Primary abdominal hydatid cyst presenting in emergency as appendicular mass: a case report

Hydatid disease (HD), caused by cestode Echinoccocus granulosus, is a significant health problem where animal husbandry is common. [1] Dogs or other carnivores are definitive hosts, whereas sheep or other ruminants are intermediate hosts. Man becomes an accidental intermediate host by ingestion of eggs which develop into cysts causing complication and even mortality (4%). [1,2] Common sites include liver (75%) and lungs (15%). [1] Peritoneal echinococcosis (13%) is usually secondary. [2] Primary peritoneal echinococcosis is rare. [2] Primary peritoneal hydatid cyst presenting as an appendicular lump is unique.A 56 year old lady presented with acute right lower abdominal pain, nausea, vomiting and fever since five days. Abdominal examination revealed a tender firm mass in the right iliac fossa, measuring 5 cm × 3 cm, with restricted mobility. Muscle guarding was present over the lump. Straight leg rising, cough sign and rebound tenderness were positive. Further investigations were conducted to address clinical suspicion of appendicular mass.Laboratory investigations revealed a haemoglobin level of 9.2 g/dL, neutrophilic leucocytosis (16,000/mm3) and marked eosinophilia (19%). Ultrasonography (USG) abdomen revealed a multiseptated cyst (5.2 cm × 2.5 cm) with honeycomb appearance in the right iliac fossa, suggestive of HD (Figure 1). Rest of the abdomen did not reveal any other hydatid cyst. ELISA (enzyme-linked immunosorbent assay using purified Echinococcus antigen, positive with a titre of more than 1:128.) for hydatid was positive.At laparotomy the cyst was found to be located in the appendicular mesentry. Excision and appendectomy was performed. Other areas of the abdomen did not reveal any cysts. Recovery was uneventful and patient was discharged with Albendazole (800 mg/day) for one month. The patient is doing well after one year follow-up. Repeat abdominal USG after one year follow-up was within normal limits.Intraperitoneal hydatid cysts usually develop second