THE ROENTGENOGRAPHIC FEATURES OF CHONDROBLASTOMA

* From the Department of I)iagnostic Roentgenology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota. JUNE, 1973 464 THE ROENTGENOGRAPHIC FEATURES OF CHONDROBLASTOMA* By RICHAR1) A. MCLEOD, M.D., and JOHN W. BEABOUT, M.D. ROCHESTER, MINNESOTA B ENIGN chondroblastoma of bone is a primary neoplasm. It is of cartilagi- noDs origin, and the proliferating cell is probably the chondroblast.45 The tumor is benign and has neither a malignant coun- terpart non a propensity for malignant transformation.2’6 Attention was first fo- cused on this tumor in 1928 by Ewing, who believed that the lesion was a variant of a giant cell tumor.’ Codman,’ in 1931, de- scribed the lesion in some detail, although he too believed that it belonged within the giant cell group. It was not until 1942, through the work of Jaffe and Lichten- stein,4 that benign chondroblastoma be- came established as a separate and distinct entity. The basic concepts which they set forth at that time have since been firmly established. This entity is rare and probably repre- sents less than I per cent of all primary tumors of bone.2 Although the age range of patients is wide, most lesions occur in patients who are io to 25 years old.2’9 About two-thirds of the lesions have been noted in males.2’7’9 The most common sites are the knee, hip, and shoulder, but no portion of the axial or appendicular skeleton can be exempt as a possible location.2’7’9 Most patients present with the chief complaint of pain, which is usually mild and often of long duration, sometimes lasting many years.2’5 Swelling and local tenderness also are encountered. In reviewing this subject, we found 72 cases of histologically proved chondroblastoma at our institution in which roentgenograms or photographs of roentgenograms were available for study. CLINICAL FEATURES Symptoms and Signs.-By far the most common presenting symptom was pain. The pain was characteristically local and usually mild, and its duration varied from a few weeks to many years. More than one- third ofthe patients had pain for more than I year before they sought medical aid. The only other frequent symptom was local swelling, which also was often oflong dora- tion (16 years in one instance). In most cases, there were no physical findings or a palpable mass was the sole finding. Other occasional findings were tenderness, muscular atrophy, and limited range of motion of the adjacent joint. zige and Sex.-Of the 72 patients, 46 (64 per cent) were males and 26 (36 per cent) were females (Fig. I). The ages of the patients ranged from #{231} to 6 years; more than 6o per cent were in the second decade, and nearly 20 per cent were in the third decade. ROENTGENOGRAIHIC FEATURES Location in Skeleton.-Approxim ately 6o per cent of the tumors were located in the long tubular bones, with 23 in the femur, Jo in the proximal tibia, 7 in the proximal humerus, 2 in the proximal fibula, and i in the distal radius (Fig. i). Twenty-five lesions (35 per cent) occurred in the knee region. Ifthe pelvic tumors that were at or adjacent to the acetabulum are included in the hip region, then this area accounted for another i 8 cases (25 per cent). When they arise in the pelvis (Fig. 2A), chondroblas- tomas, like other cartilaginous tumors, show a marked tendency to originate near the tniradiate cartilage. Ten lesions (14 per cent) occurred in the shoulder, with 3 being located in the scap- ula. Eight tumors (II per cent) were found Downloaded from www.ajronline.org by 117.3.248.167 on 06/21/23 from IP address 117.3.248.167. Copyright ARRS. For personal use only; all rights reserved

THE ROENTGENOGRAPHIC FEATURES OF CHONDROBLASTOMA

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