Epidermotropic Pagetoid Spread and Squamous Cell Carcinoma in Situ in the Overlying Epidermis of Merkel Cell Carcinoma

Sir, A 71-year-old female visited the Department of Dermatology at Tokyo Metropolitan Bokuto Hospital, complaining of a nodule in the face. She was diagnosed as Merkel cell carcinoma by a skin biopsy in another clinic, and referred to our hospital for operation. A physical examination revealed a dome-shaped reddish nodule, sized 1-cm in diameter, in the center of the left cheek. Cervical lymph nodes were not palpable. The nodule was totally removed with a margin. Histological examination revealed the tumor nests extending from the dermoepidermal junction into the deep dermis. The tumor cells had uniform small round or spindle-shape cells with hyperchromatic nuclei and numerous mitoses, which were consistent with Merkel cell carcinoma (Fig. 1, 2). Tumor cells were immunoreactive for neuron-specific enolase (NSE). Also, tumor nests were scattered within the overlying epidermis (Fig. 3). In addition, bowenoid changes were recognized within the overlying epidermis or at the border of MCC, showing many atypical disarrayed cells and clusters of large hyperchromatic nuclei (Fig. 4). EPIDERMOTROPIC PAGETOID SPREAD AND SQUAMOUS CELL CARCINOMA IN SITU IN THE OVERLYING EPIDERMIS OF MERKEL CELL CARCINOMA