Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 55, Num. 3, 2007, pp. 289-291

Neurology India, Vol. 55, No. 3, July-September, 2007, pp. 289-291

Original Article

Isolated cerebral Aspergillus granuloma with no obvious source of infection

Challa Sundaram, Uppin ShantveerG, Purohit AnirudhK

Department of Pathology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad - 500 082, AP

Correspondence Address: Department of Pathology, Nizam’s Institute of Medical Sciences, Punjagutta, Hyderabad - 500 082, Andhra Pradesh, India. E-mail: challa_sundaram@yahoo.com

Date of Acceptance: 11-May-2007

Code Number: ni07089

Abstract

Keywords: Aspergillus , fungal granuloma, intracerebral

Intracranial fungal granulomas are uncommon, but surgically treatable lesions. ^{[1],[2],[3],[4],[5]} Most often, the fungal granulomas are due to contiguous spread of the infection from the paranasal sinuses and ear. Rarely, they may be due to hematogenous spread from a focus in the lungs. ^{[3],[4],[5],[6],[7]} Isolated cerebral fungal granulomas without any obvious extracranial focus of infection are extremely uncommon ^[7] and have not received much attention in the literature. This paper presents eight patients with isolated cerebral aspergillus granulomas without obvious extracranial source of infection and discusses the diagnostic challenges.

Materials and Methods

Case records of patients with biopsy/autopsy confirmed intracranial Aspergillus spp. granulomas from January 1986 to December 2006 available in the Department of Pathology, Nizam′s Institute of Medical Sciences, Hyderabad, were reviewed. The data collected included demographic data, clinical characteristics, imaging findings, treatment and outcome. Patients with isolated cerebral aspergillus granuloma without obvious source of infection, as evaluated by imaging studies were included in the study. Histological slides were reviewed for the type of tissue reaction and fungal morphology. Histochemical stains studied included hematoxylin and eosin (H and E), Gomori's silver methenamine (GMS) and periodic acid Schiff (PAS). Culture reports were collected whenever material was submitted for culture.

Results

During the study period of 19 years, there were 86 patients with intracranial fungal granulomas, of which 13 (15.1%) were only intracerebral (i.e. no extracerebral lesions). Of them, eight (61.5%) were Aspergillus spp. granulomas. These accounted for 9.6% of 83 Aspergillus spp. granulomas seen during the study period. The clinical characteristics, radiological features, and outcome are given in [Table - 1].

None of the patients had any predisposing risk factors and all were deemed immuno-competent. The duration of symptoms ranged from one to three months. All the granulomas were supratentorial in location, seven in the right hemisphere and one in the left hemisphere. On computerized tomography (CT) scan, all of them were heterogeneously enhanced lesions with perilesional edema [Figure - 1]. In none of the patients, the diagnosis was suspected preoperatively and/or peroperatively.

The pathology was granulomas with predominance of foreign body giant cells, some of which showed negative staining structures within the cytoplasm in all the eight patients [Figure - 2]. Fibrosis was minimal. Gomori′s silver methenamine stain delineated narrow septate acute angle branching hyphae [Figure - 3]. Based on the morphological characteristics in the histological sections the fungus was typed as Aspergillus spp. Material was submitted for culture in one patient at autopsy which grew Aspergillus niger .

All the patients were started on amphotericin B after the diagnosis was obtained. Two patients died postoperatively. Complete autopsy was done in one of them for whom the pathology was disseminated within the brain [Figure - 2]. No source of infection was identified, even at autopsy, in the rest of the body and contiguous structures. In two patients, there was recurrence of lesion. Four patients were followed up until six months to one year. No subsequent follow-up was available.

Discussion

The preoperative diagnosis of isolated Aspergillus spp. granuloma without an obvious source of infection is quite challenging. ^[7] In none of the patients in the present study the diagnosis of Aspergillus spp. granuloma was suspected preoperatively and intra-operatively. This had resulted in: i) non-submission of the biopsy material for fungal cultures; ii) unnecessary exposure to steroid treatment. There is a possibility of dissemination with steroid exposure as had probably happened in one of our patients.

In the reported series of fungal granulomas the long-term outcome was poor and total cure was achieved in only a few cases. ^[2],[4],[8] Sharma et al. reported six patients in whom the granulomas were located within the brain parenchyma. ^[2] Three of them had ear discharge. Sharma et al. compared the differentiating features between the rhinocerebral and primary intracranial group of patients and concluded that the latter had high mortality due to delayed diagnosis. Surgical intervention with antifungal treatment is crucial in the management of CNS fungal granulomas. ^[2] For fungal granuloma, the treatment options for complete cure are total or near total surgical excision and antifungal treatment. Often, as these lesions are not suspected preoperatively and intraoperatively, the surgical excision may not be optimal as happened in two of our patients.

Isolated cerebral Aspergillus granuloma without obvious source of focus of infection is extremely rare. ^[7] The possible source of infection in these patients is speculative and may be an undetectable small focus of infection in the paranasal sinuses or in the lungs. In all the patients reported herein, we were not able to find an extracerebral infectious focus. For the patient who underwent autopsy, we looked carefully for any focus in the lung, heart and other organs. Our conjuncture is that in patients with frontal and temporal location of the lesion, the portal of entry may be the paranasal sinuses and the ears, respectively. In patients with parietal lesions, the spread may be hematogenous.

In tropical countries from where Aspergillus spp. granulomas are more frequently described, any isolated mass lesion with imaging characteristics of inflammatory pathology should raise the possibility of fungal granuloma. Such an approach is likely to result in an early diagnosis and may avoid poor outcome.

References

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