Mesocolic Myxoid Hamartoma Showing Neural Differentiation: An Ultrastructural and Immunohistochemical Study

Abstract

A myxoid mesocolic tumor in a 4-month-old female infant is described. The tumor weighed 190 g and measured 8 cm in diameter and presented as a single mass composed of stellate and round cells with vesicular nuclei and prominent nucleoli in a myxoid, well-vascularized stroma. Electron microscopy showed mesenchymal cells with dilated rough endoplasmic reticulum, cell projections with primitive and desmosome-like cell junctions, and basal membrane–like material. Immunohistochemical studies demonstrated immunoreactivity with antibodies against vi-mentin and S-100 protein. The infant is well and without evidence of disease 3 years after surgery. This is an example of a peripheral myxoid hamartoma with neural differentiation, and the tumor is expected to have a benign clinical course.

Key Words:

• myxoid hamartoma
• Schwannoma
• mesocolon