Tuhcwle ondLun,q Disease (1994) 75, 156-162 0 1994 Longman Group Ltd Correspondence Tuberculosis of the skull: an unusual manifestation A 27-year-old man was admitted with a 2 week history of fever and constitutional symptoms. He was an intra- venous drug user (IVDU). Physical examination showed an axillary temperature of 39°C and soft hepatomegaly. Chest X-ray revealed a miliary pattern. Sputum speci- mens were negative for acid-fast bacilli. Specimens obtained from bronchoalveolar lavage, transbronchial lung biopsy and bone marrow biopsy showed acid-fast bacilli. A diagnosis of miliary tuberculosis was made. Anti-HIV antibodies and antigen p24 of HIV were nega- tive. Four drug treatment (rifampin, isoniazid, etham- butol and pyrazinamide) was started, resulting in clinical improvement. A few days later fever reappeared and the patient developed severe anaemia. Therapy was then changed to ethambutol, pyrazinamide and cycloseryne, resulting in good control of symptoms and improvement of anaemia. The patient was discharged. One month later he was seen again with a 5 x 6 cm soft, non-tender mass in the left parieto-occipital area of the skull. Skull X-ray showed an osteolytic lesion (Figure) just under the mass. Percutaneous needle aspiration yielded 2.50 ml of pus. Ziehl-Nielsen and auramine-rhodamine stains showed acid-fast bacilli. Lowenstein culture failed to grow mycobacteria. Rifampin and isoniazid were added to therapy; no further complications occurred, and two new specimens of pus were sterile. Extrapulmonary tuberculosis (ETB) accounts for 10% of all tuberculous infection. Tuberculous osteitis is found in 20% of all ETB. Tuberculosis of the skull (TS) is a rare manifestation of tuberculosis disease, account- ing for 0,2-1,3% of all tuberculous osteitis. TS is com- monly associated with tuberculosis localized elsewhere (50-75% associated with lung tuberculosis).‘,* Figure-Skull X-ray showing an osteolytic lesion. ETB is much more prevalent in IVDU than in other population groups, independently of the HIV status of the patients. Unhygienic living conditions and immuno- suppression due to drug use are probably key factors.’ Unlike lymphatic spread commonly seen in tuber- culous osteitis of other localisations, in TS the myco- bacteria reach skull bones through the bloodstream. Concentrally placed, fibroblasts proliferate and encircle the tuberculous granulation tissue, preventing infection spread through the diploe. If the limiting process does not succeed, infection spreads through either of the tables. It follows a silent course, appearing as an epi- dural and/or subgaleal abscess. The frontal and parietal bones are those most usually involved.’ Radiological features are non-specific (osteolytic and osteoblastic lesions). Many lesions enter into the radio- logical differential diagnosis such as: pyogenic osteo- myelitis, calvarial metastasis, myeloma, hemangioma, meningioma, giant cell tumor; histiocytosis X and aneu- rismal bone cysts.?,” Definitive diagnosis is usually made by the demonstration of mycobacterium bacilli in speci- mens obtained by percutaneous needle aspiration, bone biopsy or both. However, when it fails, the association of suggestive clinical, radiological and histopathological data with the existence of active tuberculosis elsewhere, establishes a highly probable diagnosis.‘*3 In our case re- port, the early withdrawal of rifampin and isoniazid could have played an important role in the development of TS. The increasing incidence of tuberculosis in IVDU and in HIV-infected patients5 must alert clinicians to a future increase in the number of atypical presentations of tuberculosis. F. Gamboa J. Gomez-Mateos L. F. Lopez-Cortes F. Lozano de Leon F. Garcia-Bragado Infectious Diseases Unit Internal Medicine Department Hospital Universitario De Valme Ctra de Cadiz sin. 41014 Sevilla Spain References 1. Le Roux P D et al. Tuberculosis of the skull - a rare condition: Case Report and Review of the Literature. Neurosurgery 1990; 26: 85 l-856. 156