Superficial acral fibromyxoma are benign fibromyxoid lesions. They are small isolated lesions with a predilection for the fingers, toes, and nails.
Histology of superficial acral fibromyxoma
In superficial acral fibromyxoma, sections show a paucicellular fibromyxoid lesion arising in the dermis of acral skin (figure 1). Subcutaneous involvement is common. The cells are bland, spindled or stellate and set in a fibromyxoid stroma (figures 2 and 3).
Superficial acral fibromyxoma pathology
Special studies for superficial acral fibromyxoma
Immunohistochemical studies of superficial acral fibromyxoma reveal positivity with CD34, EMA. S100, cytokeratins and smooth muscle markers are negative.
Differential diagnosis of superficial acral fibromyxoma
Neurofibroma – These also have a fibromyxoid stroma. S100 will be positive in neurofibroma.
Perineurioma – Sclerosing perineuroma often involves acral sites. Myxoid change is less common in these lesions. Both of these entities will be positive with EMA and negative with S100. Glut-1 positivity and CD34 negativity favours perineurioma.