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.

71 results found
Article

Acute airspace opacification with lymphadenopathy (differential)

Acute airspace opacification with lymphadenopathy is a subset of the differential diagnosis for generalised airspace opacification and includes: post-obstructive causes (usually chronic, but 'new' changes can occur) primary lung cancer pulmonary metastases lymphoma/leukaemia infection pri...
Article

Adrenal calcification

Adrenal calcification is not a rare finding in healthy asymptomatic people and is usually the result of previous haemorrhage or tuberculosis. Addison's disease patients only occasionally have calcification.  Pathology Aetiology Haemorrhage sepsis: Waterhouse-Friderichsen syndrome blunt abdo...
Article

Adult cervical lymphadenopathy (differential)

Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include: malignancy metastases  from head and neck tumours lymphoma other neoplastic lesions Castleman disease Kaposi sarcoma infection bacterial infection viral infection Epstein-Barr virus herpes...
Article

AFP elevation

Human alpha fetoprotein (AFP) elevation may occur in a vast number of conditions: liver tumours (hepatocellular carcinoma, hepatoblastoma) <10 ng/ml is within normal limits >20 ng/ml is above normal limits but has low specificity for tumor since it may occur in a setting of diffuse liver inju...
Article

Architectural distortion in mammography

Architectural distortion is a mammographic descriptive term in breast imaging. It may be visualised as tethering or indentation of breast tissue.  Pathology Architectural distortion per se is not a mass. It is often due to a desmoplastic reaction in which there is focal disruption of the norma...
Article

Asymmetrical density in mammography

Asymmetrical mammographic density is a mammographic morphological descriptor. It is given when there is increased density in one of the breasts, on either one or both standard mammographic views but without evidence of a discrete mass. An asymmetrical density can be further characterised as: ma...
Article

Bat wing opacities (lungs)

Bat's wing or butterfly pulmonary opacities refer to a pattern of bilateral perihilar shadowing. It is classically described on a frontal chest radiograph but can also refer to appearances on chest CT 3-4. Differential diagnosis Bat's wing pulmonary opacities can be caused by: pulmonary oedem...
Article

Benign metastasising tumours

There are a number of benign metastasising tumours: benign metastasising meningioma 1,2 benign metastasising leiomyoma 3 primary adenoma of thyroid 4 giant cell tumour of bone 5
Article

Bilateral testicular lesions

Bilateral testicular lesions have a relatively limited differential diagnosis.  Neoplastic  lymphoblastic leukemia (acute or chronic) lymphoma (non-Hodgkin's) primary testicular lymphoma is rare but the testes are often the site of lymphoma/leukemia recurrence due to the chemoptherapy inabil...
Article

Bone lesions with sequestrum

There are several bony lesions that can involve or depict a sequestrum. They include: Common brodie abscess: osteomyelitis Less common eosinophilic granuloma certain soft tissue tumours (with bony extension)  malignant fibrous histiocytoma lymphoma metastasis (especially from breast ca...
Article

Brachytherapy

Brachytherapy, also known as sealed source radiotherapy or endocurietherapy, is a form of radiotherapy where a radioactive source is placed, under the guidance of imaging, within or next to the area requiring treatment. Brachytherapy is commonly used to treat localised prostate cancer, breast c...
Article

Bulging duodenal papilla

Major duodenal papilla is a conic or cylindric protuberance at the medial aspect of the descending or horizontal duodenum at the site of the sphincter of Oddi. It is finding on small bowel follow-though (and endoscopy) and has a relatively long differential. On cross sectional imaging, the unde...
Article

CA 19-9 elevation

CA 19-9 is a serum antigen (monosialoganglioside) that has increased diagnostic use in the management of several malignancies, mainly of hepato-pancreatico-biliary origin. It is nonspecific, however, and can rise in both malignant and nonmalignant conditions. Elevation of serum CA 19-9 has been...
Article

CA-125

Serum CA-125 is well recognised as an ovarian cancer-associated marker and is an antigen determinant on a high-molecular-weight glycoprotein. The normal range of CA-125 is 0-35 U/mL. Serum CA-125 levels can also be used to monitor the response to treatment as well as a prognostic indicator sinc...
Article

Calcified mediastinal lymph nodes (differential)

There are numerous causes of calcified mediastinal lymph nodes. Common causes include: infectious granulomatous diseases tuberculosis histoplasmosis sarcoidosis silicosis treated lymphoma Uncommon causes include: Pneumocystis jiroveci (PCP) pneumonia metastases thyroid carcinoma: papi...
Article

Carcinoembryonic antigen

Serum carcinoembryonic antigen (CEA) is a cell-adhesive glycoprotein that was discovered in colorectal cancer in 1965, and is hence one of the oldest and most used tumour markers. Its name derives from its normal expression in fetoembryonic liver, gut and pancreas tissue. Normal range of CEA is...
Article

Cardiophrenic angle lesions

The cardiophrenic space is usually filled with fat. However, lesions originating above or lower to the diaphragm can present as cardiophrenic angle lesions. The more common lesions encountered include: pericardial fat pad pericardial cyst pericardial fat necrosis Morgagni's hernia lymphade...
Article

Cerebral ring enhancing lesions

The differential for peripheral or ring enhancing cerebral lesions includes: cerebral abscess tuberculoma neurocysticercosis metastasis glioblastoma subacute infarct /haemorrhage /contusion demyelination (incomplete ring) tumefactive demyelinating lesion (incomplete ring) radiation necr...
Article

Childhood malignancies

Unfortunately the paediatric population is susceptible to malignancies. The most common entities, in overall order of frequency, are 1-4: leukaemia/lymphoma: ~35% * acute lymphoblastic leukaemia: 23% Hodgkin disease: 5% acute myelogenous leukaemia: 4% central nervous system malignancies: ~2...
Article

Cutaneous and subcutaneous metastases

Cutaneous and subcutaneous metastases are uncommon, occurring in ~5% (range 0.7-10%) of internal malignancies. Sister Mary Joseph nodule is a well known cutaneous metastases. Pathology These metastases can come from haematogenous or lymphatic spread, or may result from seeding from a surgical ...
Article

Cystic (necrotic) lymph nodes

Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions: Systemic squamous cell carcinoma metastases treated lymphoma leukemia plasmacytoid T-cell leukemia acute myeloid leukemia viral lymphadenitis herpes simplex lymphadenit...
Article

Cystic lesions of the pancreas (differential)

The differential for cystic lesions of the pancreas includes: unilocular pancreatic pseudocyst intraductal papillary mucinous neoplasms (IPMN) serous cystadenoma uncommonly uni/macrolocular pancreatic cysts occur in association with  von Hippel Lindau syndrome autosomal dominant polycysti...
Article

Cystic pulmonary metastases

Cystic pulmonary metastases are atypical morphological form on pulmonary metastases where lesions manifest as distinct cystic lesions. It is slightly different form the term cavitating pulmonary metastases in that the lesions are extremely thin walled. Pathology It has been reported with many ...
Article

Differential for an anterosuperior mediastinal mass

An anterosuperior mediastinal mass can be caused by neoplastic and non-neoplastic pathology. As their name suggests, they are confined to the anterior mediastinum, that portion of the mediastinum anterior to the pericardium and below the level of the clavicles.  The differential diagnosis for a...
Article

Diffusely increased bone marrow FDG uptake

A diffuse homogeneous bone marrow FDG uptake usually reflects hyperplastic bone marrow which can be seen in the following conditions: therapy-related granulocyte colony stimulating factor (G-CSF) post-chemotherapy erythropoietin pathological process myelodysplastic syndromes beta thalasse...
Article

Endosteal scalloping

Endosteal scalloping refers to the focal resorption of the inner margin of cortical bones, typically seen in 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 benign aetiology. In fact...
Article

Fetal cardiac tumours

Fetal cardiac tumours refer to primary cardiac tumours that can present in the in utero population.  Epidemiology Fetal cardiac tumours are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017-0.28 % 2. Pathology Known cardiac tumour types that pres...
Article

Generalised osteopaenia

Generalised osteopaenia refers to to osteopaenia diffusely affecting the bones. Differential diagnosis The differential diagnosis is wide and includes includes: osteoporosis: decreased osteoid production osteomalacia: undermineralisation of osteoid hyperparathyroidism multiple myeloma dif...
Article

HIV associated neoplasms

HIV-associated neoplasms are numerous and can be broadly divided into two groups: AIDS-defining malignancies associated but not AIDS defining malignancies AIDS-defining malignancies The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4: Ka...
Article

Hypervascular metastases

There are several tumours which are noted to cause hypervascular metastases. The list includes: renal cell carcinoma (RCC) breast cancer: homogeneously hypervascular liver metastases from breast are considered rare 3 lung cancer neuroendocrine tumours carcinoid tumours 2 thyroid carcinoma ...
Article

Hypothalamic lesions

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 it's proximity to the optic chiasm, third ventricle and pituitary region, many lesions of these locations ca...
Article

Intramedullary spinal metastasis

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 haematogenous dissemination direct extension from leptomeninges Epidemi...
Article

Leptomeningeal enhancement

Leptomeningeal enhancement refers to a diffuse or focal gyriform or serpentine enhancement that can be seen in the following conditions: Diffuse meningitis pyogenic meningitis viral meningitis tuberculous meningitis (can also be focal) CNS cryptococcal infection coccidioidal meningitis (c...
Article

Lymphoma

Lymphoma is a malignancy arising from lymphocytes or lymphoblasts. Lymphoma can be restricted to the lymphatic system or can arise as extranodal disease. This, along with variable aggressiveness results in a diverse imaging appearance. Epidemiology Lymphoma accounts for ~4% of all cancers 4. T...
Article

Male breast disease

Male breast disease includes a wide spectrum of conditions. Many conditions and entities that affect the female breast may also affect the male breast.  Pathology Malignant male breast cancer lymphoma dermatofibrosarcoma Benign gynaecomastia pseudogynaecomastia - fat deposition within th...
Article

Malignant melanoma

Malignant melanoma is a malignant neoplasm that arises from melanocytes (or cells that derive from melanocytes).  Melanocytes predominantly occur in the basal layer of the epidermis and most melanomas, therefore, arise in the skin.  However, melanocytes do occur in other locations and can give r...
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

Multiple cystic neck lesions (differential)

The differential diagnosis for multiple cystic neck lesions is different to that for a solitary cystic neck mass. Differential diagnosis Cystic neck lesions are seen in: necrotic metastatic SCC nodes: older patient, M>F papillary thyroid carcinoma metastases: usually a younger patient, F>M ...
Article

Ocular pathology

Ocular pathology covers a wide range of conditions and therefore represents the cause of a wide range of symptoms, signs and radiographic features. Ocular metastases account for over 80% of all ocular pathology. With regard to the remainder of ocular lesions, the primary differentiating factor ...
Article

Oligometastases

Oligometastases refers to distant disease that is limited in number and distribution, Niibe et al defined this as ≤5 metastatic/recurrent lesions with control of the primary lesion 1,2. These metastases can be treated with local measures (surgery, radiation therapy, etc) with the aim of increasi...
Article

Omental cake

Omental cake refers to infiltration of the omental fat by material of soft-tissue density. The appearances refer to the contiguous omental mass simulating the top of a cake. Masses on the peritoneal surfaces and malignant ascites may also be present.  Pathology The most common cause is metasta...
Article

Optic nerve enlargement

Enlargement of the optic nerves is uncommon and has a surprisingly broad differential: optic nerve glioma optic nerve meningioma orbital pseudotumour optic neuritis sarcoidosis leukemia orbital lymphoma metastases perioptic haemorrhage Erdheim-Chester disease juvenile xanthogranuloma ...
Article

Pancreatic calcifications

Pancreatic calcifications can arise form many aetiologies. Punctate intraductal calcifications acute alcoholic pancreatitis (20-40%)  intraductal, numerous, small, irregular preponderant cause of diffuse pancreatic intraductal calcification chronic pancreatitis idiopathic: no underlying ca...
Article

Pancreatic neoplasms

There are numerous primary pancreatic neoplasms, in part due to the mixed endocrine and exocrine components. Classification Classification based on function exocrine: ~99% of all primary pancreatic neoplasms pancreatic ductal adenocarcinoma ~90-95% cystic neoplasm intraductal papillary muc...
Article

Parotid enlargement

Parotid enlargement has a wide differential given the significant breadth of pathology that can affect the parotid gland. These can be separated by the standard surgical sieve approach into infective, inflammatory, immune, neoplastic, infiltrative and congenital causes. Differential diagnosis ...
Article

Patellar tumours

Patellar tumours are extremely rare. They can be either benign or malignant primary bone tumours, or metastases.  Epidemiology Patellar tumours represent just 0.1% of all primary bone tumours 1.  Clinical presentation Patients may present with anterior knee pain and/or a palpable mass 1,3. ...
Article

Pedunculated intratracheal mass

A predunculated intratracheal mass has a variety of differential diagnoses: benign tumour, e.g. hamartoma, chrondroma, lipoma haemangioma inspissated mucus metastasis to tracheal mucosa, e.g. renal cell carcinoma, melanoma polyp, e.g. inflammatory, antrochoanal papilloma post-intubation t...
Article

Pelvic masses in females

Pelvic masses in females carry a broad differential diagnosis: benign adnexal cyst: 34% leiomyoma: 14% pelvic malignancy: 14% dermoid: 13% endometriosis: 10% pelvic inflammatory disease: 8% tubo-ovarian abscess hydrosalpinx pregnancy Extra-gynaecological masses, e.g. colorectal carcino...
Article

Peritoneal calcification

Peritoneal calcification is seen in a limited number of conditions that result in calcification of peritoneal structures. Therefore, the differential diagnosis is small: psammoma bodies in malignancy (most frequently cystadenocarcinoma of the ovary): fine sand like calcification pseudomyxoma p...
Article

PET-CT indications

PET-CT is a combination of cross-sectional anatomic information provided by CT and the metabolic information provided by positron emission tomography (PET). PET is most commonly performed with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG). F-18 is an unstable radioisotope and has a half-life of approx...
Article

Post surgical breast scar

Post surgical breast scar is a benign complication that usually occurs following  surgical intervention to breast tissue. It can however be a strong and potentially very confusing mimicker of breast malignancy. Radiographic features Review of the patient's past history and previous mammography...
Article

Primary benign cardiac tumours

Primary benign cardiac tumours are much less common than secondary metastatic deposits. However they are more likely when a cardiac mass is seen outside of the setting of terminal metastatic disease. Tumours include 1-2: cardiac myxoma most common in adults accounts for ~50% of all primary be...
Article

Primary malignancy of the nasopharynx

There are a number of primary malignancies of the nasopharynx: nasopharyngeal carcinoma (squamous cell carcinoma): 70% lymphoma (sinonasal lymphoma): 20% other adenocarcinoma adenoid cystic carcinoma carcinosarcoma extramedullary plasmacytoma fibrosarcoma melanoma rhabdomyosarcoma sin...
Article

Pulmonary metastases

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

RASopathies

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...
Article

Response evaluation criteria in solid tumours

Response evaluation criteria in solid tumours or RECIST refers to a set of published rules used to assess tumour 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).  The cr...
Article

Salivary gland tumours

Salivary gland tumours are variable in location, origin, and malignant potential.  Pathology In general, the ratio of benign to malignant tumours 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 a...
Article

Smoking related lung disease

Smoking related lung diseases are the respiratory manifestations of disease that is related to smoking. Smoking affects the lungs in numerous ways, and can be classified under the following headings: smoking related interstitial lung diseases (SR-ILD) respiratory bronchiolitis respiratory br...
Article

Solid and enhancing pituitary region mass

Solid lesions with enhancement is by far the most commonly encountered appearance of pituitary region masses. The differential includes :  macroadenoma by far the most common entity typically enhances less vividly than other entities elevates the dura of the diaphragma sella (as the origin i...
Article

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 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 when solitary may be the only one visible of many or the only one imaged enostosis (bone island) osteosarcoma calcifying enchondroma osteoblast...
Article

Spinal metastases

Spinal metastases is a vague term which can be variably taken to refer to metastatic disease to any of the following:  vertebral metastases (94%) may have epidural extension intradural extramedullary metastases (5%) intramedually metastases (1%) Each of these are discussed separately. Below...
Article

Squamous cell carcinoma (head and neck)

Squamous cell carcinomas (SCC) of the head and neck 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...
Article

Superscan

Superscan is intense symmetric activity in the bones with diminished renal and soft tissue activity on a Tc99m diphosphonate bone scan. This appearance can result from a range of aetiological factors: diffuse metastatic disease prostatic carcinoma breast cancer transitional cell carcinoma (...
Article

Terminal ileitis (differential)

The differential diagnosis for a terminal ileitis is quite extensive, and includes: inflammatory bowel disease Crohn's disease (most common) backwash ileitis due to ulcerative colitis infectious colitis Yersinia spp.  Yersinia enterocolitica Yersinia pseduotuberculosis Salmonella spp. C...
Article

Tracheal masses

The differential for tracheal masses can be rather wide. For a single mass consider: metastasis  direct invasion from adjacent organ (lung, thryoid,esophagus) distant metastsis ( such as melanoma)  primary neoplasms: squamous cell carcinoma: commonest primary tracheal malignancy 2 ~50 % a...
Article

Tuberculosis (intracranial manifestations)

Tuberculosis of the central nervous system can result from either haematogenous spread from distant systemic infection (e.g. pulmonary tuberculosis) or direct extension from local infection (e.g. tuberculous otomastoiditis). Intracranial manifestations of tuberculosis are protean and can affect...
Article

Tumour markers

Tumour markers are a group of molecules in serum that are elevated in various malignancies and are often used to monitor treatment response as well as alert for potential progressive disease when in remission. Commonly used markers include: AFP beta-hCG CA 19-9 CA-125 CEA chromogranin A P...
Article

Tumours of the male urethra

Tumours of the male urethra are uncommon. They can be categorised both on the grounds of histology and location. Histology squamous cell carcinoma of the urethra: 80% urothelial/transitional cell carcinoma of the urethra: 15% (predominantly posterior urethra) adenocarcinoma of the urethra: 5...
Article

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...
Article

Vertebra plana

Vertebra plana or pancake vertebra is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced crush fracture. It can occur with a variety of settings, including: trauma osteoporosis Langerhans cell histiocytosis (LCH) mo...

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.