Imaging features of calvarial tuberculosis: a study of 42 cases

Tuberculosis of the calvaria is a rare entity, and only anecdotal reports describing its imaging features have been previously published in the literature. We report the role of conventional radiography and CT findings on in the evaluation of calvarial tuberculosis in 42 cases.

Forty-two cases of pathologically verified calvarial tuberculosis were analyzed retrospectively by using conventional radiography and CT imaging. The patients included 28 male and 14 female subjects ranging in age from 5 to 48 years (mean age, 16 years). Surgery was performed in 28 patients, and the remaining 14 patients underwent fine needle aspiration cytology. The histologic findings were consistent with the diagnosis of tuberculosis. At follow-up after 2 years, all patients had completely recovered.

The male-to-female ratio was 2:1 (28 male and 14 female). The maximum number of patients affected by calvarial tuberculosis ranged in age from 11 to 20 years (61.2%). The average duration of symptoms was 2.5 months. Thirty-nine (92.8%) patients had subgaleal soft tissue swelling, whereas 31(73.8%) patients had a well-defined lytic lesion in the calvaria. The parietal bone was most commonly affected site of the calvaria (ie, in 22 patients [52.4%]). These lesions were detected at conventional radiography in 34 (80.95%) patients. CT depicted bone destruction in 36 patients (85.7%) cases. Extradural lesions and intraparenchymal pathologies were detected in 22 (52.3%) patients and 5 (11.9%) patients, respectively.

In calvarial tuberculosis, conventional radiographs of the skull show focal bone destruction often with accompanying soft tissue opacity. CT helps in assessing the extent of bone destruction, scalp swelling, and degree of intracranial involvement. Surgery involving bone debridement is resorted to only in cases where bone destruction is extensive.