Solitary Mucosal Neuroma of the Hard Palate Without Multiple Endocrine Neoplasia Type 2B: A Rare Non-syndromic Case Report and Literature Review

Mucosal neuromas are benign proliferations of peripheral nerves that most commonly occur as part of multiple endocrine neoplasia type 2B (MEN2B), a hereditary syndrome associated with germline mutations of the RET proto-oncogene. MEN2B is characterized by mucosal neuromas, medullary thyroid carcinoma, pheochromocytoma, intestinal ganglioneuromatosis, and marfanoid habitus. Oral mucosal neuromas often represent the earliest manifestation of the syndrome and therefore have important diagnostic significance. However, isolated mucosal neuromas occurring in the absence of MEN2B are extremely rare, particularly within the oral cavity. This case report describes a 25-year-old female who presented with a solitary, firm, painless mass on her right posterior hard palate. Radiographic examination revealed no osseous involvement. Following an excisional biopsy, microscopic examination revealed unencapsulated proliferation of tortuous and haphazardly arranged neural bundles within a collagenous stroma. Immunohistochemical analysis demonstrated strong and diffuse positivity for S-100 protein, confirming the diagnosis of mucosal neuroma. Comprehensive systemic evaluation, including endocrine assessment, biochemical testing, and thyroid ultrasonography, revealed no evidence of MEN2B. The patient demonstrated satisfactory postoperative healing with no recurrence during eight months of follow-up. Thus, this case highlights an exceedingly rare presentation of a solitary mucosal neuroma at an unusual site occurring in the absence of MEN2B. While mucosal neuromas are typically pathognomonic for MEN2B, solitary forms are rare, particularly when located on the hard palate. This report adds to the limited literature on non-syndromic oral mucosal neuromas and emphasizes the importance of clinicopathologic correlation and long-term surveillance.