Incidental Cytodiagnosis of Carotid Body Tumour on Fine Needle Aspiration Cytology.

A carotid body tumor is a rare form of neoplasm that arises near the carotid artery bifurcation and it has an incidence rate of less than 0.3 per 100,000 population. The low incidence rate of such tumors is due to their origination from the paraganglion cells which is relatively uncommon as compared to other forms of tumor. Here we present an incidental and unusual cytodiagnosis of carotid body tumors. A 45-year-old male presented to the surgery outpatient department with swelling in the left-sided anterior region of the neck. The swelling was gradually progressing over three years and was insidious. Clinically the swelling was 3 cm x 3 cm in size and the patient complained of pain in the last two months which was intermittent. The patient was sent to the cytopathology section for fine needle aspiration cytology with the clinical diagnosis of tubercular lymphadenopathy. The patient underwent fine needle aspiration cytology by 26 SW needle by standard institutional protocols. The cytodiagnosis of "Paraganglioma/ Carotid Body Tumour" was offered. Histomorphological features at excision were consistent with carotid body tumors (paraganglioma). The sections of the tumor immunohistochemically were positive for neuron-specific enolase. The incidental cytodiagnosis of carotid body tumors is reported in the literature sparsely. This case is presented for the cytomorphology of carotid body tumor which is unfamiliar to the reporting pathologist because of its rare occurrence.