Cytologic diagnosis of neuroendocrine neoplasms including carcinoid tumours- A retrospective study

Abstract

The classification of neuroendocrine neoplasms has evolved substantially over time but remains a topic of controversy and debate. Cytology has become one of the mainstays of diagnosis for these tumors, and the treatment may be entirely based on the FNA report.: This is a retrospective study which aims to describe the cytological features found in different groups of Neuroendocrine neoplasms. We have also tried to enumerate the not so typical features which we have seen in our cases. Cases of Neuroendocrine neoplasms diagnosed by cytology in the year 2018 were included in this study. The slides of these cases were retrieved, cytological features reviewed, and clinicopathological features evaluated. Histopathological correlation was done wherever possible. In this retrospective study, there were 43 cases which included FNA (n=38), Fluid cytology(n=3), Bronchial washings and Brushings(n=2). FNA sites included lung, cervical lymph nodes, scalp, liver, pancreas, and mesentery with the cytological diagnoses of Small cell carcinoma (n=22) Neuroendocrine tumor (n=7), Large cell Neuroendocrine carcinoma (n=3) and Poorly differentiated carcinoma with neuroendocrine features (n=11). Features that are of help include scanty cytoplasm, fine or coarse granular chromatin, nuclear moulding and streaking, cells adhering to vessels, inconspicuous nucleoli, nuclear debris in small cell carcinomas; larger cell size, a moderate amount of cytoplasm, coarse granular chromatin in large cell neuroendocrine carcinomas; uniformity of cell size, round to plasmacytoid cells with stippled chromatin and rosette formation in carcinoid tumors. The identification of neuroendocrine morphology in cytology specimens is crucial as this would be the initial step towards using the appropriate markers for confirmation, which in turn has got therapeutic and prognostic significance.