Skeletal myxoid chondrosarcoma with microtubular aggregates within rough endoplasmic reticulum.

A skeletal myxoid chondrosarcoma of the femur was examined by light and electron microscopy. Light microscopic features were characteristic for myxoid chondrosarcoma or "chordoid sarcoma." Electron microscopy disclosed crystalline arrays of microtubules within dilated rough endoplasmic reticulum, a feature previously described in extraskeletal myxoid chondrosarcomas. Tumors with the histologic characteristics of extraskeletal myxoid chondrosarcoma ("chordoid sarcoma") occurring in bone have been rarely reported. We describe herein such a tumor and document the existence of distinct microtubules within the endoplasmic reticulum.