Mucoepidermoid Carcinoma in Children: A Single Institutional Experience

Abstract

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.

Primary Lung Tumors in Children: Radiologic-Pathologic CorrelationFrom the Radiologic Pathology Archives

“…Among symptomatic patients with salivary gland-type tumors, cough, dyspnea, and wheezing are the most common complaints (65). Children with these tumors often present with persistent or recurrent lower respiratory tract obstruction (66). Other clinical presentation features include hemoptysis and postobstructive pneumonia (45,65).…”

Postoperative radiotherapy for T1/2N0M0 mucoepidermoid carcinoma positive for CRTC1/3‐MAML2 fusions

“…4 The presence of the fusions has been associated with a favorable clinical outcome in the patients with mucoepidermoid carcinoma. [20][21][22][23][24][25][26][27][28] There have been 2 mucoepidermoid carcinoma studies to date 28,29 in which the CRTC1/3-MAML2 fusion status and clinicopathological details were described. According to NCCN guidelines, version 1, 2016, PORT should be considered when a tumor shows tumor spillage, perineural invasion, or intermediate/high-grade histology.…”

“…The superior prognosis of our mucoepidermoid carcinoma cases may be associated with the low clinical stage of the mucoepidermoid carcinoma cases and may also be explained in part by the presence of CRTC1/3-MAML2 fusions because accumulating evidence shows that these fusions define a favorable mucoepidermoid carcinoma subset. [20][21][22][23][24][25][26][27][28] There have been 2 mucoepidermoid carcinoma studies to date 28,29 in which the CRTC1/3-MAML2 fusion status and clinicopathological details were described. We used these studies to summarize the clinicopathological features of T1/ 2N0M0 mucoepidermoid carcinoma cases (n 5 27) that were positive for CRTC1/3-MAML2 fusions ( Table 3).…”

“…12,13 CRTC1 belongs to a family of highly conserved cAMP response element binding protein (CREB) coactivators 14,15 and MAML2 belongs to a family of Mastermind-like, nuclear proteins that function as coactivators for Notch receptors. [20][21][22][23][24][25][26][27][28][29] This association is difficult to discern, but may be partly explained by the following observations: (1) high-resolution array-based comparative genomic hybridization showed that fusion-positive tumors had significantly fewer copy number alterations compared with fusion-negative tumors 30 and (2) mutations of the tumor suppressor TP53 gene were identified frequently in mucoepidermoid carcinoma cases with higher histological grade, but less frequently in those positive for CRTC1-MAML2 fusion. 10,11 It has been shown that CRTC1-MAML2induced activation of CREB is a critical mechanism for cell transformation 18 and that the fusion protein activates transcription of cAMP/CREB target genes.…”

“…19 We and other research groups have shown that CRTC1/3-MAML2 fusions are highly specific to mucoepidermoid carcinoma, they are not detected in any other type of salivary carcinoma, [16][17][18][19][20] and that the fusions are objective markers associated with a tumor subset with lower grade histology, less advanced clinical stage, lower incidence of lymph node metastasis, and a favorable clinical course for the patient. [20][21][22][23][24][25][26][27][28][29] This association is difficult to discern, but may be partly explained by the following observations: (1) high-resolution array-based comparative genomic hybridization showed that fusion-positive tumors had significantly fewer copy number alterations compared with fusion-negative tumors 30 and (2) mutations of the tumor suppressor TP53 gene were identified frequently in mucoepidermoid carcinoma cases with higher histological grade, but less frequently in those positive for CRTC1-MAML2 fusion. 31 In this study, we retrospectively retrieved T1/2N0M0 mucoepidermoid carcinoma cases, none of which involved further treatment with PORT after complete tumor resection.…”