Lipomatous Variant of Solitary Fibrous Tumor With CD34 Negativity: A Case Report.

The solitary fibrous tumor (SFT) in its lipomatous variant is very rare, with only a few cases described in the literature. It is a myofibroblastic mesenchymal tumor with intermediate behavior. We report the case of a 33-year-old patient with no notable pathological history, admitted following the incidental discovery of a dorsal mass involving the soft tissues, whose radiological examination suggested a schwannoma. The patient underwent a surgical biopsy showing a tumoral proliferation composed of spindle cells within mature adipose tissue. Immunohistochemical studies were necessary to rule out differential diagnoses before establishing the final diagnosis.