A V Nair1, S Anirudh2. 1. Department of Radiodiagnosis and Interventional Radiology, Kerala Institute of Medical Sciences and Research Centre, Trivandrum, Kerala, India. 2. Department of Pathology, Medical College Hospital, Trivandrum, Kerala, India.
We appreciate Karkhur Y et al.[1] for publishing a case report of suspected Trevor's disease that eventually turned out to be chondroblastoma.Dysplasia epiphysealis hemimelica (DEH), also known as Trevor's disease, is a rare hereditary disease characterized by osteochondroma arising from the epiphyses. DEH was first described in 1926 by Mouchet and Belot as “Tarsomegaly.” Later in 1950, it was Trevor who reported his case series using the term “tarsoepiphyseal aclasis.”[2]Azouz et al.[3] classified DEH into three groups; (a) classic form with characteristic hemimelic distribution involving more than one bone or epiphysis within a single lower extremity; (b) localized form with single bone affection unilateral or bilateral; (c) generalized form, involving the whole limb from pelvis to foot.Although the authors did not do an magnetic resonance imaging (MRI) knee joint in the case, MRI would be useful when evaluation of underlying secondary involvement of ligaments, cartilages, and menisci is necessary.[4] Osteochondral overgrowth will have the similar magnetic resonance signal intensity to epiphyseal cartilage and bone.Chondroblastoma occurs in young (<2 decades) skeletally immature patients with male predominance. Radiologically, chondroblastomas are lucent lesions with thin sclerotic rim commonly involving the epiphysis of long bones. Histologically, ovoid cells with grooved nucleus in a chondroid matrix with or without characteristic ’chicken wire calcification’ is pathognomonic of chondroblastoma. What makes us cautious about chondroblastoma is the possibility of small proportion of cases that can have malignant transformation with local, vascular invasion and distant metastasis.In this case, the authors had a case of radiologically suspected DEH, which histologically turned out to be chondroblastoma.[1] Remote possibility of aggressive nature should prompt us to keep chondroblastoma in the list of rare differentials while encountering atypical epiphyseal lesions that mimic DEH.