The differential diagnoses of SAFM include CD34-immunopositive neoplasms, such as dermatofibrosarcoma protuberans, superficial angiomyxoma, and myxoid neurofibroma, and CD34-immunonegative neoplasms, such as giant cell tumor of the tendon sheath, glomus tumor, sclerosing perineuroma, fibrous histiocytoma, and acral fibrokeratoma.
9) In an ultrastructural study by Pasquinelli et al, (10) the tumor cells of SAFM were found to be composed of cytoplasmic intermediate filaments and numerous cisternae of rough endoplasmic reticulum.
management of SAFM involves complete surgical excision and follow-up.
One of the differential diagnoses of SAFM includes myxoid neurofibroma, which often has a neural appearance with no increase in vascularity.
In contrast to a moderately cellular proliferation of spindled fibroblast-like and stellate cells seen in SAFM, this tumor shows sparse stellate cells embedded in a fibrocollagenous matrix with dilated or slitlike vascular channels.
In contrast to SAFM, it is paucicellular and EMA negative.
1,5,6,12) These patterns are not seen in SAFM, which has a loose storiform and focally fascicular growth pattern.
In contrast to SAFM, it rarely involves the fingers, palms, or soles and is a poorly demarcated tumor composed of fibroblast-like cells, histiocytes, and blood vessels.
To summarize, SAFM is a rare, slow-growing tumor with a predilection for the ungual region of the fingers and toes of middle-aged adults.
Because of their CD34 positivity and the presence of spindle-shaped and stellate cells embedded in a vascular, basophilic matrix, SAFMs can be confused with superficial angiomyxomas.