Cysticercosis is caused by ingestion of Taenia solium. In the intestinal tract of human host its eggs release the encysted larvae (oncospheres). These oncospheres penetrate the intestinal wall, enters the blood stream then are transported and deposited to various tissues of the body including brain, eyes, skin, and muscle. In these tissues oncospheres differentiate into metacestodes which further develop into cysticerci. In NCC, the brain parenchyma is most commonly infested with high rates of deposition at grey-white matter junction. It may be due to accumulation of metacestodes in small terminal blood vessels [6]. Most lesions are single ring enhancing lesion (SREL) or multiple ring enhancing lesion (MREL) in different stages of evolution [7]. Cystecerci of Taenia solium undergo four stages of involution in brain parenchyma. First stage is vesicular stage, showing cyst with translucent walls and viable scolex followed by colloidal stage characterised by cyst with a thick wall. Third stage is granular stage showing cyst with thicker wall and degenerated scolex. Final stage is calcification stage in which cyst develops into calcified nodule [8].

Clinical features of NCC vary widely in children and continue to pose a challenge in clinical practice. Most common symptoms are focal seizures, generalised seizures, neurological deficit and signs of raised intracranial pressure. In this series, all cases had focal seizures as primary manifestation of the disease. A study of 500 children with NCC in India reported that 95% of cases had seizures, of these 84% cases had focal seizures, 30% children showed symptoms of increased intracranial pressure, and 4% showed neurological deficit [9]. In this series, none of the cases reported to have increased intracranial pressure, neurological deficit or visual disturbances.

Neuroimaging showed five cases in colloidal-vesicular stage, two cases in granular-nodular stage, and one in calcified nodular stage in brain parenchyma. Conglomerated lesions were thought to be unusual in NCC but were commonly reported as neurotuberculosis [10]. In the present series two cases were identified to have single conglomerated ring enhancing lesion (SCREL). Conglomerated ring enhancing lesions are best seen on MRI due to its better soft tissue resolution and multiplanar capabilities. Rajshekhar et al. [11] described atypical” type B” lesions having two confluent discs or rings or a combination in 4 out of 25 and 5 out of 43 biopsy proven cases of NCC. Recently Kumar et al. [12] reported “atypical” lesion having bilobed, septate or disc configurations in 28.8% of cases on MRI. These atypical lesions often persist unresolved for a longer period and may even be associated with a higher risk of seizure recurrence because of persistence of calcified focus.

Out of eight NCC cases, three had SDREL with perilesional oedema. The commonest neuroimaging finding of NCC is “single small ring enhancing lesion”- a single lesion, < 20 mm with perilesional oedema. These solitary lesions usually resolve during treatment between few weeks to one year whereas conglomerated lesions takes longer time to resolve [13]. Reappearance of NCC at the same site after documented resolution has been sparsely described. We have reported two cases with recurrent NCC both having recurrent lesion at different locations after 2.5 and 2 years interval. Singh et al. [14] reported four cases of reappearing CT lesions; two at the same and two at different locations. It was postulated that recurrent lesions at the same location are secondary to co-localisation of a multiple stream of cysts or viable meta-cestode larvae in a particular brain region which appear and become active at different times, whereas recurrent lesions in different locations are secondary to recurrent auto infections in taeniid carriers. Kumar et al. [12] described three cases of recurrent symptomatic solitary NCC at a location different from initial site after 2.5, 4, and 7.5 years interval. The reason given was that all new granulomas resulted from reinfection rather than persistent of initial infection. VDe Souza et al. [15] described natural history of NCC in 81 patients on serial MRI over 24 months and did not report a single recurrence of NCC. In an MR-based prospective study, Kumar N et al. [16] evaluated natural course of 59 cases of single conglomerated granuloma (SCG) over 3 years without any antihelminthics or steroid treatment and did not report a single case of recurrent granuloma.

All cases in this series received antihelminthic therapy as Albendazole (15 mg/kg/day) for 28 days and corticosteroids for 5–14 days. Singhi et al. [9] reported new lesions in around 4% of NCC patients during long term clinical and radiological follow up in 500 children with parenchymal NCC.

There are no clear guidelines for management and diagnosis of paediatric NCC. A recent meta-analysis involving 16 trials and another involving 15 trials have concluded that Albendazole was effective in early resolution and radiological clearance of lesions and also preventing seizures [17, 18]. Corticosteroids are administered to reduce host inflammatory reaction and increase level of Albendazole sulfoxide in plasma [19]. Antiseizure medication (ASM) used to treat NCC are similar to those used for other seizure disorders. In our series six cases received sodium valproate and two received phenytoin.

Case 2 in this series presented with ataxia and headache as manifestations of acute phenytoin toxicity at serum phenytoin levels of 42 mg/L. Acute phenytoin toxicity manifests as nystagmus (95%), ataxia (88%), lethargy and seizures. Ataxia usually precedes nystagmus in children. Phenytoin levels > 30 mg/L may cause side effects as ataxia, dysarthria, and seizure. Somnolence is often seen at serum phenytoin levels > 40 mg/L [20].

MRS was done for three cases in this series to differentiate between NCC and tuberculoma. Case 6 shows N-acetyl aspartate (NAA) peak, Cho/Cr (choline: creatine) = 0.62 and absence of lipid peak. Case 7 had NAA peak and Cho/Cr = 0.89 with absence of lipid peak. In case 8 there was NAA peak and absence of lipid peak with choline/Cr = 1.1. The presence of a high lipid peak and an increased choline/creatine ratio were seen consistently with tuberculoma. Lipid peak may be attributed to the presence of large lipid fraction in Mycobacterium tuberculosis and the increase in choline/creatine ratio is probably due to damage to brain tissue, which is minimal in NCC [21]. MRI and MRS features differentiating NCC from tuberculoma are shown in Table 4 [22, 23].