Malignant Ectomesenchymoma of Pelvis in an Infant

Çağaptay S., Olgun H. N., Özer E.

Türkiye Klinikleri Journal of Case Reports, vol.30, no.1, pp.62-66, 2022 (TRDizin)

Abstract

Malignant ectomesenchymoma is a rare pediatric soft tissue tumor that contains both neuroectodermal and mesenchymal components. It is frequently found in the pelvis, paratesticular soft tissue, external genitalia and the head-neck region. We present a 12-month-old boy with a recurrent pelvic tumor excised 5 months ago and diagnosed as neuroblastoma. Histological consultation of the initial tumor tissue revealed a biphasic pattern with rhabdomyosarcomatous and neural components. The mesenchymal component was embryonal rhabdomyosarcoma showing desmin, myogenin, and Myo-D1 positivity. The neuroectodermal component was mainly Schwannian stroma stained with S100 antibody and scattered synaptophysin and chromogranin positive ganglion cells were also present. The patient was diagnosed with malignant ectomesenchymoma. A chemotherapy regime was started and surgical approach to the recurrent tumor was planned. We present here a pediatric case of malignant ectomesenchymoma because of its rarity and it is important that this entity should be considered in the differential diagnosis for appropriate clinical management.