CASE 17584 Published on 13.01.2022

Seudotumoral presentation of neurocysticercosis: Typical imaging findings for its diagnosis

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Atienza-Sentamans, C; Salamé Gamarra F; Revert Ventura A.J; Gunnarsdottir M; Genovés Roca, G; Pallardó Calatayud Y

Department of Radiology, Manises Hospital, Valencia, Spain

Patient

50 years, male

Categories
Area of Interest Neuroradiology brain ; Imaging Technique CT, MR, MR-Diffusion/Perfusion
Clinical History

A Bolivian 50-year-old man came to the emergency department with headache. He had no fever or other neurological focality. As medical history of interest, he was HIV + (CD4 <50) and he presented with pancytopenia in his blood test.

Imaging Findings

The emergency head CT showed a heterogeneous left parietal intraaxial lesion with associated vasogenic oedema (figure 1a). 

The brain MRI confirmed its presence and revealed another smaller lesion with similar characteristics in the right temporal region. Both lesions showed a peripheral hypointense halo in the T2WI sequence (Figure 1b). Also, the bigger lesion presented with peripheral restriction (figure 1c), although none of them showed an increase in perfusion parameters. (Figure 1d).

Both lesions demonstrated a thin and complete peripheral enhancement (Figure 2ab). In addition, the smaller lesion had within it an enhancing small eccentric mural nodule (Figure 2b) that appeared hyperintense in the volumetric T1WI sequence without contrast (Figure 2c).  In that T1WI sequence, other small lesions became visible; one in the right frontal lobe and another in the left cerebellar hemisphere (figure 3ab).

Retrospectively, in the previous emergency CT, a microcalcification was also seen in the right occipital lobe (figure 3c).

Discussion

The differential diagnosis of ring-enhancing brain lesions is very extensive and patient's clinical history is fundamental. 

In HIV+ patients with focal brain lesions there are two main entities to be considered: toxoplasma and lymphoma [1]. In immunocompromised patients these two entities can be indistinguishable by imaging, so in clinical practice they can be differentiated according to the response or non-response to antibiotics (responding only in toxoplasma).

The left parietal lesion in our case is unspecific to any of those entities. It behaves like a pseudotumoral lesion because its big size and heterogenicity, and because it presents with a thin complete ring enhancement without an increase in perfusion parameters.

It must be considered that our patient was also from Bolivia. Therefore, parasitic diseases such as neurocysticercosis should be included in the differential diagnosis [2].  

The differential diagnosis between toxoplasma and neurocysticercosis can be very difficult by imaging. It is characteristic in both diseases the visualization of an eccentric mural nodule within the lesion, which may also enhance [3]. However, the T1WI sequence, preferably volumetric and high resolution, can be helpful to its differentiation. The fact of seeing the mural nodule hyperintense in T1WI sequence without contrast in the minor temporal lesion is very characteristic of neurocysticercosis, as well as the visualization of new small lesions only in that sequence. This is because they correspond to the scolex (head of Taenia Solium’ larvae) [2,4] and are the key for the diagnosis.

In one same patient, as in our case, several evolutive stages can be seen at the same time. This results in the visualization of the scolex in the early evolutionary stages, but also other lesions without it can appear. These lesions can be seen in many ways depending on the inflammatory reaction that occurs after the death of the larvae, as the big left parietal lesion seen in our case. Also, small and calcified lesions without oedema or enhancement can be seen in the final stage, as the microcalcification visualized retrospectively in the right occipital lobule in our patient. 

A third diagnosis possibility to consider could be pyogenic abscesses. However, none of the lesions showed its characteristic marked central and homogeneous restriction in the diffusion sequences.

Due to the suspicion of neurocysticercosis by imaging, our patient received antiparasitic treatment with consequent clinical improvement. Six months later, a new brain MRI showed a significant reduction of the lesions, thereby confirming the entity.

Differential Diagnosis List
Neurocysticercosis
Toxoplasma
Lymphoma
Pyogenic Abscesses
Final Diagnosis
Neurocysticercosis
Case information
URL: https://www.eurorad.org/case/17584
DOI: 10.35100/eurorad/case.17584
ISSN: 1563-4086
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