Rapidly Growing Superficial Angiomyxoma in Mandibular Gingiva: A Case Report and Literature Review.

Superficial angiomyxoma (SA) is a benign tumor characterized by extensive myxoid stroma, numerous small blood vessels, sparse spindle-shaped fibroblastic cells, and inflammatory cell infiltrate. Oral cavity SA is extremely rare and typically presents as a painless, slow growth. We experienced SA in the mandibular gingiva that is rapidly growing. The patient was a 15-year-old female whose chief complaint was a painless mass in the lingual gingiva of the mandible that increased in size over 1 month. An excisional biopsy was performed under local anesthesia. According to histopathological examination, the mass was diagnosed as SA. The patient experienced recurrence twice because of positive margins. The second recurrent lesion, including periosteum, was resected, and no recurrence has been observed for 1 year. The cause of rapid growth was attributed to edematous changes due to tongue habit or traumatic stimuli. As this case exhibited repeated local recurrence, careful follow-up is required.