Encysted Odyssey: A Clinical and Pictorial Analysis of Hydatid Cysts From Head to Toe

Cystic echinococcosis, a zoonotic disease caused by the larval form of Echinococcus granulosus, predominantly affects the liver and lungs, with humans acting as accidental hosts.

Our retrospective study at the Department of Radiology and Imageology, Nizam's Institute of Medical Sciences, included 187 histopathologically or serologically proven cases. The mean age of presentation was 49.4 years.

Liver involvement was most prevalent, accounting for 83.4% (n=156) of cases, followed by sporadic involvement of other organs such as the mesentery, spleen, pancreas, thalamus, kidney, lung, spine, and omentum. Characteristic diagnostic features observed on imaging included peripheral calcifications in 33% of cases, internal septations in 25% (n=47), dense calcifications in 15% (n=29), daughter cysts in 6% (n=11), and floating membranes in 5% (n=10). Among hepatic lesions, 90% (n=141) were showing involvement of a single lobe. Notably, 78% (n=110) of lesions were limited to the right lobe, 21% (n=30) to the left lobe, and 1% (n=1) to the caudate lobe. The most affected hepatic segment was segment VIII, while the least common was segment I (caudate lobe). Complications were identified in 13% (n=25) of cases of hepatic hydatidosis.

The findings of our study emphasize the systemic nature of E. granulosus infection which can affect various organs in the body. It also illustrates the invaluable insights imaging provides for timely and accurate diagnosis of hydatid disease.