Malignant Nodular Hidradenoma of the Fingertip: A Case Report

Malignant nodular hidradenoma (MNH) is an infrequent, highly malignant tumor derived from eccrine sweat glands. MNH usually occurs on the scalp, trunk, and proximal extremities, and rarely on the hand. A 55-year-old male patient visited clinics with a gradually enlarging painless mass at fingertip. It begins a year ago. Recently, it has grown rapidly and starts ulceration, and bleeding over the past 3 weeks. According to the biopsy report, it has focal necrosis, atypia, atypical mitoses, and nuclear pleomorphism suggested that the mass was MNH. After histological diagnosis, tiny bone erosion was observed in the re-read radiographic finding. For the oncologic evaluation, the patient was transferred to the cancer center. Radical amputation was performed to the residual tumor that might remain based on re-reading of radiographs. MNH of the finger is especially difficult to the diagnosis given its rarity and variable histology. When ulcerative skin lesion and radiographic bone erosion are observed, one should suspect malignancy and makes out a proper therapeutic plan after histologic biopsy.