Sac over the sac - a rare case of subcutaneous dirofilariasis over the lacrimal sac area.

INTRODUCTION Dirofilariasis is a rare parasitic infestation in humans. CASE A 33-year-old female from the coastal area presented with a swelling over the right lacrimal sac area. It was clinically diagnosed as a lacrimal abscess and was incised under local anaesthesia. A live coiled worm was found and removed along with the cyst. OBSERVATIONS The worm looked like a thin white thread measuring 101 mm in length. On microscopic examination, the anterior end was slightly tapered and had a rounded head. The H & E stained section of the worm revealed longitudinal ridges with transverse striations on the cuticle. Based on these findings,the worm was identified as dirofilaria repens. CONCLUSION Dirofilariasis should be considered in the differential diagnosis of orbital region swelling and conjunctivitis. Surgical removal of the worm not only establishes the diagnosis but provides a definitive cure.