We report a rare case of a malignant granular cell tumor in the maxilla. A 61-year-old woman presented with painless swelling and bleeding of the hard palate. Clinical examinations revealed diffuse swelling of the right side of the hard palate with a necrotic ulcer. CT and MRI showed a tumor-like mass extending from the right maxillary sinus to the palate and nasal cavity. Histopathologically, the tumor consisted of clusters of eosinophilic granular cells exhibiting marked atypia, polymorphism, and vesicular nuclei with a high nuclear-to-cytoplasmic ratio.Immunohistochemical examination revealed that the tumor cells were positive for S100, NSE, CD68, CD57, and vimentin, but not for HMB45, KL1, CAM5.2, EMA, α-SMA, desmin, or MBP. We diagnosed the tumor as a malignant granular cell tumor and performed partial maxillectomy. Seven months after the operation, multiple metastatic lesions were detected in the lungs, liver, scapula, vertebrae, and iliac bone on PET-CT. The patient died 14months after surgery, even though she received 2 courses of chemotherapy with cisplatin and etoposide.
