A case report and literature review of pediatric multifocal melorheostosis in a unilateral limb

Introduction and importance: Melorheostosis (Léri-Joanny syndrome) is a rare, nonhereditary, congenital sclerotic bone dysplasia with an estimated prevalence of 0.9 per million. Its enigmatic etiology and distinctive “melting wax” radiological appearance warrant detailed case reporting to enhance understanding of diagnosis and management, particularly in pediatric populations. Case presentation: A 9-year-old male presented with incidental right upper limb bone abnormalities discovered post-trauma. Asymptomatic without pain/swelling, he had no relevant family history. Laboratory tests (CBC, CRP, ESR) were normal. Imaging revealed unilateral cortical sclerosis with increased density in the right scapular coracoid process, humeral head, distal humerus, ulnar head, wrist, and metacarpals, exhibiting a pathognomonic “melting wax drip” pattern. Histopathology confirmed irregular endosteal bone proliferation, densely arranged lamellar bone, and enlarged/distorted Haversian canals . Clinical discussion: Melorheostosis predominantly affects limbs unilaterally; multifocal involvement (as here) is uncommon. Radiography remains the diagnostic cornerstone, supplemented by CT/MRI for spatial extent. This case was classified as endosteal subtype. Management is symptom-directed: asymptomatic cases require monitoring only. Surgical correction (e.g., osteotomy) is reserved for severe pain/deformity refractory to analgesics/physiotherapy. Long-term follow-up is critical due to theoretical malignant transformation concerns, though unreported clinically. Conclusion: This pediatric case underscores melorheostosis’ incidental presentation and diagnostic reliance on classic imaging. The patient remained asymptomatic over 6 months, obviating intervention. Longitudinal surveillance is planned to elucidate natural history, contributing to management paradigms for this rare entity.