RT - Journal TY - JOUR A1 - Kottangal, Gittwa A1 - Prasad, Chaya A1 - Jojo, Annie T1 - “Primitive myxoid mesenchymal tumor of infancy” - A rare childhood soft-tissue tumor of the mandible YR - 2019/7/1 JF - International Journal of Head and Neck Pathology JO - Int J Head Neck Pathol SP - 29 OP - 32 VO - 2 IS - 2 UL - https://www.ijhnp.org/article.asp?issn=2590-2997;year=2019;volume=2;issue=2;spage=29;epage=32;aulast=Kottangal;t=5 DO - 10.4103/JHNP.JHNP_13_20 N2 - Primitive myxoid mesenchymal tumor of infancy (PMMTI) is an extremely rare soft-tissue tumor of childhood. We report a case of an 18-month-old male child diagnosed with PMMTI of the mandible. Till now <30 cases had been reported in the English literature. Histologically, the tumor consists of primitive spindle/polygonal cells dispersed in a myxoid background with delicate blood vessels. Immunohistochemically, tumor cells are positive for vimentin and negative for all other myoid, neural, epithelial, vascular, and neuroendocrine markers. This tumor was previously included under the diagnostic categories of congenital infantile fibrosarcoma or infantile fibromatosis. Increased awareness of this novel entity is a must as its biological and chemosensitive nature is vastly different from its differentials. Recent immunohistochemical stains and cytogenetic studies have helped to differentiate PMMTI from the other tumors of similar morphology. ER -