Microtubular aggregates within rough endoplasmic reticulum: An unusual ultrastructural feature of extraskeletal myxoid chondrosarcoma

Two extraskeletal myxoid chondrosarcomas were examined by electron microscopy. In addition to the well-described ultrastructural features indicative of chondroblastic origin, both of these chondrosarcomas had unusual parallel microtubules packed within rough endoplasmic reticulum. This paper reviews the differential diagnosis of extraskeletal myxoid chondrosarcoma and discusses ultrastructural examination as a valuable adjunct in the diagnosis of this uncommon soft tissue tumor.