Abstract
Four patients with an unusual type of bone lesion are reported. the histological diagnosis in two of them was non—specific chronic inflammation and one case was diagnosed as chronic eosinophilic granuloma. on subjecting the material to culture Mycobacterium Kansasii (a photochromogen) were isolated. It is suggested that M. Kansasii are capable of producing osteoarticular lesions with a rather vague clinical and radiological picture not typical of osteoarticular tuberculosis.