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Case ReportsAbstract
Acral fibrochondromyxoid tumor (AFCT) is a rare, benign soft tissue neoplasm of the distal extremities, first described in 2020. It is characterized by distinctive histopathologic, immunohistochemical, and molecular features. Due to its subtle clinical presentation and limited awareness, AFCT may be underrecognized or misdiagnosed.
We report the case of a 49-year-old woman with a slow-growing, asymptomatic nodule on the left fourth finger present for several years. Histologic examination revealed a well-circumscribed, lobulated dermal lesion composed of bland spindle and stellate cells in a chondromyxoid stroma. Immunohistochemistry demonstrated diffuse CD34 positivity, with negative S100 and SMA, and a low Ki-67 proliferative index. Alcian blue highlighted mucopolysaccharides within the stroma. These features were consistent with AFCT. Conservative surgical excision was recommended.
This case contributes to the growing body of literature on AFCT, emphasizing the role of histopathology and immunoprofiling in differentiating it from other acral soft tissue tumors. Awareness of its distinctive features—including the recurrent THBS1::ADGRF5 gene fusion—is essential to avoid misdiagnosis.