Superficial angiomyxoma of the thumb: Report of a rare case and review of literature

We report a very rare case of a superficial angiomyxoma located at the thumb. A 41-year-old man presented with a painful, slowly growing mass at the distal phalanx of his swollen left thumb. There was a history of several, slight bleedings. Radiography revealed a spoon-like osteolysis, and MRI a soft-tissue mass of 1 cm size in diameter. Signal intensity was high in T2 weighted images, and low in T1 weighted images with a marked, but inhomogeneous contrast enhancement. Histopathology revealed sparse spindle-shaped fibroblasts and interstitial capillary vessels based on copious multilobular myxoid stroma forming nodules. Furthermore, there were aggregates of inflammatory cells, mainly neutrophils. Immunohistochemical staining was positive for vimentin. Only two reports of digital superficial angiomyxomas are found in the literature, and this case report is the first presentation of MRI findings of a superficial angiomyxoma.