Imaging in tuberculosis of the skull and skull-base: case report

Neuroradiology (2003) 45: 160–163 DOI 10.1007/s00234-002-0921-9 S. Sencer A. Sencer K. Aydin K. Hepgül A. Poyanlı O. Minareci Received: 4 December 2001 Accepted: 6 November 2002 Published online: 13 February 2003
Springer-Verlag 2003 S. Sencer (&) Ataköy, 9 Kisim, A4-B D: 81 veya 87, 34750 Istanbul, Turkey E-mail: [email protected] Tel.: +90-212-5331380 Fax: +90-212-5331380 S. Sencer Æ K. Aydin Æ A. Poyanlı O. Minareci Department of Radiology, Istanbul School of Medicine, Istanbul University, Istanbul, Turkey A. Sencer Æ K. Hepgül Department of Neurological Surgery, Istanbul School of Medicine, Istanbul University, Istanbul, Turkey DIAGNOSTIC NEURORADIOLOGY Imaging in tuberculosis of the skull and skull-base: case report Abstract We report a 19-year-old girl, who presented with headache and tonic/clonic seizures. Imaging revealed a lytic parietal skull lesion with an adjacent epidural mass, masses in the right parietal lobe and a posterior skull-base mass. The diagnosis of tuberculosis was made after resection of the extradural mass and later verified with culture of Mycobacterium tuberculosis. The parenchymal and skull-base lesions resolved following antituberculous treatment. We present CT, scintigraphic, angiographic and MRI findings. Introduction Tuberculosis of the skull and skull base is rare. Calvarial tuberculosis accounts for only 1% of cases of skeletal tuberculosis [1]. Skull-base involvement has seldom been reported with CT and MRI findings [2, 3, 4, 5, 6]. Published reports concentrate on the radiographic and CT findings in skull tuberculosis and there are only three in the English literature reporting MRI findings of calvarial tuberculosis [7, 8, 9, 10]. Case report A 19-year-old girl was admitted with right frontal headache of 3 months’ duration, which had worsened during the last weeks. She also reported one episode of tonic/clonic seizures starting on the Keywords Skull Æ Tuberculosis left 4 days before admission. Examination revealed a 1·1 cm bone defect, palpable over the right parietal bone, and a left hemiparesis. Laboratory investigations were normal except for mild monocytosis (13.4%) and an increased erythrocyte sedimentation rate (76 mm/h). A relatively well-circumscribed lytic lesion with no sclerotic reaction was detected in the right parietal region on skull radiographs (Fig. 1). CT showed the right parietal lytic lesion and an adjacent homogeneous, extra-axial mass isodense with the adjacent cerebral cortex, which enhanced diffusely with contrast medium. There was considerable oedema in the right parietal lobe and some nodular parenchymal enhancement next to the extradural mass. On bone windows, destruction in the right side of the clivus was evident (Fig. 2). Tc 99M-MDP scintigraphy was performed to search for other bone lesions; increased uptake was detected in the right parietal region, but not in the skull base or elsewhere (Fig. 3). On MRI, a right parietal epidural mass was seen, isointense with cortex on T1-weighted and giving intermediate to low signal on T2weighted images, and showing diffuse, strong contrast enhancement. A few intra-axial masses with irregular rim enhancement were detected in the adjacent brain. There was considerable oedema 161 Fig. 1 Lateral skull radiograph showing a well-circumscribed right parietal lytic lesion Fig. 2 CT, bone window, shows erosion of the greater wing of the sphenoid wing on the right and the adjacent half of the clivus Fig. 3 Bone scintigraphy: there is increased right parietal uptake; the skull base is normal in the white matter. A small scalp mass was also present adjacent to the lytic lesion (Fig. 4). The fatty marrow in the right side of the clivus and right petrous apex was replaced by intermediate-signal material. A soft-tissue mass extended from the posterior clivus into the pontine cistern. There was strong contrast enhancement of the bone and soft tissue mass (Figs. 5, 6). A presumptive diagnosis of metastasis or haematological malignancy was made. Thoracoabdominal CT performed for localisation of possible malignancy showed pleural and parenchymal sequelae of tuberculosis in the lung apices and some nonspecific infiltration in the upper lobes. We decided to resect the parietal epidural mass, for the Fig. 4 Coronal contrast-enhanced T1-weighted image showing a right parietal epidural mass with diffuse enhancement, adjacent to the lytic lesion Fig. 5a, b MRI. a Axial T2 and b contrast-enhanced T1-weighted images show a diffusely enhancing mass, giving intermediate signal in a, in the right parasellar area extending to the posterolateral clivus Fig. 6 Sagittal T1-weighted image: the skull-base mass extends posterolateral to the clivus purposes of diagnosis and decompression. Preoperative cerebral angiography, with a view to possible embolisation showed no pathological blush. A right parietal craniotomy was performed and the lytic part of the bone was removed. The lesion had already infiltrated the galea. A greyish extradural mass was totally excised together with the infiltrated underlying dura mater. The latter was repaired with a homologous fascia lata graft. Cranioplasty was planned for a later time. The histological diagnosis from the surgical specimen was tuberculosis due to detection of Langhans type giant cells and caseous necrosis. Material sent for Ziehl-Nielsen stain revealed 162 acid-fast bacilli and there was subsequently growth of mycobacteria in culture, verifying the diagnosis. The parenchymal and skullbase lesions were assumed also to be tuberculomas. The patient made an uneventful recovery and we initiated fivedrug antituberculous treatment with isoniazid (300 mg/day), rifampacin (600 mg/day), ethambutol (2 g/day), pyrazinamide (2 g/ day) and streptomycin (1 g/day). The headache and hemiparesis resolved following surgery. The patient was kept on anticonvulsants for 2 months’ follow-up, during which there were no new seizures. MRI 2 and 4 months after the operation showed no recurrent or residual right parietal mass and total resolution of the parenchymal lesions. The skull base lesion had disappeared. At 6-month follow-up, the patient appeared well; no imaging was performed. Antituberculous treatment will be continued for a total of 12 months. Discussion Tuberculosis, a disease previously thought to exist mainly in the developing countries, has had a worldwide resurgence because of increasing immigration and an immunosuppressed population in the developed countries. Involvement of the skull is rare; the most recent large series, dating from 1981, highlights plain radiographic findings [11]. Since then, occasional case reports concentrating on radiographic and CT findings and surgical treatment of calvarial tuberculosis have been published [1, 8, 9, 11, 12, 13, 14]. On plain films the skull may show circumscribed or diffuse lytic or circumscribed sclerotic lesions [11]. Both our patient’s lesions were lytic with no sclerotic reaction, although lesions in the sphenoid bone in four cases reported by Witcombe and Cremin [3] did show a sclerotic reaction. Uptake in the skull-vault lesion on scintigraphy suggests osteoblastic activity; there was no uptake in the skull-base lesion. Spatial resolution of scintigraphy may be lower for skull-base lesions or it may be that the metabolic response of the bone to infection challenge is different in the two sites. CT usually shows in the form of peripherally enhancing, low density, extradural soft-tissue masses on both sides of a lytic skull lesion [1,7, 11, 12, 13, 14]. Although nonspecific, peripheral enhancement on CT and MRI is suggestive of tuberculosis given appropriate clinical and laboratory findings [9, 12]. In our case, the extracranial portion of the lesion was very small with no evident soft-tissue swelling on examination. The extradural soft-tissue mass had radiographic features similar to those of cerebral cortex on CT and T1-weighted images and gave low to intermediate signal on T2 weighting. Enhancement on both CT and MRI was diffuse rather than peripheral, suggesting of a solid tumour, not granulation tissue or pus, which made diagnosis of tuberculosis difficult. Both skull lesions were avascular on catheter angiography, although some blush has been reported with parenchymal tuberculomas [1]. With these imaging findings, the presumptive diagnosis was a haematological neoplastic disease, metastasis or myeloma; however, there were no specific diagnostic criteria. The mycobacterium reaches the bone by haematogenous spread from a focus, usually in lung and skull involvement is in the cancellous bone and diploe, especially in the bones of the vault in children and young adults [12]. Our patient was in the common age range for skull involvement and retrospectively, the infiltration in the upper lobes was thought to be reactivation tuberculosis. In intracranial tuberculosis, definitive diagnosis of tuberculosis by isolation of mycobacteria and growth in culture [1] can be achieved by acquiring material during open surgery, as in our case or drainage of material from a sinus tract or fistula. Surgery is indicated whenever there is sinus formation, neurological deficit or diagnostic uncertainty [7]; in our patient, the last two of these applied. The dura mater is extremely resistant to calvarial tuberculosis and cerebral tuberculosis occurs in only a small number of patients with skull lesions [12]. In our patient, the dura mater was found to be infiltrated; it was resected, with a patch graft. The parenchymal tuberculomas near the epidural mass may have resulted from direct spread through the broken dural barrier. References 1. LeRoux PD, Griffin GE, Marsh HT, Winn HR (1990) Tuberculosis of the skull - a rare condition: case report and review of the literature. Neurosurgery 26: 851–856 2. Selvapandian S, Chandy MJ (1993) Tuberculous granuloma of the clivus. Br J Neurosurg 7: 581–582 3. Witcombe JB, Cremin BJ (1978) Tuberculous erosion of the sphenoid bone. Br J Radiol 51: 347–350 4. Krishnan A, Patkar D, Patankar T, et al (2001) Craniovertebral junction tuberculosis: a review of 29 cases. J Comput Assist Tomogr 25: 171–176 5. Moon WK, Han MH, Chang KH, et al (1997) CT and MR imaging of head and neck tuberculosis. 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