Background: Myoepitheliomas are rare tumors and infrequently develop in the skin. These tumors are often recurrent and difficult to diagnose and therefore require immunohistochemical staining.
Case Report: The case of a 45-year-old male patient presenting to the Otorhinolaryngology Department of Tlemcen University Medical Center in northwest Algeria with a painful and voluminous bumpy facial mass which was hard, sensitive, and highly adherent to underlying tissue mass is reported. Questioning revealed two recurrences after two surgeries. The third excision revealed the presence of multiple infiltrated nodules of various size. Histological analysis showed a proliferation of elongated cells, rarely globular, which had abundant cytoplasm, were slightly eosinophilic, and with nuclei presenting a fine chromatin. Immunohistochemical diagnosis showed that the tumor cells were positive for S100 protein (PS100), pankeratin KL-1, and CAM5.2, moderately positive for desmin (DES), calponin (CALP), and glial fibrillary acidic protein (GFAP), and negative for actin (ACT), cytokeratin (AE1/AE3), high-molecular-weight cytokeratin (HMWCK), and epithelial membrane antigen (EMA).
Conclusions: The tumor’s clinical aspect as well as its histological and immunohistochemical examination evoked the diagnosis of an unusual myoepithelioma. Additionally, the recurrences of myoepithelioma would be due to excisions which neglected resection of myofilament.

Keywords: Facial polynodular myoepithelioma, Immunohistochemical diagnosis, recurrences