Intra-articular giant synovial osteochondroma: case reports of the ankle and knee joint

Solitary Extraskeletal Giant Osteochondroma of the Ankle in a Four-Year-Old Boy

Solitary extraskeletal osteochondromas are rare benign lesions usually located close to a joint and are characterized by the absence of continuity with the adjacent bone. They are usually found in the hand and feet and are extremely rarely reported in the growing skeleton. In this paper, we describe a four-year-old boy who presented with a solitary calcified tumor in the posterior part of his ankle. We performed a detailed evaluation using plain X-rays, a CT scan, and an MRI, which revealed a well-demarcated calcified tumor that had the characteristics of an osteochondroma but without any continuity with the bones of the ankle joint. The lesion was treated surgically with the excision of a giant osteochondral lesion. Pathological examination revealed mature cartilage at the periphery with cancellous bone in the central part. Thus, we present the clinical and laboratory investigation of a solitary extraskeletal osteochondroma in the ankle of a four-year-old boy, which is an extremely rare case.

Giant Extra-Articular Synovial Chondromatosis of the Ankle Joint - A Rare Case Report

INTRODUCTION

Synovial chondromatosis (SC) commonly involves large joints such as the knee and hip with smaller joints being less frequently involved. Extra-articular involvement is very rare, and here, we are presenting the first case of giant extra-articular SC originating from the ankle joint.

CASE REPORT

A 42-year-old male presented to the outpatient department with painless swelling over the lateral malleolus for 2 years. Diagnostic imaging suggested the involvement of the synovial lining with the swelling. The mass was excised and histopathology proved the diagnosis of SC.

CONCLUSION

Extra-articular involvement in SC has been mainly reported in the synovial sheath or bursae of the hand and foot, but they can involve ankle joint also. In recent times, there have been concerns about potential malignant transformation of these lesion to chondrosarcoma, diagnosing these lesions have become important.