Cytology-Histology Correlation of Hydatid Cyst: A Case Study and Literature Review

Abstract

Abstract Casestudy: Hydatid cyst results when humans get infected by ingesting the eggs of Echinococcus Granulosus. Upon release, the six-hooked oncospheres penetrate the intestinal wall and migrate via circulation to various organs, mostly liver and lung. Here, they develop into hydatid cyst. The cyst enlarges gradually and is filled with daughter cysts and protoscolices. We report the case of a 69-year old female, native of Uzbekistan, who presented with right upper quadrant pain. Imaging showed a 20 cm liver cyst and multiple pelvic cysts with a stage of CE2 implying that they were most likely functional. Serum Echinococcal antibody was positive. After 2 months of Albendazole treatment, there was no radiological change. The patient underwent laparoscopic puncture aspiration and injection with 20% saline (PAIR) and pericystectomy of the pelvic cysts. The aspirate revealed scattered scolices, inflammatory cells and abundant amorphous debris consistent with hydatid cyst. Bilateral 5-cm pelvic cysts had pale yellow, soft to firm walled, multiple cavities. Microscopy revealed a fibrofatty outermost layer with chronic inflammation and a two-layered cyst wall including a thin germinal epithelium covered by a thick acellular outer membrane. Multiple parasites, some degenerate (dense eosinophilic) were present, confirming the cytologic diagnosis of cystic echinococcosis. Following further treatment with Albendazole, she underwent a robotic assisted PAIR and partial peri-cystectomy of the liver cyst with repair of the duct to cyst communication. The liver cyst contained daughter cysts of Echinococcus and brood capsule with protoscolices. After 2 months more of Albendazole her Elisa was intermediate. A prior study reported cytopathologic diagnosis of hydatid cyst in 17 patients evaluated for various masses. Our case highlights the role of cytology sampling in confirming the diagnosis of hydatid disease. Potentially fatal in untreated patients, this entity has to be considered in the differential diagnosis of cystic lesions.