Carcinoid tumorlet/typical carcinoid of the lung: An incidental bronchoscopic finding and cytological dilemma

Abstract

Carcinoid tumors of the lung are low-grade neuroendocrine tumors with the potential to progress to high-grade tumors. Diagnosing a typical carcinoid of the lung/tumorlet is a tough nut to crack, especially in their early stages when there is no well-defined lesion in the imaging. Besides, differentiating a carcinoid from low-grade adenocarcinomas of the lung cytologically is quite challenging due to their similar morphology. We report a case of typical carcinoid of lung/tumorlet in a 42-year-old male who presented with hemoptysis. Flexible fibreoptic bronchoscopy revealed a bump in the right middle bronchus. Bronchial biopsy showed a cellular smear with a monotonous round to oval bland-looking cells distributed in singles and in acini, having a high nuclear-cytoplasmic ratio, scant cytoplasm, regular round nuclei, and inconspicuous nucleoli. No atypical mitotic figures or necrosis were seen. With these features, a cytological diagnosis of a typical carcinoid was made. Biopsy was not attempted again due to the small size of the lesion and inaccessibility. Serum chromogranin levels were elevated, confirming the diagnosis. The PET scan was unremarkable. The patient was referred to medical oncology for further management. This report will create awareness about diagnosing early carcinoid/tumorlet, especially with the increasing use of bronchoscopy and cytological diagnostic caution of overdiagnosis of malignancy.