A rare malignant tumor of scalp in a 3-month-old Taiwanese infancy: case report of primitive myxoid mesenchymal tumor of infancy with molecular study

Abstract

Primitive myxoid mesenchymal tumor of infancy is an extremely rare and recently recognized soft tissue tumor entity with a tendency for multiple recurrences. Only ten cases have been described in the literature and most cases are reported in Western countries. This tumor ranges in size from 2 to 15 cm and is characterized microscopically by a diffuse growth of primitive cells in a myxoid background with focal fascicles or a herringbone pattern. In this study, we describe a primitive myxoid mesenchymal tumor of infancy on the scalp of a 3-month-old Taiwanese boy. The histology showed typical morphology and the tumor cells showed vimentin and CD99 immunoreactivities. The translocation t(12,15)(p13;q25) was not found by fluorescence in situ hybridization. After complete surgical excision, no recurrence was noted during an 18-month follow-up.