Renal oncocytoma is a relatively benign renal tumour. The main clinical importance of this lesion is the difficulty in pre-operatively distinguishing it from renal cell carcinomas, as epidemiology, presentation, imaging and even histology can be very similar.
Renal oncocytomas ac...
Renal osteodystrophy (ROD), also known as uraemic osteopathy, is the constellation of musculoskeletal abnormalities that occur in patients with chronic renal failure, due to concurrent and superimposed:
osteomalacia (adults) / rickets (children)
secondary hyperparathyroidism: abnormal calcium ...
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).
Rhabdomyosarcomas of the genitourinary tract are uncommon tumours occurring in pelvic organs. It is a disease nearly exclusive to the paediatric population.
For a general discussion of this type of tumour, please refer to the article on rhabdomyosarcomas.
The peak incidence of ...
Rhabdomyosarcomas of the biliary tract are rare tumours, usually identified in children, with a very poor prognosis. They are usually grouped under botryoid rhabdomyosarcomas.
For a general discussion of this type of tumour, please refer to the article on rhabdomyosarcomas.
Rubinstein-Taybi syndrome (RTS) is a very rare genetic multi-system disorder primarily characterised by mental retardation, broad and often angulated thumbs and halluces, and distinctive facial features.
The estimated incidence is 1 in 100,000-125,000 live births 5.
Salivary gland tumours are variable in location, origin, and malignant potential.
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...
Sarcoid-like post-immunotherapy granulomatosis has been reported as an uncommon complication in patients treated with immunotherapy agents such as monoclonal antibodies. It was first reported in TNF inhibitors used to treat rheumatoid arthritis and has also been reported in various immunotherapy...
Pulmonary manifestations of scleroderma are demonstrated histologically in 90% of patients with scleroderma. It is a leading cause of mortality and at autopsy. The lung is reportedly involved in close to 100% of cases. However, only 25% of patients will present with respiratory symptoms or demon...
Secondary hepatic involvement with lymphoma (secondary hepatic lymphoma) is common, much more so than primary hepatic lymphoma.
Hepatomegaly with deranged liver function tests is the most common presentation. Jaundice is common. Rarely, patients may present with acute li...
Secondary involvement of the bone with lymphoma, also referred as secondary bone lymphoma, is much more common than primary bone lymphoma, occurring in ~15% of disseminated lymphomas.
Secondary bone lymphoma is defined as lymphoma involving the bone with nodal disease occurring wit...
Secondary involvement of the pleura with lymphoma (secondary pleural lymphoma) is very common, occurring in ~20% of lymphomas. It may be a result of an extension of lymphoma into the visceral or parietal pleura or be a complicating pleural effusion and is a poor prognostic factor.
Second branchial cleft cysts are a cystic dilatation of the remnant of the 2nd branchial apparatus, and along with 2nd branchial fistulae and sinuses accounts for 95% of all branchial cleft anomalies.
Although a congenital abnormality, they tend to present in early adulth...
Sinonasal adenocarcinomas are primary tumours of the sinonasal region with glandular differentiation. They are grossly classified as salivary and non-salivary subtypes. However, generally in the literature and IARC/WHO classification, the term Sinonasal adenocarcinoma refers to non-salivary aden...
Sinonasal lymphoma refers to the involvement of the nasal cavity and/or paranasal sinuses with lymphoma. It can be primary or secondary.
Presenting symptoms of sinonasal lymphoma are are variable but are usually similar to those of benign inflammatory diseases. The clinic...
Sinonasal mucosal melanoma (SNMM) is a very rare and unique subtype of malignant melanoma.
SNMMs account for ~1% of malignant melanomas and <4% of head and neck cancers 1,2. They affect older patients (60-90 years old) 2. There is a higher incidence in Japan 5.
Skeletal muscle metastases are uncommon compared to other sites and are generally seen in the context of widespread metastatic disease.
Post-mortem rates of skeletal metastases vary between 0.03% and 17% 1.
Most commonly asymptomatic 2,3.
The small bowel carcinoid tumours are the most common gastrointestinal carcinoid tumours. Within the small bowel, the most common site is at the terminal ileum.
Small bowel carcinoid tumours account for ~40% of gastrointestinal carcinoid tumours 1.
Small bowel lymphoma is the most common small bowel malignancy, accounting accounts for ~25% of all primary small bowel malignancies and ~40% of all primary gastrointestinal lymphomas.
Small bowel lymphoma is most commonly secondary extranodal involvement in widespread systemic ly...
Small cell carcinomas of the bladder are rare bladder cancers with a poor prognosis. Its appearance overlaps other bladder cancers, in particular, urothelial/transitional cell carcinoma.
A very rare tumor, it has been estimated at <0.0001% of bladder cancers. It is thought to have...
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)
Mnemonics to remember the causes of soft tissue calcification include:
My GHOSTS 1
TIC MTV 2
My: myositis ossificans
S: scleroderma/connective tissue disease
T: tumoral calcinosis
S: sarcoma (synovial cell)
Solid lesions with enhancement is by far the most commonly encountered appearance of pituitary region masses. The differential includes:
by far the most common entity
typically enhances less vividly than other entities
elevates the dura of the diaphragma sella (as the origin is...
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:
Solitary bone plasmacytomas (SBP) may involve any bone, but they have a predisposition for the red marrow-containing axial skeleton:
spinal disease is observed in ~50% (range 34-72%) of cases
the thoracic vertebrae are most commonly involved, followed by lumbar, sacral, and cervical vertebrae
The differential diagnosis of a solitary sclerotic bone lesion is heavily influenced by the age of the patient, and includes:
when solitary may be the only one visible of many or the only one imaged
enostosis (bone island)
SpaceOAR is a technique in which a physical space is created between the prostate gland and rectum for electron beam radiotherapy targeted to the prostate cancer.
OAR stands for "organ at risk", and in cases of prostate cancer radiotherapy treatment the rectum is the main organ at risk. The in...
Spinal astrocytomas are the second most common spinal cord tumour overall, representing 40% of intramedullary tumours 3. They account for 60% of paediatric intramedullary tumours, making them the most common spinal cord tumour in children 6.
This article specifically relates to spinal astrocyto...
The spinal instability neoplastic score (SINS) helps to assess tumour related instability of the vertebral column. It has been shown to useful in guiding the mobilisation or operative management of patients with neoplastic spinal disease.
Studies have reported good inter-observer agreement amon...
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...
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...
Squamous cell carcinoma (SCC) is one of the non-small cell carcinomas of the lung, overtaken by adenocarcinoma of the lung as the most commonly encountered lung cancer.
Squamous cell carcinoma accounts for ~30-35% of all lung cancers and in most instances are due to heavy smoking...
Staging of oral cavity squamous cell carcinoma uses the TNM staging system.
Primary tumour staging (T)
Tx - tumour cannot be assessed
T0 - no evidence of primary tumour
Tis - carcinoma in situ
T1 - tumour 2 cm or less in greatest dimension
T2 - tumour greater than 2 cm and less than 4 cm i...
Squamous cell carcinoma of the penis arises most commonly at the distal end of the penile urethra with local invasion of the glans.
In addition to TNM classification, the following staging is used:
stage I: confined to the glans or foreskin
stage II: invasion of penile shaft
Stereotactic ablative radiotherapy (SABR) is a technique used to treat certain cancers as an alternative to surgical resection. It can be used to treat early lung cancer and hepatocellular carcinoma.
The stipple sign refers to the pointillistic end-on appearance on intravenous pyelography or retrograde pyelography of contrast material tracking into the interstices of a papillary lesion. Because the majority of transitional cell carcinomas (TCC) have a papillary configuration, the presence of...
Superior vena cava (SVC) obstruction can occur from extrinsic compression, intrinsic stenosis or thrombosis. Malignancies are the main cause and are considered an oncologic emergency. Superior vena cava syndrome (SVCS) refers to the clinical syndrome with symptoms that results from this obstruct...
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
transitional cell carcinoma (...
Sweet syndrome (acute febrile neutrophilic dermatosis) is characterised by a constellation of clinical symptoms, physical features, and pathologic findings which include:
tender erythematous skin lesions (papules, nodules, and plaques)
a diffuse infiltrate consisting predo...
Synonyms, located below references when in edit mode, are used in a number of scenarios.
To view a YouTube screencast tutorial please click here.
What is a synonym?
A synonym is essentially a 'redirect' to an article. This enables links created to article A to pass to article B, provided ar...
Tamoxifen has pro-oestrogenic effects on the endometrium and thus is associated with an increased prevalence of:
endometrial polyps: occurs in ~8-36% of women in treated 8
endometrial hyperplasia: occurs in ~1-20% of women treated ref
cystic endometrial atrophy
Masking is very important when viewing mammograms, especially with high-density breasts. It helps the adaptation of the eye to the luminance of the mammograms on the viewbox.
The technique of masking allows the comparative study of small areas of both breasts and is a featur...
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
Testicular cancers are the most common neoplasm in men between the ages of 20 and 34.
Testicular cancer is uncommon, accounting for less than 1% of all internal organ malignancies 2.
The demographics of affected individuals depends on the age of the histology of the tumour. Over ...
Testicular lymphoma is an uncommon cause of testicular malignancy. Lymphoma can involve the testes in three ways:
primary site of extranodal disease (primary testicular lymphoma)
secondary involvement of systemic disease
primary manifestation of subclinical systemic disease
This article is c...
Testicular seminomas are the most common testicular tumours and account for ~45% of all primary testicular tumours. This article concerns itself only with testicular seminomas, however, seminomas can arise outside of the testicle most often within the anterior mediastinum, e.g. anterior mediasti...
Testicular teratoma, unlike ovarian teratoma, is often aggressive in its biological behaviour, and often exists as part of testicular mixed germ cell tumours.
Pure testicular teratomas account for only 4-9% of all testicular tumours. A similar number are seen in the context of t...
Thymic carcinoma is part of the malignant end of thymic epithelial tumours.
Patients are typically 50 to 70 years of age at presentation 9.
The incidence of paraneoplastic syndromes is thought to be low. At least 10 different histologic variants have been described 4. ...
Thymic hyperplasia is a disorder whereby there is hyperplasia of the thymus gland.
Thymus hyperplasia can be subdivided into two forms:
true thymic hyperplasia
Both true thymic hyperplasia and lymphoid hyperplasia manifest as diffuse symmetric enlargement of...
Thyroid-associated orbitopathy (TAO) is the most common cause of proptosis in adults and is most frequently associated with Graves disease.
On imaging, it is characterised by enlargement of the extraocular muscles' bellies (frequently: inferior rectus > medial rectus > superior rectus) sparing...
Thyroid lymphoma is rare, accounting for a minority of both thyroid malignancies and lymphoma in general.
The thyroid may be affected primarily or secondary to lymphoma elsewhere. This article is concerned with primary thyroid lymphoma.
Thyroid lymphoma accounts for <5% of thyr...
Thyroid scan (thyroid scintigraphy) is a nuclear medicine examination used to evaluate thyroid tissue.
functional status of a thyroid nodule
thyrotoxicosis: differential diagnosis
whole body scan for distant metastases
estimation of local residual thyro...
The TNM system has been widely adopted in many areas as a replacement for idiosyncratic disease specific systems. The number of Ts Ns and Ms depend on the tumour/site but in general:
Tx: primary tumour cannot be assessed
T0: no evidence of primary tumour
Tis: carcinoma in situ...
Tolosa-Hunt syndrome (THS) is an idiopathic inflammatory condition that involves the cavernous sinus and orbital apex, and is essentially a clinical diagnosis of exclusion.
Clinically it refers to the presence of a painful ophthalmoplegia secondary to surrounding cavernou...
The differential for tracheal masses can be rather wide.
For a single mass consider:
direct invasion from adjacent organ (lung, thryoid,esophagus)
distant metastsis ( such as melanoma)
squamous cell carcinoma: commonest primary tracheal malignancy 2 ~50 %
Trachelectomy (sometimes known as a cervicectomy) refers to removal of uterine cervix.
It is sometimes performed as a uterine sparing surgery for certain cases with cervical malignancy 2-3. When it is performed with curative intent it is often termed a radical trachelectomy and is often accomp...
Tram-track sign refers to the parallel thickening and enhancement around the optic nerve, and is most frequently seen in the setting of optic nerve meningioma. It may however also be seen in 1:
Transcoelomic spread describes the spread of a malignancy into body cavities that occurs via penetrating the surface of the peritoneal, pleural, pericardial, or subarachnoid spaces. For example, ovarian tumours can spread transperitoneally to the surface of the liver.
Transitional cell carcinoma of the bladder staging uses the TNM system which has replaced the previously widely used Jewett-Scott-Marshall tumour staging system. It is very similar to the staging of TCC of the renal pelvis and staging of TCC of the ureter.
Ta - non-invasive papi...
Staging of transitional cell carcinomas of the urinary tract vary according to the location of the tumour, and are staged using the TNM staging system.
transitional cell carcinoma of the renal pelvis
transitional cell carcinoma of the ureter
transitional cell carcinoma of the bladder
Transplantation of a transverse rectus abdominis myocutaneous (TRAM) flap is a commonly used surgical procedure for breast reconstruction following mastectomy.
An autologous myocutaneous flap consisting of abdominal skin, subcutaneous fat, the rectus abdominis muscle, and adjoining vasculature ...
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...
Tuberculous cervical lymphadenitis, also known as scrofula and King's evil, continues to be seen in endemic areas and in the industrialised world particularly among the immunocompromised.
Tuberculous cervical lymphadenitis is the most common manifestation of extrapulmonary tubercu...
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:
Tumours of the male urethra are uncommon. They can be categorised both on the grounds of histology and location.
squamous cell carcinoma of the urethra: 80%
urothelial/transitional cell carcinoma of the urethra: 15% (predominantly posterior urethra)
adenocarcinoma of the urethra: 5...
Typhlitis, also called caecitis or neutropaenic colitis, is a necrotising inflammatory condition which typically involves the caecum and, sometimes, can extend into the ascending colon or terminal ileum.
Typhlitis was first described in children with leukaemia and severe neutropae...
Undifferentiated embryonal sarcomas of the liver are rare, aggressive, and malignant liver tumours encountered in the paediatric population.
Approximately 90% of cases occur in patients under 15 years of age, most commonly between 6 and 10 years of age, but some cases have been r...
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
Urethral diverticulum, or urethrocoele, is a focal outpouching of the urethra. It should not be confused with a ureterocoele of the distal ureter.
Urethral diverticula occur far more frequently in women than in men and are estimated to occur in 1-6% of women, especially those with...
Vertebral metastases represent the secondary involvement of the vertebral spine by haematogenously-disseminated metastatic cells. They must be included in any differential diagnosis of a bone lesion in a patient older 40 years.
This article will focus only on the metastasis involving the bony s...
Vertebra plana (a.k.a. pancake / silver dollar / coin-on-edge vertebra) is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced compression fracture. Plural is vertebrae planae. It can occur in a variety of settings, incl...
VIPomas are a very rare type of pancreatic endocrine tumour that secrete, and get their name from, vasoactive intestinal peptide (VIP). The clinical syndrome resulting from these tumours is commonly known as WDHA syndrome, as an acronym of the cardinal symptoms of watery diarrhoea, hypokalaemia,...
Visceral pleural invasion is a feature that can be seen in lung cancers. It is defined as tumour extension beyond the elastic layer of the visceral pleura. It is considered an aggressive sign and one of the most important adverse prognostic factors in non-small cell lung cancers 1.
Von Hippel-Lindau (vHL) disease is characterised by the development of numerous benign and malignant tumours in different organs (at least 40 types 1) due to mutations in the VHL tumour suppressor gene on chromosome 3.
The disease is rare with an estimated prevalence of 1:35,000-5...
The WHO classification of anal margin tumours or perianal skin tumours is:
Bowen disease (precursor of squamous cell carcinoma)
Paget's disease (precursor of adenocarcinoma)
squamous cell carcinoma
basal cell carcinoma
The WHO classification scheme for thymic epithelial tumours is one of many classifications systems for thymoma and related tumours, and classifies them according to histology:
spindle cell thymoma
type ab: mixed thymoma
type b1: lymphocyte rich
The WHO criteria introduced the concept of assessing tumor burden on the basis of the sum of the products of diameters (SPD) (ie, longest overall tumor diameter and longest diameter perpendicular to the longest overall diameter) and determining response to therapy by evaluating the changes from ...
Wilms' tumour staging is largely anatomical and relates to the invasion and spread of the tumour. Where there is invasion or metastasises, prognosis is poorer. Wilms tumour, is one of the more common childhood malignancies.
confined to kidney
complete resection possible
Xanthogranulomatous cholecystitis is an uncommon inflammatory disease of the gallbladder which may be difficult to differentiate from malignancy, both on imaging and pathologically. It is characterised by presence of multiple intramural nodules.
It is seen predominantly in female ...