Dedifferentiated Chondrosarcoma of Bone – Description of Five Cases andReview of the Literature with a View of Histogenesis

Overview

Five cases of dedifferentiated chondrosarcoma of bone are presented. Three women and two menof age ranging from 57–72 years (median 63 years) suffered from tumors located in femur (2),scapula (1), humerus (1) and pelvis (1). They were all bulky tumors destroying the bones andinfiltrating into the adjacent soft tissues in maximum diameter from 5–20 cm (median 12 cm).Both the short clinical histories lasting from 2–24 months (median 5 months) and persistent painsunrelieved by acylpirin were constant findings in all the cases. Four patients died of metastaticdisease (mainly to lungs) with median survival of 8 months. All cases were the so-called „de novo“dedifferentiated chondrosarcomas without clinical or morphological evidence of the primarilybenign or malignant chondroid lesions. The tumors displayed a typical dual composition with anabrupt interface between chondroid and nonchondroid components. The chondroid tissue resembledG1 chondrosarcoma in three cases, G2–3 chondrosarcoma in two cases. The second nonchondroidmesenchymal portion had the appearance of undifferentiated pleomorphic sarcoma inthree cases, rhabdoid and giant cell tumor-like in one case. The new data and evidence providedby molecular biology dramatically changed the opinions of histogenesis of this unique neoplasm.At present, there is a generally accepted idea of common origin of both portions from a primitivestem cell. Therefore, this peculiar tumors should not be viewed merely as dedifferentiated conventionalchondrosarcomas.

Key words:
skeleton – chondrosarcoma – dedifferentiated chondrosarcoma