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 continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
1,114 results found
Article
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...
Article
Ovarian collision tumor
Ovarian collision tumors are an uncommon ovarian neoplasm where there is co-existence of two adjacent but histologically distinct tumors in an ovary with no histologic admixture at the interface.
Pathology
The exact pathogenesis is not well known. They are most commonly composed of ovarian ter...
Article
Tumor pseudoprogression (lung cancer)
Radiologic tumor pseudoprogression on imaging denotes an imaging appearance of tumor response where the tumor first exhibits findings suggestive of progression (i.e. growth, new lesions). However, during sustained therapy, response is eventually demonstrated 1.
Epidemiology
With the advent of ...
Article
Asbestosis
Asbestosis is an occupational fibrotic lung disease associated with high levels of asbestos fiber inhalation. Fibrosis is lower lobe predominant and can progress. Even without progression the risk of lung cancer is increased. The presence of pleural plaques is variable 10.
Epidemiology
Asbest...
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
Residual tumor classification
Residual tumor classification, also known as R classification, defines how complete the resection of a malignancy has been at surgery. It has an important prognostic implication.
Classification
R0: no residual tumor
R1: microscopic residual tumor
R2: macroscopic residual tumor
An R0 resecti...
Article
Chylous ascites
Chylous ascites (also known as chyloperitoneum) is defined as the abnormal intraperitoneal accumulation of milky lymphatic fluid with a triglyceride level >110 mg/dL 1. Etiologically it is due to a disruption of the lymphatic system, most commonly obstructive due to a mass or traumatic (which ma...
Article
Pancreatic calcifications
Pancreatic calcifications can arise from many etiologies.
Punctate intraductal calcifications
chronic pancreatitis
alcoholic pancreatitis (20-40%) 2
intraductal, numerous, small, irregular
preponderant cause of diffuse pancreatic intraductal calcification
gallstone pancreatitis (2%) 2
m...
Article
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 tumo...
Article
Sea anemone sign
The sea anemone sign is a unique (but not wholly exclusive) appearance seen in ovarian serous surface papillary borderline tumors (SSPBT). It refers to its surface stroma frequently branches into exophytic papillary stalks, macroscopically 1.
Radiographic features
On cross-sectional imaging, p...
Article
Superior vena cava obstruction
Superior vena cava obstruction (SVCO) can occur from extrinsic compression, intrinsic stenosis, or thrombosis of the superior vena cava. Malignancies are the main cause and are considered an oncologic emergency. Superior vena cava syndrome (SVCS) refers to the clinical syndrome with symptoms tha...
Article
Mandibular lesions
Mandibular lesions are myriad and common. The presence of teeth results in lesions that are specific to the mandible (and maxilla) and a useful classification that defines them as odontogenic or non-odontogenic. While it may often not be possible to make a diagnosis on imaging alone, this classi...
Article
Undifferentiated pleomorphic sarcoma
Undifferentiated pleomorphic sarcoma (UPS), previously known as malignant fibrous histiocytoma (MFH), is considered the most common type of soft tissue sarcoma. It has an aggressive biological behavior and a poor prognosis.
In the majority of cases, undifferentiated pleomorphic sarcoma affects ...
Article
Peritoneal metastases
Peritoneal metastases are a relatively common location for metastases, particularly from tumors of the abdomen and pelvis, that generally imply a poor prognosis, often with a significant impact on palliation 1.
Terminology
If peritoneal metastases are of an epithelial origin (as most are) and ...
Article
Seminal vesicle invasion
Seminal vesicle invasion (SVI) is referred to as the secondary involvement of the seminal vesicles and ductus deferens by neoplasms not originating from the seminal vesicles themselves and are much more common than their primary counterparts. Involvement of the seminal vesicles stages prostate c...
Article
Pituitary stalk abnormal enhancement (differential)
Abnormal nodular enhancement of the pituitary stalk can be seen in a number of entities.
Differential diagnosis
tumors
germinoma
craniopharyngioma
hypothalamic glioma
pituitary lymphoma
pituicytoma
granular cell tumor of the pituitary (pituitary choristoma)
pilocytic astrocytoma of the...
Article
Anaplastic rhabdomyosarcoma
Anaplastic rhabdomyosarcomas are a subtype of embryonal rhabdomyosarcoma, characterized by extensive anaplastic cells seen throughout the tumor 1.
Article
NTRK-rearranged soft tissue neoplasm
NTRK-rearranged soft tissue neoplasms (emerging), lipofibromatosis-like neural tumors or NTRK-positive tumor-resembling peripheral nerve sheath tumors are a group of rare molecularly defined spindle cell neoplasms excluding infantile fibrosarcoma 1.2. The tumors form a provisional category of un...
Article
Diffuse brainstem glioma (historical)
Diffuse brainstem gliomas or diffuse intrinsic pontine gliomas was a term used to describe infiltrating astrocytomas arising in the brainstem, usually in children. It is no longer recognized as a distinct entity, removed from the 2016 update to the WHO classification of CNS tumors replaced by a ...
Article
Mediastinal seminoma
Mediastinal seminomas or mediastinal germinomas are primary malignant germ cell tumors of the mediastinum.
Epidemiology
Mediastinal seminomas are rare mediastinal tumors and account for up to one-third of primary malignant mediastinal germ cell tumors 1. They are almost only found in males ≥10...
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