Skeletal muscle regeneration in post-myofascial flap reconstruction specimens mimicking sarcoma: A potential...

Skeletal muscle regeneration (SMR) encompasses a sequence of events that unfolds after injury to muscle fibers. Nearby satellite cells become activated and function as precursor muscle cells by proliferating and differentiating into myoblasts, which eventually fuse to form myotubes and ultimately mature muscle fibers. Compared to other forms of mesenchymal repair, SMR has higher morphologic heterogeneity with the potential to show histopathologic similarities to sarcomas and other malignancies. It is important to recognize SMR and settings in which this can occur to avoid misdiagnosis. We report two cases where a diagnosis of SMR was made from tissue taken from locations previously treated with Mohs micrographic surgery followed by myofascial flap reconstruction. In both cases, histopathologic features identified with hematoxylin and eosin as well as immunostaining were used to support the diagnosis of SMR. These cases highlight the importance of recognizing this clinic entity to ensure accurate diagnosis.