Primary hydatid cyst masquerading as pseudocyst of the pancreas with concomitant small gut obstruction--an unusual presentation.

Isolated retroperitoneal hydatid cyst is an exceptionally rare entity. Owing to vague and varied symptomatology, it is seldom diagnosed without puncture cytology or surgery. We report an unusual presentation of primary retroperitoneal hydatid cyst with concomitant small gut obstruction. Ultrasonography and computed tomography of the abdomen showed localized abscess or pseudocyst of pancreas. Preoperatively, ultrasound-guided puncture cytology of the lesion revealed suspicious hydatid pathology. The patient was examined and, peroperatively, the cyst masqueraded as hydatid cyst of pancreas along with an inflammatory band, and the diagnostic dilemma about its exact site of origin was solved by histopathology only. Complete excision of the cyst along with the tail of pancreas was done with concomitant excision of inflammatory band, causing small intestinal obstruction. The patient was discharged in satisfactory condition on albendazole. In follow-up of 8 months, there was no recurrence.