Immunohistochemical Approach to the Study of Pulmonary Neuroendocrine Tumors

  Background: Tumors that arise from neuroendocrine cells can present throughout the body, most commonly in the gastrointestinal tract and pulmonary systems. Neuroendocrine tumors (NETs) of the lungs account for about 25% of primary lung cancers, as well as 20–25% of primary NETs Objective: To analyze the immune-histochemical aspects of Neuro-endocrine Tumors and apprise the reactivity of various immune-histochemical markers. Methodology: This cross-sectional study was conducted in Pathology Department of Gulab Devi Hospital Lahore from January 2021 to December 2021. Total 112 patients with pulmonary NETs cases diagnosed with medical records patients data, clinical features and radiologic images were obtained and both genders with CT scan findings of lung mass were included in the study. Data was entered and analyzed in SPSS. Gender, diagnosis, techniques etc. were presented as frequency and percentage. Age was presented as mean and SD. Results: The mean age was 45.2+12.1 years. The age range between 20 to 60 years. There were 96(86%) male and 16(14%) female. Typical carcinoid was prevailing in young age group while small cell neuro-endocrine tumor was dominant in older patients.  Most of the samples were collected using bronchial biopsy 86(77%), 18(16%) of the samples were collected by CT guided biopsy while 7(6%) were collected by ultrasound guided biopsy and 1(1%) by surgical resection. Patients were diagnosed as small cell lung carcinoma 96(86%), typical carcinoid was the second most common diagnosis 10(9%), large cell lung carcinoma was 4(3.0%) and atypical carcinoid tumor was seen in 2(2%) in cases. Conclusion: SCLC was found to be the predominant pulmonary NET. Chromogranin is less sensitive than synaptophysin, raised Ki67 and TTF1 demarcates SCLC from carcinoid particularly in minute biopsy with obscure morphology. Key words   Immunohistochemistry, Neuroendocrine carcinoma, Small cell lung carcinoma.