Mucoepidermoid Carcinoma in Children: A Single Institutional Experience

Purpose and objective: To determine the clinicopathologic and molecular features and outcome of children with mucoepidermoid carcinoma (MEC). Methods: A retrospective analysis of clinical and histopathologic findings was performed in patients with MEC diagnosed at Texas Children's Cancer Center between 2000 and 2014. Results: Ten female and four male patients with median age 12 years (range 7-19 years) were included in the study. Tumors involved major salivary glands, minor salivary glands of the palate, and the tracheobronchial tree. Nine of 11 patients with salivary MEC underwent more than one surgical resection at the time of initial diagnosis to achieve a gross total resection. Three patients with tracheobronchial tumors underwent pulmonary lobectomy. Three patients received postoperative radiation therapy. No patient was treated with chemotherapy. Histopathologic grades were classified as low (n = 2), intermediate (n = 9), and high (n = 3). All 12 patients with tumor tissue available for testing were positive for MECT1/MAML2 fusion transcripts. There were no deaths, metastases, or recurrences in this series, with a median follow-up of 24 months (range 5-96 months). Conclusions: Low to intermediate histopathologic grade MECs are more common than high grade MEC in children. In contrast to adults, MECT1/MAML2 fusion transcripts occur with a frequency of 100% in our pediatric MEC series. Complete excision is the treatment of choice and is associated with excellent outcome. The role of radiotherapy is unclear, but may be indicated in patients with high grade tumors with positive surgical margins.