A case report of carotid body tumor.

A case of left carotid body tumor is presented. A 47-year-old female patient consulted our otorhinolaryngological clinic with a neck swelling that had persisted for 5 months. On physical examination, a movable and pulsating hard mass measuring 2 x 2.5 cm in size was found on the left side of her neck, near the angle of the mandible. Computed tomography, magnetic resonance image and angiography all demonstrated a well-circumscribed tumor mass showing high vascularity and located at the bifurcation of the left carotid artery. The tumor involved the left carotid artery, but the patency of the artery was preserved. The patient showed satisfactory temporary balloon occlusion test results without neurological complications. Since the tumor was strongly adherent to the carotid arterial wall, the tumor was resected together with the carotid artery. Histologically, the tumor was composed of organoid clusters of round cells with eosinophilic granular cytoplasm. Involvement of tumor cells was seen to the adventitia of the carotid artery, but only slight cellular atypia was seen. Ultrastructurally, two types of cells were observed in the central and marginal portion of the tumor; these were round chief cells with few cytoplasmic neurosecretory granules and spindle-shaped sustentacular cells. Immunohistochemically, the chief cells and sustentacular cells showed positive reaction for neuron-specific enolase and S-100, respectively. The ultrastructural findings suggested the benign nature of the tumor.