Intracranial parasitic infection caused by the pork tapeworm, Taenia solium.
Four pathologic stages: Vesicular, colloidal vesicular, granular nodular, nodular calcified.
Diagnostic clue is Cyst with "dot" inside.
Most common location is convexity subarachnoid spaces. May involve cisterns> parenchyma> ventricles. Basal cistern cysts may be racemose (grape-like). Parenchymal cysts often hemispheric, at gray-white junction. Intraventricular cysts are often isolated. Fourth ventricle is most common intra ventricular location. Rare locations are Sella, orbit, spinal cord.
Size of Cysts variable, typically 1 cm, range from 5-20 mm and contain a scolex; scolex 1-4 mm. Subarachnoid cysts may be larger, up to 9 cm reported. Cysts are often rounded or ovoid cyst, solitary in 20-50%. When multiple, usually small number of cysts, disseminated form ("miliary" NCe) is rare.
Imaging varies with developmental stage of cyst and host immune response. Lesions may be at different stages in same patient.
o Vesicular stage: Cystic lesion isointense to CSF. May see discrete, eccentric scolex (hyperintense)
o Colloidal vesicular stage: Cyst is mildly hyperintense to CSF.
o Granular nodular stage: Thickened, retracted cyst wall; edema decreases.
o Nodular calcified stage: Shrunken, Ca++ lesion.
o Useful to detect intraventricular cysts.
o Vesicular stage: Cystic lesion isointense to CSF. May see discrete, eccentric scolex. No surrounding edema.
o Colloidal vesicular stage: Cyst is hyperintense to CSF. Surrounding edema, mild to marked.
o Granular nodular stage: Thickened, retracted cyst wall; edema decreases
o Nodular calcified stage: Shrunken, Ca++ lesion
o Vesicular stage: Cystic lesion isointense to CSF. May see discrete, eccentric scolex (hyperintense to
CSF); no edema.
o Colloidal vesicular stage: Cyst is hyperintense to CSF. Surrounding edema, mild to marked. Useful to detect intraventricular cysts (hyperintense).
• T2* GRE: Useful to demonstrate calcified scolex.
• DWI: Cystic lesion typically isointense to CSF
• TI C+
o Vesicular stage: No enhancement typical, may see mild enhancement. May see discrete, eccentric scolex enhancement.
o Colloidal vesicular stage: Thick cyst wall enhances. Enhancing marginal nodule (scolex)
o Granular nodular stage: Thickened, retracted cyst wall; may have nodular or ring-enhancement
o Nodular calcified stage: Small calcified lesion, rare minimal enhancement
In children, may see "encephalitic cysticercosis" with multiple small enhancing lesions and diffuse edema. Intraventricular cysts may cause ventriculitis and/or hydrocephalus.
Cisternal NCC may appear racemose (multilobulated, grape-like), typically lacks scolex
E/o Complications: Meningitis, hydrocephalus, vasculitis
NCC is the most common cause of acquired epilepsy in developing countries like india.
It can present variably depending on the location and stage of cysts in the nervous system and the host immune response. The most common presentation of parenchymal NCC is seizures that are usually focal and brief. Status epilepticus occurs in some cases. About a third of cases have headache and vomiting.
Although treatment with cysticidal therapy continues to be debated, there is increasing evidence that it helps through increased and faster resolution of CT lesions; whether there is any improvement in long-term seizure control needs further study. It should not be used in cysticercus encephalitis or in ophthalmic NCC and used with caution in extraparenchymal NCC. It is of no use in calcified lesions.
Corticosteroids are used simultaneously to reduce cerebral oedema.
Seizures respond well to a single antiepileptic, and the seizure recurrence rate is low in cases with single lesions. Those with multiple, persistent or calcified lesions usually have recurrent seizures.
Extraparenchymal NCC is often associated with intracranial hypertension, hydrocephalous and chronic meningitis; it has a guarded prognosis; surgical intervention is required in many cases.
Management of NCC needs to be individualized. NCC is potentially eradicable; proper sanitation, hygiene and animal husbandry are warranted.