Isolated Cerebral Alveolar Echinococcosis

Comparison of clinicopathological features between cerebral cystic and alveolar echinococcosis: analysis of 27 cerebral echinococcosis cases in Xinjiang, China

BACKGROUND

Cerebral echinococcosis is relatively rare, and it is important to distinguish cerebral cystic echinococcosis (CCE) from cerebral alveolar echinococcosis (CAE) in terms of pathological diagnosis. We aim to describe the different clinicopathological features among patients with CCE and CAE.

METHODS

We collected 27 cases of cerebral echinococcosis which were diagnosed in the Department of Pathology of the First Affiliated Hospital of Xinjiang Medical University from January 1, 2012, to June 30, 2023. We compared the patients' clinical characteristics, MRI features, and pathologic manifestations of CCE and CAE.

RESULTS

Among 27 cases of cerebral echinococcosis, 23 cases were CAE and 4 cases were CCE. The clinical manifestations of both CCE and CAE patients mainly included headache (21 patients, 77.78%), limb movement disorders (6 patients, 22.22%), epileptic seizures (4 patients, 14.81%) and visual disturbances (2 patients, 7.41%). The average onset age of CAE cases was 34.96 ± 11.11 years, which was 9.00 ± 7.26 years in CCE cases. All CAE patients presented with multiple involvements in the brain and extracranial organs while all CCE patients observed a solitary lesion in the brain and 3 CCE cases had no extracranial involvement. Lesions of CCE in MRI showed a single isolated circular, which was well demarcated from the surrounding tissues and with no obvious edema around the lesions, whereas CAE lesions presented as multiple intracranial lesions, with blurred edges and edema around the lesions, and multiple small vesicles could be observed in the lesions. The edge of CAE lesions could be enhanced, while CCE lesions have no obvious enhancement. CCE foci were clear cysts with a wall of about 0.1 cm. Microscopically, the walls of the cysts were characterized by an eosinophilic keratin layer, which was flanked on one side by basophilic germinal lamina cells, which were sometimes visible as protocephalic nodes. While the CAE lesion was a nodular structure with a rough and uneven nodule surface, and the cut section was cystic and solid; microscopically, the CAE lesion had areas of coagulative necrosis, and the proto-cephalic nodes were barely visible. Inflammatory cell areas consisting of macrophages, lymphocytes, epithelioid cells, plasma cells, eosinophils, and fibroblasts can be seen around the lesion. Brain tissues in the vicinity of the inflammatory cell areas may show apoptosis, degeneration, necrosis, and cellular edema, while brain tissues a little farther away from the lesion show a normal morphology.

CONCLUSIONS

With the low incidence of brain echinococcosis, the diagnosis of echinococcosis and the differential diagnosis of CAE and CCE are challenging for pathologists. Grasping the different clinical pathology characteristics of CAE and CCE is helpful for pathologists to make accurate diagnoses.

Alveolar echinococcosis in immunocompromised hosts

BACKGROUND

Alveolar echinococcosis (AE) results of an infection with the larval stage of Echinococcus multilocularis. It has been increasingly described in individuals with impaired immune responsiveness.

OBJECTIVES

This narrative review aims at describing the presentation of AE according to the type of immune impairment, based on retrospective cohorts and case reports. Implications for patient management and future research are proposed accordingly.

SOURCES

Targeted search was conducted in PubMed using ((alveolar echinococcosis) OR (multilocularis)) AND ((immunosuppressive) OR (immunodeficiency) OR (AIDS) OR (solid organ transplant) OR (autoimmunity) OR (immune deficiency)). Only publications in English were considered.

CONTENT

Seventeen publications were found, including 13 reports of 55 AE in immunocompromised patients (AE/IS) and 4 retrospective studies of 755 AE immunocompetent patients and 115 AE/IS (13%). The cohorts included 9 (1%) solid organ transplantation (SOT) recipients, 2 (0.2%) HIV patients, 41 (4.7%) with chronic inflammatory/autoimmune diseases (I/AID) and 72 (8.3%) with malignancies. SOT, I/AID and malignancies, but not HIV infection, were significantly associated with AE (odds ratios of 10.8, 1.6, 5.9, and 1.3, respectively). Compared to AE immunocompetent patients, AE/IS was associated with earlier diagnosis (PNM stages I-II: 49/85 (58%) vs. 137/348 (39%), p < 0.001), high rate of atypical imaging (24/50 (48%) vs. 106/375 (28%), p < 0.01), and low sensitivity of serology (19/77 (25%) vs. 265/329 (81%), p < 0.001). Unusually extensive or disseminated infections were described in SOT and I/AID patients.

IMPLICATIONS

Patients who live in endemic areas should benefit from serology before onset of a long-term immunosuppressive therapy, even if the cost-benefit ratio has to be evaluated. Physicians should explain AE to immunocompromised patients and think about AE when finding a liver lesion. Further research should address gaps in knowledge of AE/IS. Especially, extensive and accurate records of AE cases have to be collected by multinational registries.

An immunocompetent farmer with isolated cerebral alveolar echinococcosis: illustrative case

BACKGROUND

Alveolar echinococcosis is a rare condition, but living or working in a rural environment is a substantial risk factor. The liver is the organ primarily affected, with additional extrahepatic manifestations in approximately 25% of cases. Primary extrahepatic disease is rare, and isolated cerebral involvement is extremely unusual.

OBSERVATIONS

The authors described an illustrative case of isolated cerebral alveolar echinococcosis in an immunocompetent farmer. Magnetic resonance imaging of the brain showed a predominantly cystic lesion with perifocal edema and a “bunch of grapes” appearance in the left frontal lobe. Histology revealed sharply demarcated fragments of a fibrous cyst wall accompanied by marked inflammation and necrosis. Higher magnification showed remnants of protoscolices with hooklets and calcified corpuscles. Immunohistochemistry and polymerase chain reaction (PCR) analysis confirmed the diagnosis of cerebral alveolar echinococcosis. Interestingly, serology and thoracic and abdominal computed tomography results were negative, indicative of an isolated primary extrahepatic manifestation.

LESSONS

Isolated, primary central nervous system echinococcosis is extremely rare, with only isolated case reports. As in the authors’ case, it can occur in immunocompetent patients, especially persons with a rural vocational history. Negative serology results do not exclude cerebral echinococcosis, which requires histological confirmation. Immunohistochemical staining and PCR analysis are especially useful in cases without classic morphological findings.

Clinical Features, Radiological Characteristics, and Outcomes of Patients With Intracranial Alveolar Echinococcosis: A Case Series From Tibetan Areas of Sichuan Province, China

Objectives: Intracranial alveolar echinococcosis (IAE), a zoonotic disease, is a critical health problem in the Tibetan region. We aimed to describe the clinical and radiological characteristics and outcomes among patients with IAE.

Methods: We screened patients diagnosed with IAE between March 2015 and May 2019 at the Ganzi Tibetan Autonomous Prefecture People's Hospital. Detailed demographics, clinical characteristics, neuroimaging features, and outcomes were recorded.

Results: A total of 21 patients with an average age of 44.1 ± 12.7 years were included. Thirteen (61.9%) patients were male. The most common chief neurological complaint was headache (n = 17, 81.0%), followed by dizziness, seizure, visual disturbances, hemiparesis, disturbed consciousness, and dysphasia. All the patients had coexisting liver localizations. The typical neuroimaging features of IAE on cerebral magnetic resonance imaging scans showed obvious low-signal shadow with multiple small vesicles inside the lesions on T2-weighted images and FLAIR images. The pathological HE staining demonstrates vesicular lesions with several internal sacs. For hepatic alveolar echinococcosis (AE), the hepatic portal was invaded in six (28.6%) patients, and the portal vein (n = 5, 23.8%) was the mostly commonly involved vessel. As for treatment, 11 patients (52.4%) had poor compliance with albendazole. The duration of patients taken albendazole ranged from 2 months to 3 years. Cerebral AE surgery was performed in 11 patients, five of them underwent partial resection of AE lesions, and six patients received total resection. One patient with primary IAE underwent radical surgery. Ten patients (47.6%) died during the follow-up for a mean of 21.7 ± 11.9 (3–46) months. In total, 28.9% of the patients died within 5 years, and 71.6% died within 10 years. The median interval between the date of diagnosis as AE and death was 84 (19–144) months.

Conclusion: Despite substantial advances in diagnostic and therapeutic methods, the treatment of IAE remains difficult and results in unsatisfactory outcomes. The major critical issue is surgical treatment of IAE although the disease is disseminated. Besides, lifelong albendazole would be indicated, but most patients had poor medication compliance. It is important to educate patients about the necessity of medical treatment.