Objective: To investigate the clinicopathological features of multiple mucosal neuromas without multiple endocrine neoplasia type IIB (non-MEN-IIB MMN).
Methods: Three cases of non-MEN-IIB MMNs were analyzed for the clinical manifestations and histopathological characteristics.
Results: All the 3 cases were females, age ranging from 30 to 45 years. Two cases of them involved in the laryngopharyngeal mucosa and another one located in the left margin of the tongue. Clinically, non-MEN-IIB MMNs presented with uncertain foreign body sensation, itching, vomiting and causalgia in the laryngopharyngeal areas. Mucosal papular lesions were treated by laser ablation or local surgical excision. The cases were respectively followed up for 6 to 20 months and found nothing. Histological examination showed the lesions were not encapsulated and contained irregular tortuous nerve bundles with undefined perineurium in the lamina propria. There were no nuclear palisade. Immunophenotype showed tumor cells strongly positive for vimentin, S-100, myelin specific enolase, CD56, neurofilament and neuron specific enolase, uniformly negative to CD34, CD117 and epithelial membrane antigen.
Conclusions: Non-MEN-IIB MMN is a very rare disease and the possibility of MEN-IIB should be excluded before making diagnosis. The lesions located in the mucosal tissue with polyp-like or papular appearance, so they should be differentiated from other neoplasms or non-neoplastic lesions.