Minute foci of atypical bronchiolar epithelial hyperplasia that are found multifocally; although now considered benign, they were once believed to be precursors of carcinoma.
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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].
Some sources describe linear proliferations of pulmonary NE cells with tumorlets, visible in the peripheral parts of the lung on high resolution CT scans [9, 12, 13].
Moreover, limited, small-size tumors, known as tumorlets, are considered benign preneoplastic neuroendocrine cell proliferations.
We studied 109 neuroendocrine cell neoplasms from surgical specimens, 10 tumorlets found incidentally in lung tissue resected for other reasons, and 4 normal lung samples selected from the surgical pathology archives of the Hospital Universitario Marques de Valdecilla (Santander, Spain).
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.
As they progress to carcinoid tumorlets and tumors they appear as small, well-demarcated, gray-white nodules resembling "miliary bodies.
2] Granular cell tumors (GCTs) presumably arise from enlargement of tumorlets.
These include epithelioid leiomyoma, low-grade endometrial stromal sarcoma with sex-cord elements, endometrioid carcinoma with sex-cordlike features, plexiform tumorlet, vascular plexiform leiomyoma, and metastatic ovarian sex-cord stromal tumors.