A comparative ultrastructural study of XXXX , @entity242 , @entity3580 and @entity3580 periphericum.

@entity511 @entity242 @entity11262 @entity5 @entity3293 @entity1358 @entity3580
The present study is based on electron microscopical examinations of 15 conventional @entity511 , 1 clear cell @entity511 , 3 @entity11262 , 2 so-called @entity242 (extraskeletal @entity3293 ), 4 sacrococcygeal @entity3580 , 2 ecchordoses and 1 @entity5 of tibia with features of a true peripheral @entity3580 (parachordoma). The neoplastic cells from various types of @entity511 shared a number of features with nonneoplastic chondrocytes as e.g. a well-developed rough endoplasmic reticulum and microvillous cytoplasmic processes. In @entity1358 , glycogen accumulation in the @entity5 cells was a prominent feature. The cells of @entity11262 usually showed the characteristics of immature mesenchymal cells. In contrast, @entity3580 commonly contained physaliferous cells with two types of vacuoles in their cytoplasm. The first type can be most adequately characterized as intracytoplasmic pseudoinclusions of intercellular substance, whereas the other type, glycogen-containing, single membrane-bound vacuoles most probably correspond to autophagosomes (cytolysosomes). Only vacuoles of the first type were recorded in the so-called @entity242 . They were also seen in @entity511 . In contrast, both types of vacuoles were identified in the above-mentioned tibial @entity5 which, in addition, showed even other cytological characteristics of @entity3580 . The findings presented here have demonstrated distinct structural relationships between @entity242 and @entity5 . On the other hand, our observation of the uncommon tibial @entity5 indicates the possibility that @entity5 identical with @entity3580 may occur at sites other than the axial skeleton.
