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Erosion of the Distal Phalanx

Superficial Acral Fibromyxoma of the Toe, with Erosion of the Distal Phalanx

            Superficial acral fibromyxoma (SAFM) is a slow growing soft tissue tumor commonly located at the distal ungual region of the fingers and toes. SAFM, was first medically acknowledged in 2001. SAFM has a predilection towards males, ages 14-72.

             In this clinical study, a 35-year-old male living in a rural setting with a two-year history of the tumor is discussed. The tumor was located at the right toe, distal phalanx and was approximately 2 cm in diameter. It was a painless, raised lesion and showed no signs of metastasis to the proximal area of skin. The tumor had displaced the overlying nail. Radiographic analysis of the tumor identified it as a soft tissue mass with lytic lesions affecting the distal phalanx with sclerosis. MRI studies revealed that the tumor was fibrous in nature and its depth spanned the ungual bed and the cortical bone of the distal phalanx. Tumor was surgically excised and the toe nail was spared.

            Tumor histology revealed it to be nodular without a capsule. Tumor was confined to dermal layer. Soft tissue biopsy showed fibroblast type fusiform and stellate cells within a matrix of myxoid material and collagen. Immunohistochemical study of the tumor revealed a positive CD34, CD99 and vimentin markers. With the positive immunohistochemical markers many differential diagnosis were taken into account: myxoid neurofibroma, superficial angiomyxoma, sclerosing perineuroma, dermatofibrosarcoma, myxoinflammatory acral fibroblastic sarcoma, and low grade myxofibrosarcoma. Differential diagnosis were scrutinized and ruled out based on the location of the tumor and the histological appearance. 


References

Superficial Acral Fibromyxoma of the Toe, with Erosion of the Distal Phalanx. A Clinical Report. Oteo-Alvaro A, Meizoso T, Scarpellini A, Ballestín C, Pérez-Espejo G (Hospital Virgen de la Torre, Madrid, Spain; Hospital 12 de Octubre, Madrid, Spain)
Arch Orthop Trauma Surg 2008 Mar;128(3):271-274

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