Aggressive clear cell chondrosarcomas: do distinctive characteristics exist?: a report of 4 cases.
BACKGROUND
Clear cell chondrosarcoma (CCC) is commonly considered to be a low-grade subtype of chondrosarcoma. However, a few cases of CCC behave as high-grade lesions (with early metastases or multiple/synchronous locations).


OBJECTIVE
To investigate morphologic features that can help predict the aggressiveness of these CCCs.


METHODS
To investigate possible hallmarks of this aggressiveness, we are presenting the clinicopathologic features of 6 cases of CCC, 4 of which presented aggressive features and 2 low-grade behavior. The patients were 5 men and 1 woman; their ages ranged from 22 to 47 years. Histologic appearance, ultrastructure, and immunohistochemical expression of metalloproteinase 1 and 2 and their inhibitors were evaluated in all 6 cases.


RESULTS
Pain was the most common symptom; the lesions were located in the femur (4), humerus (2), and vertebral body (1), with 1 patient presenting a double/synchronous lesion. Although no major differences were detected using conventional light microscopy, an ultrastructural analysis--at variance with usual cases--showed a lack of superficial microvilli in more than 50% of neoplastic cells in the aggressive cases, therefore suggesting a less differentiated phenotype. In addition, metalloproteinase 2 was more diffusely expressed in the aggressive tumors than in the conventional CCCs, whereas p53 labeling was always negative.


CONCLUSIONS
The aggressive behavior of some CCCs may be, at least in part, correlated to a lesser degree of cell differentiation and to the expression of tumor cell proteins, such as metalloproteinase 2, which are able to favor neoplastic spreading.
Corradi
Domenico
D
Department of Pathology and Laboratory Medicine, Pathology Section, University of Parma, Via Gramsci 14, 43100 Parma, Italy. domenico.corradi@unipr.it
Bacchini
Patrizia
P
Campanini
Nicoletta
N
Bertoni
Franco
F
D000328:Adult; D001859:Bone Neoplasms / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D002813:Chondrosarcoma / Q000150:complications / Q000378:metabolism / Q000473:pathology* / Q000556:secondary*; D005260:Female; D005269:Femur; D006801:Humans; D006811:Humerus; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D008854:Microscopy, Electron; D008871:Microvilli / Q000648:ultrastructure; D016609:Neoplasms, Second Primary / Q000473:pathology*; D010146:Pain / Q000209:etiology; D013125:Spinal Neoplasms / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D016159:Tumor Suppressor Protein p53; D020778:Matrix Metalloproteinase 2