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.
Hickman catheters (or Hickman lines) are a type of tunnelled central venous access line.
chemotherapy administration 2
parenteral nutrition 2
long-term parenteral antibiotic administration 2
arrhythmia (most common) 1
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...
Histiocytic sarcoma is a rare malignant hematopoietic neoplasm that has been reported in association with other hematological malignancies (particularly B and T cell lymphomas).
It comprises of tumor cells derived from the monocyte/macrophage lineage.
It usually occurs in ...
HIV-associated neoplasms are numerous and can be broadly divided into two groups:
associated but not AIDS defining malignancies
The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4:
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.
There is a bimodal distribution i...
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.
Bilateral involvement is ...
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...
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.
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.
Approximately 200 cases have been reported in the med...
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...
Columns of Bertin represent the extension of renal cortical tissue which separates the pyramids, and as such are normal structures. They become of radiographic importance when they are unusually enlarged and may be mistaken for a renal mass (renal pseudotumor).
Nomenclature of such enlarged col...
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
A useful mnemonic for remembering the tumors which cause hypervascular metastases is:
MR CT PET
R: renal cell carcinoma
T: thyroid carcinoma
PET: (pancreatic) neuroendocrine tumor
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...
Squamous cell carcinoma 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 aerodigestive tra...
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...
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.
They are considerably less common than mature ovaria...
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...
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.
Indocyanine green is a fluorescent dye discovered by researchers at Kodak working on near-infrared photography in 1...
Infantile fibrosarcoma of the lung, also known as primary bronchopulmonary fibrosarcoma, is a very rare spindle-cell tumor.
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.
Inferior vena cava leiomyosarcomas are the most common type of retroperitoneal leiomyosarcoma and most common primary malignancy of the inferior vena cava.
Three-quarters of cases occur in women, usually aged 40-60 years 2.
When symptomatic, patients most c...
Inferior vena caval (IVC) thrombosis is an essential diagnosis while evaluating any neoplastic lesion, or portal hypertension. It is also important to differentiate bland thrombus from tumor thrombus.
Patient can present with many features which include
bilateral pedal edema...
Inflammatory carcinomas of the breast, also referred to as inflammatory breast cancers, are a relatively uncommon but aggressive form of invasive breast carcinoma with a characteristic clinical presentation and unique radiographic appearances.
Inflammatory carcinomas account fo...
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.
They usually present as a well define...
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.
The inguinal nodal group is s...
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...
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...
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...
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...
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:
A population-based study of 169,444 cancer patients f...
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.
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...
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.
The age at presentation depends on tumor type....
Useful mnemonics to remember the differential diagnoses for intradural extramedullary spinal neoplasms include the following:
No More Spinal Masses
No More Spinal Masses
This simplified mnemonic, as in M&M cand...
The American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) introduced a unique staging system for the intrahepatic cholangiocarcinoma in their 7th edition in 2010. They further refined the staging system in the 8th edition.
T: primary tumor
A useful mnemonic to remember the differential diagnoses of intramedullary spinal masses is:
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
direct extension from leptomeninges
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.
It is important to note that it has been argued by ...
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...
Intraventricular meningiomas are rare intracranial tumors that represent an uncommon subtype of the more classical extra-axial meningioma and represent between 0.5 and 2% of all meningiomas. Despite its rarity, they represent one of the commonest adult intraventricular neoplasms 4.
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 r...
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.
The latest (4th) edition of the W...
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).
They represent 5-10% of all breast cancer.
There is a greater rate of contral...
Inverted papillomas are a type of Schneiderian papilloma. They are uncommon with distinctive pathological and imaging features.
The term inverted papilloma is also used to describe a urothelial lesion. For a discussion of that entity, please refer to inverted papilloma of the urin...
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 ...
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...
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.
Ischemic bowel is typically a disease...
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...
The ISSVA classification of vascular anomalies encompasses all vascular malformations and tumors in a framework of internationally consistent nomenclature. It is based on the initial classification published by Mulliken and Glowacki in 1982 and has since been updated with recognition of causal g...
The ivory vertebra sign refers to 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.
The cause for an ivory vertebra depends on the age of...
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:
expression of JAK1 mutations in cancer cells is thought to enabl...
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,...
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.
They tend to present around the 2nd to 4th decades. There is a recognized male...
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.
Juxtaglomerular cell tumor affect all age groups, but are most common in adolescents and ...
Kaposiform hemangioendothelioma is a rare, locally invasive vascular tumor that often presents in infancy, most commonly as an enlarging cutaneous mass 1,2.
Kaposiform hemangioendothelioma is a rare disease of childhood. The exact incidence and prevalence has not been accurately ...
Kimura disease, also known as eosinophilic hyperplastic lymphogranuloma, is a rare benign inflammatory disease that characteristically manifests as enlargement of cervical lymph nodes and salivary glands.
Kimura disease typically affects males (80%) between 20 and 40 years of age ...
KRAS (shortened name for the gene Kirsten RAt Sarcoma viral oncogene homolog) mutations are associated in a number of malignancies including:
certain adenocarcinomas of the lung
colorectal carcinoma 1
pancreatic ductal adenocarcinoma
Several germline KRAS mutations have also been found to b...
The Krenning score is a proposed semi-quantitative method of assessing the degree of tracer uptake on octreotide scintigraphy.
Initially designed for assessment of 111In-DTPA on planar imaging, the Krenning score is applicable to SPECT or SPECT/CT using various radiopharmaceuticals....
This article lists a series of labeled imaging anatomy cases by system and modality.
CT head: non-contrast axial
CT head: non-contrast coronal
CT head: non-contrast sagittal
CT head: angiogram axial
CT head: angiogram coronal
CT head: angiogram sagittal
CT head: venogram axial
Lactate dehydrogenase (LDH or LD) is a key enzyme in most cells, catalyzing the reversible conversion of pyruvate to L-lactate. Its contemporaneous main clinical uses are limited primarily to the investigation of hemolysis, serous collections and as a tumor marker.
Lambert-Eaton myasthenic syndrome (LEMS) is a rare neuromuscular junction disorder of paraneoplastic or primary autoimmune etiology.
LEMS is the second most common neuromuscular junction disease after myasthenia gravis.
Two-thirds of LEMS present as a paraneoplastic syndrome sec...
The skeleton is the most commonly involved organ system in Langerhans cell histiocytosis (LCH) and is by far the most common location for single-lesion LCH, often referred to as eosinophilic granuloma (EG) (the terms are used interchangeably in this article). For a general discussion of this dis...
Large-cell lung cancer is one of the histological types of non-small-cell carcinomas of the lung.
It is thought to account for approximately 10% of bronchogenic carcinoma 1.
Patients present with dyspnea, chronic cough and hemoptysis.
Large cell neuroendocrine carcinoma (LCNEC) of the lung is classified as a subtype of large cell carcinoma of the lung. It is also classified as a pulmonary neuroendocrine tumor.
The incidence peaks around the 6th decade 6. There is an increased male predilection 7. They are rare ...
Laryngeal carcinoma staging refers to TNM staging of carcinomas involving the supraglottic, glottic, and subglottic larynx. The vast majority of applicable cases are squamous cell carcinomas, but other epithelial tumors are also included. The following article reflects the 8th edition published ...
Leiomyoma is a benign smooth muscle (myometrial) tumor, most commonly found in the uterus.
Leiomyoma is classified by location:
leiomyoma of the urinary bladder
solitary cutaneous leiomyoma
vascular leiomyoma (angiol...
Leiomyosarcomas (LMS) are extremely rare malignant neoplasms that originate from smooth muscle cells and may be considered the malignant counterpart of a leiomyoma. They are classified as a soft tissue tumor and account for ~8% of malignant soft tissue tumors 10.
Lepidic-predominant adenocarcinoma (LPA) of the lung, formerly known as non-mucinous bronchoalveolar carcinoma, is a subtype of invasive adenocarcinoma of the lung characterized histologically when the lepidic component comprises the majority of the lesion.
The category of 'lepid p...
Leptomeningeal enhancement refers to a diffuse or focal gyriform or serpentine enhancement that can be seen in the following conditions:
tuberculous meningitis (can also be focal)
CNS cryptococcal infection
coccidioidal meningitis (c...
Leptomeningeal metastases, also know as carcinomatous meningitis, refers to the spread of malignant cells through the CSF space. These cells can originate from primary CNS tumors (e.g. drop metastases), as well as from distant tumors that have metastasized via haematogenous spread.
The Leser-Trélat sign is a dermatological paraneoplastic syndrome referring to the explosive and rapid eruption of multiple seborrheic keratoses. It is associated with a number of different cancers including adenocarcinoma (e.g. gastric, colorectal), breast cancer and lymphoproliferative disorde...
Leukemia is a hematological neoplasm characterized by the overproduction of immature (blasts) or abnormally differentiated cells of the hematopoietic system in the bone marrow that often, but not always, extends into the peripheral blood.
This article aims to provide an overview of leukemia as...
Leukemia CNS manifestations can be divided into those related to the disease itself and those associated with its treatment. Leukaemias are hematologic malignancies in which occur a proliferation of hematopoietic cells at an undifferentiated or partially differentiated stage of maturation.
Lhermitte-Duclos disease, also known as dysplastic cerebellar gangliocytoma, is a rare tumor of the cerebellum. It is probably hamartomatous, although the exact pathogenesis remains unknown 2,6. Even though it may not be neoplastic, it is considered a WHO grade I tumor in the current WHO classif...
Lichen planus refers to a dermatological condition that typically affects the skin, nails, oral cavity, genitals or perineum.
Skin lesions are characterized by violaceous scaly pruritic plaque eruption while oral lesions are characterized by erosions and lace-like reticular plaques. It is a chr...
Lipoblastoma is a rare, benign, encapsulated tumor arising from embryonic white fat.
It occurs primarily in infancy and early childhood (more than 90% before age 3 years).
May present as a rapidly enlarging mass 4. It most often occurs in the extremities an...
There a number of features that can help distinguish between lipoma and well-differentiated liposarcoma. This article relates to superficial well-differentiated liposarcomas that typically occur in the extremities, also known as atypical lipomatous tumors, and not retroperitoneal liposarcoma.
Liposclerosing myxofibrous tumors (LSMFT), also known as polymorphic fibro-osseous lesions of bone, are rare benign fibro-osseous lesions that have a predilection for the intertrochanteric region of the femur.
It is slightly more common in males with mean age of 30-40 yea...
Liver Imaging Reporting and Data System (LI-RADS) is both a set of standardized terminology and a classification system for imaging findings in liver lesions. The LI-RADS score for a liver lesion is an indication of its relative risk for hepatocellular carcinoma (HCC).
The classification system...
Littoral cell angioma of the spleen is a rare, benign primary vascular tumor of the spleen.
Littoral cell angiomas may occur at any age and have no gender predilection.
Littoral cell angiomas have been diagnosed in association with various malignancies outside the s...
Liver tumors, like tumors of any organ, can be classified as primary or secondary.
Liver metastases are by far the most common hepatic malignancy, with many of the most common primaries readily seeding to the liver. This is especially the case with gastrointestinal tract tumors, due...
A lobectomy (plural: lobectomies) is the complete resection of one lobe of the lung and is the commonest lung surgery performed for bronchogenic carcinoma.
A posterolateral thoracotomy is the commonest approach for the resection of lung malignancies. For other surgical approaches for...
Lobular breast carcinoma is a subtype of breast cancer can range from lobular carcinoma in situ (LCIS) to invasive lobular carcinoma.
Multicentricity and bilaterality tend to be quite common with lobular breast carcinomas.
Lobular carcinoma in situ (LCIS) represents the next step up from atypical lobular hyperplasia (ALH) along the malignant spectrum of lobular breast carcinoma.
LCIS occurs predominantly in premenopausal women with a mean age of 45 years old, approximately 10-15 years younger than t...
The lollipop sign is seen in hepatic epithelioid hemangioendothelioma (HEHE). It represents hepatic/portal vein and/or their tributaries/branches tapering and terminating at or just within the edge of a well defined peripherally enhancing (or non-enhancing) lesion with an avascular core on CT or...
The lower limb lymph nodes consist of the:
inguinal lymph nodes
superficial inguinal lymph nodes
deep inguinal lymph nodes
popliteal lymph nodes
Low-grade appendiceal mucinous neoplasms (LAMN), previously known as appendiceal mucinous cystadenomas, are rare mucinous tumors of the appendix showing low-grade cytologic atypia, c.f. high-grade appendiceal mucinous neoplasms.
Considerable controversy still exists on mucinous ne...
Mnemonics for the differential diagnosis of lucent/lytic bone lesions include:
They are anagrams of each other and therefore include the same components. They are by no means exhaustive lists, but are a good start for remembering a differential for a lucent/lytic bone...
The Lugano classification is a lymphoma staging system resulting from recommended changes in 2011 to the Cotswolds modified Ann Arbor staging. This article outlines the lesion measurement guidelines for the system:
lymph nodes: the longest diameter in axial plane should be >1....
The Lugano classification is a lymphoma staging system for non-Hodgkin and Hodgkin lymphoma. This article outlines the classification's response to treatment based on PET-CT.
Also included in the classification are staging and response to treatment based on CT.
The Lugano clas...
The Lugano classification is a lymphoma staging system resulting from recommended changes in 2011 to the Ann Arbor staging with Cotswolds modifications. This article outlines the classification's response to treatment based on CT.
Also included in the classification are staging and reponse to ...
The Lugano staging classification is the lymphoma staging system that is most commonly used in clinical practice currently. The categories for initial staging are defined in this article. See separate articles for the Lugano criteria for response assessment by PET-CT or by CT alone, as well as g...