Large primary intraorbital hydatid cyst in elderly
An 80-year-old female resident of Delhi was admitted to the hospital with 6 months history of proptosis of left eye and gradual diminution of vision in the same eye. The general physical examination showed no evidence of any neurocutaneous markers or swelling over the body. The neurological examination revealed proptosis of left eye with restricted movements in all directions. Visual acuity was only perception of light in left eye. There was no evidence of chemosis, redness in the eye. There was no bruit on auscultation.\nMagnetic resonance imaging (MRI) brain and orbit revealed a well-marginated cystic lesion in the left orbital apex. The lesion was located supero-laterally displacing optic nerve medially. The lesion was hypointense on T1 and hyperintense on T2 image without any septations or scolex []. Approximate dimension of the lesion was 3 cm × 3 cm × 2 cm. There was mild rim enhancement after contrast administration. Based on the MRI the differential diagnosis of hydatid cyst, neurocysticercosis, dermoid, lipodermoid, mucocele, encephalocele, inclusion cyst, teratoma, hematocele, schwannoma and paraganglioma were considered. The serological test for hydatid and neurocysticercosis were negative. Erythrocyte sedimentation rate was 10 mm at the end of 1st h, total leukocyte count-5600/cmm, differential leucocyte count: P-70%, L-20%, M-5%, E-5%. Computed tomography (CT) scan of the chest and abdomen were unremarkable.\nPatient underwent left lateral orbitotomy and gross total removal of cyst without rupture.\nOn macroscopic examination of the excised cyst wall a pearly white membranous tissue was appreciated, characteristic of hydatid cyst, measuring 3 cm × 3 cm and 0.2 cm thickness []. Histological examination of multiple longitudinal strips from the cyst wall revealed pale eosinophilic acellular laminated membranes lined by germinal epithelium, along with multiple scolices, confirming the diagnosis of ocular hydatid disease []. The scolices were seen to contain an array of refractile sickle-shaped hooklets.\nThe proptosis settled in the immediate post-operative period and there were some improvement in the eye movements. Patient had visual acuity of finger counting at 1 m at the time of discharge.