Brain abscess mimicking an intracranial mass on radiologic examinations: a case report

A 49-year-old woman who had a headache for ten days was evaluated in the emergency department. Because the physical examination was normal, an intracranial mass was suspected, and brain computed tomography (CT) revealed an edematous intracranial lesion with an 8.3-millimeter shift in the right occipito-parietal region. In venous blood samples, leukocyte count was 17360 uL (normal range:4000-10000 uL), C-reactive protein level was 9.42 mg/L (normal range:0-5 mg/L), procalcitonin 0.027 ng/ml (normal range:0-0.05 ng/ml). Choline/NAA (N-acetyl aspartate) peaks that may be in favor of malignancy were obtained in the mentioned lesion in brain MR-spectroscopy images. Contrast-enhanced CT scan of the thorax, abdomen, and pelvis revealed no tumor focus. She underwent a right occipital craniotomy. After opening the mass capsule, a yellow-green, thick, odorless purulent material discharged. Gram-positive diplococci were detected in the emergency smear preparations of this purulent material and "Streptococcus porcinus" growth was detected in the subsequent culture. After the normalization of blood biochemistry values and marked improvement in brain MR images, the Infectious Diseases Department terminated antibiotic treatment at the end of the fifth month. As seen in this patient, radiologic imaging may sometimes not be sufficient to make the correct diagnosis and may lead to different diagnoses.