A Rare Case of Peripheral Primitive Neuroectodermal Tumor Arising from the Minor Salivary Gland in a Young Woman

We report here a case of peripheral primitive neuroectodermal tumor (PNET) arising from the minor salivary gland. A 22-year-old woman was admitted to our hospital for surgical excision of a small painless cheek tumor with a 7-month history. Macroscopically, the tumor measured 10 × 5 × 6mm and was located in the minor salivary gland. Microscopically, the tumor comprised proliferating, small, round cells with scant cytoplasm and high nuclear cytoplasmic ratios. The tumor cells showed some mitotic figures and Homer-Wright-type rosettes. Immunohistochemically, the tumor cells were immunopositive for CD99, synaptophysin, CD56, S-100 protein, and vimentin. Based on these findings, the patient was diagnosed as having PNET arising from the minor salivary gland. There are very few case reports of PNET in the head and neck region, and to the best of our knowledge, this is the first case report of PNET arising from the minor salivary gland.