British Thoracic Society guidelines for pulmonary nodules were published in August 2015 for the management of pulmonary nodules seen on CT. In the United Kingdom, they supersede the Fleischner Society guidelines.
They are based initially on identifying whether the nodule is solid or subsolid an...
Bronchial carcinoid tumors are carcinoid tumors primarily occurring in relation to a bronchus. They were previously incorrectly termed as bronchial adenomas. They usually occur in association with a segmental or larger bronchus.
Typically affects patients from 3rd to 7th decades w...
A mnemonic to remember diseases that undergo bronchovascular spread is:
K: Kaposi sarcoma
I: infection (e.g. pneumocystis pneumonia, tuberculosis)
L: lymphangitis carcinomatosis
The B symptoms (a.k.a. inflammatory symptoms) are a triad of systemic symptoms associated with more advanced disease and a poorer outcome in lymphoma 1,2:
>10% unintentional decrease in body weight in the 6 months preceding the diagnosis
B symptoms are ...
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...
Bulging duodenal papilla is a conical or cylindrical protuberance at the medial aspect of the descending or horizontal duodenum at the site of the sphincter of Oddi. It is a finding on small bowel follow-though (and endoscopy) and has a relatively long differential. On cross-sectional imaging, ...
Bunch of grapes sign refers to the imaging appearance of multiple cystic spaces or lesions and it has been described for multiple pathologies:
bunch of grapes sign (hydatidiform mole) 7
bunch of grapes sign (bronchiectasis) 3
bunch of grapes sign (IPMN) 6
bunch of grapes sign (botryoid rhabd...
Burkitt lymphoma is an aggressive B-cell lymphoma predominantly affecting children.
Burkitt lymphoma is the most common (40%) type of non-Hodgkin lymphoma in childhood. Median age is eight years with a male predominance (M:F = 4:1) 1. It is less common in adults, accounting for 1-...
Abdominal manifestations of Burkitt lymphoma occur in the non-pandemic variant of Burkitt lymphoma. For a general discussion of Burkitt lymphoma, and for links to other system specific manifestations, please refer to Burkitt lymphoma.
Whenever Burkitt lymphoma presents, it is predominantly an e...
CA-125 is a high-molecular-weight glycoprotein found on the surface of Mullerian and celomic epithelial-derived cell types and is the best known tumor marker for epithelial ovarian cancer 6. Importantly, it may also be elevated in several other conditions (see differential diagnosis section belo...
Carcinoma antigen 15-3, usually shortened to CA 15-3 is a tumor marker used in monitoring breast cancer. The test detects levels of MUC-1, a mucin protein in the blood. MUC-1 is thought to be important in the invasiveness and metastasization of cancer cells.
MUC-1 is a normal epithe...
CA 19-9 (carbohydrate antigen 19-9 or cancer antigen 19-9) is a serum antigen (monosialoganglioside) that has increased diagnostic use in the management of several malignancies, mainly of hepatopancreaticobiliary origin. It is non-specific, however, and can rise in both malignant and non-maligna...
CA 27-29 is a tumor marker and is a soluble form of glycoprotein MUC1. It may be elevated in patients with breast cancer. Tumors of the colon, stomach, kidney, lung, ovary, pancreas, uterus, and liver may also raise CA 27-29 levels.
Certain non-malignant conditions are also associated with its ...
In order of decreasing frequency, a useful mnemonic to remember glial tumors which calcify is:
Old Elephants Age Gracefully
There are numerous causes of calcified mediastinal lymph nodes.
Common causes include:
infectious granulomatous diseases
Uncommon causes include:
Pneumocystis jiroveci (PCP) pneumonia
thyroid carcinoma: papi...
Calcifying fibrous pseudotumors (CFPT) of the lung are very rare, benign lesions of the lung.
They are composed of hyalinised collagen with psammomatous-dystrophic calcification and a typical pattern of lymphocytic inflammation.
CFPTs usually occur within soft tissues but have bee...
Calcifying fibrous tumors, previously known as calcifying fibrous pseudotumors, are rare, benign fibroblastic tumors of the soft tissues.
It can occur at all ages and there is no strong gender predilection 1. Fewer than 200 cases have been reported in the English literature 1.
A useful mnemonic to remember the causes of calcifying pulmonary metastases is:
B: bone (chondrosarcoma, osteosarcoma)
A: any primary post-chemotherapy
Cancer (malignancy is synonymous) refers to neoplasms with malignant potential, i.e. for local invasion and metastasis. This article is a list of different cancers or relevant tumor classification systems, although noting that not all tumors are cancerous. For a list of cancer staging systems, s...
Cancer staging involves a number of systems to help direct treatment and aid prognosis. The AJCC TNM staging schema is the most common, but other systems are used for specific malignancies or body parts.
breast cancer staging
lung cancer staging
malignant pleural mesothelioma s...
Cannonball metastases refer to multiple large, well-circumscribed, round pulmonary metastases that appear not unsurprisingly like cannonballs. The French terms "envolée de ballons" and "lâcher de ballons", which translate to "balloons release", are also used to describe this same appearance.
Cannonball metastases refer to multiple large, well-circumscribed, round pulmonary metastases. The primary tumors for these lesions can be remembered with the help of this mnemonic:
R: renal cell carcinoma
E: endometrial carcinoma
S: synovial sarcoma
Carcinoid heart disease, also known as Hedinger syndrome, is a known complication of carcinoid tumors, and is particularly prevalent in patients who develop carcinoid syndrome.
Cardiac lesions are present in approximately 50% of patients with carcinoid syndrome 1.
Carcinoid tumors are a type of neuroendocrine tumor that can occur in a number of locations. Carcinoid tumors arise from endocrine amine precursor uptake and decarboxylation (APUD) cells that can be found throughout the gastrointestinal tract as well as other organs (e.g. lung). In general, they...
Carcinoid tumors of the lung are a subgroup of neuroendocrine tumors of the lung, of lower grade than small cell carcinoma of the lung and large cell neuroendocrine carcinoma of the lung.
For a general discussion, please refer to the article on carcinoid tumors.
Carcinoma of the cervix is a malignancy arising from the cervix. It is the third most common gynecologic malignancy (after endometrial and ovarian).
It typically presents in younger women with an average age of onset at around 45 years.
human papillomavirus (HPV) 1...
Carcinosarcomas are highly malignant biphasic tumors with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.
It can arise in many organs:
lung 5: pulmonary carcinosarcoma
esophagus 1: esophageal carcinosarcoma
genitourinary tract 2
Cardiac myxomas, although uncommon are one of the commonest primary cardiac tumors and account for ~50% primary benign cardiac tumors.
Cardiac myxomas are the most common primary cardiac tumor in adults (~50%) but are relatively infrequent in childhood, where cardiac rhabdomyomas...
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 fat necrosis
Carney-Stratakis syndrome is a rare autosomal dominant condition comprising of familial paraganglioma and gastric stromal sarcoma.
It is considered to be distinct from, but perhaps related to, the Carney triad 1. Neither should be confused with the unrelated Carney complex.
There are several causes leading to a perfusion defect on a VQ scan with an acute pulmonary embolus being only one of them:
acute pulmonary embolus
previous pulmonary embolus (including fat embolism, thromboembolism, air embolism, tumor)
vasculitides affecting the pulmonary v...
Serum CEA (carcinoembryonic antigen) is a cell-adhesive glycoprotein that was discovered in colorectal cancer in 1965, and is hence one of the oldest and most used tumor markers. Its name derives from its normal expression in fetoembryonic liver, gut and pancreas tissue.
Normal range of CEA is ...
Central neurocytomas are WHO grade II neuroepithelial intraventricular tumors with fairly characteristic imaging features, appearing as heterogeneous masses of variable size and enhancement within the lateral ventricle, typically attached to the septum pellucidum. They are typically seen in youn...
Cerebral radiation necrosis refers to necrotic degradation of brain tissue following intracranial or regional radiation either delivered for the treatment of intracranial pathology (e.g. astrocytoma, cerebral arteriovenous malformation) or as a result of irradiation of head and neck tumors (e.g....
The differential for peripheral or ring enhancing cerebral lesions includes:
demyelination (incomplete ring)
tumefactive demyelinating lesion (incomplete ring)
Convenient mnemonics for the causes of cerebral ring enhancing lesions are:
MAGIC DR or DR MAGIC
DR MAGIC L
MAGIC DR or DR MAGIC
I: infarct (subacute phase), inflammatory - neurocysticercosis (NCC), tuberculoma
Cervical lymph node staging refers to evaluating regional nodal metastasis from primary cancer of the head and neck. The following article reflects the 8th edition of the TNM staging system published by the American Joint Committee on Cancer, which is used for staging starting January 1, 2018 1,...
Chemotherapy induced cholangitis is caused when intra-arterial chemotherapy is introduced to treat liver metastases. This causes strictures of the common hepatic duct and main ducts, but spares distal and proximal (i.e. common bile duct and intrahepatic ducts).
Unfortunately the pediatric population is susceptible to malignancies. The most common entities, in overall order of frequency, are 1-4:
leukemia/lymphoma: ~35% *
acute lymphoblastic leukemia: 23%
Hodgkin disease: 5%
acute myelogenous leukemia: 4%
central nervous system malignancies: ~20%
The solitary use of the size of the tumor during evaluation for response to chemotherapy has some pitfalls and limitations, especially for specific tumors such as gastrointestinal stromal tumor (GIST).
The Choi response criteria for GIST proposed that tumor attenuation could provide an addition...
Cholangiohepatoma, also referred to as mixed hepatocellular cholangiocarcinoma (HCC-CC), refers to synchronous cholangiocarcinoma and hepatocellular carcinoma (HCC) in the same tumor. It is a rare and aggressive primary hepatic tumor combination. The origin of cholangiohepatoma is closely linked...
Choledochal cysts represent congenital cystic dilatations of the biliary tree. Diagnosis relies on the exclusion of other conditions (e.g. tumor, gallstone, inflammation) as a cause of biliary duct dilatation.
Choledochal cysts are rare, with an incidence of 1:100,000-150,000. Alt...
Carbon-11-choline (choline C-11 or 11C-choline) is the most studied isotope carbon-11 PET radiopharmaceutical. The molecule is used for oncologic Imaging 1-4. Choline is one of the components of phosphatidylcholine, a fundamental element of cell membrane phospholipids 5. Cancer cells tend to ha...
Chondromesenchymal hamartomas are rare, benign, tumor-like nasal masses in children that have been associated with DICER1 mutations.
The entity is rare: a systematic review of the literature in 2015 identified fewer than 50 reported cases 2. The mean age of presentation is 10 year...
Choriocarcinoma is an aggressive, highly vascular tumor. When it is associated with gestation, it is often considered part of the spectrum of gestational trophoblastic disease; it is then termed gestational choriocarcinoma. When it occurs in the absence of preceding gestation, it is termed non-g...
Choroid plexus malignancies can be classified as primary or secondary neoplasms of the choroid plexus:
choroid plexus papilloma (WHO grade I or II "atypical")
choroid plexus carcinoma (WHO Grade III)
choroid plexus metastases
Chromophobe renal cell carcinoma is one of the less common subtypes of renal cell carcinoma (RCC).
This is the least common major subtype of RCC, occurring 5% of the time 1. Similar incidence in men and women.
This type of RCC arises from intercalated cells of collecti...
Chronic lymphocytic leukemia (CLL) is a hematological malignancy characterized by the proliferation of mostly mature but abnormal leukocytes.
Chronic lymphocytic leukemia is considered the most common type of leukemia in the Western hemisphere; its prevalence in Europe and North ...
Chronic myeloid leukemia (CML), also known as chronic myelogenous leukemia, is a myeloproliferative neoplasm characterized by the overproduction of granulocytes with fairly normal differentiation.
The annual incidence is about 1 per 100,000 1,3. The typical age at presentation is ...
Chronic myelomonocytic leukemia (CMML) is a relatively rare clonal hematologic disorder. In the World Health Organization classification, it is listed as a disorder with features of both myelodysplastic syndromes and myeloproliferative neoplasms.
Can be variable but many ...
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...
Circulating tumor cells (CTC's) refer to cells that have shed into the blood stream or lymphatics from a primary tumor. They are thought constitute "seeds" for the subsequent development of metastases.
History and etymology
They were first observed in blood in a patient with metastatic cancer ...
Circumferential resection margin (CRM) is a term used to denote the standard plane of excision of total mesorectal excision, used for resection of rectal cancers. The anatomic correlate is the mesorectal fascia. The distance between tumor tissue or satellite tumor deposits and the mesorectal fas...
Clavicle tumors may be malignant or benign.
osteoma: uncommon, sclerotic, hamartomatous surface lesion
enchondroma: rare, geographic, intramedu...
Clear cell meningiomas are a histological variant of meningioma with poorer prognosis and a higher rate of recurrence. They are therefore considered WHO grade 2 tumors, regardless of mitotic index, cellular atypia/anaplasia, or presence of brain invasion.
Clear cell meningiomas h...
Clear cell renal cell carcinoma is the most common type of renal cell carcinoma.
The average age of onset of sporadic clear cell renal carcinoma is 61 years-old. In cases associated with Von Hippel-Lindau disease the average age of onset is 37 years 1.
Clear cell sarcomas of the kidney (CCSK) are a rare mesenchymal renal tumor that account for ~5% of primary renal neoplasms in the pediatric population 1.
Clear cell sarcoma of the kidney is the second most common primary malignant pediatric renal neoplasm after Wilms tumor, with...
Clear cell tumors of the lung are rare benign pulmonary neoplasms that contain an abundant amount of glycogen. It is often classified under the spectrum of perivascular epithelioid cell tumors (PEComas).
Usually seen as a rounded, smooth-walled, and peripheral parenchymal...
CNS capillary telangiectasiae(s) are small, asymptomatic low flow vascular lesions of the brain.
As these lesions are asymptomatic, diagnosis usually matches the age of first imaging with MRI, and as such are most frequently found in middle-aged and elderly adults. Their inciden...
CNS lymphoma refers to the involvement of the central nervous system with lymphoma. It can be broadly divided into primary and secondary, with a number of special types of also recognized.
primary CNS lymphoma (PCNSL)
MALT lymphoma of the dura 5
secondary CNS lymphoma...
Celiac plexus block under image guidance is an easy and safe percutaneous procedure with good outcomes for pain palliation in patients who have chronic abdominal pain related to the celiac ganglia.
This usually includes patients with advanced cancers, especially from upper abdominal viscera, s...
Colloid adenocarcinoma of the lung is an extremely rare (i.e. only accounting for ~0.2% of all lung cancers) variant of invasive lung adenocarcinoma.
It is histologically characterized by the presence of abundant mucus in the tumor with neoplastic cells seen floating in large pools o...
Colon polyps are mucosal outgrowths of the colon wall. They are of interest to physicians and radiologists because of the accepted progression of adenomatous polyps to colon carcinoma.
adenomatous colon polyps
villous colon polyps
Colorectal cancer (CRC) is the most common cancer of the gastrointestinal tract and the second most frequently diagnosed malignancy in adults. CT and MRI are the modalities most frequently used for staging. Surgical resection may be curative although five-year survival rate is 40-50%.
This is a basic article for medical students and other non-radiologists
Colorectal cancer, also called colorectal carcinoma (CRC), is the most common cancer of the gastrointestinal tract and the second most frequently diagnosed malignancy in adults. CT and MRI are the modalities most frequently...
Complications of thoracic radiation therapy have significantly reduced since conventional radiotherapy has been largely replaced by modern conformational techniques. Even though, given the usually high radiation doses required for most thoracic cancers, some degree of collateral effects will be ...
Composite hemangioendotheliomas are locally aggressive and rarely metastasizing vascular tumors consisting of different and histologically distinct elements.
Composite hemangioendotheliomas are very rare and mostly seen in adults. Women are slightly more commonly affected 1,2.
Computed tomography texture analysis (or CTTA) is a method to obtain new useful biomarkers that provide objective and quantitative assessment of tumor heterogeneity by analyzing the differences and patterns within the pixel values of an image. CTs can be worked with as a matrix of numbers, corre...
With the advent of echocardiography, and cardiac CT and MRI, the role of chest x-rays in evaluating congenital heart disease has been largely been relegated to one of historical and academic interest, although they continue to crop up in radiology exams. In most instances a definite diagnosis ca...
Congenital neuroblastoma is defined as neuroblastoma identified within a month of birth, and is divided into:
In most cases they present as stage 1, 2 or 4S (see neuroblastoma staging).
In 90% of cases, fetal neuroblastomas aris...
Conventional (2D) radiation therapy refers to the old techniques of radiation therapy where treatments would be planned by defining a limited number of beams with the boundaries delineated on orthogonal x-rays of the patient. It has been largely replaced by other highly conformal external beam r...
A handy mnemonic to recall cortically-based brain tumors is:
P: pleomorphic xanthoastrocytoma
D: dysembryoplastic neuroepithelial tumor (DNET); desmoplastic infantile astrocytoma and ganglioglioma
The Cotswolds-modified Ann Arbor classification is a lymphoma staging classification system for both Hodgkin lymphoma and non-Hodgkin lymphoma. They came about in 1988 following recommended modifications to the Ann Arbor staging system after a meeting in Cotswold, England.
This classification h...
The CT angiogram sign refers to vessels appearing prominent during a contrast enhanced CT as they traverse an airless low attenuation portion of consolidated lung. Although initially thought to be specific for bronchoalveolar carcinoma, it has now been recognized as a generic appearance provided...
CT guided thoracic biopsy is usually performed for the diagnosis of suspicious lung, pleural, or mediastinal lesions. It can be performed as an outpatient procedure where patient monitoring and complications support are available. A small percentage of lung and pleural biopsies may be performed...
The curtain sign, also known as the draped curtain sign, in neuroimaging refers to the appearance of a vertebral body mass that extends posteriorly towards the anterior epidural space.
The posterior longitudinal ligament is strongly attached to the posterior vertebral body cortex in the midline...
Cutaneous and subcutaneous metastases are not uncommon, occurring in ~5% (range 0.7-10.4%) of internal malignancies, and representing 2% of skin cancers. The Sister Mary Joseph nodule is a well known cutaneous metastasis.
These metastases can come from hematogenous or lymphatic sprea...
Cutaneous carcinoma of the head and neck staging refers to TNM staging of nonmelanoma skin cancer involving the scalp, external ear, neck, or face including external lips. The system applies to cutaneous squamous cell carcinoma and numerous other skin carcinomas, notably excluding eyelid carcino...
CyberKnife® is a stereotactic radiotherapy system which uses a compact linear accelerator mounted on a robotic arm, coupled with a digital x-ray image guidance system. The robotic arm allows movement with many degrees of freedom compared to typical linear accelerators which only rotate around t...
Cystic adrenal neoplasms are uncommon and only account for a minority of cystic adrenal lesions 3. They may be represented several histological types:
adrenal adenoma 1
adrenal cortical carcinoma 1,2
adrenal epithelioid angiosarcoma 2
teratoma (pediatric population) 4
Cystic glioblastoma is a descriptive term for one form of glioblastoma that contains a large cystic component, rather than being a pathological subtype.
Please refer to the main article on glioblastoma for a broad discussion on this tumor.
The main challenge in discrim...
The differential for cystic lesions of the pancreas includes:
intraductal papillary mucinous neoplasm (IPMN)
serous cystadenoma uncommonly uni/macrolocular
simple pancreatic cyst
pancreatic cysts occur in association with
von Hippel Lindau syndrome
The term cystic meningioma is applied to both meningiomas with intratumoral degenerative cyst formation as well as those with peritumoral arachnoid cysts or reactive intraparenchymal cysts.
They should not be confused with microcystic meningiomas, a distinct variant, in which the cysts are mic...
Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions:
squamous cell carcinoma metastases
plasmacytoid T-cell leukemia
acute myeloid leukemia
herpes simplex lymphadenit...
Cystic pulmonary metastases are atypical morphological form on pulmonary metastases where lesions manifest as distinct cystic lesions. It is slightly different from the term cavitating pulmonary metastases in that the lesions are extremely thin walled.
It has been reported with many ...
The Deauville five-point scale (Deauville 5PS) is an internationally-recommended scale for routine clinical reporting and clinical trials using FDG PET-CT in the initial staging and assessment of treatment response in Hodgkin lymphoma (HL) and certain types of non-Hodgkin lymphomas (NHL).
Dedifferentiated liposarcomas (DDLPS) are malignant adipocytic soft tissue neoplasms that have progressed from primary or recurrent atypical lipomatous tumors/well-differentiated liposarcomas and are characterized by a much higher rate of recurrence, metastasis in about ¼ of the cases and a much...
The deep inguinal lymph nodes (often shortened to the deep inguinal nodes) form a subgroup of the inguinal lymph node group, and are located within the femoral sheath, medial to the femoral vein. They receive afferent lymphatic drainage from the deep lymphatics of the distal lower extremity and ...
The dense hilum sign suggests a pathological process at the hilum or in the lung anterior or posterior to the hilum. Malignancy, especially lung cancer, should be suspected.
On a well-centered chest posteroanterior (PA) radiograph the density of the hilum is comparable on...
A Denver shunt, or peritoneovenous shunt, is a device used to shunt ascites to the superior vena cava in patients with refractory ascites.
The proximal end is located in the peritoneal cavity and the distal end in the superior vena cava, with a subcutaneous course in the anterior chest wall. It...
Dermal nerve sheath myxomas are benign peripheral nerve sheath tumors usually originating from the skin or subcutaneous tissues.
The previous term was ‘classic or myxoid variant of neurothekeoma’ but recent data has shown that they are biologically and clinically distinct from neur...
Dermatofibrosarcoma protuberans (DFSP) is a low-grade malignant tumor arising from dermal and subcutaneous tissues and is the most common cutaneous sarcoma (although overall still quite rare). It is most commonly found at the trunk and proximal extremities 6.
Its behavior is notable for a high ...
Dermatomyositis is an autoimmune inflammatory myositis, which like its closely-related condition polymyositis, carries an increased risk of malignancy.
There is a recognized female predilection. It has a bimodal age of presentation depending on the variant: