IMT was regarded as a<unk>  that occurs in children or young adults and presented in the lung, mesentery, greater omentum or, less commonly, heart, liver, spleen, pancreas, colon, small intestine, spermatic cord, prostate, uterus, eye orbit, peripheral or central nervous system nerves, brain meninges, spinal cord, or other sites. However, a more recent retrospective study of 92 patients accumulated by the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute found the mean age of disease onset was 47.4 years with peak occurrences at 0 to 4, 36 to 40, and >50 years old; middle-aged individuals (41 to 64 years) represented 1/3 of all cases. In this study, the commonest sites of<unk>  occurrence were the lower limb and hip (22% of cases), upper limb and shoulder (12% of cases), and head, face, and neck (9% of cases). Another recent study of 25 patients found the commonest sites of IMT were the abdomen (40% of cases) and lung/thoracic wall (32% of cases). Individual IMT cases are also reported to present in the urinary bladder, anal canal, and parameningeal spaces (i.e. sites adjacent to the meninges such as the nasopharynx, middle ear, paranasal sinuses, infratemporal fossa and pterygopalatine fossa). Apparently, the age and organ/tissue distribution of IMT various with the patient population examined: in general it can present in individuals of almost any age and in almost any organ or tissue site. IMT most commonly presents as a<unk>  localized to a single site but may be associated with distal metastases in up to 5% of all cases or up to 10% of cases in which the<unk>  cells express an ALK fusion protein. The<unk> s range in size from 1–25 cm (average 6.5 cm) with two-thirds being 1.5–6.5 cm. In rare cases, the<unk> s have spontaneously regressed. Individuals with IMT present with a wide range of symptoms (e.g. pain, swelling, a mass, organ dysfunction, etc.) depending on the<unk>  location(s). Up to 1/3 of these individuals have symptoms of systemic inflammation such as fever, chills, night sweats, and weight loss. Rare cases of IMT have developed in individuals with: a) organizing pneumonia; b) infection by Mycobacterium avium intracellulare or Corynebacterium equi (pneumonia-causing bacteria); Campylobacter jejuni (causes gastroenteritis); Lysinibacillus sphaericus (previously termed Bacillus sphaericus, a rare cause of lung infections and sepsis); Coxiella burneti (causes Q fever); Epstein–Barr virus (causes infectious mononucleosis and Epstein–Barr virus-associated lymphoproliferative malignant diseases); and E. coli-related occlusive phlebitis of intrahepatic veins; or c) previous abdominal surgery; trauma; ventriculoperitoneal shunt in the brain; radiation therapy; and corticosteroid usage. The relationship (i.e. cause or merely association) of these disease relationships to IMT is unknown.
Inflammatory myofibroblastic tumour
Reticulohistiocytoma
Plexiform angiomyxoid myofibroblastic tumor
Giant-cell reticulohistiocytoma
Adenomatoid tumor
Angiomatoid fibrous histiocytoma
Multinucleate cell angiohistiocytoma
Epithelioid sarcoma