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.

755 results found
Article

Primary uveal malignant melanoma

Malignant uveal melanomas, also referred to as choroidal melanomas, are the most common primary tumor of the adult eye 3.  Epidemiology Malignant melanoma of the uvea is the most common primary intraocular malignancy and is predominantly seen in Caucasians 5. The incidence of these tumors incr...
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Prostate cancer (staging)

Prostate cancer staging takes into account TNM (primary site, nodal and distant metastases), pretreatment PSA and histological grading. The Gleason score is used to determine the Grade Group.  An old, superseded staging system is the Whitmore-Jewett staging system. Additionally, there is some ...
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Prostate Imaging-Reporting and Data System (PI-RADS)

PI-RADS (Prostate Imaging–Reporting and Data System) is a structured reporting scheme for multiparametric prostate MRI in the evaluation of suspected prostate cancer in treatment naive prostate glands. This article reflects version 2.1, published in 2019 and developed by an internationally repre...
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Prostate sarcoma

Prostatic sarcoma is an uncommon and heterogenous group of tumor arising from mesenchymal cells in and around the prostate.  Pathology In children the most common tumor type is a prostatic rhabdomyosarcoma, which accounts for approximately a third of all prostatic sarcomas 1.  In adults leiom...
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Prostate specific antigen

Prostate specific antigen (PSA) is currently used as a tumor marker for prostate adenocarcinoma. PSA is a 33 kilodalton glycoprotein produced in prostate epithelial cells. Its normal physiologic role is as a liquefying agent for seminal fluid; only a tiny amount leaks into the blood, therefore ...
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Prostate-specific membrane antigen

Prostate-specific membrane antigen (PSMA) (also known as glutamate carboxypeptidase II) is a type II transmembrane glycoprotein that has become an increasingly prominent imaging biomarker 1. PSMA has emerged as a useful target in PET imaging of prostate cancer, especially in the evaluation of sm...
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Prostatic carcinoma

Prostatic carcinoma ranks as the most common malignant tumor in men and the second most common cause of cancer-related deaths in men. Prostatic adenocarcinoma is by far the most common histological type and is the primary focus of this article. Epidemiology It is primarily a disease of the eld...
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Proton therapy

Proton therapy, also referred to as proton-beam therapy, is the most common type of particle therapy. It represents one of the highly conformal radiation therapy techniques that, differing from the other external-beam photon therapies, uses the proton particle properties to minimize the toxic ef...
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Protoplasmic astrocytoma

Protoplasmic astrocytoma is a rare variant of diffuse low-grade astrocytomas with histological and imaging features which overlap with other entities.  Until recently, they were classified as a subtype of low-grade diffuse astrocytoma. However, in the latest (2016) update to WHO classification ...
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PSA density

The PSA density (PSAD), is a calculation performed at diagnosis and is the serum PSA level (ng/mL) divided by the volume of the prostate gland (mL)1. Prostate volume is calculated from TRUS measurements2,3.  Alternatively, PSAD may be calculated using MRI measurements3 of prostate volumes or le...
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Pseudocirrhosis

Pseudocirrhosis is a radiological term used to recapitulate imaging findings of cirrhosis, but occurring in the setting of hepatic metastases. It is most commonly reported following chemotherapeutic treatment of breast cancer metastases, although has also been reported before treatment, and with...
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Pseudo Meigs syndrome

Pseudo Meigs syndrome refers to a clinical syndrome of pleural effusion, ascites associated with an ovarian tumor that is not a fibroma or a fibroma-like tumor. Pathology Entities that have been reported to result in pseudo Meigs syndrome include Krukenberg tumors colon carcinoma metastases ...
Article

Pseudomyxoma peritonei

Pseudomyxoma peritonei refers to syndrome of progressive intraperitoneal accumulation of mucinous ascites related to a mucin-producing neoplasm. It is most commonly caused by a mucinous tumor of the appendix 10. Much less commonly, mucinous tumors of colon, rectum, stomach, pancreas , and urach...
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Pulmonary artery sarcoma

Pulmonary artery sarcomas are extremely rare tumors that originate from the intimal mesenchymal cells of the pulmonary artery. It is frequently misdiagnosed as pulmonary thromboembolism.  Epidemiology  Primary malignant tumors of the pulmonary arteries are very rare with an incidence of 0.001–...
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Pulmonary lymphoma

Pulmonary lymphoma refers to lung parenchymal involvement with lymphoma. Pathology It can be broadly divided as primary or secondary: primary pulmonary lymphoma: (rare) usually non-Hodgkin lymphoma which is limited to the lung with or without mediastinal lymph node involvement and with no evi...
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Pulmonary metastases

Pulmonary metastases are common and the result of metastatic spread from a variety of primary tumors via blood or lymphatics. This article describes haematogenous pulmonary metastases with lymphangitis carcinomatosis discussed separately. Epidemiology The epidemiology will match that of the u...
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Pulmonary opacification

Pulmonary opacification represents the result of a decrease in the ratio of gas to soft tissue (blood, lung parenchyma and stroma) in the lung. When reviewing an area of increased attenuation (opacification) on a chest radiograph or CT it is vital to determine where the opacification is. The pat...
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Pure ground glass nodules

Pure ground glass lung nodules are a subtype of ground glass lung nodules where there is no associated solid component. They have been shown to represent various pathologies such as 1,3 adenocarcinoma in situ of lung minimally-invasive adenocarcinoma of lung invasive adenocarcinoma of lung ...
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Pyrexia

Pyrexia (or fever) is a clinical sign, indicated by an abnormally elevated core body temperature, which is defined by several medical societies as ≥38.3°C (≥101°F). The temperature elevation may be persistent or episodic. The commonest cause of fever is infection, in one study of hospital inpati...
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Pyrexia of unknown origin

A pyrexia of unknown origin, commonly shortened to PUO and also known as a fever of unknown origin (FUO), was originally defined in 1961 as the condition in which the core body temperature is >38.3oC for a period of three weeks or more, with no diagnosis reached after one week of inpatient inves...
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Radial scar

Radial scar, or complex sclerosing lesion, is a rosette-like proliferative breast lesion. It is not related to surgical scarring. Some authors, however, reserve the latter term to lesions over 1 cm 5.  It is an idiopathic process with sclerosing ductal hyperplasia.  Its significance is that it...
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Radiation-induced breast cancer

Radiation-induced breast cancers are a potential long-term complication of radiotherapy to the chest, in particular, in those patients receiving irradiation for breast cancer or Hodgkin lymphoma.  Besides breast cancer, sarcomas (breast angiosarcoma or osteosarcomas arising from the irradiated ...
Article

Radiation-induced breast changes

Radiation-induced breast changes are a consequence of radiotherapy toxicity over the breast tissues either related to targeted breast cancer treatment or other thoracic malignancies (eg. lung cancer).  Radiographic features The radiation-induced breast changes may be seen in either dedicated b...
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Radiation-induced carcinogenesis

Radiation-induced carcinogenesis is widely but not universally believed to occur at exposures from ionizing radiation used in medical imaging. It is thought to be a stochastic effect of ionizing radiation, with the linear no-threshold theory (LNT) proposing no "safe" level of radiation exposure,...
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Radiation-induced cerebral vasculopathy

Radiation-induced cerebral vasculopathy encompasses a complex and broad range of effects on the intra- and extracranial vessels resulting from injury from radiation exposure. Manifestations can include hemorrhages and ischemic strokes, cavernoma and capillary telangiectasias, and large vessel st...
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Radiation-induced glioma

Radiation-induced gliomas are a rare complication of cranial irradiation, occurring in less than 3% of cases 15 years post-treatment. Glioblastomas correspond to three-quarters of all radiation-induced gliomas.  The risk of developing a secondary CNS cancer following radiation exposure has been...
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Radiation-induced heart disease

Radiation-induced heart disease, also known as radiation cardiotoxicity, describes an uncommon constellation of potential cardiac complications of thoracic radiotherapy. Epidemiology The demographics of patients affected by radiation-induced heart disease are those of the underlying condition ...
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Radiation-induced liver disease

Radiation-induced liver disease (RILD), also referred to as radiation hepatitis, represents the toxic effect of radiation therapy on normal hepatocytes.   This article will discuss liver toxicity appearances after external beam radiotherapy techniques. Please refer to the dedicated article on s...
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Radiation-induced lung cancer

Radiation-induced lung cancers are a potential long-term complication of radiotherapy to the chest.  Besides lung cancer, sarcomas (osteosarcomas are the most common arising from the irradiated bones and malignant fibrous histiocytomas, the most frequently arising from the soft tissues), breast...
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Radiation-induced neuritis

Radiation-induced neuritis is a complication of radiotherapy that may present with visible changes on MRI. It is likely to be most relevant in the head and neck region. There is only scarce radiology literature on the subject and radiation-induced optic neuritis is best documented. Radiographic...
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Radiation-induced esophagitis

Radiation-induced esophagitis is a consequence of radiotherapy toxicity over the esophagus resulting in both acute or chronic complications:  acute esophagitis: usually 2 to 4 weeks after radiotherapy start 1 extending within ≤ 3 months after completion of the radiotherapy 3 chronic esophagiti...
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Radiation-induced pulmonary fibrosis

Radiation-induced pulmonary fibrosis is the late manifestation of radiation-induced lung disease and is relatively common following radiotherapy for chest wall or intrathoracic malignancies. This article does not deal with the changes seen in the acute phase. Please refer to the article on radi...
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Radiation-induced sarcoma

Radiation-induced sarcoma (RIS) can originate in either the irradiated bone or soft tissues after a period of latency. They are usually high-grade tumors with a poor prognosis when compared with primary sarcomas. Malignant fibrous histiocytoma and osteosarcoma are the two most common histologica...
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Radiation-induced thyroid cancer

Radiation-induced thyroid cancer is an important etiology of thyroid cancer.  Epidemiology Information about radiation-induced thyroid malignancies comes from several long-term cohort studies along with some case-controlled studies and their subsequent meta-analyzes. Although these studies var...
Article

Radiation therapy

Radiation therapy, or radiotherapy, is a common oncologic treatment modality utilizing ionizing radiation to control or eliminate malignant cells. Radiotherapy plays a role in primary curative treatment (eg. head and neck cancer), adjuvant therapy (e.g. reducing recurrence rate after local breas...
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Radioembolization

Radioembolization is the delivery of radioactive microspheres to cancers using an endovascular approach. It is often performed as an outpatient procedure.  Indications hepatocellular carcinoma hepatic metastases from colorectal carcinoma Contraindications Absolute contraindications excessi...
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Radiologically inserted gastrostomy (RIG)

A radiologically inserted gastrostomy (RIG) is a procedure where a tube is inserted percutaneously in the stomach, principally to provide nutritional support for patients with swallowing disorders 1. Indications inadequate oral intake due to dysphagia (neurologic disorder, oesophagal obstructi...
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Radiomics

Radiomics (as applied to radiology) is a field of medical study that aims to extract a large number of quantitative features from medical images using data characterization algorithms. The data is assessed for improved decision support. It has the potential to uncover disease characteristics tha...
Article

Raindrop skull

The raindrop skull appearance of calvarial multiple myeloma is the presence of multiple, well-defined lytic lesions (punched out lesions) of various size scattered throughout the skull. This term is applied as an analogy to rain hitting a surface and splashing, where it leaves a random pattern o...
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RANO criteria for glioblastoma

Response assessment in neuro-oncology criteria (RANO), published in 2010 1, are used to assess response to first-line treatment of glioblastoma (as well as lower grade astrocytoma 3) and have largely superseded the older Macdonald criteria (which only dealt with glioblastoma multiforme) 2. For ...
Article

RASopathy

RASopathies are a class of developmental disorders caused by germline mutations in genes that encode for components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway. Epidemiology As a group, RASopathies represent one of the most common malformation syndromes, with an in...
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RECIST 1.1: comparison with RECIST 1.0

Response Evaluation Criteria In Solid Tumors (RECIST) was updated to version 1.1 in 2009. For both RECIST 1.0 and 1.1, the requirement for measurable disease at baseline depends on the endpoints of the clinical trial. The fundamental concept common to both versions of RECIST is that measurable...
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Rectal cancer

Rectal cancer, although sharing many of the features of generic colorectal carcinoma (CRC), has some features that make it unique. These are predominantly related to its anatomical location which has implications in both preoperative imaging assessment and surgical technique. Epidemiology Rect...
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Rectal cancer (staging)

Staging strongly influences the success of and rate of local recurrence following rectal cancer resection. MRI is the modality of choice for the staging of rectal cancer, to guide surgical and non-surgical management options. MRI is used at diagnosis, following downstaging chemoradiotherapy, and...
Article

Renal cell carcinoma

Renal cell carcinomas (RCC) (historically also known as hypernephroma or Grawitz tumor) are primary malignant adenocarcinomas derived from the renal tubular epithelium and are the most common malignant renal tumor. They usually occur in 50-70-year old patients and macroscopic hematuria occurs in...
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Renal cell carcinoma (TNM staging)

Renal cell carcinoma staging using the TNM staging system for renal cell carcinoma. Older but still widely used system in some practices is the Robson staging system. TNM staging (7th edition) T T1 T1a: tumor confined to kidney, <4 cm T1b: tumor confined to kidney, >4 cm but <7 cm T2: limi...
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Renal leiomyoma

Renal leiomyomas are benign tumors of the kidney originating from smooth muscle cells of the renal capsule, pelvis, calyces, or blood vessels. There is a 4-5.5% prevalence based on autopsy findings 1. Clinical presentation Renal leiomyomas are usually incidental findings. In symptomatic cases...
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Renal lymphoma

Renal lymphoma is usually a part component of multi-systemic lymphoma - primary renal lymphoma is unusual. Typical imaging findings are multiple bilateral hypodense or infiltrative renal masses. Epidemiology While renal lymphoma has an autopsy incidence of ~45% (range 30-60%) in lymphoma pati...
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RENAL nephrometry scoring system

The RENAL nephrometry scoring system was developed to categorize renal masses into low, intermediate and high complexity, based on cross-sectional imaging findings. Its purpose is to aid in decision making, patient counseling, surgical planning, and patient follow-up, as well as academic reporti...
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Renal oncocytoma

Renal oncocytomas are relatively benign renal tumors. The main clinical importance of this lesion is the difficulty in pre-operatively distinguishing it from renal cell carcinomas, as epidemiology, presentation, imaging and even histology can be very similar.  Epidemiology Renal oncocytomas ac...
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Renal osteodystrophy

Renal osteodystrophy (ROD), also known as uremic osteopathy, is the constellation of musculoskeletal abnormalities that occur in patients with chronic renal failure, due to concurrent and superimposed: osteomalacia (adults)/rickets (children) secondary hyperparathyroidism: abnormal calcium and...
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Response evaluation criteria in solid tumors

Response evaluation criteria in solid tumors or RECIST refers to a set of published rules used to assess tumor burden in order to provide an objective assessment of response to therapy. They were initially introduced in 2000 and have undergone subsequent revision in 2009 (RECIST 1.1). For the ev...
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Retroperitoneal leiomyosarcoma

Retroperitoneal leiomyosarcoma, leiomyosarcoma arising within the retroperitoneum, is one of the commonest primary retroperitoneal neoplasms. The retroperitoneum is considered the most common extra uterine site for leiomyosarcoma.  Epidemiology They are more common in women. Clinical presenta...
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Rhabdoid meningioma

Rhabdoid meningioma is a rare and aggressive subtype of meningioma, it is classified as WHO grade III. Rhabdoid morphology is associated with a poor prognosis, regardless of tumor histogenesis. It resembles other types of rhabdoid tumors with a great tendency for recurrence 1,2. Extensive necros...
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Rhabdomyosarcoma (genitourinary tract)

Rhabdomyosarcomas of the genitourinary tract are uncommon tumors occurring in pelvic organs.  It is a disease nearly exclusive to the pediatric population.  For a general discussion of this type of tumor, please refer to the article on rhabdomyosarcomas. Epidemiology The peak incidence of tum...
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Rhabdomyosarcomas (biliary tract)

Rhabdomyosarcomas of the biliary tract are rare tumors, usually identified in children, with a very poor prognosis. They are usually grouped under botryoid rhabdomyosarcomas. For a general discussion of this type of tumor, please refer to the article on rhabdomyosarcomas. Epidemiology Rhabdom...
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ROS1 mutation

The ROS1 mutation is a mutation occurring in the ROS1 oncogene on chromosome 6 resulting in a defective receptor tyrosine kinase which has structural similarity to the anaplastic lymphoma kinase (ALK) protein. It is thought to be present in several cancers of the subtype non-small cell lung can...
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Rotational/helical/arc intensity-modulated radiation therapy

Rotational/helical/arc intensity-modulated radiation therapy (IMRT) is the most advanced form of IMRT is conceptually similar to helical or cone-beam CT 1. The radiation beam remains turned on throughout the treatment while the gantry is moved around the patient at variable speed and the multi-l...
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Rotter lymph nodes

Rotter lymph nodes (also known as interpectoral nodes) are lymph nodes located in the interpectoral fascia in Rotter space, between the pectoralis major and pectoralis minor muscles. Their number varies from one to four. They are usually considered to be a separate nodal group from the level I a...
Article

Rubinstein-Taybi syndrome

Rubinstein-Taybi syndrome (RTS) is a very rare genetic multi-system disorder primarily characterized by intellectual disability, broad and often angulated thumbs and halluces, and distinctive facial features. Epidemiology The estimated incidence is 1 in 100,000-125,000 live births 5. Clinical...
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Salivary gland tumors

Salivary gland tumors are variable in location, origin and malignant potential.  Pathology In general, the ratio of benign to malignant tumors is proportional to the gland size; i.e. the parotid gland tends to have benign neoplasms, the submandibular gland 50:50, and the sublingual glands and ...
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Samarium-153

Samarium-153 (Sm-153) is a radioisotope used in metabolic radiotherapy for the treatment of pain from bone metastases. It is produced in nuclear reactors, by neutron irradiation of samarium-152 (Sm-152 Sm2O3). Samarium-153 decays by emitting both beta minus particles and gamma photons with a ch...
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Sarcoid-like post-immunotherapy granulomatosis

Sarcoid-like post-immunotherapy granulomatosis has been reported as an uncommon complication in patients treated with immunotherapy agents such as monoclonal antibodies. It was first reported in TNF inhibitors used to treat rheumatoid arthritis and has also been reported in various immunotherapy...
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Scleroderma (gastrointestinal manifestations)

Gastrointestinal manifestations of scleroderma can occur in up to 90% of patients with scleroderma 2 with the commonest site of gastrointestinal involvement being the esophagus. After skin changes and Raynaud phenomenon, gastrointestinal changes are 3rd most common manifestation of scleroderma. ...
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Screening for breast cancer

Screening for breast cancer includes activities which test members of asymptomatic populations for breast cancer. Many advanced countries have breast screening programs. The most widely adopted method for breast cancer screening is mammography. There are few areas in imaging fraught with more c...
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Secondary hepatic involvement with lymphoma

Secondary hepatic involvement with lymphoma (secondary hepatic lymphoma) is common, much more so than primary hepatic lymphoma.  Clinical presentation Hepatomegaly with deranged liver function tests is the most common presentation. Jaundice is common. Rarely, patients may present with acute li...
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Secondary involvement of the bone with lymphoma

Secondary involvement of the bone with lymphoma, also referred as secondary bone lymphoma, is much more common than primary bone lymphoma, occurring in ~15% of disseminated lymphomas. Terminology Secondary bone lymphoma is defined as lymphoma involving the bone with nodal disease occurring wit...
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Secondary involvement of the pleura with lymphoma

Secondary involvement of the pleura with lymphoma (secondary pleural lymphoma) is very common, occurring in ~20% of lymphomas. It may be a result of an extension of lymphoma into the visceral or parietal pleura or be a complicating pleural effusion and is a poor prognostic factor.  Epidemiology...
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Secondary malignant cardiac tumor

Secondary malignant cardiac tumors or cardiac metastases refer to a secondary malignant tumor involving any structural component of the heart. It represents spread of a primary neoplasm via lymphatic, haematogenous, or endovascular pathways, or potentially by direct extension from an adjacent ti...
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Secondary organizing pneumonia

Secondary organizing pneumonia (SOP) refers to organizing pneumonia that can be attributed to a specific cause, in contrast to cryptogenic organizing pneumonia (COP). Pathology Etiology SOP can be attributed to the following causes 1: Prior infection bacteria atypical pneumonias (e.g. Legi...
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Second branchial cleft cyst

Second branchial cleft cysts are a cystic dilatation of the remnant of the 2nd branchial apparatus, and along with 2nd branchial fistulae and sinuses accounts for 95% of all branchial cleft anomalies. Clinical presentation Although a congenital abnormality, they tend to present in early adulth...
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Selective internal radiation therapy

Selective internal radiation therapy (SIRT), also know as hepatic radioembolization, is a relatively new and developing modality for treating non-resectable liver tumors. The procedure consists of a transcatheter injection of radioactive particles via the hepatic artery.  It is generally consid...
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Sentinel lymph node

The sentinel lymph nodes (SLNs) are defined as those lymph nodes that directly drain a malignancy, or alternatively can be considered as the first node(s) that a tumor metastasizes to. History and etymology "Sentinel node" as the initial draining node of a malignancy was first used in a paper ...
Article

Sezary syndrome

Sézary syndrome (SS) is a type of cutaneous T-cell lymphoma. It is sometimes considered an advanced and leukemic form of cutaneous T-cell lymphoma (CTCL). Clinical presentation It is clinically characterized by an extensive erythematous rash covering most of the body as well as the presence of...
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Siewert-Stein classification of esophageal adenocarcinoma

The Siewert-Stein classification of esophageal adenocarcinoma classes these tumors according to their relationship to anatomical landmarks 1. It was initially proposed by Siewert et al in 1996, becoming widely used in predicting lymph node spread and directing optimal management. As of the 7th e...
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Sinonasal adenocarcinoma

Sinonasal adenocarcinomas are primary tumors of the sinonasal region with glandular differentiation. They are grossly classified as salivary and non-salivary subtypes. However, generally in the literature and IARC/WHO classification, the term Sinonasal adenocarcinoma refers to non-salivary adeno...
Article

Sinonasal lymphoma

Sinonasal lymphoma refers to the involvement of the nasal cavity and/or paranasal sinuses with lymphoma. It can be primary or secondary. Clinical presentation Presenting symptoms of sinonasal lymphoma are variable but are usually similar to those of benign inflammatory diseases. The clinical s...
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Sinonasal mucosal melanoma

Sinonasal mucosal melanoma (SNMM) is a very rare and unique subtype of malignant melanoma. Epidemiology SNMMs account for ~1% of malignant melanomas and <4% of head and neck cancers 1,2. They affect older patients (60-90 years old) 2. There is a higher incidence in Japan 5.  Clinical presenta...
Article

Skeletal metastasis

Skeletal metastases are common and result in significant morbidity in patients with metastatic disease. Although the diagnosis is often straightforward, especially as in many cases there is a well-documented history of metastatic malignancy, sometimes they may mimic benign disease or other prima...
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Skeletal muscle metastases

Skeletal muscle metastases are uncommon compared to other sites and are generally seen in the context of widespread metastatic disease.  Epidemiology Post-mortem rates of skeletal metastases vary between 0.03% and 17% 1.  Clinical presentation Most commonly asymptomatic 2,3.  Pathology Com...
Article

Skin cancer

Skin cancers refer to malignancies arising from the skin. This is a general discussion of skin cancers, for discussions of specific skin cancers please refer to individual articles. Epidemiology Overall, skin cancers are the most common human malignancy 1. Pathology Primary skin malignancy ...
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Skull metastases

Metastases to the skull are very common in patients with disseminated skeletal metastatic disease, although they are often asymptomatic. For a more detailed general discussion please refer to the article on skeletal metastatic disease. Epidemiology Skull metastases are seen in ~20% (range 15-2...
Article

Small bowel carcinoid tumor

Small bowel carcinoid tumors are the most common gastrointestinal carcinoid tumors and most frequently involves the terminal ileum. Epidemiology Small bowel carcinoid tumors account for ~40% of gastrointestinal carcinoid tumors 1.  Clinical presentation Small bowel carcinoids are slow growin...
Article

Small bowel lymphoma

Small bowel lymphoma is one of the most common small bowel malignancies, accounting for ~25% of all primary small bowel malignancies, and ~40% of all primary gastrointestinal lymphomas. Epidemiology Small bowel lymphoma is most commonly secondary extranodal involvement in widespread systemic l...
Article

Small cell carcinoma (urinary bladder)

Small cell carcinomas of the bladder are rare bladder cancers with a poor prognosis. Its appearance overlaps other bladder cancers, in particular, urothelial/transitional cell carcinoma. Epidemiology A very rare tumor, it has been estimated at <0.0001% of bladder cancers. It is thought to have...
Article

Small cell lung cancer (staging - superseded)

Previously, small cell lung cancer (SCLC) was not staged in the same manner as non-small cell lung cancer (NSCLC), but since 2013 both are staged using the IASLC (International Association for the Study of Lung Cancer) lung cancer staging system (currently in its 8th edition, published in 2016)....
Article

Soft tissue calcification (mnemonic)

Mnemonics to remember the causes of soft tissue calcification include: My GHOSTS 1 TIC MTV 2 Mnemonics My GHOSTS My: myositis ossificans G: gout H: hyperparathyroidism O: ochronosis S: scleroderma/connective tissue diseases T: tumoral calcinosis S: sarcoma (synovial cell) TIC MTV T:...
Article

Soft-tissue sarcoma

Soft-tissue sarcomas are a heterogeneous group of malignant tumors of mesenchymal origin (sarcoma) that originate from the soft tissues rather than bone. They are classified on the basis of tissue seen on histology. The commoner sarcomas in the adult and pediatric population are listed below. A...
Article

Solid and enhancing pituitary region mass

Solid lesions with enhancement are by far the most commonly encountered appearance of pituitary region masses. Differential diagnosis macroadenoma by far the most common entity typically enhances less vividly than other entities elevates the dura of the diaphragma sella (as the origin is wi...
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Solid periosteal reaction

Solid periosteal pattern is thought to evolve from single layer and multilayered periosteal reactions, forming a solid layer of new bone adjacent to the cortex. It can be seen in: osteoid osteoma osteomyelitis osteosarcoma chondrosarcoma fibrous dysplasia non-ossifying fibroma osteoblast...
Article

Solitary bone plasmacytoma

Solitary bone plasmacytomas is an uncommon plasma cell tumor which is localized to bone. They may involve any bone, but they have a predisposition for the red marrow-containing axial skeleton: spinal disease is observed in ~50% (range 34-72%) of cases the thoracic vertebrae are most commonly i...
Article

Solitary pulmonary nodule (an approach)

A solitary pulmonary nodule, according to the Nomenclature Committee of the Fleischner Society, is defined as a rounded opacity, well or poorly-defined on a conventional radiograph, measuring up to 3 cm in diameter and is not associated with lymphadenopathy, atelectasis, or pneumonia. Several r...
Article

Solitary sclerotic bone lesion

The differential diagnosis of a solitary sclerotic bone lesion is heavily influenced by the age of the patient, and includes: sclerotic metastasis solitary either because no others are present or no others have been imaged enostosis (bone island) osteosarcoma calcifying enchondroma osteobl...

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