A Case of Merkel Cell Carcinoma on the Left Cheek of an Elderly Woman with Dementia

Abstract

A 77-year-old woman was referred to our department for a growing nodule on her left cheek, which had appeared three months earlier. At the first visit, an 11 mm pale red nodule with smooth surface and telangiectasia was observed on the left cheek. Skin biopsy revealed dense proliferation of small, basophilic tumor cells in the dermis. Immunostaining was positive for CK20, chromogranin A, and Merkel cell polyomavirus, and negative for TTF-1, leading to a diagnosis of Merkel cell carcinoma. No obvious metastases were found in the whole-body search. Due to her advanced age and dementia, neither sentinel lymph node biopsy nor enlarged resection could be performed. Resection was performed with a margin of 5 mm, and postoperative radiation therapy was administered around the primary lesion and in the left cervical lymph node area. No metastasis or recurrence has been observed three years after the surgery. As the prognosis of Merkel cell carcinoma is generally poor, extended resection and sentinel lymph node biopsy are recommended. However, because of its high radiosensitivity, postoperative radiation therapy may reduce the risk of recurrence even in cases where sufficient margins are not available, as in this case. Skin Research, 24: 61-65, 2025