Angiomatoid metastatic melanoma.

Two patients with metastatic melanoma, both with the same bizarre morphology and an unusual, comparatively benign course, are described: a 50-year-old female who more than 20 years after a primary melanoma on the right upper arm, Clark level III, maximum tumor thickness of 1.1 mm, developed multiple metastases in the deep soft tissue and a 62-year-old male with an acrolentiginous melanoma, Clark level III, maximum tumor thickness of 0.55 mm, who 6 months after the excision of the primary tumor developed metastasis in regional lymph nodes. Histology of all metastases revealed extensive central necrosis and hemorrhage with a demarcating granulomatous reaction imitating angiomatoid malignant fibrous histiocytoma but no obvious melanoma tissue. Although extensive immunohistochemistry and ultrastructural examination failed to solve the quandary, careful macroscopy revealed tiny foci of remnants from melanoma in the granulation center. The female developed multiple soft tissue metastases managed by surgery, immunochemotherapy, and autologous vaccination. Both patients are well without internal manifestations 9 and 5 years, respectively, after the first metastatic episode.