Histopathological Spectrum and Demographic Features of Hydatid Disease: A Five-Year Study From a Tertiary Care Center in Southern Saudi Arabia

Background Hydatid disease (cystic echinococcosis) is a neglected zoonotic parasitic infection caused by the larval stage of Echinococcus granulosus. It remains endemic in livestock-raising regions, including the Middle East, where humans serve as accidental intermediate hosts. The liver and lungs are most commonly affected, although any organ may be involved. Histopathology remains the definitive diagnostic modality, particularly in atypical cases. Methods This retrospective observational study was conducted at a tertiary care center in southern Saudi Arabia over a five-year period (January 2018 to December 2022). All histopathologically confirmed cases of hydatid disease were included. Data on age, sex, and anatomical site were retrieved from pathology records. Diagnosis was based on characteristic microscopic features, including laminated acellular membranes, fibrous pericyst, and protoscolices or hooklets. Only descriptive statistics were used. Results A total of 18 cases were identified. The mean age was 39.4 years (range: 20-71 years), with a female predominance (n = 11, 61.1%). The liver was the most frequently involved organ (n = 11, 61.1%), followed by the lungs (n = 5, 27.7%). Rare involvement of the spleen and stomach was observed in one case each (n = 1, 5.6%). Histopathological examination consistently demonstrated the characteristic trilaminar structure of hydatid cysts, with protoscolices and hooklets identified in several cases. Conclusion Hydatid disease in this cohort predominantly involved the liver, followed by the lungs, with a female predominance and occasional atypical organ involvement. Histopathology remains essential for definitive diagnosis, particularly in unusual presentations. Awareness of its clinicopathological spectrum is important for early recognition in endemic regions.