Pulmonary neuroendocrine tumors: An entity in search of cytologic criteria
ABSTRACT Pulmonary neuroendocrine tumors (PNET) are histologically subclassified into typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell carcinoma (SCLC). The criteria for subclassification in cytological specimens are not well defined. In this study, we reviewed histologically confirmed 18 TC, 8 AC, 10 LCNEC, and 10 SCLC cytologic specimens from 45 patients. The following features were reviewed: small clusters, geographic sheets, trabecular structures, pseudo-rosettes, single cells, doublets, triplets or short cords, papillary-like structures, capillary vasculatures, necrosis, smear background, cell size, cell pleomorphism, amount of cytoplasm, plasmacytoid cells, spindle cells, nuclear atypia, molding, palisading and smearing, chromatin textures, nucleoli, and mitotic figure count. Based on our results, geographic clusters and necrosis were often seen in LCNEC and SCLC; while AC only showed scattered single cell necrosis. TC and AC commonly exhibited trabecular structures. Papillary-like structures and capillary vasculature were only present in TC, AC, and LCNEC. Cells forming doublets, triplets, and short cords were more commonly seen in SCLC and rarely seen in other entities. Plasmacytoid and spindle cells were only seen in TC and AC. Nuclear smearing was not identified in TC, rare in AC, focally present in LCNEC and obvious in SCLC. Mitotic figures were nearly absent in TC, ≤5/10 HPF in AT, and ≥10/10 HPF in SCLC. LCNEC showed a wide span of mitotic count ranging between 2 and 16/10 HPF. In this study, we propose a set of cytological features that are essential for subclassification of PNETs in cytologic specimens. Diagn. Cytopathol. 2012;. © 2012 Wiley Periodicals, Inc.
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Article: High-grade neuroendocrine carcinoma.[Show abstract] [Hide abstract]
ABSTRACT: This review presents an update on classification, diagnosis and potentially 'drugable' molecular alterations of small cell carcinoma (SCC) and large cell neuroendocrine carcinoma (LCNEC) of the lung. The main controversies in the classification of lung neuroendocrine tumors are: whether SCC and LCNEC should remain separated or should be unified into a high-grade category; and what the role is of Ki67 as an adjunct to the classical parameters (mitotic rate and necrosis). Regarding the diagnosis of SCC and LCNEC, in difficult cases it requires the combined evaluation of clinical-radiological data, histological and cytological material and selected immunostains. The prognosis of both tumors remains very poor. Despite the promising identification of potential molecular targets on preclinical studies, including antiangiogenetic drugs and tricyclic antidepressants, at the moment no specific molecular-driven therapy is available. The field of high-grade neuroendocrine carcinomas remains complex in several respects, and studies on molecular targets are urgently needed.Current opinion in pulmonary medicine 05/2014; DOI:10.1097/MCP.0000000000000061