Dermatomyofibroma on the Breast

Figure 1

A 70-year-old woman presented with a hand-sized lesion on the right breast characterized by well-defined, raised margins and firmness on palpation (Figure a). The asymptomatic lesion had been present since the age of 17 and had always been diagnosed as a keloid. Due to the discrepancy with the clinical picture, a punch biopsy was performed. Histology revealed a proliferation of spindle-shaped cells extending deep into the dermis (Figure b). Immunohistological analysis revealed strong vimentin expression while desmin, muscle actin, CD34, CD68, and factor XIII were negative. Taking all the clinical and histological findings together, a dermatomyofibroma was diagnosed, although involvement of the breast is extremely uncommon. This rare, benign entity typically occurs during adolescence and predominantly affects females. In the majority of investigated cases, mutations in the platelet-derived growth factor receptor beta gene are detected, which is typical for tyrosine kinase-dependent tumors. Surgical excision is the only recommended treatment option to date. Malignant dermatofibrosarcoma protuberans, which is more frequently located in the shoulder and breast region, is an important differential diagnosis.

Prof. Dr. med. Ulrich Mrowietz, Prof. Dr. med. Thomas Schwarz, Universitäsklinikum Schleswig-Holstein, Klinik für Dermatologie, Germany, [e-mail]

Prof. Dr. med. Ulrich Mrowietz, Prof. Dr. med. Thomas Schwarz, Universitäsklinikum Schleswig-Holstein, Klinik für Dermatologie, [e-mail]

Conflict of interest statement: The authors state that no conflict of interest exists.

Translated from the original German by Christine Rye.

Cite this as: Mrowietz U, Schwarz T: Dermatomyofibroma on the breast. Dtsch Arztebl Int 2026; 123: 326a. DOI: 10.3238/arztebl.m2026.0039