- Department of Neurosurgery, Nagoya City University West Medical Center, Nagoya, Japan,
- Department of Neurosurgery, Nagoya City University Graduate School of Medical Sciences and Medical School, Nagoya, Japan.
Teishiki Shibata, Department of Neurosurgery, Nagoya City University West Medical Center, Nagoya, Japan.
DOI:10.25259/SNI_541_2021Copyright: © 2021 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Teishiki Shibata1, Nobukazu Hashimoto1, Atsuhiko Okura1, Mitsuhito Mase2. Brain abscess of odontogenic origin in patients with malignant tumors: A report of two cases. 16-Aug-2021;12:417
How to cite this URL: Teishiki Shibata1, Nobukazu Hashimoto1, Atsuhiko Okura1, Mitsuhito Mase2. Brain abscess of odontogenic origin in patients with malignant tumors: A report of two cases. 16-Aug-2021;12:417. Available from: https://surgicalneurologyint.com/surgicalint-articles/11038/
Background: Oral infection and dental manipulations can lead to the development of brain abscesses, a rare but potentially life-threatening condition. Herein, we report patients undergoing cancer treatment who developed brain abscesses of odontogenic origin at our hospital.
Case Description: Two patients developed brain abscesses during cancer treatment. Both underwent neurosurgical aspiration, and the causative microorganism was identified as Streptococcus intermedius of the Streptococcus anginosus group, which is a part of the normal bacterial flora in the oral cavity. There was clinical and radiographic evidence of dental infection in one of the patients diagnosed with a brain abscess of odontogenic origin. No infectious foci were found in the other patient during hospitalization for the abscess. However, the patient had undergone extraction of an infected tooth approximately 3 months before admission for the abscess, suggesting origination from an oral infection or dental manipulation. The patients’ cancers rapidly worsened because cancer treatment in both patients was interrupted for several months to treat the brain abscess.
Conclusion: Oral infections can cause severe infections, such as brain abscesses, particularly during the treatment of malignant tumors. Improving the oral environment or treating oral infections before initiating treatment for malignant tumors is highly recommended. In addition, the possibility of odontogenic origin should always be considered as a potential etiology of brain abscesses.
Keywords: Brain abscess, Malignant tumor, Odontogenic infection
Brain abscess, a focal pyogenic infection of the brain, can be caused by bacteria, mycobacteria, fungi, or parasites (protozoa and helminths).[
A 62-year-old man presented to the emergency department of our hospital with headache and fever for 3 days; he had a history of esophageal cancer and type 2 diabetes mellitus. Approximately 4 weeks before the visit to the emergency department, he had received one cycle of preoperative high-dose chemotherapy with 5-fluorouracil (700 mg/m2 on days 1–4) and cisplatin (70 mg/m2 on day 1). Neurological examination revealed motor aphasia and right hemiparesis. Cranial computed tomography (CT) showed a left frontal mass-like lesion with surrounding vasogenic edema. Subsequent cranial magnetic resonance imaging (MRI) showed a 5.0-cm large left frontal mass lesion, which appeared as a ring-enhancing lesion on gadolinium-enhanced T1-weighted imaging [
After obtaining blood cultures, empirical treatment with intravenous meropenem and vancomycin was initiated, and levetiracetam was administered to prevent seizures; the patient then underwent stereotactic biopsy the next day to definitively diagnose and treat the abscess. During surgery, CT-guided needle aspiration of the lesion yielded purulent discharge, leading to the confirmation of brain abscess. A drainage tube was placed in the abscess cavity after complete abscess evacuation. The blood and purulent fluid were cultured, and S. intermedius growth was observed only in the purulent fluid culture, not in the blood cultures. Antibiotics were de-escalated to intravenous ceftriaxone based on antibiotic-sensitivity test results, and early postoperative MRI revealed a marked shrinkage in the abscess size. Intraoral examination and panoramic radiography revealed that the right maxillary second premolar and second molar had chronic suppurative apical periodontitis [
At 1 month after the surgery, the right hemiparesis had disappeared and the motor aphasia had almost completely disappeared. Gadolinium-enhanced T1-weighted MRI approximately 4 months after the surgery showed shrinking of the lesion with only a very small area of high signal intensity and hydrocephalus secondary to central nervous system infection [
(a and b) Gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) approximately 4 months after the surgery showing shrinking of the lesion with only a very small area of high signal intensity (arrow) and hydrocephalus secondary to central nervous system infection. Hyperintensity in the lesion disappeared completely on diffusion-weighted MRI (not shown).
A 68-year-old man presented to the emergency department of our hospital with a 6-day history of left hemiparesis and 1-day history of fever. The patient had a history of advanced non-small-cell lung cancer and was receiving 3-week cycles of pembrolizumab (200 mg) for approximately 4 months before admission. Initial cranial CT and MRI showed two lesions in the left frontal and right parietal lobes. Both lesions were <2 cm in size and exhibited homogeneous hyperintensity on diffusion-weighted MRI [
Magnetic resonance imaging (MRI) showing two mass lesions of <2 cm in the left frontal and right parietal lobes. Both lesions exhibited ring enhancement on gadolinium-enhanced T1-weighted imaging (a) and homogeneous hyperintensity on diffusion-weighted imaging (b), with vasogenic edema surrounding the lesions on fluid-attenuated inversion recovery (FLAIR) imaging (c). (d) FLAIR MRI obtained 7 weeks later showing slight enlargement of the mass lesion in the right frontal lobe with worsening vasogenic edema.
After blood cultures were obtained, empirical treatment with intravenous meropenem administration was initiated. Levetiracetam was started for seizure prophylaxis. Although the causative pathogen was not identified by blood culture, the lesion sizes reduced remarkably following antibiotic treatment, and left hemiparesis was improved. Therefore, neurosurgical aspiration was not performed. However, his left hemiparesis worsened 7 weeks after treatment initiation. Cranial MRI revealed that the mass lesion in the right frontal lobe was slightly enlarged and the surrounding vasogenic edema was exacerbated [
At 2 months after the surgery, the left hemiparesis had disappeared. Approximately 4 months after the surgery, the lesions had disappeared and the surrounding vasogenic edema had partially improved on the non-contrast MRI [
Approximately 4 months after the surgery, the lesions disappeared on diffusion-weighted magnetic resonance imaging (MRI) (a) and the surrounding vasogenic edema partially improved on FLAIR MRI (b). Postoperative gadolinium-enhanced MRI was not performed because the gadolinium-enhanced MRI was refused.
None of the two patients had sinusitis, ear infection, or recent head trauma or surgery. Echocardiography was negative for cardiac diseases, including endocarditis and congenital heart defects. In addition, no infectious foci were found on the CT of the chest, abdomen, and pelvis.
Despite advances in imaging techniques, laboratory diagnostics, surgical interventions, and antimicrobial treatment, brain abscess remains a serious and potentially life-threatening condition.[
In both cases presented herein, the likely cause of brain abscess was hematogenous dissemination of odontogenic bacteremia. Ewald et al.[
S. intermedius, together with Streptococcus constellatus and S. anginosus, is a member of the SAG, also referred to as the Streptococcus milleri group.[
In the present cases, both patients had malignant tumors as the underlying disease and had oral infection or a history of dental manipulation. In Case 1, the presence of diabetes mellitus, chronic suppurative apical periodontitis, and chemotherapy-induced immunosuppression might have contributed to the brain abscess formation. In Case 2, an immunocompromised state has not been reported as an adverse event of pembrolizumab, a checkpoint inhibitor. However, oral infection or dental manipulation during cancer treatment might have contributed to the development of brain abscess.
Skallsjö et al.[
In this report, we described cases of two patients undergoing cancer treatment who developed brain abscesses of odontogenic origin. In these patients, cancer treatment had to be interrupted for several months. Their cancers rapidly deteriorated during cancer treatment interruption. During treatment for malignant tumor, oral infections can lead to serious infections, such as brain abscess formation. Therefore, improving the oral environment or treating oral infections is recommended before initiating treatment for malignant tumor.
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