A 31‐year‐old South Korean woman was referred to the dermatology department from the oncology department for the evaluation of a subcutaneous nodular lesion on the back. Three years before, she noted a palpable, fingertip‐sized, nontender mass on her right lower abdomen. The mass had increased in size slowly. One year ago, she visited a local clinic and physical examination revealed a 7 × 8 × 7 cm, slightly tender, deep‐seated mass on the right lower quadrant of the abdomen. The mass on the ilial mesentery was resected by surgical exploration and tissue examination revealed leiomyosarcoma. She refused adjuvant chemotherapy. Approximately 3 months later, she re‐visited the clinic with a tender, subcutaneous nodule on the back. Cutaneous examination revealed a solitary, 2 × 2 cm, well‐defined, hard, movable, subcutaneous nodule on the upper back without skin color change (Fig. 1). She complained of tenderness on touching the lesion. Histologic examination of a biopsy specimen showed irregularly arranged spindle cells scattered throughout the dermis. They were arranged in haphazardly oriented or interweaving fascicles. Most of the spindle cells possessed elongated nuclei with blunt ends and some cells had a polygonal outline with irregularly shaped nuclei (Fig. 2). There were many mitoses: 3–4 per high‐power (× 400) field. Immunohistochemically, smooth muscle actin and desmin were positive in most of the tumor cells (Fig. 3). S‐100 reactivity was not observed. A diagnosis of metastatic leiomyosarcoma was made. About 1 month later, computed tomography showed two, ill‐defined, heterogeneous, low attenuation masses in the right lobe of the liver, suggesting liver metastasis. The patient was treated with chemotherapy for 2 months and remains in good condition. 1 2 × 2 cm, solitary, well‐defined, hard, movable, subcutaneous nodule without any overlying skin change 2 (a) Characteristic findings of cutaneous leiomyosarcoma with markedly high cellularity and densely packed transverse and longitudinal fascicles of cells (hematoxylin and eosin, × 40). (b) High magnification of the neoplasm revealing spindle cells with blunt‐ended nuclei, pleomorphism, and mitotic figures (hematoxylin and eosin, × 200) 3 Dense cytoplasmic reactivity for smooth muscle actin is apparent (smooth muscle actin, × 200)

A 82‐year‐old Korean woman had had a 6‐month history of an asymptomatic, flat, hard, red to brown tumor on her right thigh. This lesion had been slowly enlarging with an advancing margin. She had noted gradually developing pain associated with necrosis and ulceration on the lesion. Examination revealed a solitary, 8 × 7.5 cm, yellow to dark red, telangiectatic tumor with multiple areas of punched out ulceration and a peripheral elevated yellowish margin on the right inner upper thigh (Fig. 1). No clinically similar lesions on the periorbital area or other sites were seen. Histologic examination revealed a massive palisading granulomatous infiltration with several layers of extensive bands of necrobiotic zone in the entire dermis and deep subcutaneous tissue (Fig. 2a). In the granulomatous infiltrate in the dermis and subcutis, many various‐shaped, some bizarre, angulated, foreign‐body type multinucleated giant cells, many Touton giant cells, and a few Langhans giant cells were found to be scattered (Fig. 2b). There were numerous xanthomatized histiocytes. Dense infiltration of lymphoplasma cells was seen in the periphery of the granuloma and perivascularly. Conspicuous granulomatous panniculitis composed of lymphoplasma cells, polymorphonuclear cells, foam cells, and Touton and foreign‐body giant cells was also seen. However, cholesterol clefts and lymphoid follicles were not seen. Subcutaneous septae were widened by necrobiotic change and fibrosis with thrombosed large vessels. Gram, Gomeri‐methenamine silver and acid‐fast stains were negative. The necrobiotic areas were positive to alcian blue. Laboratory investigation revealed elevated white blood cell counts, anemia and elevated erythrocyte sedimentation rate. The following parameters were within the normal range: lipids, glucose, renal and liver function tests, serum complements, serum immunoglobulins, cryoglobulins and antinuclear antibodies. The findings of chest X‐ray, skull X‐ray and ectorcardiography were normal. Serum electrophoresis and serum immunoelectrophoresis revealed no abnormality. The patient was diagnosed as having necrobiotic xanthogranuloma without paraproteinemia. She was treated with oral steroid (0.5–0.6 mg/kg) and NSAIDS for 1 month with partial improvement of pain and the lesion ceased to enlarge. In the following 1 year of follow‐up, with only intermittent NSAIDS, her lesion did not progress and there were no signs of systemic involvement or new skin lesions. Figure 1  (a) A solitary, red to brown plaque with multiple ulcerations and a peripheral elevated yellowish margin on the inner upper thigh 2 (a) A dermal and subcutaneous massive xanthogranulomatous infiltrate with zonal necrobiosis of collagen (× 20). (b) Prominent infiltrate of xanthomatized histiocytes and giant cells with perivascular lymphoplasma cells (H&E, × 100)

No abstract