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Neuroendocrine carcinomas represent an important group of primary neoplasms in the lung. During the last decades, the nomenclature of these tumors has evolved and the current use of immunohistochemical and molecular biology studies have, to some extent, expanded the conventional view of these tumors. However, the primary diagnosis of most of these lesions is performed on limited biopsy specimens, which may not translate well when one is confronted with a nomenclature that is based on resected material. In addition, for some of these specific entities, some confusion and controversy apparently remain, allowing for the proliferations of different terms that, although they may be dismissed as "semantics," may have a role in interpretation, further subclassification, and, possibly, treatment. Herein we review current concepts regarding the classification of these neoplasms and the role of this classification in our daily practice and discuss how it may impact treatment. [ABSTRACT FROM AUTHOR]

High-resolution melting amplicon analysis (HRMAA) was used to detect c-kit and platelet-derived growth factor receptor α (PDGFRA) activating mutations in 96 gastrointestinal stromal tumors (GISTs). HRMAA detected mutations in 87 GISTs (91%). Of the 87 cases, 69 (79%) contained c-kit mutations and 18 (21%), PDGFRA mutations. One c-kit mutation-positive case contained an exon 9 mutation, ins FY at codon 503, that has not been previously described. One PDGFRA mutation-positive case contained mutation D842V del 843, also not previously described. Of 18 PDGFRA mutation-positive cases, 3 (17%) were strongly positive for kit expression as measured by CD117 immunohistochemical analysis. Of 69 c-kit mutation-positive cases, 66 (96%) showed strong kit immunohistochemical expression, but 3 (4%) showed negative to weak CD117 expression. Of 96 cases, 9 (9%) were wild type for c-kit and PDGFRA. Of the wild-type cases, 8 still showed strong immunohistochemical kit expression, whereas 1 showed weak kit expression.GISTs with PDGFRA mutations were found in the stomach, omentum, and peritoneum but not the small intestine. GISTs with c-kit exon 9 mutations were found primarily in the small intestine.HRMAA is a sensitive technique that can be used to rapidly identify c-kit and PDGFRA activating mutations in GISTs. [ABSTRACT FROM AUTHOR]