The 2005 WHO histological classification of odontogenic tumours lays out a classification system for neoplasms and other tumours related to the odontogenic apparatus. At the time of writing (2016), it is still the most widely used classification system.
The 2008 WHO classification of tumours of haematopoietic and lymphoid tissues is at the time of writing (mid 2016) the most widely used classification system.
nodular lymphocyte predominance
classical Hodgkin lymphoma
Endometrial stromal tumours (EST) constitute <2% of all uterine tumours and <10% of uterine mesenchymal neoplasms 1.
Over the past four decades, EST classification has gone through various modifications starting from the earliest study by Norris and Taylor 2. This was primarily due to the rari...
Accessory breast tissue is a relatively common congenital condition in which abnormal accessory breast tissue is seen in addition to the presence of normal breast tissue. This normal variant can present as a mass anywhere along the course of the embryologic mammary streak (axilla to the inguinal...
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
Adrenal adenomas are the most common adrenal mass lesion and are often found incidentally during abdominal imaging for other reasons. In all cases, but especially in the setting of known current or previous malignancy, adrenal adenomas need to be distinguished from adrenal metastases or other ad...
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.
sepsis: Waterhouse-Friderichsen syndrome
Adrenal haemangiomas are rare benign tumours that are usually incidentally identified (one example of an adrenal incidentaloma). Its significance mainly relates to the difficulty in differentiation from other malignant lesions.
Although these can be found at any age, they are mos...
Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include:
from head and neck tumours
other neoplastic lesions
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...
Ameloblastomas are locally aggressive benign tumours that arise from the mandible, or less commonly from the maxilla. Usually presented slowly but continuously growing hard painless lesion near the angle of the mandible in the 3rd to 5th decades of life which can be severely disfiguring if left ...
Anal cancer is a relatively uncommon malignancy. It accounts for less than 2% of large bowel malignancies and 1-6% of anorectal tumours (~1.5% of all gastro-intestinal tract malignancies in the Unites States 14).
There may be a slight male predilection where its incidence has bee...
The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge.
Head and neck anatomy
Abdominal and pelvic anatomy
Lower limb anatomy
Upper limb anato...
Getting a film with an anterior mediastinal mass in the exam is one of the many exam set-pieces that can be prepared for.
The film goes up and after a couple of seconds pause, you need to start talking:
There is a left sided mediastinal mass that makes obtuse angles with the mediastinal c...
Architectural distortion is a mammographic descriptive term in breast imaging. It may be visualised as tethering or indentation of breast tissue.
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...
Asbestosis refers to later development of diffuse interstitial fibrosis secondary to asbestos fibre inhalation and should not be confused with other asbestos related diseases.
Asbestosis typically occurs 10-15 years following the commencement of exposure to asbestos and is dose re...
Assessment of thyroid lesions is commonly encountered in radiological practice.
hyperplastic / colloid nodule / nodular hyperplasia: 85%
papillary: 60-80% of carcinomas
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:
Atypical ductal hyperplasia (ADH) is a histologically borderline lesion that has some, but not all the features of ductal carcinoma in situ (DCIS). Sometimes the distinction between ADH and DCIS is simply on the basis of the number of ducts involved.
Atypical ductal hyperplasia is a...
Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis associated with autoimmune manifestations on clinical, histological, and laboratory grounds 1.
Distinguishing this entity from other forms of chronic pancreatitis (such as alcohol-induced) is important as steroid treatment is effec...
Autosomal dominant polycystic kidney disease (ADPKD), also sometimes more vaguely referred to as "adult polycystic kidney disease", is as the name would suggest, a hereditary form of adult cystic renal disease.
Autosomal dominant polycystic kidney disease is one of the most commo...
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.
Bat's wing pulmonary opacities can be caused by:
Benign and malignant characteristics of breast lesions at ultrasound allow the classification as either malignant, intermediate or benign based on work published by Stavros et al in 1995.
Malignant characteristics (with positive predictive values)
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
The Bethesda criteria are an alternative to the Amsterdam criteria for the clinical diagnosis of hereditary non-polyposis colorectal cancer (HNPCC).
Diagnosis of HNPCC is made if any of the following criteria are fulfilled:
Amsterdam criteria are met
2 or more HNPCC related malignancies
A BIRADS IV lesion under the breast imaging reporting and data system refers to a suspicious abnormality. BIRADS IV lesions may not have the characteristic morphology of breast cancer but have a definite probability of being malignant. A biopsy is recommended for these lesions. If possible, the ...
Bilateral testicular lesions have a relatively limited differential diagnosis.
lymphoblastic leukemia (acute or chronic)
primary testicular lymphoma is rare but the testes are often the site of lymphoma/leukemia recurrence due to the chemoptherapy inabil...
There are several bony lesions that can involve or depict a sequestrum.
brodie abscess: osteomyelitis
certain soft tissue tumours (with bony extension)
malignant fibrous histiocytoma
metastasis (especially from breast ca...
Normal bone marrow is divided into red and yellow marrow, a distinction made on the grounds of how much fat it contains.
Red marrow is composed of:
reticulum (phagocytes and undifferentiated progenitor cells)
scattered fat cells
a rich vascular supply...
Mnemonics to help remember common causes of bony sequestrum include:
E: eosinophilic granuloma
I: infection (brodie abscess)
L: lymphoma (skeletal lymphoma)
M: malignant fibrous histiocytoma or metastasis (especially from breast carci...
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...
Brain abscess is a potentially life threatening condition requiring rapid treatment, and prompt radiological identification. Fortunately MRI is usually able to convincingly make the diagnosis, distinguishing abscesses from other ring enhancing lesions.
Demographics reflect at-ris...
Common brain tumours in infancy (i.e. under one year of age) are quite different from those of brain tumours in adulthood:
intracranial teratoma (germ cell tumour)
primitive neuroectodermal tumour (CNS-PNET)
medulloblastoma (SHH and Group 3)
choroid plexus papilloma
A breast abscess is a relatively rare but significant complication of mastitis that may occur during breastfeeding, particularly in primiparous women. The clinical context is a key to diagnosis as imaging appearances (particularly ultrasound) can mimic many other entities such as breast carcinom...
BIRADS classification is proposed by American College of Radiology, last updated in November 2015, and is widely used classification system at time of writing this article (July 2016).
The BIRADS acronym stands for Breast Imaging-Reporting and Data System which is a widely accepted risk assessm...
Breast lymphoma refers to involvement of the breast with lymphoma and may be primary or secondary.
Both primary and secondary breast lymphoma are rare accounting for ~ 0.5% (range 0.3-1.1%) of all breast malignancies.
Breast lymphoma may present either as a...
Breast MRI is a rapidly growing field, especially in the assessment of high risk women.
Editorial board note: this article is probably outdated, lacks structure and is in need of a major rewrite. If you are interested in refining it you are more than welcome.
T1 C+ (Gd...
The bright rim sign has been described in DNETs and is seen, as the name so aptly describes, as a rim of high signal around the DNET on FLAIR sequences.
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...
Burkitt lymphoma (BL) is an aggressive B-cell lymphoma that predominantly affects children.
Burkitt lymphoma is the most common (40%) type of non-Hodgkin lymphoma in childhood. The median age of Burkitt lymphoma is eight years, and it has a male predominance (M:F = 4:1) 1. It is l...
CA 19-9 is a serum antigen (monosialoganglioside) that has increased diagnostic use in 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 ass...
Serum CA-125 elevation 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 indi...
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...
Cancer staging using a number of systems to help direct treatment and aid prognosis.
FIGO (in gynaecological cancer)
Dukes staging system
breast cancer staging
non-small cell lung cancer staging
small cell lung cancer staging
Cannonball metastases refer to large, well circumscribed, round pulmonary metastases that appear, well, like cannonballs. The French term "envolée de ballons" which translates to "balloons release" is also used to describe this same appearance.
Metastases with such an appearance are classically...
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...
Carcinoid cardiac lesions are a known complication of carcinoid tumours, and are particularly prevalent in those who develop the carcinoid syndrome (up to 50%).
There is thickening of mural and valvular endothelial surfaces of right-sided cardiac structures. This is thought to occur ...
Carcinoma of the cervix is a malignancy arising from the cervix and is considered the third most common gynaecologic malignancy (after endometrial and ovarian).
It typically presents in younger women with the average age of onset at around 45 years.
Carcinosarcomas are highly malignant biphasic tumours with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.
It can arise in many organs:
lung 5: pulmonary carcinosarcoma
oesophagus 1: oesophageal carcinosarcoma
genitourinary tract ...
Cardiac myxomas, although uncommon are one of commonest primary cardiac tumours and account for ~50% primary benign cardiac tumours.
Cardiac myxomas are the most common primary cardiac tumour in adults but are relatively infrequent in childhood, where cardiac rhabdomyomas are mor...
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
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, tumour)
vasculitides affecting the pulmonary ...
Central neurocytomas are WHO Grade II neuroepithelial intraventricular tumours with fairly characteristic imaging features, appearing as heterogeneous masses of variable size and enhancement within the lateral ventricle. They are typically seen in young patients, and generally have a good progno...
Cerebral radiation necrosis refers to necrotic degradation of brain tissue following intracranial or regional radiation.
The brain is exposed to therapeutic radiation both for treatment of intracranial pathology (e.g. astrocytoma, cerebral arteriovenous malformation) and is also a bystander in ...
The differential for peripheral or ring enhancing cerebral lesions includes:
subacute infarct / haemorrhage / contusion
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)
D: demyelinating disease
R: radiation necrosis or re...
Cervical lymph node staging is important in a variety of tumours, especially squamous cell carcinoma of the head and neck.
TNM nodal staging
Nodal staging is the same for squamous cell carcinomas of most regions of the upper aerodigestive tract of the head and neck, including those of the of t...
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 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...
Choledochal cysts represent congenital cystic dilatations of the biliary tree. Diagnosis relies on the exclusion of other conditions (e.g. tumour, gallstone, inflammation) as a cause of biliary duct dilatation.
Choledochal cysts are rare, with an incidence of 1:100,000-150,000. Al...
Choriocarcinoma is an aggressive highly vascular tumour. When it is associated with gestation, it is often considered part of the spectrum of gestational trophoblastic disease. It is then termed a gestational choriocarcinoma. When it occurs in the absence of preceding gestation, it is termed a n...
The circumferential resection margin (CRM) is a term used in rectal carcinoma excision surgery (such as total mesorectal excision (TME).
Pathologic evaluation of the resection margin on the excised rectum has been considered important for determining the risk of local recurrence. A margin of ≤1...
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 incidenc...
Coarsened hepatic echotexture is a sonographic descriptor where there uniform smooth hepatic echotexture of the liver is lost. This can occur due to number of reasons which include:
conditions that cause hepatic fibrosis 1
various types of hepatitis 3
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 used for staging. Surgical resection may be curative although five-year ...
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 used for staging. Surgical resection may be curative although five-year survival rate is 40-50%.
With the advent of echocardiography, and cardiac CT and MRI, the role of chest radiographs 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 diagnos...
A 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 ar...
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 recognised 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 where patient monitoring and complications support are available.
pulmonary lesion inaccessible to bronchoscopy, or in which pri...
The curtain sign (or draped curtain sign) in neuroimaging refers to the appearance of a vertebral body mass that extends to the anterior epidural space.
The posterior longitudinal ligament is strongly attached to the posterior vertebral body cortex in the midline and is more loosely attached la...
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.
These metastases can come from haematogenous or lymphatic spread, or may result from seeding from a surgical ...
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 adrenal neoplasms are uncommon and only account for a minority of cystic adrenal lesions 3.
They may be represented several histological types
Reported lesions include
adrenal adenoma 1
adrenal cortical carcinoma 1,2
adrenal epithelioid angiosarcoma 2
The differential for cystic lesions of the pancreas includes:
intraductal papillary mucinous neoplasms (IPMN)
serous cystadenoma uncommonly uni/macrolocular
pancreatic cysts occur in association with
von Hippel Lindau syndrome
autosomal dominant polycysti...
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 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.
It has been reported with many ...
The Deauville five-point scale (Deauville 5ps) is an internationally recommended scale for clinical routine and clinical trials using FDG-PET/CT in the initial staging and assessment of treatment respons in Hodgkin lymphoma (HL) and certain types of non-Hodgkin lymphomas (NHL).
The dense hilum sign suggests a pathological process at the hilum or in the lung anterior to posterior to the hilum. Malignancy, especially lung cancer, should be suspected.
On a well-centred chest PA radiograph the density of the hilum is comparable on both sides. In the...
Dermatofibrosarcoma protuberans (DFSP) is an uncommon exophytic, slow growing, low grade, spindle cell tumour arising in the dermal and subcutaneous tissues, particularly of the trunk region with excellent outcome after complete surgical resection.
The tumour occurs in patients of...
Diabetic mastopathy (DMP) is a condition characterized by the presence of benign tumour like breast masses in women with long-standing type 1 or type 2 insulin-dependent diabetes. The condition has also been reported in men.
Diabetic mastopathy manifests clinically as a l...
A gas filled focal collection in the right upper upper quadrant on plain film can occur from a number of pathologies. Things to consider are
entero biliary fistula : common types include cholecysto-duodenal fistula and cholecysto-colic fistula and. Can occur with
gallstone ileus (majority of ...
Unilateral axillary lymphadenopathy while being more concerning than bilateral axillary lymphadenopathy can still arise from a various benign as well as malignant causes.
other regional infective causes
ipsilateral arm infection, e.g. cellulitis
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...
Diffuse bony sclerosis has many causes. Useful mnemonics for remembering them include:
3 M's PROOF
Regular Sex Makes Occasional Perversions Much More Pleasurable And Fantastic 1
3 M's PROOF
metastases (osteoblastic metastases)
A diffuse homogeneous bone marrow FDG uptake usually reflects hyperplastic bone marrow which can be seen in the following conditions :
granulocyte colony stimulating factor (G-CSF)
A ductal adenoma of the breast is a benign glandular tumour 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 pres...
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 focussed on intracranial dural masses.
Dysembryoplastic neuroepithelial tumours (DNET) are benign (WHO Grade I) slow growing tumours arising from either cortical or deep grey matter. The vast majority are centred in cortical grey matter, arise from secondary germinal layers and are frequently associated with cortical dysplasia (up to...
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.
increased fat or glyco...
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 t...
Endometrial carcinoma is generally considered the most common gynaecological malignancy 1,5. It frequently presents with vaginal bleeding and both ultrasound and pelvic MRI are useful modalities for evaluation.
Incidence peaks at around the 6th decade, though 12% of cases present ...