A Rare and Interesting Case of Sciatic Nerve Compression Due to Proximal Femoral Osteochondroma in a Young Adult – A Case Report

Introduction: Osteochondromas (OCs) are benign hamartomatous lesions composed of cartilage and bone, arising from aberrant growth-plate cartilage. They characteristically project from the bone surface through the cortex and grow by endochondral ossification beneath the periosteum. Lesion growth usually parallels skeletal growth and typically ceases after physeal closure, although minimal growth of the cartilage cap may persist and generally stops by the third decade of life. This developmental mechanism explains the predilection for involvement of the distal femur, proximal tibia, and proximal humerus. Most OCs are asymptomatic and do not require surgical intervention. However, intra-articular or atypically located lesions may produce pain, restricted joint movement, or compression of adjacent neurovascular structures, necessitating operative management. Case Report: A 39-year-old male presented to the outpatient department with complaints of left-sided hip pain associated with restricted range of motion and radiating pain along the posterior aspect of the left thigh, accompanied by buttock pain for 6 months. The symptoms had gradually progressed and were aggravated by activity. The patient also reported mild paresthesia over the anteromedial aspect of the left knee and the dorsum of the left foot. He noticed a gradually enlarging, ill-defined mass in the left gluteal region during the same period. On clinical examination, a firm, immobile mass measuring approximately 10 × 6 cm was palpated in the left buttock. Left hip flexion was limited to 60° due to pain. Neurological examination revealed weakness of both plantar flexion and dorsiflexion of the left ankle. The patient had previously received conservative treatment, including rest, non-steroidal anti-inflammatory drugs, and physiotherapy at another institution, with no improvement in symptoms. Results: The lesion was excised through a posterior approach with the patient positioned in the right lateral decubitus position, as described by Yu et al. The sciatic nerve was identified, carefully dissected, and protected throughout the procedure. The OCs were excised using an osteotome. Intraoperative assessment of the femoral neck revealed no cortical defects or fractures, and no fixation was required. Histopathological examination confirmed the diagnosis of OCs with a cartilaginous cap measuring <1 cm. Conclusion: Sciatic nerve compression symptoms in non-traumatic cases in young adults may result due to intra or extraspinal causes, depending on the anatomical site of involvement. Lumbar intervertebral disc prolapse and spinal canal stenosis constitute the most frequent intraspinal causes. Extraspinal etiologies are comparatively rare and include conditions such as piriformis syndrome and pelvic bone lesions. Benign bone tumors, particularly OCs, though uncommon, should be considered as a potential source of sciatic nerve compression. OCs arising from the femoral neck with intra-articular or posterior extension are rare, particularly in adults, and may present with pain, mechanical restriction of movement, and neurological symptoms due to mass effect. Awareness of such atypical presentations is essential to avoid misdiagnosis and delays in appropriate management.