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Neurocysticercosis

Last Updated: March 27, 2020

Open Table of Contents: Neurocysticercosis

Figure 1: There is a cluster of cyst-like structures in the right central sulcus compatible with racemose neurocysticercosis. Notice that there is only minimal rim enhancement (middle row right). Often, when in the subarachnoid space or basilar cisterns, neurocysticercosis will take on a grape-like appearance with minimal to no enhancement.

Figure 2: Multiple peripherally enhancing neurocysticercosis lesions (top row left-middle row right) look remarkably similar to brain metastases, with a similar amount of associated hyperintense vasogenic edema on FLAIR (bottom row). The patient’s clinical scenario and the presence of an eccentric mural nodule in some of the lesions (middle row left) can help to narrow the differential.

Description

  • Intracranial parasitic infection caused by pork tapeworm Taenia solium

Pathology

  • Four pathologic stages:
    • Vesicular
    • Colloidal vesicular
    • Granular nodular
    • Nodular calcified

Clinical Features

  • Symptoms
    • Typically asymptomatic until larvae degenerate
    • Seizure, headaches, hydrocephalus
  • Demographics
    • Any age but commonly young, middle-aged adults
    • Slight male predominance
    • More commonly seen in certain locations such as Latin America
  • Prognosis
    • Increased morbidity and mortality with intraventricular neurocysticercosis

Imaging

  • General
    • Imaging varies with developmental stage and host response
    • Often multiple stages in same patient
    • Usually small lesions that may have exuberant cerebral edema depending on the stage
    • Most commonly visible within the subarachnoid space over the cerebral convexities
      • May develop an inflammatory response which seals the sulcus and can be mistaken for a parenchymal lesion
    • Racemose subtype: grape-like lesions in the basal cisterns
  • CT
    • Vesicular:
      • Small thin-walled cyst isodense to CSF
      • Central dot sign - hyperdense dot within the cyst represents a protoscolex
  • Colloidal vesicular:
    • Usually small hyperdense cyst with a thick ring-enhancing fibrous capsule and surrounding edema
  • Granular nodular:
    • Involuting enhancing nodule
  • Nodular calcified:
    • Small calcified nodule
  • MR
    • Vesicular
      • T1, T2 and FLAIR:
        • Cystic lesions isointense to CSF, may see discrete eccentric intermediate signal intensity scolex
    • Colloidal vesicular
      • T1, T2, and FLAIR:
        • Cyst is hyperintense to CSF
    • Granular nodular
      • T1, T2, and FLAIR:
        • Thickened, retracted cyst wall, edema decreases
    • Nodular calcified
      • Shrunken low signal intensity lesion on all sequences, most easily seen on GRE/SWI
      • May not be visible
    • DWI: not particularly helpful
    • GRE/SWI: useful to demonstrate calcified scolex
    • Contrast:
      • Vesicular: minimal enhancement of the scolex
      • Colloidal vesicular: enhancement of the wall and scolex
      • Granular nodular: nodular or ring-like enhancement
      • Nodular calcified: minimal
  • Imaging Recommendations:
    • MR with contrast (include SWI)
  • Mimic
    • Depends on the phase of disease the particular lesion is in. In the vesicular phase, can mimic an arachnoid cyst or enlarged perivascular space. The multiplicity and location of the lesions can help distinguish. When in the colloidal vesicular or granular nodular phase, can be difficult to distinguish from metastatic disease. Often times, the most helpful way to distinguish is through identifying multiple lesions in multiple different stages.

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Sean Dodson, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.02.19

References

Kimura-Hayama ET, et al. Neurocysticercosis: Radiologic-Pathologic Correlation. Radiographics. 2010. 30(6):1705-19.

Lucato LT, et al. The Role of Conventional MR Imaging Sequences in the Evaluation of Neurocysticercosis: Impact on Characterization of the Scolex and Lesion Burden. AJNR. 2007; 28:1501-04.

Rabelo NN, et al. Differential Diagnosis between Neoplastic and Non-Neoplastic Brain Lesions in Radiology. Arq Bras Neurocir. 2016. Doi: 10.1055/s-0035-1570362.

Shih RY, et al. Bacterial, Fungal, and Parasitic Infections of the Central Nervous System: Radiologic-Pathologic Correlation and Historical Perspectives: From the Radiologic Pathology Archives. Radiographics. 2015; 35(4):1141-69.

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