Track

Case Reports

Abstract

Atypical fibroxanthoma (AFX) with osteoclast-like giant cells is exceptionally rare, with 18 cases reported in the literature. Herein, we present a case of AFX with osteoclast-like giant cells, adding to the spectrum of histopathologic presentations of AFX. A 93-year-old male presented with an enlarging 1.4 cm exophytic crateriform pink nodule with central keratinaceous debris on the left tragus. Tangential skin biopsy was performed. Sections demonstrated a polypoid, dermal-based tumor composed of sheets of atypical oval and spindled mononuclear cells with hyperchromasia and prominent nuclear pleomorphism, and partially ulcerated overlying epidermis with associated serous crust. There were numerous admixed multinucleated osteoclast-like giant cells. Mitotic figures, including atypical mitotic figures, were readily identified. Tumor cells were reactive for CD68, CD10, p63 (focal), and SMA (patchy, weak) and non-reactive for cytokeratin AE1-AE3, keratin 5, SOX10, Melan-A, desmin, CD34, H3 G34W, S100, and CD1a. The histologic and immunohistochemical features were consistent with atypical fibroxanthoma/pleomorphic dermal sarcoma with osteoclast-like giant cells. The lesion was managed with Mohs micrographic surgery without residual neoplasm in the central debulk specimen or surgical margins, supporting the diagnosis of an atypical fibroxanthoma with osteoclast-like giant cells. Our case aligns with previous reports of AFX with osteoclast-like giant cells in its presentation in the head and neck region of an elderly patient, characteristic histopathology, and positive CD68 immunohistochemistry.