Infectious Granulomas of Bones and Joints, with Special Reference to Coccidioidal Granuloma

OCCASIONAL infections of bone and joint, pathologically infectious granulomas, are caused by pathogenic fungi. They include blastomycosis, coccidial granuloma, actinomycosis, mycetoma, and torulosis. Because of their comparative rarity and resemblance, clinically and roentgenographically, to more common infections, they are readily overlooked. Diagnosis frequently comes as a surprise by recognition of the organism. Presenting symptoms vary widely and cases will be seen by many kinds of medical workers. Positive diagnosis depends upon identification of the organism, therefore, upon general alertness, in order that this study be made. Proper cultures and animal inoculation are required, since the organisms are frequently not recovered by direct examination of discharges and tissues. Even on culture, the report is frequently “staphylococci” or “nogrowth.” Repeated animal inoculation is sometimes required. Therefore, suspicion of mycosis should be readily roused and persistently followed. The roentgenologist will see cases properly studied and may aid diagnosis if there are criteria suggesting the diseases. Our approach to mycosis of bone and joint must be through coccidioidal granuloma, 70 cases of which we have seen to date. Comparisons may be made with common infections, and attempted with other mycoses through the literature and our own few cases. The following description is made with reservation that the lesions observed are too few to include all types, and are particularly inadequate upon which to erect criteria for exclusion of the disease. Coccidioidal Granuloma By extension, lesions of bone may occur from adjacent primary infection of skin. A granulomatous node or intractible infection of skin develops to a slowly growing ulcer which may invade deeper structures. Lesions arising metastatically (the majority) may either arise in bone or invade it from adjacent soft tissue foci. Origin in bone may be central or peripheral, epiphyseal or diaphyseal, in a region of cancellous bone. One lesion arising in tubular bone is not positively established. Peripheral lesions may rise subperiosteally or by extension from soft tissue. Except in the hand and foot, lesions by extension appear also to elect spongy bone. Spread to bone at ligamentous and tendinous attachments may partially explain a “bony prominence” predilection, later to be mentioned. The origin of advanced lesions is often not determinable. Osseous involvement is predominately destructive, complete, or a partial “permiation.” Margins of lesions may be “punched out” or diffuse. Bone production is variable: many foci have none, some have it marginally, and a few have it within the focus of destruction. Rarely it predominates. The one sclerosis seen is so at variance with all the others that it cannot be accepted on the fact that it occurred in a proven case.