factors.  There are at least four JAKs: JAK1 expression of JAK1 mutations in cancer cells is thought to enabl...
Article

Jugulodigastric lymph nodes

The jugulodigastric lymph nodes, also known as subdigastric lymph nodes, are deep cervical nodes located below the posterior belly of the digastric muscle and anterior to the internal jugular vein. They are located in neck node level IIa and receive lymphatic drainage from the tonsils, pharynx,...
Article

Juxta-articular myxoma

Juxta-articular myxomas or periarticular myxomas are benign myxoid soft tissue tumors with similarities to intramuscular myxomas. They are classified as tumors of uncertain differentiation. Epidemiology Juxta-articular myxomas are rare and seen over a wide age range with a peak in the fourth t...
Article

Juxtacortical chondroma

Juxtacortical chondromas, also known as periosteal chondromas, are rare benign chondral tumors that arise from the periosteum of tubular bones. They are thought to account for ~2% of benign bone tumors. Epidemiology They tend to present around the 2nd to 4th decades. There is a recognized male...
Article

Juxtaglomerular cell tumor

Juxtaglomerular cell tumors, also known as reninomas, are uncommon renal tumor of the juxtaglomerular cells. The tumor cells secrete renin and often cause severe hypertension and hypokalemia. Epidemiology Juxtaglomerular cell tumor affect all age groups, but are most common in adolescents and ...
Article

Kaposiform hemangioendothelioma

Kaposiform hemangioendothelioma is a rare, locally invasive vascular tumor that often presents in infancy, most commonly as an enlarging cutaneous mass 1,2.  Epidemiology Kaposiform hemangioendothelioma is a rare disease of childhood. The exact incidence and prevalence has not been accurately ...

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