Human neurocysticercosis unexpectedly caused by Taenia martis in Italy: a case report and literature review.

BACKGROUND

Cysticercosis is caused by the larval stages of Taenia and Versteria species. While Taenia solium, associated with a domestic life cycle, is the primary etiological agent of human (neuro)cysticercosis worldwide, sporadic cases involving Taenia species linked to wildlife have also been reported. A 72‑year‑old immunocompetent woman presented in October 2024 to the Emergency Department with paresthesia, gait imbalance, and severe headache. Neuroimaging revealed a <1‑cm edematous lesion in the frontal cortex, suspicious for metastasis. Surgical removal was performed. Histopathological examination showed necrotic tissue with abundant inflammatory infiltrate, ruling out neoplasia and raising suspicion of an infectious etiology. She was discharged in February 2025 with improved symptoms. Ongoing follow-up demonstrated progressive improvement leading to complete remission.

METHODS

Serological tests, coproparasitological examinations, and panfungal PCR targeting the 18S rRNA gene were performed. Intraoperative material, including formalin-fixed paraffin-embedded (FFPE) tissue samples, was collected and processed for histological, immunohistochemical, and molecular analyses. Histological sections were stained with hematoxylin and eosin (H&E) and Periodic acid-Schiff (PAS). Immunohistochemical analyses were carried out on FFPE sections to investigate infection with Echinococcus spp. For molecular analysis, genomic DNA was extracted from FFPE tissue using a dedicated commercial kit, following the manufacturer's instructions. Mitochondrial gene targets (cox1, nad1, and 12S rRNA) were amplified by PCR and subsequently sequenced.

RESULTS

Serological tests, coproparasitological examinations, and panfungal PCR targeting the 18S rRNA gene were negative. Histological analysis showed an inflammatory lesion with a necrotic core, while immunohistochemical analyses were negative for Echinococcus spp. Molecular analysis was positive, and sequence and phylogenetic analyses identified the cestode Taenia martis.

CONCLUSIONS

This finding underscores the need for clinicians to consider less common Taenia species as potential causes of cysticercosis and neurocysticercosis, particularly when serological tests are negative or inconclusive despite a clinically suggestive presentation.