Bones are frequently involved in advanced mycetoma of the soft tissue. Occasionally primary bone mycetoma in the absence of soft tissue involvement is seen. M. mycetomatis produces lytic lesions which are large in size, few in number and have well defined margins.
Actinomycetoma destroys bone and also evokes new bone formation. The cavities produced are usually smaller in size, numerous and have no definite margins. A periosteal reaction with new bone formation and sun-ray appearance may be seen in radiographs. This features along with Codaman’s triangle simulates the radiographic changes in osteogenic sarcoma.