A Rare Case of Melorheostosis Presenting with Extra-osseous Lesions Around the Knee: Case Report

Melorheostosis was initially identified in 1922 by Leri and Joanny. It is often referred to as candle bone disease, melting wax syndrome, or Leri disease. This mesenchymal condition is uncommon, benign, and non-heritable. There is still a lack of clarity regarding the underlying cause of the condition. The estimated incidence is 0.9% per million. No inherited traits have been identified, and both sexes are equally affected. Pain or swelling is the most typical symptoms, and the onset is insidious. People often call this condition "candle disease of the bone" because the radiological signs of it look like dripping candle wax.

A 56-year-old female presented with an 8-year history of the left knee pain, swelling, and movement restriction. On examination, a hard, bony lump measuring 12×5 cm was located on the outer aspect of the left knee. The skin over the lump's surface was neither erythematous nor warm. Plain radiographs revealed a wide, dense, undulating, or irregular cortical hyperostosis, resembling candle wax, spreading along the length of the fibula bone as well as an extra-osseous calcification mass across the lateral aspect of the left knee. The patient underwent excision with complete left knee motion.

Melorheostosis' actual etiology is yet unknown. There is no established treatment for this condition. Only symptomatic treatment helps patients feel better; in some circumstances, the excision of a bone mass yields more beneficial results.