Solitary long-bone epiphyseal lesions in children: radiologic-pathological correlation and epidemiology.

Abstract

Solitary epiphyseal lesions are rare and present with nonspecific imaging features. Knowledge regarding etiologies of pediatric epiphyseal lesions is limited to small studies. The purpose of this study was to determine the relative incidence of pathologies affecting the pediatric epiphysis based on biopsy-proven cases with imaging. We conducted a retrospective review of imaging studies including the terms "biopsy" or "resection" and entities known to affect the epiphysis and cross-referenced these with pathology reports, recording the relevant clinical data. Two radiologists performed comprehensive imaging review and recorded relevant features. Forty-nine children and adolescents met inclusion criteria. The long-bone epiphyseal lesion etiologies included chondroblastoma (n=22, 45%), nonspecific nonmalignant pathology (n=11, 22%), osteomyelitis (n=9, 18%), lymphoma (n=2, 4%) and 1 case of each of aneurysmal bone cyst, chondrosarcoma, enchondroma, hemangioendothelioma, and non-Langerhans cell histiocytosis. Median age was 13.1years old (range 1.5-18.6years). We performed comparative analysis of the two most common lesions in our series, chondroblastoma and osteomyelitis. Chondroblastoma was significantly more likely to be peripherally located (94% vs. 33%, P=0.002) and to demonstrate a discrete T1-weighted hypointense rim (94% vs. 33%, P=0.002); there were no significant differences in enhancement or intrinsic signal properties. Children with chondroblastoma were older (15.1years vs. 7.3years, P=0.001), and chondroblastoma lesions were significantly larger, with mean maximum lesion diameter of 25mm (interquartile range [IQR] 20-30) vs. 12mm (IQR 11-18) (P=0.001) and lesion volumes of 4.4mL (IQR 2.4-7.9) vs. 0.4mL (IQR 0.2-1.4) (P=0.01). This study reports the relative frequency of pathology of pediatric solitary epiphyseal lesions and describes several features that might assist in differentiating between chondroblastoma and osteomyelitis.