Distal appendicular skeletal metastases, especially distal to the knee and elbow joints, are uncommon.
Localized pain and swelling, along with pathological fractures, are the most common 3.
Malignancies that most commonly spread to appendicular skel...
Drash syndrome, also known as the Denys-Drash syndrome, is associated with an abnormal WT1 gene (Wilms tumor gene) and consists of:
A ductal adenoma of the breast is a benign glandular tumor of the breast that usually fills and distends the ductal lumen.
They may occur in women of all ages, although the majority of patients are 60 years of age or greater 3.
Ductal adenomas usually prese...
Duodenal adenocarcinoma is the most common primary malignancy of the duodenum.
Adenocarcinoma is the most common primary malignant neoplasm of the duodenum. It represents 0.3% of all gastrointestinal malignancies and accounts for 50-70% of small bowel adenocarcinomas occurring ei...
Duodenal filling defects may be caused by a wide variety of duodenal pathology which may be divided by their location and pathological process.
common bile duct impression
Note: please refer to duodenal mucosal nodular fill...
Dural or pachymeningeal metastases are a relatively common cause of dural masses, although they are less common than brain metastases and meningiomas. They can occur both within the spine and intracranially - this article is focused on intracranial dural masses.
A useful mnemonic to remember differential diagnoses associated with a dural tail sign is:
My Scary Dog Likes To Stand Guard
D: dural metastases
Dysembryoplastic neuroepithelial tumors (DNET) are benign (WHO Grade I) slow growing glioneuronal tumors arising from either cortical or deep grey matter. The vast majority are centered in cortical grey matter, arise from secondary germinal layers, and are frequently associated with cortical dys...
Dysplastic liver nodules are focal nodular regions (≥1 mm) without definite evidence of malignancy.
They have been found in cirrhotic patients with a prevalence of 14% (size >1.0 cm) to 37% (size >0.5 cm) 2.
Epstein-Barr virus-associated smooth muscle tumors (EBV-SMT) are rare and encountered in immunocompromised individuals.
These tumors are generally exceedingly rare, and only seen with any frequency in the setting of immunosuppression, particularly in HIV/AIDS patients, but also po...
The Eastern Cooperative Oncology Group (ECOG) is one of the largest clinical cancer research organizations in the United States and conducts clinical trials in all types of adult cancers.
The ECOG performance status is a scale used to assess how a patient's disease is progressing, assess how th...
Epidermal growth factor receptor (EGFR) mutation can be expressed in a large proportion of non-small cell lung carcinomas (NSCLC). However, certain subtypes such as invasive mucinous adenocarcinoma of the lung can have very low expression.
The presence of this mutation can be assessed on biopsy...
Electron therapy, or electron beam therapy, is a form of radiotherapy which is used to treat superficial lesions. Electron beams are rapidly attenuated by soft tissue and thus can only treat to a depth of a few centimeters (typically 0-3 cm), compared to megavoltage x-rays which are much more pe...
Elevated vitamin B12 (also known as hypervitaminosis B12 or hypercobalaminemia) is most important as a diagnostic and prognostic marker for malignant disease 1,3.
Very high serum levels of vitamin B12, following dietary megadosing, does not seem to have any observable deleterious effects 2.
Primary neoplasms which may result in endobronchial metastases may be memorized by utilizing the following mnemonic:
Kiss My RBC 1
K: Kaposi sarcoma
R: renal cell carcinoma
B: breast cancer
C: colorectal carcinoma, cervical carcinoma, carcinoid
Endometrial carcinoma is generally considered the most common gynecological malignancy 1,5. It frequently presents with vaginal bleeding. Both ultrasound and pelvic MRI are useful modalities for evaluation.
Endometrial carcinoma is the most common gynecological malignancy, with pe...
Endometrial hyperplasia is abnormal proliferation of the endometrial glands and stroma, defined as diffuse smooth thickening >10 mm 13. One of the main concerns is the potential malignant transformation of the endometrial hyperplasia to endometrial carcinoma.
Endosteal scalloping refers to the focal resorption of the inner layer of the cortex (i.e. the endosteum) of bones, most typically long bones, due to slow-growing medullary lesions.
It is important to note that although it is evidence of a slow non-infiltrative lesion, it does not equate to ben...
Engraftment syndrome (ES) refers to a potential early complication of haematopoetic stem cell transplantation. It is thought to be related to increased capillary permeability and comprises of a combination of symptoms and signs which include
erythrodermatous skin rash
Eosinophils, also less commonly known as acidophils, are myeloid granulocytes and form one of the main types of white blood cells. Their counts are routinely measured as part of a full blood count. They have important roles in fighting parasitic infections, but are increasingly recognized as hav...
Ependymomas represent a relatively broad group of glial tumors most often arising from the lining the ventricles of the brain or the central canal of the spinal cord. They account for ~5% of all neuroepithelial neoplasms, ~10% of all pediatric brain tumors and up to 33% of brain tumors occurring...
Esophageal and esophagogastric junction adenocarcinoma staging refers to TNM staging of adenocarcinoma originating in the esophagus or esophagogastric junction (including tumors whose center is within the proximal 2 cm of the gastric cardia). Related histologies included in this system are high ...
Esophageal and esophagogastric junction neuroendocrine tumor staging refers to TNM staging of epithelial cancers other than the squamous cell carcinoma and adenocarcinoma groups located in the esophagus or esophagogastric junction (including tumors whose center is within the proximal 2 cm of the...
Esophageal and esophagogastric junction squamous cell carcinoma staging refers to TNM staging of squamous cell carcinoma originating in the esophagus or esophagogastric junction (including tumors whose center is within the proximal 2 cm of the gastric cardia). Related histologies included in thi...
Ewing sarcomas are the second most common malignant primary bone tumors of childhood after osteosarcoma, typically arising from medullary cavity with invasion of the Haversian system. They usually present as moth-eaten destructive permeative lucent lesions in the shaft of long bones with large s...
The Ewing sarcoma family of tumors are a group of small round blue cell tumors that are closely histogenetically related, all demonstrating non-random t(11;22)(q24;q12) chromosome rearrangement resulting in the formation of the EWS-ETS fusion gene 1-3.
Although the literature is l...
Exophytic is a descriptive term used by radiologists/pathologists to describe solid organ lesions arising from the outer surface of the organ of origin.
Literally exophytic only refers to those lesions arising from the outer surface, however radiologists and pathologists use the term to include...
External beam radiotherapy (EBRT) (also known as teletherapy) is a form of ionizing radiation therapy delivered by a medical linear accelerator (or historically a cobalt-60 source) to a patient lying on a treatment bed. Megavoltage x-rays (4-25 MV) are the most commonly used. Alternative forms o...
Extra-adrenal myelolipomas occur outside the adrenal glands, with the most common sites being the retroperitoneum, thorax, and pelvis.
The widespread application of modern imaging techniques has led to increase in the detection of extra-adrenal myelolipomas. The exact incidence i...
Extramammary Paget disease (EMPD) is the rarer non-breast form of Paget disease of the nipple. It is considered a form of adenocarcinoma of the apocrine glandular tissue. In men the penis and scrotum are most frequently involved, and in women the vulva. Nodal and distant organ metastatic disease...
Extramedullary hematopoiesis is a response to the failure of erythropoiesis in the bone marrow.
This article aims to a general approach on the condition, for a dedicated discussion for a particularly involved organ, please refer to the specific articles on:
extramedullary hematopoiesis in the...
Extramedullary hematopoiesis in the spleen represents a physiologic compensatory event that may be seen in many hematologic diseases leading to chronic anemia. The liver and the spleen are the most common site of extramedullary hematopoiesis, both usually manifesting on imaging as organomegaly a...
Extranodal extension refers to the growth of a nodal cancer metastasis beyond the confines of the capsule of a lymph node into adjacent tissues. Less preferred synonyms include extranodal spread, extracapsular extension, or extracapsular spread.
This finding holds prognostic implications. For e...
Extraprostatic (extracapsular) extension of prostate cancer refers to local tumor growth beyond the fibromuscular band surrounding the prostate gland. It is a pathological finding important to prostate cancer staging.
Though imperfect, MRI is superior to transrectal ultra...
F-18 fluorodeoxyglucose (FDG) is the most common PET radiotracer.
The radiopharmaceutical consists of the fluorine-18 radionuclide substituting the hydroxyl group at the C-2 position of glucose. The IUPAC chemical name is 2-deoxy-2-[F-18]fluoroglucose.
F-18 fluoride ion ...
Facial nerve schwannoma (FNS), also known as facial nerve neuroma/neurilemoma, is a schwannoma that arises from the facial nerve. They are generally uncommon, and when involving the temporal bone, make up less than 1% of all temporal bone tumors.
FNS is a rare tumor 2.
Familial adenomatous polyposis syndrome (FAPS) is characterized by the presence of hundreds of adenomatous polyps in the colon. It is the most common of the polyposis syndromes.
Familial polyposis coli, attenuated familial adenomatous polyposis and Gardner syndrome are all variants...
Familial atypical multiple mole melanoma (FAMMM) syndrome is an autosomal dominant genodermatosis characterized by multiple melanocytic nevi (often more than 50) and a family history of melanoma.
It is associated with mutations in the CDKN2A gene and shows reduced penetranc...
Fascicular sign is a finding on T2-weighted MRI images that suggests a lesion of neurogenic origin. It is characterized by multiple small ring-like structures with peripheral hyperintensity representing the fascicular bundles within the nerves.
It is found in various neurogenic tumors, includin...
Fetal adenocarcinoma of the lung (FLAC) is a rare form of adenocarcinoma of lung (falls under invasive category).
Some reports suggest its occurence at ~0.1%-0.5% of all pulmonary neoplasms 1. Despite its "fetal" tissue morphology it typically presents in middle aged to elderly p...
Fetal cardiac tumors refer to primary cardiac tumors that can present in the in utero population.
Fetal cardiac tumors are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017-0.28 % 2.
Known cardiac tumor types that present ...
Fibrinous pericarditis results from fine granular roughening of the pericardium.
Pericardial friction rub may be heard.
acute rheumatic fever
myocardial infarction: Dressler syndrome
chronic renal fail...
Fibrolamellar hepatocellular carcinoma is a distinct histological variant of hepatocellular carcinoma characterized on microscopy by laminated fibrous layers between the tumor cells. It is important as it has different demographics and risk factors compared to 'standard' hepatocellular carcinoma...
Fibrosarcomas are malignant tumors of fibroblast origin. They are a type of soft tissue sarcoma that can be grouped by the patient age, i.e. adult fibrosarcoma and infantile fibrosarcoma, and/or anatomical region, for example:
fibrosarcoma of the breast
fibrosarcoma of the chest wall
Fibrosarcoma of the breast is a type of malignant stromal sarcoma that rarely occurs as a primary tumor within the breast.
A fibrosarcoma is composed of immature mesenchymal elements surrounded by a collagenous substance. It is a type of breast sarcoma with a predominant “herringbon...
The FIGO staging systems are determined by the International Federation of Gynecology and Obstetrics (Fédération Internationale de Gynécologie et d’Obstétrique).
In general, there are five stages:
stage 0: carcinoma in situ (common in cervical, vaginal, and vulval cancer)
stage I: confined to...
Finger clubbing, also called "drumstick fingers", is a common clinical sign in patients with heart or lung disease. The term is used to describe an enlargement of the distal phalanges of the fingers, giving them a drumstick or club-like appearance.
Finger clubbing presen...
Flare phenomenon or osteoblastic flare phenomenon refers to interval visualization of lesions with a sclerotic rim around an initially lytic lesion or sclerosis of lesions previously undetected on radiograph or CT in the setting of follow-up of an oncological patient with other signs of partial ...
Fluid-fluid levels in bone tumors is a commonly encountered finding, both in benign as well as malignant bone tumors, and can be used to differentiate between the two.
Method of assessment
On the sagittal T2W image:
measure the length of the largest fluid-fluid level (A)
measure the maximum ...
Fluorine-18-labeled sodium fluoride (also known as 18F-NaF or sodium fluoride) is a PET radiotracer used primarily for skeletal imaging.
Fluorine-18-labeled sodium fluoride is an ionic compound comprised of a single sodium atom bound to a positron-emitting isotope of fluorine.
Focal gas collection in right upper quadrant on plain radiographs can occur from a number of pathologies. Things to consider are:
enterobiliary fistula: common types include cholecystoduodenal fistula and cholecystocolic fistula. It may occur with:
gallstone ileus (being most common) 3
A popular mnemonic to help remember causes of focal sclerotic bony lesions is:
H: healed non-ossifying fibroma (NOF)
E: Ewing sarcoma
I: infection or infarct
F: fibrous dysplasia
Follicular lymphoma is the most common subtype of non-Hodgkin lymphoma (NHL)
Estimated to account for ~45% of all NHL cases 1. Higher rates in North America and Europe 4.
Nodal effacement by closely packed follicles containing small cleaved cells without nucleoli (cen...
Follicular thyroid carcinoma (FTC) is the second most frequent malignancy of the thyroid gland after papillary cancer and accounts for ≈10-20% of all thyroid neoplasms.
It typically occurs in women and in an older age group than papillary (i.e. 40-60 years of age).
Fukuoka consensus guidelines, also referred to as the Tanaka criteria, is a classification system for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs).
The prior international consensus guidelines (2006) were referred to as the Sendai criteria, which later ...
Gallbladder carcinoma is a term referring to primary epithelial malignancies arising from the gallbladder, in which the great majority (90%) are adenocarcinomas and the remainder are squamous cell carcinomas. They are more prevalent in elderly women and, in most cases, are only symptomatic when ...
Gallbladder malignancy (or gallbladder cancer) is relatively uncommon. The commonest histopathological type is carcinoma.
gallbladder adenocarcinoma: most common 1
gallbladder squamous cell carcinoma
gallbladder neuroendocrine carcinoma
gallbladder sarcoma: ve...
Gallbladder metastases are rare and usually represent an advanced and end-stage of malignancy. Malignant melanoma and gastric carcinoma account for the most common primary malignancies to see metastases to the gallbladder, in the Western and Asian societies, respectively.
Gallium-68 DOTATATE (or Ga-68 DOTATATE) is a PET radiotracer that is useful for evaluating primary and metastatic well-differentiated neuroendocrine tumors. It is a form of somatostatin-receptor (SSTR) functional imaging and most often combined with cross-sectional imaging in the form of PET-C...
Gamma Knife®, also known as Gamma Knife radiosurgery (GKRS), is a form of radiosurgery historically employing 201 cobalt-60 sources arranged in a hemispheric array. The latest system, the Gamma Knife Perfexion™, uses 192 cobalt-60 sources 1. The emitted gamma rays are focused on a target point w...
Gangliogliomas are uncommon, usually low-grade, CNS tumors. Epilepsy is a common clinical presentation and this tumor has a typical occurrence in the temporal lobes, although they have been described in all parts of the central nervous system.
Their appearance on imaging is very variable: from ...
Gastric adenocarcinoma, commonly referred to as gastric cancer, refers to a primary malignancy arising from the gastric epithelium. It is the most common gastric malignancy.
Gastric cancer is rare before the age of 40, but its incidence steadily climbs after that and peaks in the...
This is a basic article for medical students and other non-radiologists
Gastric cancer, also known as stomach cancer or gastric carcinoma, refers to a cancer that arises from the mucosal lining of the stomach. It is the commonest gastric malignancy.
This is a summary article...
Gastric lymphoma may either represent secondary involvement by systemic disease or primary malignancy confined to the stomach.
Gastric lymphoma represents the most common site of extranodal lymphoma, accounting for 25% of all such lymphomas, 50% of all gastrointestinal lymphomas...
Gastric metastases are rare, found in less than 2% of patients who die of a carcinoma 6.
Usually affects the middle-aged and elderly population. Affects males and females equally without predilection.
The patient may be asymptomatic, but the most common sig...
Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. They account for ~5% of all sarcomas, and are mostly found within stomach and mid-distal small bowel. They respond remarkably well to chemotherapy.
Previously these tumors h...
Generalized osteopenia refers to osteopenia diffusely affecting the bones.
The differential diagnosis is wide and includes:
osteoporosis: decreased osteoid production
osteomalacia: undermineralisation of osteoid
A mnemonic for the differential diagnosis for germ cell tumors is:
E: embryonal cell carcinoma
E: endodermal sinus tumor (yolk sac tumor)
Gestational trophoblastic disease (GTD) results from the abnormal proliferation of trophoblastic tissue and encompasses a wide spectrum of diseases, including:
coexistent molar pregnancy
invasive mole ~10%
choriocarcinoma (gestational choriocarc...
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...
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.
Giant cell tumo...
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.
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.
Findings are classified into five categories 1:
normal ovaries identified and no adn...
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 ...
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,
solid tumors, e.g...
Hemophagocytic lymphohistiocytosis (HLH), also known as macrophage activation syndrome when occurring in the setting of a rheumatologic disorder, is a non-malignant but often-fatal disorder of immune dysregulation affecting multiple organs.
It typically affects infants and young c...
The hemorrhage exclusion sign can be a useful MRI finding following prostate biopsy.
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...
A mnemonic for primary malignancies responsible for hemorrhagic intracranial metastases is:
MR CT BB
R: renal cell carcinoma
T: thyroid carcinoma, teratoma
B: bronchogenic carcinoma
B: breast carcinoma
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.
A hamartoma 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 mimic malignancy. Several hamartomata ha...
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.
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...
The head and neck cancer therapy response interpretation (Hopkins criteria) is a qualitative system of interpretation for therapy response assessment using PET-CT.
Widely used options for therapy response assessment are clinical examination, histopathology, CT and MR imaging, howeve...
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
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...
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 ...
Hepatic carcinosarcoma is a very rare tumor that is defined by mixed histological features.
This tumor has also been referred to as malignant mixed tumor, spindle cell carcinoma, pseudosarcoma or sarcomatoid carcinoma 1,2.
Hepatic carcinocarcinoma contain a mixture of...
Hepatic epithelioid hemangioendothelioma (HEHE) is a rare, low to intermediate grade malignant hepatic vascular tumor.
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.
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.
The demographics of patients with l...
As expected there are a number of different staging systems for hepatoblastoma.
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 ...
Hepatomegaly refers to an increase in size or enlargement of the liver.
Hepatomegaly can result from a vast range of pathology including, but not limited to, the following:
Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly).
Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive!
Human epidermal growth factor receptor 2 (HER-2) mutations may be detected in approximately 3% of lung adenocarcinomas 1.
Early studies have suggested HER2-mutant tumors exhibit more aggressive features in general and tend to:
exhibit a locally-invasive behavior comp...