Unusual Presentation of Merkel Cell Carcinoma

Abstract

A 78-year-old otherwise healthy Caucasian male presented to our ENT clinic with a 4-week history of intermittent odyno– dysphagia and globus pharyngeus. The patient denied tobacco and alcohol consumption. He presented a noticeable hot potato voice. His physical examination revealed a left palpable 1.5 cm level IIa lymphadenopathy, and his flexible laryngoscopy showed a brown polypoid pedunculated mass in the left pyriform sinus. The patient also mentioned a bump on his right posterior thigh that had been present for 2 years without any change in size, causing him major discomfort when sitting. It was a 6 4 cm, nonsuspicious-looking, subcutaneous, domeshaped purple lesion. A contrast-enhanced computed tomography (CT) of the neck showed a well-circumscribed 1.5 0.8 cm left pyriform sinus mass in addition to an ipsilateral 1.6 cm level IIa necrotic lymphadenopathy (Figure 1). A rigid laryngoscopy was performed under general anesthesia and allowed excisional biopsy of a 2.3 1.6 0.8 cm brown-colored, pedunculated lesion of the medial wall of the left pyriform sinus (Figure 2). A concomitant complete excision of the right posterior thigh lesion was also performed (Figure 3). Both surgical specimens were sent for routine pathology. Histological examination of the thigh mass showed a blue round cell tumor arranged in sheets. The cells exhibited scant cytoplasm and round vesicular nuclei with granular chromatin. Mitotic figures were numerous. Immunohistochemistry stains showed a dot-like positivity with pan-cytokeratin (AE1/AE3) and CK20. The tumor cells were positive for neuroendocrine markers (synaptophysin and chromogranin A) in a diffuse, granular cytoplasmic pattern. Histological examination of the pyriform sinus mass revealed a largely necrotic round cell tumor that stained positive for pan-cytokeratin (AE1/AE3), CK20, and neuroendocrine markers. Both lesions were consistent with Merkel cell carcinoma (MCC), and the hypopharyngeal location was considered a metastasis of the primary cutaneous carcinoma. The patient underwent a full metastatic workup consisting of a brain magnetic resonance imaging and a positron emission tomography CT scan, which did not reveal any additional suspicious lesion. He was diagnosed with metastatic MCC and was referred to the oncology department where he was offered a VP16-Cisplatin-based chemotherapy regimen. The patient was then lost to follow-up. Merkel cell carcinoma is an uncommon, highly aggressive, primary cutaneous neuroendocrine tumor originating from the epidermal neurocutaneous mechanoreceptors called Merkel cells. Toker was the first to describe this skin neoplasm in 1972. It commonly affects sun-exposed areas in the elderly and immunosuppressed individuals, and it presents as a red violet cutaneous tumor nodule that is typically dome-shaped or plaquelike. During the last 2 decades, the worldwide incidence of MCC has been increasing steadily due to the increasing age of