Symptomatic orbital cysticercosis: Patterns of positive imaging findings on CT

Abstract

BackgroundOrbital cysticercosis is a common disease in the developing world. Although previous studies reported the spectrum of imaging findings of orbital cysticercosis and variable involvement of the extraocular muscles, the relationship between the lesion and the extraocular muscle (within the muscle or on the surface), as well as its distribution within the muscle (muscle belly or the tendinous insertion) was uncertain. PurposeTo characterize the predominant imaging findings of orbital cysticercosis on computed tomography (CT) and assess the relationship between orbital infection and extraocular muscles. Methods and MethodsA cohort of 35 patients with orbital cysticercosis was included in the analysis. All patients underwent CT examination, whereas 6 underwent magnetic resonance imaging. Results52 lesions were visualized on CT. The nodular calcified stage was rather common, followed by the colloidal vesicular or granular nodular stage and vesicular stage. Approximately, two-thirds of the lesions were presented as a cyst with/without an intramural nodule and the remaining as calcification. The extraocular muscle involvement consisted of a single, two, and three lesions, respectively; these were predominantly located within the extraocular muscles, whereas 12 lesions were attached to the extraocular muscles. The lesions were frequently within or adjacent to the muscle belly and less frequently associated with the tendinous insertion. The lateral rectus was frequently involved. The intracranial or extra-orbital involvement was found in 12 patients. ConclusionOrbital cysticercosis mainly presented as a cyst containing an intramural nodule and frequently residing within an extraocular muscle, with a predilection for the muscle belly.