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.

582 results found
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Tumors of the seminal vesicles

Tumors arising primarily from the seminal vesicles are rare. Most frequently, when a mass is seen in the seminal vesicles, it represents a contiguous spread from tumors in adjacent organs, in particular, the prostate. Epithelial tumors adenocarcinoma of the seminal vesicle the most common pri...
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Tumor thrombus

Tumor thrombus is defined as tumor extending into a vessel, typically a vein. It occurs in a wide variety of malignancies. It is vital to distinguish tumor thrombus from "bland" thrombus (free of neoplastic cells) in the setting of neoplasia, as this often impacts staging and treatment approach....
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Typhlitis

Typhlitis, also called cecitis or neutropaenic colitis, is a necrotizing inflammatory condition which typically involves the cecum and, sometimes, can extend into the ascending colon or terminal ileum. Epidemiology Typhlitis was first described in children with leukemia and severe neutropaenia...
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Ultrasound appearances of liver metastases

Ultrasound appearance of liver metastases can have bewildering variation, and the presence of hepatic steatosis can affect the sonographic appearance of liver lesions. Radiographic features Ultrasound Patterns do exist between ultrasound appearance of the liver metastases and the likely prima...
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Ultrasound "U" classification of thyroid nodules

The ultrasound "U" classification of thyroid nodules has been developed by the British Thyroid Association (BTA) as part of their 2014 guidelines on the management of thyroid cancer 1. It allows for stratifying thyroid nodules as benign, suspicious or malignant based on ultrasound appearances t...
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Undifferentiated embryonal sarcoma of the liver

Undifferentiated embryonal sarcomas of the liver are rare, aggressive, and malignant liver tumors encountered in the pediatric population.  Epidemiology Approximately 90% of cases occur in patients under 15 years of age, most commonly between 6 and 10 years of age, but some cases have been rep...
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Unilateral axillary lymphadenopathy (differential)

Unilateral axillary lymphadenopathy while being more concerning than bilateral axillary lymphadenopathy can still arise from a various benign as well as malignant causes. Benign mastitis other regional infective causes tuberculosis ipsilateral arm infection, e.g. cellulitis silicone induce...
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Unilateral testicular lesions

The differential diagnosis for unilateral testicular lesions is wide-ranging.  Neoplastic Common seminoma (40-50% of testicular malignancies) non-seminomatous germ cell tumors: testicular teratoma testicular epidermoid (teratoma with ectodermal elements only) testicular choriocarcinoma t...
Article

Urethral diverticulum

Urethral diverticula, or urethroceles, are focal outpouchings of the urethra. They should not be confused with a ureterocele of the distal ureter. Epidemiology Urethral diverticula occur far more frequently in women than in men and are estimated to occur in 1-6% of women, especially those with...
Article

Vertebral metastases

Vertebral metastases represent the secondary involvement of the vertebral spine by haematogenously-disseminated metastatic cells. They must be included in any differential diagnosis of a bone lesion in a patient older than 40 years. This article will focus only on the metastasis involving the b...
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Vertebra plana

Vertebra plana (a.k.a. pancake / silver dollar / coin-on-edge vertebra) is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced compression fracture. Plural is vertebrae planae. It can occur in a variety of settings, incl...
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VIPoma

VIPomas are a very rare type of pancreatic endocrine tumor that secrete, and get their name from, vasoactive intestinal peptide (VIP). The clinical syndrome resulting from these tumors is commonly known as WDHA syndrome, as an acronym of the cardinal symptoms of watery diarrhea, hypokalemia, and...
Article

Visceral pleural invasion

Visceral pleural invasion is a feature that can be seen in lung cancers. It is defined as tumor extension beyond the elastic layer of the visceral pleura. It is considered an aggressive sign and one of the most important adverse prognostic factors in non-small cell lung cancers 1. Pathology Gr...
Article

Volcano sign (meningioma)

Volcano sign refers to the appearance of classical meningioma that resembels the appearance of volcano (viewed in cross-section MRI, parallel to dural attachment) in which there is triangular hyperostosis at the base of the meningioma (mountain) with the tumor being the cloud around it. The intr...
Article

Von Hippel-Lindau disease

Von Hippel-Lindau (vHL) disease is characterized by the development of numerous benign and malignant tumors in different organs (at least 40 types 1) due to mutations in the VHL tumor suppressor gene on chromosome 3. Epidemiology The disease is rare with an estimated prevalence of 1:35,000-50,...
Article

Von Hippel-Lindau disease (mnemonic)

Features of von Hippel-Lindau disease can be remembered by the mnemonic: HIPPEL Mnemonic H: hemangioblastoma I: increased risk of renal cell cancer P: phaeochromocytoma P: pancreatic lesions (cyst, cystadenoma, cystadenocarcinoma) E: eye dysfunction (retinal hemangioblastoma) L: liver, r...
Article

WAGR syndrome

The WAGR syndrome stands for: Wilms tumors (greatly increased risk) aniridia genital anomalies mental retardation Pathology Genetics Occurs from a mutation related to chromosome 11p13 3 which is in close proximity to the WT1 gene.
Article

Waldenström macroglobulinemia

Waldenström macroglobulinemia, previously also known as lymphoplasmacytic lymphoma, is a type of B-cell lymphoma. Terminology Recent publications classify Waldenström macroglobulinemia as a lymphoplasmacytic lymphoma with any level of an IgM paraprotein 10.  Therefore the two entities are not ...
Article

WHO classification of anal margin tumors

The WHO classification of anal margin tumors or perianal skin tumors is: intraepithelial tumors Bowen disease (precursor of squamous cell carcinoma) Paget's disease (precursor of adenocarcinoma) invasive tumors squamous cell carcinoma adenocarcinoma basal cell carcinoma  verrucous carcin...
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WHO classification scheme for thymic epithelial tumors

The WHO classification scheme for thymic epithelial tumors is one of many classifications systems for thymoma and related tumors, and classifies them according to histology: type a medullary thymoma spindle cell thymoma type ab: mixed thymoma type b1: lymphocyte rich predominantly cortical...
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WHO criteria in tumor response

The WHO criteria have been developed in the 1980s to standardized reporting of cancers in clinical trial.​ These criteria Nowadays, newer criteria often based on the WHO criteria (such as RECIST, mRECIST, Choi criteria, Lugano response criteria), have widely replaced the WHO criteria in clinical...
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WHO histological classification of tumors of the uterine cervix

The WHO histological classification is a detailed classification of tumors of the uterine cervix. epithelial tumors squamous tumors and precursors squamous cell carcinoma, not otherwise specified - 8070/3 keratinizing - 8071/3 non-keratinizing - 8072/3 basaloid - 8083/3 verrucous - 8051/3...
Article

Wilms tumor

Wilms tumor, also known as nephroblastoma, is a malignant pediatric renal tumor. Epidemiology Wilms tumors are the most common paediatic renal mass, accounting for over 85% of cases 1,8 and accounts for 6% of all childhood cancers 2. It typically occurs in early childhood (1-11 years) with pea...
Article

Wilms tumor (staging)

Wilms' tumor staging is largely anatomical and relates to the invasion and spread of the tumor. Where there is invasion or metastasises, prognosis is poorer. Wilms tumor, is one of the more common childhood malignancies. stage I confined to kidney complete resection possible stage II local ...

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