Superficial Acral Fibromyxoma: Report of 13 Cases With New Immunohistochemical Findings

Abstract

Nestin is the best immunohistochemical marker for SAF with higher sensitivity than CD34, although nestin is also positive in dermatofibrosarcoma protuberans and therefore is not helpful in differential diagnosis between SAF and dermatofibrosarcoma protuberans. Cellular digital fibromas and acquired reactive digital fibroma probably are neoplasms closely related to SAF. The homogeneous reactivity for CD99, the negativity for Bcl-2 and lack of the honeycomb infiltration of the subcutis help to rule out myxoid dermatofibrosarcoma protuberans, whereas the negativity for MUC4 and Bcl-2 are helpful tools to rule out low-grade fibromyxoid sarcoma and spindled-cell lipoma, respectively.

Cellular Digital Fibroma: A Comprehensive Review of a CD34-Positive Acral Lesion of the Distal Fingers and Toes

“…In contrast to cellular digital fibroma that do not have a prior history of tumor site-associated trauma and are almost universally asymptomatic, superficial acral fibromyxoma may be preceded by trauma to the location in 19% (7 of 37) [ 11 ] to 25% (14 of 55) [ 12 ] of cases and up to 41% (19/46) of the lesions are painful [ 12 ]. Also, in contrast to cellular digital fibroma that do not affect the underlying bone and do not recur, superficial acral fibromyxoma is not only associated with invasion of the digit’s bone in 25% (1 of 4) [ 37 ] to 36% (9 of 25) [ 12 ] of cases, but also with recurrence after incomplete removal ranging from 21% (3 of 14) [ 36 ] to 42% (5 of 12) [ 10 ] of cases.…”

“…Similarly, the tumor typically demonstrates positive staining with vimentin and frequently with CD99; often, the tumor also expresses EMA. Recently, positive staining of superficial acral fibromyxoma with cluster of differentiation 10 (CD10) [ 39 ] and nestin [ 37 ] has been observed. Factor XIIIa only shows focally positive staining.…”

Painful subungual nodule

“…SAFM is a benign fibrotic neoplasm classically presenting as a pink-to-fleshe colored nodule commonly affecting the periungual and subungual regions with insidious onset. [1][2][3] Although pre-existing trauma to the affected site has been reported in some cases, the causative pathophysiology has yet to be determined. 2,3 Histologic findings of a SAFM, as seen in our case, involve a nonencapsulated tumor comprised of proliferative spindle-shaped cells embedded in a variably myxoid dermis.…”

Superficial Acral Fibromyxoma with Ossification on the Fingertip

“…It presents as a solitary fleshcolored papule or nodule extending through the dermis with possible extension to underlying subcutaneous tissue, fascia, and periosteum. 3,5 Metastasis has never been reported, however mass effect can cause local bone erosion and lytic lesions. Osseous SAFM should be kept in mind for masses on the distal extremities especially when there is nailbed involvement.…”

“…2,3,5 Additional helpful markers for SAFM that are often positive include CD99, vimentin, and epithelial membrane antigen and anti-smooth muscle actin is typically negative. 3,5 Management of SAFM should be based on location, size, involvement of underlying structures, atypical features, and associated complications. Definitive treatment of SAFM is complete surgical excision.…”