Malignant Fibrous Histiocytoma Occurring in the Digit

Corresponding author: Yu-Ling Hsu, Department of Dermatology, Far Eastern Memorial Hospital, No. 21, Sec. 2, Nan-Ya S. Rd., Pan-Chiao, Taipei 220, Taiwan TEL: 886-2-89667000 ext. 4286 FAX: 886-2-89665567 E-mail: [email protected] Funding source: none Confl ict of interest: none declared CASE REPORT A 65-year-old Taiwanese female initially presented an 1-year history of experiencing an asymptomatic dark reddish subungual mass on the left thumb (Fig. 1A). The patient’s medical history included diabetes mellitus, hypertension, coronary arterial disease, and a right hemiparesis resulting from an intracerebral hemorrhage ten years prior. No history of trauma, irradiation, or chemical exposure to her hands was disclosed. A skin biopsy from the periphery of the lesion was performed and histopathologic examination revealed multinucleated giant cells and mononuclear inflammatory cells dispersed in the dermis (Fig. 1B, C). A diagnosis of giant cell tumor of tendon sheath was made to the patient. The patient preferred to preserve the function of the left thumb and undergo a conservative course of treatment so the tumor was removed by treatment with a carbon dioxide laser. At that point the patient discontinued further follow-up. Three years later, this patient presented to our clinic with a singular, painful and gradually enlarging, ill-defi ned, pink-colored nodule at the same site on her left thumb (Fig. 2). Computed tomography (CT) detected a heterogeneous, well-enhancing soft tissue mass occupying the distal phalanx of the left thumb, along with osteolytic destruction of the distal phalanx bone. Histopathologic examination of a biopsy taken from the tumor revealed spindle cells forming a storiform pattern and focal areas composed of multinucleated giant cells. These tumor cells were immunoreactive to vimentin, but not S-100, cytokeratin, desmin, CD31, or CD34 (Fig. 3). The patient was subsequently diagnosed with malignant fi brous histiocytoma (MFH) of the storiform-pleomorphic type. For the purpose of curative treatment, amputation of the left thumb and partial resection of the proximal phalanx salvage was performed. The patient refused any additional survey for metastasis and discontinued follow-up after surgery.