Cystic tuberculosis is a rare but well recognised variant reported first by Jungling in early part of 20th century. He called it Osteitis tuberculosa multiplex cystoides. It is also called Jungling’s disease after him. Though it was proved later that what he described was actually sarcoidosis.
Solitary cystic tuberculosis of bone in children is uncommon.
In adults the common sites of skeletal tuberculosis are the skull and axial skeleton and the shoulder and pelvic girdles .In children, the metaphyses of the long bones are often the sites of infection. This predilection is probably due to the vascular structure of the long bones in this region Tubercle bacilli probably lodge in the small terminal branches of the arteries of the metaphysis and grow, caseate and produce a cystic lesion.
Typically, the bone lesions in tuberculosis are round to oval areas of radiolucency, occasionally multilocular, expansile with periosteal reaction and are situated in the peripheral skeleton near the metaphysis. They may extend to involve the cortex and may break through it. The physis is no barrier to spread: lesions may extend into the epiphysis.
Sequestra are uncommon and smaller than in pyogenic infection . The cyst-like appearance is due to the variable marginal sclerosis. These ‘cysts’, however, can occur anywhere in the skeleton. Solitary lesions may mimic bacterial and fungal infections, simple or aneurysmal bone cysts, cartilaginous tumours and osteoid osteoma .
Cystic tuberculosis of the short tubular bones of the hands and feet in young children is uncommon usually showing osteoporosis and honeycombing with or without sequestrum formation. Cystic expansion of bone, termed ‘spina ventosa’, may occur.
Disseminated lytic skeletal lesions in children, as in other age groups, raise the differential of a number of conditions most of which can be categorized as inflammatory (e.g. pyogenic osteomyelitis, syphilis, blastomycosis and coccidioidomycosis) or neoplastic e.g. eosinophilic granuloma (EG) and some small cell tumours of bone like neuroblastoma and non-Hodgkin’s lymphoma.