Cerebral schistosomiasis
1 Department of Radiology, Xiangya First Affiliated Hospital, Changsha, Hunan, China
2 Department of Radiology, Changsha 8th Hospital, Changsha, Hunan, China
3
Department of Pathology, Xiangya First
Affiliated Hospital, Changsha, Hunan, China
Although schistosomiasis (bilharzia) is one of the most common
parasitic infections in humans, schistosomal infection of the
nervous system is rare. This report is of an unusual case of
primary cerebral schistosomiasis and describes its magnetic
resonance imaging appearance.
S Afr J Rad 2013;17(4):143-144.
DOI:10.7196/SAJR.878
A 21-year-old previously healthy man presented with symptoms of
continuous headache of 3 days’ duration. His physical
examination was unremarkable. Laboratory investigations were
significant for an elevated white blood cell count of 17 700
cells/ml of blood. MRI examination of the brain revealed a
tumour-like lesion in the left temporoparietal lobe that was
hypo-intense on T1-weighted imaging (Fig. 1) and hyperintense on
T2WI (Fig. 2). There was intense perilesional oedema, with
considerable mass effect. Additionally, there was a diffuse
region of hyperintense T1 signal within the lesion that was
attributed to haemorrhage. On post-contrast T1WI (Fig. 3), a
cluster of intensely enhancing nodular lesions were detected.
Some of these nodules coalesced, forming a confluent lesion, and
some were arranged around regions of linear or slit-like
enhancement, creating an arborising appearance. The patient then
underwent surgical resection of the lesion which was
pathologically proven to be a schistosomal granulomatous lesion
(Fig. 4). Postoperatively, the patient received praziquantel and
corticosteroids, and made an uneventful recovery.
Fig. 1. Axial MR T1WI demonstrating a hypo-intense mass-like lesion of the left temporoparietal region with mass effect. The diffuse hyperintense signal within the lesion can be attributed to haemorrhage.
Discussion
An estimated 200 million people globally have schistosomiasis.1 It is endemic in over 70 tropical and sub-tropical countries worldwide.1 However, cerebral schistosomiasis (CS) is an uncommon form of schistosomal infection; most cases result from S. japonicum.2
Individuals affected by CS commonly present with headache, confusion, speech disturbances, motor deficits, visual abnormalities, seizures, altered mental state, vertigo, sensory impairment, vomiting and ataxia.2 On MRI, CS usually has a pseudotumour-like appearance that is hypo-intense on T1WI and hyperintense on T2WI. It is often associated with an intense perilesional oedema and mass effect.3 , 5 On contrast administration, the characteristic feature described is that of a central linear (slit-like) enhancement surrounded by numerous enhancing nodules, creating an arborised appearance.3 , 5 Some of the nodules may be clustered together, creating a confluent enhancing mass.3 At present, the most accurate way of diagnosing CS is the demonstration of schistosoma eggs surrounded by a granulomatous reaction on nervous tissue biopsies.2 , 4
Recently, it has been suggested that the treatment approach for CS should be based on the presence or absence of signs of raised intracranial pressure and/or hydrocephalus.4 When present, the treatment should include prompt surgical resection followed by antiparasitic medications (praziquantel), corticosteroids and anticonvulsants. In their absence, a non-invasive approach using a combination of praziquantel, corticosteroids and anticonvulsants should be tried.4
1. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/schistosomiasis (accessed 18 March 2012).
2. Ferrari TCA, Moreria PRR. Neuroschistosomiasis: Clinical symptoms and pathogenesis. Lancet Neurol 2011;10(9):853-864. [http://dx.doi.org/10.1016/S1474-4422(11)70170-3]
3. Liu H, Lim CCT, Feng X, et al. MRI in cerebral schistosomiasis: Characteristic nodular enhancement in 33 patients. AJR 2008;191(2):582-588. [http://dx.doi.org/10.2214/AJR.07.3139]
4. Vale TC, de Sousa-Pereira SR,Ribas, Lambertucci JR. Neuroschistosomiasis mansoni literature review and guidelines. Neurologist 2012;18:333-342. [http://dx.doi.org/10.1097/NRL.0b013e3182704d1e]
5. Sanelli PC, Lev MH, Gonzalez RG, Schaefer PW. Unique linear and nodular MR enhancement pattern in schistosomiasis of the central nervous system: Report of three patients. AJR 2001;177(6):1471-1474.