Reversible dementia as presenting manifestation of racemose neurocysticercosis.

Sir,

We read with great interest the article “reversible dementia as presenting manifestation of racemose neurocysticercosis (NCC)” by Sharma et al. (2013).[1] We certainly agree with the fact that evolution of cyst as seen in racemose NCC is not appreciated in parenchymal form. The prevalence of parenchymal cysticercosis is indeed more common in Indian scenario as compared with its racemose form; hence, sensitizing clinicians regarding varied presentations of NCC is essential.

We have also come across a case of racemose NCC recently, who presented with recurrent episodes of seizures. Magnetic resonance images (MRI) in our case showed the presence of a large multi-lobed cyst in the right temporal lobe, which was subjected to surgical excision and histopathology proved it to be of racemose form of NCC.

The reported here patient had dementia of subcortical type, but the mechanism resulting in dementia has not been explained by the authors. Curiously, apart from the enzyme-linked immunosorbent assay for immunoglobulin G antibodies for NCC, the detailed findings on cerebrospinal fluid (CSF) analysis have not been mentioned as cisternal NCC can often result in basal meningitis.

Furthermore, the reason patient was subjected to initially high dose steroids and later on oral corticosteroids after discharge when there was neither perilesional edema nor signs of impending herniation are difficult to understand.

Instead of endoscopic removal of third ventricular cyst that should have been contemplated in the same sitting, authors opted only for ventriculoperitoneal shunting as a counter measure for obstructive hydrocephalus and therefore the case is not histopathologically proven.

Racemose NCC has variable presentation depending on their location resulting in basal arachnoiditis, meningeal fibrosis, adhesions and impairment of CSF flow.[2] Because the cysts lie in cisterns and sulci, they cause focal dilatation of these CSF spaces resulting in the mass effect on adjacent brain parenchyma.[3] Whereas, supratentorial cysts commonly produce epilepsy while those situated in the basal ganglia may give rise to manifestations simulating parkinsonism.[4]

Surgical removal of cysts has been the well-established treatment for NCC characterized by giant subarachnoid cysts or racemose form of NCC. There is a common consensus for the endoscopic removal of cysts confined to ventricles.[56]

Racemose cysticercosis not a commonly encountered clinical entity, but still can pose a challenge as it did in this particular patient. However, in an endemic region as ours NCC should always be prominent differential considered for any cystic lesion on MRI and index of suspicion toward a racemose variety should be always there in the presence of a subarachnoid-cisternal cyst.