ATYPICAL CARCINOID-TUMOR OF THE LARYNX - AN IMMUNOHISTOCHEMICAL, ULTRASTRUCTURAL, AND FLOW CYTOMETRIC ANALYSIS

The clinicopathologic features, including a detailed immunohistochemic al, ultrastructural, and flow cytometric analysis, are described in th ree cases of atypical carcinoid tumor of the larynx. All patients had metastatic disease within cervical lymph nodes at presentation and eve ntually developed distant metastases. Special stains revealed focal in tracytoplasmic mucin accumulation, and immunohistochemistry showed the tumors to be positive for CAM 5.2, CEA, chromogranin A, and calcitoni n. In two cases, double-staining techniques revealed occasional cells that stained for both mucin and chromogranin A. The histochemical and immunohistochemical findings in these two cases were confirmed at the ultrastructural level, with most tumor cells containing many neurosecr etory granules. Smaller numbers of cells contained mucin vacuoles and, in occasional cells, both mucin and neuroendocrine granules were iden tified. The three tumors exhibited positive staining with D07 (anti-p5 3), and flow cytometric analysis revealed DNA aneuploidy and polyploid y. The double-staining and ultrastructural features indicate that lary ngeal atypical carcinoid qualifies for the designation of true amphicr ine carcinoma. Further study is necessary to determine whether mutatio n of the p53 gene is important in the evolution of laryngeal neuroendo crine tumors and whether DNA aneuploidy or polyploidy identifies a sub set of these tumors with a poor prognosis.