[Malignant transformation of chronic osteomyelitis: a case report]

Malignant transformation of chronic osteomyelitis is a rare and late complication which mainly occurs at the level of the edges of a fistulous tract with extension and infiltration to the surrounding soft tissues and more rarely to bones. We here report the case of Mr N.J. aged 67 years, followed up for chronic osteomyelitis of the right femur fistulized to the skin and evolving since the age of 16 years. He presented with secerning fistulas. Imaging examination showed pathologic fracture due to osteolytic lesion of the lower extremity of the right femur associated with poorly defined intra-medullary collection of fluid measuring 8 cm along its longer axis. The patient underwent surgical resection of the fistulas with complete evacuation and curettage of the bone cavity. Pathological examination showed differentiated keratinising squamous cell carcinoma, infiltrating the fistulous tract and extending to the soft parts and to the lower extremity of the right femur. Staging was negative. Disarticulation of the HIP was performed. At two-years follow-up the patient was doing well without local recurrence or distant metastasis. Initial treatment of chronic osteomyelitis is essential to prevent alarming complications. Amputation is the treatment of choice in patients with malignant transformation of chronic osteomyelitis in particular to squamous cell carcinoma, as in the case of our patient, in order to to prevent secondary involvement.