Primitive Myxoid Mesenchymal Tumor Of The Infancy In Abdominal Cavity: Report Of A Rare Case

Primitive myxoid mesenchymal tumor of the infancy (PMMTI) is an extremely rare soft tissue tumor. We report a case of 2-year-old girl presenting with omentum and intestinal wall involvement in abdominal cavity with prominent refractory ascites. Histologically, the tumor consisted of primitive spindle or polygonal cells dispersing in a myxoid background with delicate blood vessels. Immunohistochemically, tumor cells expressed vimentin and NSE but were negative for AE1/AE3, CK5/6, TTF1, desmin, SMA, MyoD1, myogenin, ALK, CD34, calretinin, WT1, HBME1, D2-40, S-100 protein, CD56, synaptophysin, CD99, CD20, CD3, CD30. Fluorescence in situ hybridization (FISH) showed absences of chromosome translocation involving DDIT3, EWSR1 and ETV6. The patients undergone a palliative surgery and succumbed after 2 months. To our knowledge, this is the first case of PMMTI affecting abdominal cavity and demonstrating a more unfavorable prognosis.