Orbicularis Oculi Cysticercosis: A Diagnostic Pitfall in an Endemic Region

Abstract

Objective: To describe the diagnostic challenges and management approach in a case of vesicular stage cysticercosis of the orbicularis oculi muscle presenting as a clinically silent periorbital mass.
Methods: An adolescent male presented with a four-month history of a gradually enlarging, firm, non-tender right periorbital mass (15×10 mm) with no inflammatory signs, no visual disturbance, and no systemic symptoms. The clinical impression was a benign periorbital mass; cysticercosis was not considered pre-operatively. Complete excisional biopsy was performed under local anesthesia without pre-operative imaging. Following unexpected histopathological findings, post-operative systemic evaluation was undertaken, including non-contrast CT of the head and orbits, chest radiograph, and bilateral limb radiographs.
Results: Histopathological examination confirmed vesicular stage cysticercosis with identifiable hooklets, suckers, a coelomic cavity, and an intrinsic larval cyst wall distinct from a host-derived fibrous capsule. This distinction explained the absence of a surgical capsular plane intraoperatively. Systemic evaluation excluded concurrent neurocysticercosis and musculoskeletal disease, confirming isolated periorbital involvement. Adjuvant oral albendazole (15 mg/kg/day for 28 days) with tapering prednisolone achieved complete clinical and radiological resolution at six-month follow-up.
Conclusions: Vesicular stage orbicularis oculi cysticercosis is clinically indistinguishable from a benign periorbital tumor and is only reliably detected by histopathological examination. Unexpected histopathological confirmation mandates comprehensive systemic evaluation before anthelmintic therapy is commenced.