The biopsy specimen from the hand showed a superficial and deep, perivascular and periadnexal infiltrate of mononuclear cells and focal dermal fibrosis. Many of the mononuclear cells displayed large nucleoli with cerebriform contours. Immunohistochemical stains showed that most of the cells expressed CD3, with a predominance of CD4 over CD8 cells. These findings supported the diagnosis of MF. Based on the number of large cells (more than 25% of the infiltrate), the patient was considered to have large-cell transformation.