Disseminated cysticercosis with racemose neurocysticercosis- an uncommon presentation in an immunocompetent individual

A 23-year-old, normotensive and euglycemic male patient presented to the neurology OPD complaining of increasing mental dullness and altered behaviour for a few months. He had suffered a convulsive episode three years back but was not on any medication for the same. TLC was within normal limits, with DLC showing mild elevation of eosinophilic counts. Neurological examination revealed no focal neurological deficit.

A contrast-enhanced brain MRI was advised, which revealed multiple cystic, peripherally enhancing parenchymal lesions which followed CSF signal on T1W, T2W/FLAIR, and DWI/ADC sequences, with an eccentric T2/FLAIR hyperintense scolex within, suggestive of vesicular stage of neurocysticercosis. Similar cystic lesions were also diffusely distributed in skeletal muscles and subcutaneous tissue of the head and neck, notably in masticator muscles, muscles of tongue and extra-ocular muscles. MRI brain also revealed lobulated enlargement of sub-arachnoid spaces of basal cisterns and bilateral sylvian fissures, with normal-looking ventricular system. On 3D-DRIVE sequence, thin-walled cysts could be demonstrated in the basal cisterns and sylvian fissures, with no visible scolex within.

Suspecting dissemination, a whole body T2W-TSE sequence was applied, showing similar elongated cysts with eccentric scolices in sub-cutaneous tissue and skeletal muscles of chest wall and bilateral extremities. Thus, an imaging diagnosis of disseminated cysticercosis with racemose neurocysticercosis was made.

Neurocysticercosis (NCC), one of the most common human parasitic neural infections, is commonly found in four sites- sub-arachnoid/cisternal spaces (most common form), intraparenchymal, intraventricular and intraspinal.[1] Radiologically, neurocysticercosis lesions often present in different stages- non-cystic, vesicular (cysts with scolex), colloid-vesicular, granular nodular and calcified nodular.[2, 3] Racemose NCC (RNCC) is a rare form of subarachnoid NCC, which develops following aberrant proliferation of cestode membrane post degeneration of the scolex, causing development of new cysts without scolices.[4, 5] In contrast to parenchymal cysts, racemose cysts are often large and clustered, growing from 3-5mm to up to a few centimetres in size (bunch of grapes appearance).[6] Mainly found in the sub-arachnoid spaces like basal cisterns and ventricles, RNCC is more aggressive than the parenchymal variety, clinically manifesting as hydrocephalus, chronic meningitis, seizures, cerebral vascular accident, and reversible dementia.[7] Such forms of NCC may be missed by CT scans and routine MR sequences, as they may only show secondary signs such as mass effect, asymmetry of ventricles or enlargement of cisterns without clear delineation of the cyst wall.[8] On MRI, cysts are seen to follow CSF signal, appearing hypointense on T1W, hyperintense on T2W, showing complete suppression on FLAIR sequences with no diffusion restriction or contrast enhancement.[4] 3D heavily T2W MRI sequences, such as FIESTA, CISS and DRIVE seem to have the highest sensitivity for identifying the cyst membrane within CSF spaces.[9] Disseminated Cysticercosis (DCC) is quite rare, most commonly presenting as pseudohypertrophy of the muscles, followed by palpable nodules and seizures.[10] Whole body MRI is the investigation of choice for anatomic localization of the cysts, detection of viable scolexes and for monitoring of treatment.[11] As such, no consensus has been reached regarding the treatment of racemose NCC. Proano et al. demonstrated complete resolution of cysts with prolonged medical anti-helminthic and cortico-steroid treatment in 19 out of 33 patients.[12] Currently, interventional procedures are reserved for rapid alleviation of acute hydrocephalus or in case of failure of medical management.[13] Endoscopic and micro-surgical cyst removal procedures are the procedures of choice for intraventricular cysts, while open surgical methods are considered better for sub-arachnoid cisternal cysts due to frequently high cyst burden and widespread subarachnoid distribution and inflammatory response. A relative contraindication to such methods includes underlying hyperenhancement of meninges or ependyma, suggesting inflammation and probable adhesions.[3, 14, 15] Treatment of DCC includes a combination of anti-helminthic drugs like praziquental and albendazole, with anti-epileptics for symptomatic NCC, under a corticosteroid cover.[16]

Written informed patient consent for publication has been obtained.