Keywords
racemose neurocysticercosis - basal subarachnoid cysts - subtemporal approach - neurosurgery
Palavras-Chave
racemose neurocisticercose - cistos subaracnóideos basais - subtemporal abordagem
- neurocirurgia
Introduction
Neurocysticercosis (NCC) is the most common parasitic disease affecting the human
nervous system and is a substantial public health concern throughout the developing
world. The clinical presentation of NCC has many variables such as lesion quantity
and location, and the host's immune response to the parasitic agent. Diagnosis primarily
depends on neuroimaging and is complemented by serological detection of antibodies/antigens
in the serum or occasionally in the cerebrospinal fluid.[1] Patients with exclusively intra-parenchymal brain parasites typically manifest seizures,
which tend to lessen over time. Conversely, parasites situated within the ventricles
and the basal subarachnoid space undergo progressive growth and infiltration, potentially
giving rise to hydrocephalus and/or intracranial hypertension. Such manifestations
often lead to morbidity and mortality. Calcified NCC still contributes to a persistent
and heavy burden of disease.[1]
[2]
The present case series underscores the multifaceted nature of NCC and emphasizes
the importance of personalizing therapeutic strategies for each patient. This disease
also poses challenges to management which must be considered. The integration of advanced
diagnostic modalities and evolving therapeutic strategies reveals significant progress
in addressing this rare and complex variant of NCC.
Case Presentation
Case 1
A 34-year-old female patient presented with severe headache without other reported
signs or symptoms. The magnetic resonance imaging (MRI) revealed a voluminous cystic
lesion in the quadrigeminal cistern with subtemporal extension and involvement of
the ambient cistern and pontocerebellar angle ([Fig. 1]). A posterior petrous approach was undertaken, and, with superior traction of the
temporal lobe, the voluminous cystic lesion was expelled and completely excised via
the subtemporal route. Notably, there was no need to open the presigmoid dura mater
or the dura mater of the posterior fossa, and the patient had an uneventful postoperative
recovery. Histopathological analysis confirmed the diagnosis of NCC. Postoperative
treatment included a 5-day course of albendazole.
Fig. 1 Axial and coronal T2-weighted magnetic resonance imaging revealing a voluminous multiloculated
cystic lesion occupying the quadrigeminal cistern (A, B). Resected walls of the cyst (C). Postoperative skull computed tomography showing cyst resection.
Case 2
A 54-year-old male patient presented with bilateral papillary edema, without focal
neurological signs, and a history of prior ventriculoperitoneal shunting. The gadolinium-enhanced
MRI revealed multilobulated cystic lesions in the basal cisterns, left Sylvian fissure,
and quadrigeminal cistern ([Fig. 2]). A left extended frontotemporal approach was chosen, the Sylvian fissure was widely
dissected, and the cysts were easily resected. Additional cysts were removed from
the left opticocarotid and interpeduncular cisterns. After this, the posterior incisural
space was approached through the subtemporal route. The exposed cyst was drained,
and its capsule was excised with a forceps. The patient developed mild aseptic meningitis
and experienced one episode of generalized tonic-clonic seizure. Nevertheless, he
was discharged from the hospital after 7 days, asymptomatic, and put on a 5-day course
of albendazole.
Fig. 2 Axial T2-weighted magnetic resonance imaging (left and right), sagittal (middle),
revealing multiple loculated cystic lesions in the territory of the Sylvian fissure
(arrow) and in the quadrigeminal cistern (asterisk).
Discussion
In both cases presented, a multilobulated cyst exhibited a component in the posterior
incisural space that extended below the mesial temporal region. As a result, a more
intricate approach to the pineal region was deemed unnecessary, and cyst removal was
accomplished exclusively through the subtemporal approach. This was feasible due to
the cysts' lack of adherence to neurovascular structures, facilitating their straightforward
removal with forceps following drainage.
The therapeutic spectrum encompasses symptomatic management, antiparasitic regimens,
and surgical modalities, and a combined approach is often necessary. Notably, albendazole
administered over a five-day period has emerged as a viable therapeutic option for
intramedullary spinal cord cysts.[3] In cases warranting surgical intervention, options range from lesion resection to
shunt placement.
Racemose NCC presents a distinctive and rare manifestation within the NCC pathology
spectrum. It is characterized by cyst development in the basal subarachnoid region.
This uncommon presentation involves the formation of multiple non-encapsulated cystic
membranes that resemble a bunch of grapes. These are the exogenous budding of aberrantly
proliferating Taenia solium larvae. Typically observed in expansive brain regions, such as the suprasellar, Sylvian,
and quadrigeminal cisterns, or around the rostral brainstem, these cysts lack scolex,
do not always involve edema, and can escape detection with contrast enhancement depending
on their life cycle.[4]
Clinical consequences of racemose NCC include mass effect, cranial nerve entrapment,
arachnoiditis leading to meningeal inflammation and/or hydrocephalus. Less frequently,
small-vessel infarcts may occur secondary to occlusive endarteritis. These manifestations
are often challenging to detect on computed tomography (CT) scans and so require MRIs
for accurate diagnosis. Treatment challenges are not uncommon, and multiple courses
of antiparasitic therapy may be required for parasitic clearance. In instances of
intraventricular NCC, neuro-endoscopic procedures may be essential for optimizing
outcomes.[5]
Advancements in NCC management over the past few decades include the use of anti-parasitic
drugs, improved antiinflammatory treatments, and minimally invasive neurosurgical
interventions. However, prognosis remains contingent upon the specific location and
burden of parasites, with subarachnoid and intraventricular NCC exhibiting heightened
rates of morbidity and mortality.[6]
These cases illustrate the intricacies of NCC and emphasize the significance of carefully
chosen surgical approaches, along with the crucial role of postoperative pharmacological
treatment, for effective treatment and recovery. Ongoing clinical monitoring is imperative
to identify and manage potential complications.
Conclusion
The cases of NCC herein presented exemplify the nuanced nature of this parasitic affliction
and underscore the importance of personalized surgical approaches guided by the specific
characteristics of the lesions. Notably, the multilobulated cysts in both cases exhibited
extensions into the posterior incisural space, requiring a meticulous surgical strategy.
The decision to employ a subtemporal approach proved effective in both instances,
obviating the need for more intricate procedures involving the pineal region. Success
was attributed to the unique property of these cysts, which did not adhere to neurovascular
structures. Furthermore, the ease of cyst capsule removal with forceps postdrainage
contributed to the overall surgical success.
These cases highlight the significance of a comprehensive understanding of NCC variations
and reinforce that the effective treatment of NCC is still evolving. Continued vigilance
and research in this domain will further enhance our capabilities in managing the
complexities associated with this parasitic neurological condition.
