Intracranial epidural tuberculoma presenting as a scalp swelling

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Intracranial Epidural Tuberculoma Presenting as a Scalp Swelling Zain Alabedeen B. Jamjoom, M.D., Hasan M. Assaf, M.D., Farouk Hamid, F.R.CR., Qais Haddad, M.R.CP., Abdul-Hakim B. Jamjoom, F.R.CS., and Naim-Ur-Rahman, F.R.CS. Division of Neurosurgery, Departments of Pathology, Radiology, and Medicine, Security Forces Hospital, and Division of Neurosurgery, King Khalid University Hospital, Riyadh, Saudi Arabia

Jamjoom ZAB, Assaf HM, Hamid F, Haddad Q, Jamjoom A-HB, Naim-Ur-Rahman. Intracranial epidural tuberculoma presenting as a scalp swelling. Surg NeuroI1994;42:322-S.

The first case of an intracrtanial epidural tuberculoma with the absence of dural and brain involvement in a 27year-old woman is presented. The possible pathogenesis of this unique lesion is discussed. KEY WORDS: Dural and brain involvement; Intracranial epidural tuberculoma

Intracranial tuberculoma, though rare in Western countries, is a relatively common pathology in many regions of the developing world [4,lOl The literature is fairly rich with studies covering the various aspects of these lesions [3,5,8,9,14-17}. However, to the best of our knowledge, intracranial epidural tuberculoma in the absence of dural and brain involvement has not been reported before. In this article, we describe a case of this kind and discuss its possible pathogenesis.

Case Report A 28-year-old woman presented with a 2-month history of a progressive scalp swelling in the right parietal region, associated with local tenderness and right-sided headache. Her past medical history was unremarkable apart from a cesarian section 6 months prior to admission. Examination There was a firm swelling measuring 4 cm in diameter over the right parietal eminence. The overlying skin had a normal appearance and temperature. On palpation, the

Address reprint requests to: Z. B.Jamjoom, M.D., Division ofNeurosurgery, Security Forces Hospital, P. O. Box 3643, Riyadh 11481, Saudi Arabia. Received March 8,1993; accepted June 21,1993. © 1994 by Elsevier Science lnc.

swelling was slightly tender, and seemed to be fixed to the underlying bone, but not to the skin. There were no lymph nodes palpable in the head and neck, and the patient was afebrile. Otherwise, the general and neurologic examinations revealed no abnormalities. The blood investigations revealed a hemoglobin of 108 g/L (in SI-units; N: 115-165), a platelet count of 462 X 109/L (N: 150-400), and a Westergren erythrocyte sedementation rate of 85 mm in the first hour (N : 0-20). Plain x-ray films of the skull showed a localized patchy osteolytic lesion in the right parietal region, measuring about 5 cm in diameter, and associated with a soft tissue swelling (Figure 1). The chest radiographs were normal. The cranial computed tomography (CT) scan demonstrated a large isodense mass under the right parietal bone, measuring 4 X 6 X 7 cm and causing a moderate compression of the right lateral ventricle, but there was no perifocal edema. The lesion showed multiple tiny flakes of calcification and a shell-like hyperdense margin that enhanced brightly after intravenous contrast injection. The overlying bone was eroded and covered by a soft tissue swelling (Figure 2). A persumptive diagnosis of a convexity meningioma was made.

Operation A large right parietal craniotomy was performed. The scalp swelling was found to be caused by a reddish, subperiosteal mass. The underlying bone was porous with both external and internal table coarsened. After elevation of the bone flap, a large extradural lesion consisting of purulent caseo us material and granulation tissue was exposed. The lesion, which was firmly adherent to the dura, was successfully pealed off the intact dura. Intraoperative frozen section was made, and it showed caseating granuloma consistent with tuberculoma. Exploration of the intradural space was not undertaken because of the risk of spreading the infection. The bone flap was autoclaved and replaced. 0090-3019/941 $7 .00

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drug therapy was continued for 6 months, and 3 months later there was no evidence of any recurrence.

Discussion

Figure 1. Lateral x-ray of skull showing a patchy osteolytic lesion in the right parietal region (arrows).

Pathological Examination The histopathologic examination of both subperioesteal and extradural masses revealed a classic caseating tuberculous granuloma consisting of multiple confluent epitheloid granulomas with large areas of caseating necrosis and numerous Langerhans' giant cells (Figure 3). Specules of necrotic bone were seen in some of the sections. On Ziehl-Neelsen stain, a typical tubercle bacillus was detected within one of the Langerhans' giant cells, leaving no doubt about the tuberculous nature of the lesion (Figure 4).

Postoperative Course The patient was started postoperatively on oral antituberculous chemotherapy consisting of rifampicin (600 mg/d), isoniazid (300 mg/d), pyrazinamide (1.5 g/d), and ethambutol (800 mg/L). A tuberculin skin test, which was performed on the first postoperative day, was positive. The postoperative recovery was uneventful. A postoperative CT scan with and without enhancement confirmed the total excision of the lesion (Figure 5). The

The majority of intracranial tuberculomas are subcortical masses located deeply within the cerebral or cerebellar hemispheres (15]. Occasionally, however, they are more superficial lesions involving subarachnoid or subdural spaces on either convexity or base of the brain (2,9]. Although well over half of the brain lesions are attached at some point to the dura (4}, a broad dural attachment is rare, and may lead to confusion of the lesion with a meningioma (6]. Epidural tuberculoma is even more rare and in all cases reported so far, the lesion was located in the spinal canal (7,12]. Intracranial epidural tuberculoma has, in contrast, not been described. Intracranial tuberculomas commonly present with symptoms of increased intracranial pressure, generalized or partial seizures, and focal neurologic signs (1,3,14]. Although some unusual modes of presentation have been observed occasionally (4}, it is rare that an intracranial tuberculoma presents as a scalp swelling. We were able to identify three cases with a similar presentation in the literature (13, 16}. In all of them, the subcutaneous lesion involved the bone as well as the dura and brain. Our case differs from them in that the lesion was entirely epidural and did not penetrate through the dura to the brain. The paucity of the neurologic manifestations in our patient despite the large size of the intracranial lesion is remarkable. It has been suggested that the symptoms and signs caused by intracranial tuberculomas tend to be less than expected from the size and location of the lesion on the CT scan (4,8]. Nevertheless, in our experience, none of 29 other cases of intracerebral tuberculomas treated in our hospital had produced so little neurologic disturbance as the present lesion. On CT scan, intracranial tuberculoma typically appears as an isodense or slightly hyperdense mass lesion, surrounded by a zone of edema, and enhancing homogeneously, ringlike, or in an irregular fashion. There is, however, no CT finding that is absolutely diagnostic of an intracranial tuberculoma (3,17]. In our case, the broad bone contact, the subgaleal extension through eroded bone, and the absence of perifocal cerebral edema were all atypical CT findings of an intracranial tuberculoma. With the negative history of apyrexial onset and the absence of a concomitant extracranial tuberculous infection, the lesion was difficult to distinguish from a meningioma. The only preoperative laboratory investigation that was suggestive of an inflammatory process was the elevated erythrocyte sedimentation rate. However, this test is unspecific. Unfortunately, the tu-

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Figure 2. Pre-contrast (A-D) and post-contrast (E-H) CT scans demonstrating a large, right parietal, intracranial mass lesion with capsular enhancement.

berculin skin test that was positive, was performed only postoperatively and, thus, not included in our differential diagnostic considerations. However, the diagnostic value of a positive tuberculin skin test has been questioned by some authors because of the high incidence

Figure 3. Photomicrograph of the epidural lesion showing a tubercle with caseating necrosis (thin arrow) and a Langerhans' multinucleated giant cell (thick arrow) (H & E X 160).

Jamjaam et al

of positive results in the population of endemic tuberculosis [14}. Intracranial tuberculoma develops by hematogenous spread from a primary focus, active or dormant, elsewhere in the body [5}. Typically, the primary focus is located in the lung, and mayor may not be seen on xray films of the chest. In epidural tuberculoma, however, the main question is whether the lesion is an extension of another small lesion in a neigh boring bone or starts

Figure 4. Langerhans' type giant cell with an intracellular tubercle bacillus (arrow) (Ziehl-Neelsen

X 1000).

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===============================~-~-----~---~-. Intracranial Epidural Tuberculoma

Figure 5. (A) Enhanced, early postoperative CT scan confirming total excision of the ePidural tuberculoma. There is still a noncompressive fluid collection (hypodense area) under the bone flap, probably due to incomplete expansion of the brain. (B) Bone window of the same section showing the craniotomy and the bony erosion in the middle of the bone flap (arrow).

per see as an entirely extraosseus process with a secondary involvement of the bone. In the spine, where both modes of evolution are well documented, the second mode is rare despite a well developed spinal epidural space with fat and venous plexuses [7,11,12}. In our case, the intact dura precludes that the lesion had originated intradurally, for example as a dural thrombophlebitis. Therefore, in view of the absence of epidural fibrofatty tissue, we are more inclined to believe that the lesion had probably taken its origin from a focus in the skull that extended later epidurally.

References 1. Arseni C. Two hundred and one cases of intracranial tuberculoma treated surgically. ] Neurol Neurosurg Psychiatry 1958;21: 308-11.

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