Clear Cell Acanthoma Occurring in a Split-Thickness Skin Graft

EPORTA 38-year-old man visited our hospital due to a persistenterythematous plaque developing in the split-thickness skingraft recipient site of his leg for 12 years (Fig. 1). He hadreceived a split-thickness skin graft operation on his right leg18yearsearliertotreatachroniculcercausedbyosteomyelitisof the tibia. About 6 years after the operation, an erythem-atous, exuding, plaque coated with crusts developed in thegraft. Mild itching also was noted. The lesion encompassedthe substantial area of the graft. It had been treated withtopical corticosteroids under the impression of chronic der-matitis. Because no obvious improvement was achieved after6 months of treatment, a skin biopsy was performed. Thespecimens showed focal parakeratosis, marked acanthoticepidermis with elongated intervening rete ridges, slightly en-larged clear epidermal cells, and neutrophilic exocytosis.There were dilated vessels, infiltration of inflammatory cells,and fibrosis in dermis (Fig. 2). The slightly enlarged clearepidermal cells were positively stained for periodic acid-Schiff, which was removed after diastase digestion (Fig. 3),showing that they contained rich glycogen. A diagnosis ofclear cell acanthoma was made based on these characteristichistopathologicfindings.Thepatientwassubsequentlylosttofollow-up.