Minute foci of atypical bronchiolar epithelial hyperplasia that are found multifocally; although now considered benign, they were once believed to be precursors of carcinoma.
Farlex Partner Medical Dictionary © Farlex 2012
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One reported case occurred in a background of necrotizing bronchiolitis and acute and organizing pneumonia with neuroendocrine cell hyperplasia and multiple tumorlets. (4)
Minute gastric sclerosing stromal tumors (GIST tumorlets) are common in adults and frequently show c-KIT mutations.
Both underwent lung transplantation and explanted lung showed similar histology of NSIP, PNEC hyperplasia, and carcinoid tumorlets.
In the mechanistic model, a tumor was assumed to be comprised of many small tumorlets of a PET-voxel-comparable size (4 x 4 x 4 [mm.sup.3]).
According to WHO classification of lung tumors, DIPNECH is a separate lesion regarded to as a preneoplastic condition for tumorlets, and typical/atypical carcinoids, but only those located peripherally [1].
"Cushing's syndrome caused by corticotropin secretions by pulmonary tumorlets".
Though others had noted these small lesions (tumorlets) in the bowel wall, Obern-dorfer noted from his autopsy work that they were often multiple, had less gland formation than adenocarcinomas, and initially appeared to be harmless (reviewed in Kloppel et al (1)).
Moreover, limited, small-size tumors, known as tumorlets, are considered benign preneoplastic neuroendocrine cell proliferations.
Provided they are not present at the margins, the presence of other neoplastic processes (eg, tumorlets, minute meningothelial nodules, neuroendocrine hyperplasia, atypical adenomatous hyperplasia, squamous dysplasia) does not impact tumor staging.
(94) These lesions have been variably designated as sporadic Cajal cell hyperplasia, microscopic GISTs, GIST tumorlets, or "seedling" GISTs.
Carcinoid tumorlets are distinguished from NE hyperplasia by extension beyond the basement membrane of the respiratory epithelia.
Potential Etiologies of Constrictive Bronchiolitis (a) Post lung transplantation Post bone marrow transplantation Healed infection, especially adenovirus infection Drug reactions Healed injury from exposure to fumes and toxins Collagen vascular disease, especially rheumatoid arthritis As a component or complication of: Bronchiectasis Cellular bronchiolitis Asthma Chronic bronchitis Cystic fibrosis DIPNECH or carcinoid tumorlets Inflammatory bowel disease-associated small airways disease Idiopathic Abbreviation: DIPNECH, diffuse idiopathic neuroendocrine cell hyperplasia.