Joint Bone Spine 77 (2010) 614–615 Case report An unusual case of sciatic neuropraxia due to melorheostosis Raj Singh a,* , Zile Singh a , Renu Bala b , Parveen Rana c , Sukhbir Singh Sangwan a a Department of Orthopaedics, Paraplegia and Rehabilitation, Pt. BD Sharma Post Graduate Institute of Medical Sciences, H. No. 19/11J, Medical Campus, PGIMS, 124001 Rohtak, Haryana, India b Department of Anaesthesiology and Critical Care, Pt. BD Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India c Department of Pathology, Pt. BD Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India article info Article history: Accepted 15 April 2010 Available online 1 July 2010 Keywords: Osteosclerotic dysplasia Melorrheostosis Sciatic nerve neuropraxia abstract Melorrheostosis is a rare osteosclerotic bone dysplasia of obscure etiology. The typical radiographic fea- tures are flowing candle wax, sub-periosteal bone and streaky endosteal bone formation in diaphyseal and epiphyseal area with sclerotomal pattern mainly involving appendicular skeleton. It is rarely asso- ciated with nerve palsies. The authors report a case of melorrheostotic mass causing sciatic neuropraxia and to the best of their knowledge it is the first case reported in the English language literature. © 2010 Société franc ¸ aise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved. 1. Introduction Melorrheostosis was first described by Leri and Joany in 1922 [1]. It is also known as Leri’s disease, Hyperostose en coulée de bougie, Osteosis eburnisans monomelia and Osteopathia hyperostotica congenital membri unius [1–3]. Melorrheostosis is an uncommon linear slowly progressing hyperostosis. It primarily involves bones although may be associated with soft tissue changes. We report an atypical presentation of melorrheostosis where sciatic neuropraxia occurred due to the mass, which warranted surgical procedure. 2. Case report A 22-year-old male, student presented with mild to moderate pain and paraesthesia in left lower limb while sitting on chair and on squatting, and occasional mild weakness of foot dorsiflexors on prolonged sitting for the last two years. The pain radiates from gluteal area to leg and foot. There was no history of trauma, any infection in the gluteal area or back. On examination, there was restriction of full flexion and external rotation, all other movements were normal and pain free. Other joints of the limb and spine exami- nation were unremarkable. Neurologicaly there was mild weakness of foot dorsiflexors power (4/5). Radiological examination of the pelvis with both hips showed osteosclerotic mass in the pelvi- acetabular area (Fig. 1). CT scan showed the osteosclerotic mass arising from posterosuperior wall of acetabulum and some part of ischium and overhanging the posterior wall (Fig. 2). In view of the sciatic nerve compression, the decision of surgical decompression * Corresponding author. Tel.: +91 - 9416216950; fax: +91- 9416216950. E-mail address: rajpotalia@gmail.com (R. Singh). was taken. Patient was planned for surgery and per-operatively there was a big sclerotic mass underneath the gluteus maximus and found pressing the sciatic nerve. After surgical decompression, the signs and symptoms of neuropraxia disappeared, although only partial debulking of the mass was possible (Fig. 3). At follow-up of 2 1/2 year, there was no further increase in the amount of mass and patient was free of symptoms and his hip movements improved, however full flexion could not be achieved. 3. Discussion Melorrheostosis occurs mostly in the first two decades, although the age of presentation, vary widely. Primarily, the appendicu- lar skeleton is involved in this lesion. It is usually asymptomatic and detected incidently. But in symptomatic cases, the presenting feature could be pain, joint stiffness, deformity, contractures and muscle wasting [3,4]. In our case, the presentation was limitaion of hip movement, sciatic neuropraxia and rediculopathy. Radiologi- cally there was an osteosclerotic mass present on pelvi-acetabular area and typical candle wax appearance was not there. CT scan and biopsy of the mass confirmed the diagnosis. Leri’s disease is self-limiting mesenchymal dysplasia for which conservative management is usually done. But in our case, the mass was compressing the sciatic nerve leading to its weakness, hence the surgery was performed. The whole mass could not be excised, only debulking was done and sciatic nerve was decompressed. Neuropraxia of the sciatic nerve resolved completely and patient remained completely asymptomatic except for the limitation of terminal flexion of hip. Melorrheostosis have been reported to cause carpel tunnel syn- drome in children owing to osteosclerosis of cortical bone making the carpal tunnel smaller. Median nerve compression occurs as a 1297-319X/$ – see front matter © 2010 Société franc ¸ aise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved. doi:10.1016/j.jbspin.2010.04.006