METASTATIC LEIOMYOSARCOMA OF THE PALATAL GINGIVA MASQUERADING AS A PYOGENIC GRANULOMA

Abstract

Leiomyosarcoma (LMS) is a smooth muscle neoplasm, accounting for 7% of soft-tissue and 1-4% of head-neck sarco- mas. Oral-LMS is extremely uncommon and may represent primary or metastatic disease. We describe a 46-year- old female with a medical history of "stomach cancer" who presented with a palatal mass. Upon further inquiry, it was discovered that the patient had been diagnosed with high-grade LMS of the retroperitoneum six years prior, which had been treated with radical resection and right nephrectomy followed by post-operative radiation and ad- juvant chemotherapy. She subsequently developed liver metastasis requiring modification of her chemotherapy. However, she had elected to discontinue treatment one year prior to the presentation of the oral lesion. A biopsy of the palatal mass revealed a malignant spindle-cell proliferation expanding the overlying epithelium, with brisk mitotic activity and atypical mitosis, nuclear pleomorphism, and focal areas of tumor necrosis, raising the concern for LMS. Immunohistochemical (IHC) stains for SMA were strongly positive while negative for DOG1 and CD 117. Based on the history and supportive histopathological and IHC findings, a diagnosis of metastatic LMS of the palate was given. Oral metastases of LMS are exceedingly rare and aggressive lesions that arise mostly in females in their sixth-decade. Literature review shows that metastases to the tongue, gingiva, lip, and buccal mucosa are typically associated with primary uterine tumors, while metastasis to the mandibular gingiva is documented frequently with non-uterine primaries. Clinically, lesions can present as a nonspecific painful mass. Microscopic diagnosis is often challenging due to significant overlap with other spindle-cell neoplasms, requiring careful correlation with medical history, physical examination, and ancillary studies. We herein report a rare case of a retroperitoneal LMS that metastasized to the palate. A literature review of metastatic oral-LMS and retrospective institutional analysis of oral metastases will also be presented.