Periorbital dirofilariasis: clinical profile and role of ultrasonography in its diagnosis

PURPOSE: To describe the clinical profile and imaging findings of orbital dirofilariasis and to describe the role of ultrasonography in its diagnosis. METHODS: Prospective study, over 4 years, included 14 patients based on clinical suspicion and biopsy proven periorbital dirofilariasis. All patients underwent orbital USG and MRI and analyzed their role in diagnosis. RESULTS: All patients had a unilateral involvement with a palpable periorbital mass. High resolution USG showed a well-defined cystic swelling, containing serpiginous structure with parallel echogenic walls in all cases. MRI showed hyperintense soft tissue swelling. On T1-weighted images, central tubular signal was visible in the lesion in 4 cases. Microscopic examination confirmed dirofilariasis in all these cases. CONCLUSION: Periorbital filariasis can be a mimicker of most of the orbital diseases. It should be included in the differential of orbital inflammatory disease. Role of MRI scan is limited. USG has potential role in confirming the diagnosis.