A 55‐Year‐Old Male with Intermittent Headache

Clinical History

A 55‐year‐old male patient presented with a half‐month history of intermittent headache; no nausea, weakness, convulsion, fever or any other symptoms were accompanied. His physical examination was normal. The neurologic examination did not reveal any abnormalities. Laboratory findings were unremarkable. The results of chest radiograph and abdominal ultrasonography were normal. Axial T1‐weighted MRI of brain showed heterogeneous enhancement signal in the deep sites of left temporal and insula lobe (Figure 1A). FLAIR sequence showed the lesion was slightly hyperintensity signal surrounded by obvious edema (Figure 1B). Then, a glioma was highly suspected and an operation of subtotal resection was performed under neuronavigation.

Figure 1.

Microscopic Pathology

The “tumor” tissue was processed with standard pathology technique. Histologic examination showed schistosomal granulomas in tissue slice (Figure 1C); there were heavy infiltration of eosinophilics, epithelioid cells and necrotic tissue round Schistosoma japonicum ova (Figure 1C,D). In addition, a test for serum schistosome antibody was positive. What is your diagnosis?

Diagnosis

Cerebral schistosomiasis.

Discussion

After surgery, when examining minutely medical history in detail, the patient reported a history of exposure to schistosome‐infected water. Then, the patient was treated with praziquantel (20 mg/kg per day) for six days with concurrent administration of dexamethasone. The patient was followed up 5 months later with complete resolution of the symptoms, companying with the complete disappearance of lesion on MR images.

Schistosomiasis is one of the most widespread parasitic infections, which is caused by blood flukes of the genus Schistosoma. Worldwide, about 200 million people are infected with schistosomes 4. Although digestive system involvement appears to be a common manifestation of schistosomiasis, brain involvement is exactly rare. In addition, isolated intracranial schistosomiasis without hepatosplenomegaly is even rare.

The diagnosis for isolated cerebral schistosomiasis may be quite challenging. The clinical manifestations are nonspecific, and laboratory findings such as eosinophilia and the evidence of schistosome ova in urine or stool may not be present. Neuroimaging examination usually shows a nonspecific tumoral form. MRI imaging usually reveals a heterogeneous enhancement mass with surrounding edema, with a central linear enhancement surrounded by multiple enhancing punctuate nodules, forming an “arborized” appearance on T1‐weighted images 3. The cerebral cortex and leptomeninges are the most frequent sites involved, whereas the white matter, hippocampus, thalamus, basal ganglia, cerebellum, midbrain and choroid plexus are less common. Pathological examination may provide accurate diagnosis with the evidence of granulomatous response to schistosome eggs 2, 4. In this case, the patient's history of nonspecific clinical manifestation, laboratory tests, abdominal ultrasonography and MRI examination was misleading and led to the initial diagnosis of glioma. Following the pathologic diagnosis, abdominal CT was taken and showed no schistosomiasis involvement in other organs.

For treatment, praziquantel is proven favorable against all species of schistosomes. For schistosomiasis japonica, cure rate attains 70% to 90%. Those who are not cured may also benefit because the egg counts fall to one fifth or less of pretreatment levels 4. In addition, corticosteroid administration is also beneficial. Nowadays, the indications of operation are still controversial. In our opinion, operation is necessary under the following conditions: (i) MRI scanning indicates intracranial mass effect with severe edema; (ii) praziquantel has no effect to control intracranial hypertension; (iii) glioma or other malignancies could not be excluded before surgery; and (iv) recurrent and intractable epilepsy 1. Our patient underwent surgical resection followed by standard therapy for schistosomiasis. In this case, the patient made a good recovery and his initial symptom of headache disappeared after operation and medicine treatment without new complaints.