Contributed by Qing Li, Xiao-He Yang, Jiang Qian
Department of Pathology & Laboratory Medicine, Albany Medical College, Albany, NY 12208
Published on line in September, 2004
CLINICAL HISTORY, RADIOLOGY AND MICROSCOPIC DESCRIPTION:
A previously healthy 6 year-old girl presented to the emergency department with gradually worsening headache, stiff neck, nausea and vomiting, and low-grade fever for several days in the early October. There was no history of trauma, chills, night sweating or upper respiratory tract infection. Physical and neurological examinations as well as routine laboratory tests and chest radiograph were within normal limits. Blood culture for microorganisms was negative.
A head MRI with contrast demonstrated a 2.0 cm ring-enhancing lesion in the right parietotemporal region, consistent with abscess formation (Figure 1. MRI with contrast). The CSF analysis showed WBC 43/mm3 with 96% of lymphocytes, RBC 1/mm3, glucose 52 mg/dl and protein 37 mg/dl. CSF Gram stain and microorganism cultures were negative. The patient was treated empirically with Acyclovir, Oxacillin and Flagyl. The abscess appeared to have responded to the therapy based on a repeat imaging study, although the patient's symptoms were not relieved.
A brain biopsy revealed tissue necrosis, acute inflammatory infiltrate as well as granulomatous response (Figure 2: H&E. Original magnification x10. Arrows indicating multinucleated giant cells). The stains for bacteria, fungi, acid-fast bacilli, herpes virus, cytomegalovirus and toxoplasma were all negative. On the follow up CT and MRI, multiple cystic lesions were noted in both cerebral hemispheres. The second brain biopsy was performed showing multiple foci of microorganisms arranged mostly in perivascular spaces (Figure 3: H&E and Figure 4: Trichrome. Original magnifications x40). Occasional bi-nucleolus form was observed (Figures 5A and 5B: H&E. Original magnification x100). Some of these microorganisms were in cystic form with an outer wall of either smooth or wrinkled contour best demonstrated on Trichrome or PAS stains (Figures 6A and 6B: Trichrome, and Figure 6C: PAS. Original magnification x100). An immunofluorescence antibody stain was performed for further classification of the microorganisms. The therapy was then switched to pentamidine, sulfadiazine, intraconazole and azithromycin. But the patient's condition kept deteriorating and she died in the late January, 75 days after admission. The blood and brain tissue cultures remained negative. At autopsy, the brain sections showed edema, necrosis, tremendous reactive astrogliosis, acute and chronic inflammation and foci of multinucleated giant cell reaction. Scant eosinophils were also present. Partially degenerated microorganisms were focally abundant (not shown).