Gnathic osteosarcoma is a subtype of osteosarcoma that primarily affects the mandible (horizontal ramus) and maxilla (alveolar ridge, sinus floor, and palate).
represents ~6% of osteosarcomas 3
60% in males
has an older onset (~30 years) and a peak incidence: 30-40 years
Goitre refers to enlargement of the thyroid gland. It can occur from multiple conditions.
The definition of a goitre depends on age and sex; below are the upper limits of normal for thyroid gland volume 1:
adult males: 25 mL
adult females: 18 mL
13-14 years: 8-10 mL
3-4 years: 3 mL
The Gosselin fracture is a fracture of the distal tibia with a V-shaped fractured fragment and intra-articular involvement.
History and etymology
It is named after Leon Athanese Gosselin (1815–1887), a French surgeon.
A gossypiboma, also called textiloma or cottonoid, refers to a foreign object, such as a mass of cotton matrix or a sponge, that is left behind in a body cavity during an operation. It is an uncommon surgical complication.
The manifestations and complications of gossypibomas are so variable tha...
Gout is a crystal arthropathy due to deposition of monosodium urate (MSU) crystals in and around the joints.
Typically occurs in those above 40 years. There is a strong male predilection of 20:1.
Characterised by monosodium urate crystals deposition in periarticular so...
Graft versus host disease (GvHD) is a frequent complication of allogeneic post haematopoietic stem cell transplantation (HSCT), commonly known as bone marrow transplantation. Anti-rejection drugs have reduced the incidence, although it does still frequently occur.
GvHD can present e...
Pulmonary graft versus host disease (GvHD) is one of the thoracic manifestations that can complicate haematopoetic stem cell transplantation. Pulmonary GvHD can be broadly divided into acute and chronic disease 1-4:
acute pulmonary GvHD
pulmonary involvement is rare
the median time of onset o...
A granular cell tumour (GCT) of the breast is an uncommon, usually benign tumour which is possibly of neural origin.
They tend to occur at a younger age than other types of breast cancer 4. The age range of presentation, however, can be very variable although they occur more commo...
Granular cell tumour of the pituitary region, also known as a pituitary choristoma, are rare low-grade tumours of the posterior pituitary and infundibulum.
Care must be taken when reading older literature as granular cell tumours of the pituitary region, and alternative names incl...
Granulocytic sarcoma (also called myeloid sarcoma and chloroma) is a rare neoplasm comprised of myeloid precursor cells.
It can occur in association with:
acute myeloid leukaemia (AML)
chronic myeloid leukaemia (CML)
other myeloproliferative disorders such as
myelofibrosis with myeloid meta...
Granuloma annulare is a benign idiopathic inflammatory disorder of the dermis, characterised by formation of dermal papules in young children.
Granuloma annulare has various clinical presentations:
three cutaneous forms
Granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, is a multisystem systemic necrotising non-caseating granulomatous vasculitis affecting small to medium sized arteries, capillaries and veins, with a predilection for the respiratory system and kidneys 3.
Breast involvement in granulomatosis with polyangiitis is seen in patients with avid systemic manifestations.
Clinically they can mimic carcinoma as a palpable, tender mass.
Granulomatosis with polyangiitis (or formerly known as Wegeners granulomatosis) is a ...
Ophthalmologic manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis), both ocular and orbital, have been reported in 40-50% of GPA patients 1-3 and can occur in either the classic or limited form of the disease. 4 Ophthalmologic disease occasiona...
This article discusses the pulmonary manifestations of granulomatosis with polyangiitis (previously known as Wegener's granulomatosis). It is classified as a type of pulmonary angiitis and granulomatosis.
For a general discussion of the condition, please refer to the main article on granulomato...
The renal manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis) are occult on imaging, especially when compared to the pulmonary changes. Approximately half of GPA patients have kidney disease at presentation. Granulomatosis with polyangiitis (We...
The upper respiratory tract manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis) are common and affect most patients. . Granulomatosis with polyangiitis (Wegener granulomatosis), is a multi-system systemic necrotizing non-caseating granulomatous...
Granulomatous invasive fungal sinusitis, sometimes termed granulomatous invasive fungal sinusitis, is a form of invasive fungal sinusitis. Reports describing the imaging findings have been uncommon 1.
It is rare and been mainly reported in Sudan, India, Pakistan and sometimes in t...
Granulomatous lung disease refers a broad group of infectious and well as non infections conditions characterised by formation of granulomas.
The spectrum includes
pulmonary non tuberculous mycobacterial infection
Granulomatous mastitis is a very rare breast inflammatory disease of unknown origin that can clinically mimic carcinoma of the breast.
The condition generally manifests as a distinct, firm to hard mass that may involve any part of the breast. The subareolar regions may be...
Granulomatous prostatitis is a nodular form of chronic prostatitis. It is usually diagnosed on biopsy.
Several classification systems exist. A frequently used clas...
Graves disease is an autoimmune thyroid disease and is the most common cause of thyrotoxicosis (up to 85%).
There a strong female predilection with the F:M ratio of at least 5:1. Typically presents in middle age.
Patients are thyrotoxic. Extra-thyroid manif...
Growth arrest lines, also known as growth resumption lines, Harris lines or Park lines, are alternating transverse rings of sclerosis at the metaphysis of a long bone.
The radiographic finding occurs from alternating cycles of osseous growth arrest and growth resumption. This appears...
Gymnast wrist is defined as a chronic stress fracture (Salter Harris type I) of the distal radial (and less commonly ulnar) growth plate. It is most commonly seen in young individuals involved in gymnastics.
physeal plate irregularity
physeal plate widening
H1N1 influenza is a strain of influenza that notably resulted in a pandemic in 2009.
It is type of influenza A virus of swine origin.
There can be a wide spectrum of clinical syndromes with patient's ranging from being asymptomatic to having fulminating viral p...
Haemangiopericytoma is a term formerly used to describe a continuum of mesenchymal tumours with elevated cellularity found throughout the body in soft tissue and bone. After many years of controversy, haemangiopericytomas have been shown to not only share histological features similar to solitar...
Haemangiopericytomas of the spleen are a very rare vascular neoplasm with only a few case reports available at the time of writing.
Splenic haemangiopericytomas are typically asymptomatic or can result in splenomegaly.
These are a soft tissue vascular neoplasm...
Haemarthosis is haemorrhage into a joint space and can be regarded as a subtype of a joint effusion.
Trauma is by far the most common cause of a haemarthosis. Other causes include bleeding disorders, neurological deficits, arthritis, tumours and vascular damage.
Lipohaemarthrosis is a result o...
Haematuria occurs when blood enters the urinary collecting system. There are many aetiologies for haematuria, and they range from benign and transient to gravely concerning. Haematuria can derive from the kidneys, ureters, bladder, prostate (in men), or urethra. Imaging can often be useful to de...
Cardiac involvement in haemochromatosis typically occurs with primary haemochromatosis, as the organ is usually spared in the secondary form of the disease.
Cardiac involvement occurs in approximately 15-20% of the patients with haemochromatosis.
Pancreatic manifestations of haemochromatosis typically occur with primary haemochromatosis, as the organ is usually spared in the secondary form of the disease.
Iron deposition can occur in the pancreas with primary hemochromatosis. Pancreatic involvement is uncommon in patients wi...
Haemopericardium refers to the presence of blood within the pericardial cavity, i.e. a sanguineous pericardial effusion. If enough blood enters the pericardial cavity, then a potentially fatal cardiac tamponade can occur.
There is a very long list of causes 1,4 but some o...
Haemophilia is an inherited bleeding disorder which is X-linked recessive and therefore occurs almost exclusively in males. There are two subtypes - haemophilia A (80%) and haemophilia B (20%).
The incidence of haemophilia A is around 1 in 5000 male births, and the incidence of h...
Haemophilic arthropathy refers to permanent joint disease occurring in haemophilia sufferers as a long-term consequence of repeated haemarthrosis. Around 50% of patients with haemophilia will develop a severe arthropathy.
Haemophilia is an x-linked recessive disease affecting mal...
Haemophilic pseudotumour is a rare complication of haemophilia consisting of a progressive cystic swelling of muscle and/or bone, occurring in less than 2% of haemophiliacs.
It is reported in 1-2% of haemophiliacs patients.
Most develop in the muscles of the pelvis a...
Haemorrhagic cholecystitis refers to an inflammatory process of the gallbladder, complicated by haemorrhage into the lumen.
The presenting features may mimic non-haemorrhagic acute cholecystitis, with right upper quadrant pain being a dominant feature. If the blood is pa...
Haemorrhagic ovarian cysts (HOCs) usually result from haemorrhage into a corpus luteum or other functional cyst. Radiographic features are variable depending on the age of the haemorrhage. They typically resolve within eight weeks.
Patients may present with sudden-onset ...
Haemorrhagic pancreatitis is a possible uncommon complication that can occur with pancreatitis and is characterised by bleeding within or around the pancreas. It is usually considered a late sequela of acute pancreatitis.
Haemorrhage can occur in patients with severe necrotising panc...
Haemosuccus pancreaticus, also known as pseudohaemobilia or haemoductal pancreatitis, is defined as upper gastrointestinal tract haemorrhage originating from the pancreatic duct into the duodenum via the ampulla of Vater, or major pancreatic papilla.
male:female ratio is 7:1
The Haggitt level is a histopathological term used for describing the degree of infiltration from a malignant polypoidal lesion.
Levels of invasion
0: carcinoma in situ or intramucosal carcinoma
1: invasion of the submucosa, but limited to the head of the polyp
2: invasion extending into the...
Halitosis refers to the symptom of foul oral odour, commonly termed "bad breath", that patients can present with, usually to dental services.
It is thought to be caused by the presence of volatile sulphur compounds that are produced by bacteria. Although the underlying cause can be s...
Hallux rigidus (osteoarthrosis with restricted motion) is the second most common disabling deformity of the first metatarsophalangeal joint after hallux valgus.
It is most commonly seen in middle-aged patients, but can develop during adolescence. Unlike a hallux valgus, males appe...
Hand-Schüller-Christian disease is a clinically intermediate form of a spectrum of histiocytic disorders, which ranges from acute fulminant to chronic indolent disease. It primarily affects children, less often young adults, and rarely older adults.
Hand-Schüller-Christian disease has been desc...
Hashimoto thyroiditis, also known as lymphocytic thyroiditis or chronic autoimmune thyroiditis, is a subtype of autoimmune thyroiditis. It is one of the most common thyroid disorders.
Typically affects middle aged females (30-50 year age group with a F:M ratio of 10-15:1).
Head and neck squamous cell carcinomas (HNSCC) refer to SCCs of the aerodigestive tract of the head and neck rather than cutaneous SCCs. SCC is the most common tumour of the mucosa of the upper aerodigestive tract, and can occur anywhere there is squamous cell mucosa.
Epidemiology, risk factor...
Heberden nodes are a clinical examination sign related to the hands, most commonly found at the dorsolateral aspect of the distal interphalangeal joint (DIPJ) and are a moderate-to-strong marker of osteoarthritis 1-2.
Previously Heberden nodes and DIP osteophytes were thought to be synonymous...
Hemifacial hyperplasia or hemifacial hypertrophy is a rare developmental anomaly characterised by asymmetric growth of hard and soft tissues of the face 1.
These asymmetries are often noted at birth and are usually accentuated with increasing age, especially around puberty 2.
Hemimegalencephaly is a rare congenital disorder of cortical formation with hamartomatous overgrowth all or a part of a cerebral hemisphere. This results from either increased proliferation or decreased apoptosis (or both) of developing neurons 2.
Hemimegalencephaly is a cryptogen...
Hepascore is a biochemical severity scoring system based on liver function tests in predicting the extent of liver fibrosis/cirrhosis in patients with hepatitis C infection. Hepascore may also be applicable to other liver diseases and is being trialed for fatty liver disease and hepatitis B infe...
Hepatic and splenic tuberculosis refers to tuberculosis affecting liver and spleen. It generally occurs due to spread from primary site of infection, commonly from pulmonary tuberculosis.
Two types of lesions are known:
Angiomyolipoma (AML) is an uncommon benign hamartomatous hepatic mass lesion, containing blood vessel (angioid), smooth muscle (myoid) and mature fat (lipoid) components. There is an association with tuberous sclerosis, although this is less strong than for renal AMLs.
Hepatic angiosarcoma is a rare malignancy but is still the third most common primary liver tumour. They have a variable appearance on both CT and MRI reflecting the pleomorphic histological nature. Prognosis is very poor, with survival uncommon beyond one year from diagnosis.
Primary hepatic carcinoid is an extremely rare type of carcinoid tumor, with somewhere between 60-90 cases reported in the literature. Metastatic carcinoid tumor from the gastrointestinal tract to the liver is far more common.
Some patients present with carcinoid syndrome...
Hepatic carcinosarcoma is a very rare tumour that is defined by mixed histological features.
This tumour has also been referred to as malignant mixed tumour, spindle cell carcinoma, pseudosarcoma or sarcomatoid carcinoma 1,2.
Hepatic carcinocarcinoma contain a mixture...
Hepatic encephalopathy (also known as portosystemic encephalopathy) refers to a spectrum of neuropsychiatric abnormalities occurring in patients with liver dysfunction and portal hypertension. It results from exposure of the brain to excessive amounts of ammonia.
Hepatic haemangiomas, also known as hepatic venous malformations, are benign non-neoplastic hypervascular liver lesions. They are frequently diagnosed as an incidental finding on imaging, and most patients are asymptomatic. From a radiologic perspective, it is important to differentiate haemangi...
Hepatic haemosiderosis refers to the deposition of haemosiderin in the liver.
Hepatic iron overload can be in the form of 7
In the absence of genetic haemochromatosis and system...
Hepatic inflammatory pseudotumours (IPT) are rare benign hepatic lesions.
Most common in young adults with males affected more than females 7.
Aetiology is unknown 7.
Hepatic IPT is often seen as a well-circumscribed, encapsulated inflammator...
Hepatic leiomyosarcomas are rare primary malignant tumors derived from smooth muscle cells in the liver.
Hepatic leiomyosarcoma is rare 1. An equal sex distribution and a broad age range (5 months-66Y) has been reported. Some have suggested an associated with AIDS 2.
Hepatic lymphoma is a rather broad term given to any form of hepatic involvement with lymphoma. This can be broadly divided into:
secondary hepatic involvement with lymphoma: most common by far, many tend to be non-Hodgkin lymphoma (NHL) 1
primary hepatic lymphoma: extremely rare
Hepatic mesenchymal hamartoma is an uncommon benign hepatic tumour. Some authors even consider this to be a developmental anomaly rather than a cystic neoplasm 9,12.
It typically occurs in children and neonates, with most cases presenting within the first two years of life 3. Ther...
Hepatic solitary fibrous tumours (hepatic SFTs) are rare mesenchymal tumours.
Fewer than 60 cases have been reported in the literature. Female predominance (~70%). There is a mean age of 52 years at presentation, but a wide range of incidence (16-84 years).
Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is a condition arising from occlusion of hepatic venules.
right upper quadrant pain
abnormal liver function tests
Toxic injury to liver s...
Hepatisation of the gallbladder is a sonographic entity in which the gallbladder lumen is entirely filled with tumefactive sludge giving the gallbladder a similar appearance to liver parenchyma. It is one of the causes of non-visualisation of the gallbladder on sonography.
In the set...
Hepatoblastoma is the most common primary malignant liver tumour in children under four years of age who usually present with painless abdominal mass and raised AFP. It is tumour of embryonic origin.
Most cases are seen during the first 18 months of life and diagnosis in adulthood...
Although hepatoblastomas can be histologically classified into a variety of sub types, it is important to remember that with the possible exception of small cell undifferentiated sub type, prognosis is independent of histology when adjusted for stage gender and age 1.
Hereditary breast and ovarian cancer (HBOC) syndrome is caused by mutation to either BRCA1 or BRCA2 genes. These patients have an increased risk of breast cancer, ovarian cancer, pancreatic cancer and prostate cancer. However, these gene mutations are not the only cause of hereditary breast canc...
Hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterised by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system.
Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an inherited condition which predisposes to a host of malignancies, including colorectal carcinoma. It is considered the most frequent form of hereditary colorectal cancer. Diagnosis requires evaluation using cl...
Hereditary pancreatitis is a rare subtype of chronic pancreatitis that has an autosomal dominant inheritance. As a congenital condition, presentation with acute pancreatitis attacks typically occurs in childhood, and features of chronic pancreatitis with parenchymal and ductal calcifications and...
Heroin induced pulmonary oedema is an aetiological subtype of non cardiogenic pulmonary oedema. It may be prevalent in up to 40% of patients admitted with a heroin overdose 2.
It is defined by some authors as a syndrome in which a patient develops significant hypoxia (room air saturation< 90% w...
Herpes oesophagitis is one of the infectious oesophagitis that usually affects immunocompromised patients.
It occurs as an opportunistic infection in immunocompromised patients, particularly those with AIDS. It has also been described in immunocompetent individuals 3.
Hibernomas are rare benign fatty tumours that arise from the vestiges of fetal brown fat and are named “hibernoma” because of their resemblance to the brown fat in hibernating animals 1.
Hibernomas usually occur between the ages of 20 and 40 and have a slightly increased incidence...
Hidradenitis suppurativa is an inflammatory skin disease of unknown cause. It has an autosomal dominant inheritance pattern, and androgen excess have been postulated. The disease is associated with Crohn disease and Dowling Degos disease.
Up to 4% of the general population are af...
High-grade appendiceal mucinous neoplasms (HAMN) are rare mucinous tumours of the appendix showing high-grade cytologic atypia, c.f. low-grade appendiceal mucinous neoplasms (LAMN). The distinction between both LAMN and HAMN is done on a histologic ground and those tumours basically look the sam...
Hirschsprung disease is the most common cause of neonatal colonic obstruction (15-20%). It is commonly characterised by a short segment of colonic aganglionosis affecting term neonates, especially boys.
Hirschsprung disease affects approximately 1:5000-8000 live births. In short ...
Histological stains are chemicals dyes used to treat histological specimens to make tissues more readily visible by light microscopy and demonstrate underlying characteristics of the tissue. There are many stains, some with very specific uses, whereas other (e.g. hematoxylin and eosin stain (H&E...
Acquired immunodeficiency syndrome (AIDS) is an immunosuppressed state, caused by infection with the human immunodeficiency virus (HIV). It is characterised by opportunistic infections, neoplasms and neurological manifestations.
According to the United Nations programme on HIV/AID...
HIV-associated nephropathy (HIVAN) is commonly seen in patients with HIV/AIDS and leads to end stage renal disease (ESRD). The diagnosis is not imaging-based and must be confirmed by renal biopsy.
HIVAN is seen in patients at advanced stages of HIV and AIDS, but it can also be see...
HIV oesophagitis is a possible cause of odynophagia in immunosuppressed patients with HIV.
The actual incidence and prevalence of Idiopathic oesophagitis of HIV are unknown. Most of the patients have acquired immunodeficiency syndrome (AIDS) and CD4 count <100 3.
HNF 1 alpha mutated hepatic adenomas are a genetic and pathologic subtype of hepatic adenoma. Their appearance and prognosis is different than other subtypes.
They are the second most common (30-35%) hepatic adenoma, after the inflammatory subtype. They occur only in female patien...
Hodgkin lymphoma or Hodgkin disease (HD) is a type of lymphoma and accounts for ~1% of all cancers. HD spreads contiguously and predictably along lymphatic pathways and is curable in ~90% of cases, depending on its stage and sub-type.
There is a bimodal distribution in the age of ...
Pulmonary manifestations of Hodgkin lymphoma are relatively rare, present in 5-12% of patients at the time of diagnosis. It is relatively more common with the nodular sclerosing subtype. Pulmonary involvement usually indicates stage IV disease.
Bilateral involvement is ...
Homer Wright rosettes are differentiated tumour cells grouped around a central region containing neuropil (therefore its association with tumors of neuronal origin).
Examples of tumours where these can be seen include:
medulloblastoma (the presence of Homer Wright rosettes in a post...
An horseshoe adrenal gland is very rare anomaly. It is also sometimes called a butterfly adrenal gland, fused adrenal gland or midline adrenal gland.
It is the solitary adrenal gland that is present in the midline with the fused portion either passing between the aorta and the inferior vena cav...
Horseshoe lung is one of the rare congenital anomalies of the lung. A band of pulmonary parenchyma is formed extending between the right and left lungs. The pulmonary tissue can be seen either anterior to the aorta or posterior to the pericardium at the caudal end.
An hourglass biceps tendon refers to severe enlargement of the intra-articular portion of the biceps tendon which can entrap inside joint during flexion and become symptomatic. It can be associated with accumulation of fluid in tendon sheath within the bicipital groove.
Human epididymis protein 4 (HE4) is an emerging serum biomarker in the assessment of epithelial ovarian tumours. HE4 is a member of the whey associated protein (WAP) gene cluster and has uncertain biological function 1.
Early results indicate that HE4 has higher sensitivity and sensitivity than...
Human herpesvirus 6 (HHV-6) encephalitis is a rare CNS infection due the virus reactivation in immunosuppressed patients, especially in those following a hematopoietic cell transplant who develop a characteristic limbic encephalitis syndrome with MRI signal intensity abnormalities of the mesial ...
Hutch diverticula are congenital bladder diverticula, seen at the vesicoureteric junction, in the absence of posterior urethral valves or neurogenic bladder. They are though to result from a weakness in the detrusor muscle anterolateral to the ureteral orifice.
The occur almost e...
Hydatidiform moles are one of the most common but benign forms of gestational trophoblastic disease.
It is a common complication of gestation, estimated to occur in one of every 1,000-2,000 pregnancies 3. These moles can occur in a pregnant woman of any age, but the rate of occur...
Hydrocephalus ex vacuo, also known as compensatory enlargement of the CSF spaces, is a term used to describe the increase in the volume of CSF, characterised on images as an enlargement of cerebral ventricles and subarachnoid spaces, caused by encephalic volume loss.
It can be clas...
Hydroceles are acquired or congenital serous fluid collection between the layers of the tunica vaginalis surrounding a testis or spermatic cord. They are the most common form of testicular enlargement, and present with painless enlargement of the scrotum. On all modalities, hydrocoeles appear as...