Diagnosis and treatment of metastatic alveolar echinococcosis in the brain of a Tibetan patient : A case report

Background: A case of primary alveolar echinococcosis (AE) in the liver with kidney and brain metastases was treated at our hospital. The analysis of this case might provide suggestions for the diagnosis and treatment of other cases of AE in the brain. Methods : To determine the disease status of AE in the liver and brain in this patient, computed tomography (CT) of the abdomen and head magnetic resonance imaging (MRI) were performed before surgery. Additionally, the serum of the patient was analyzed using an enzyme linked immunosorbent assay (ELISA) for antibodies against echinococcus. The left pterional approach was selected for head surgery. Along the edema zone around the lesion, complete excision was performed encompassing an area of about 5 mm surrounding the lesion. After surgery, pathological and immunohistochemical examinations of the lesion were performed, and deoxyribonucleic acid (DNA) was extracted for molecular identification. This patient was followed up regularly post-discharge to evaluate the outcome. Results: Anti-echinococcus antibodies were strongly positive in the patient’s serum, and the eosinophil ratio was 20%. The head MRI showed a single lesion in the left temporal lobe. Multiple nodular and small cystic long T 1 short T 2 signals were seen in the lesions. An enhanced scan indicated multiple ring-enhancements, the boundary was unclear, and the size of lesion was 3.2 mm×1.8 mm. Neurological symptoms improved after the surgery. The result of histopathological examination was consistent with the characteristics of AE. Immunohistochemistry showed that the peripheral glial cells were positive for glial fibrillary acidic protein (GFAP) and the Ki-67 index was <3%. DNA analysis identified the parasite as the Asian strain of Echinococcus multilocularis, and the sequence identity with the reference strain was practically 100.00%. Conclusion: Surgery is still the first choice of treatment for single, superficial AE lesions, and those located in nonfunctional areas of the brain. It is suggested that early radical treatment and standard drug treatment of primary hepatic AE are important steps to avoid secondary encephalic AE. Patients need to take albendazole for a long time after the operation, and should be followed-up regularly.