Protumorigenic M2-like phenotype cell infiltration in the melanotic neuroectodermal tumor of infancy This work was presented as poster in XXIII Brazilian Congress of Stomatology and Oral Pathology in July, 2015.

Abstract

Objective The aim of this study is to report 2 cases of melanotic neuroectodermal tumor of infancy (MNTI), emphasizing the analysis of intratumoral immune cells by immunohistochemistry. Study Design Case 1: A 6-month-old girl presented with a 3-cm tumor in the anterior region of the left maxilla. Case 2: A 4-month-old boy presented with a 4-cm tumor in the anterior region of the left maxilla. Microscopically, case 1 had predominantly neuroblast-like cells supported by fibrillary neuropil-like stroma arranged in an alveolar pattern, whereas case 2 exhibited scattered melanocyte-like and neuroblast-like cells supported by fibrovascular stroma. A large immunohistochemical panel for characterizing intratumoral macrophage and dendritic cell subsets was performed. Results Immunohistochemical analysis indicated positivity for HLA-DR, XIIIa, CD68, and CD163 (range 6%-50%) mainly on the fibrovascular stroma, suggesting M2 macrophage-like cell phenotype. CD138 was overexpressed in the tumor stroma. Conclusions Results suggest the involvement of M2-polarized macrophages in the MNTI pathogenesis, which may act by modulating tumor growth and/or tumor stromal remodeling.