Primary pleural hydatid cyst: A rare presentation of echinococcosis with diagnostic and therapeutic insights.

Background: Hydatid disease, which is caused by Echinococcus granulosus, mainly impacts the liver and lungs. It is extremely uncommon for the pleura to be primarily affected, and this presents difficulties for diagnosis because it resembles a malignant condition. This report underscores a distinctive instance of an isolated pleural hydatid cyst, focusing on diagnostic challenges, multidisciplinary management, and treatment results. Case presentation: A Lebanese man aged 60, with no notable exposure history, showed up with an incidental pleural mass. Initial imaging indicated a potential malignancy based on rib erosion and rapid growth. A hydatid cyst was confirmed by a CT-guided biopsy, despite the presence of normal eosinophil counts and negative serology. The MRI ruled out hepatic/pulmonary involvement. Complete resolution, confirmed through serial imaging, was achieved with albendazole monotherapy (400 mg twice daily for five months). Discussion: This instance highlights how uncommon primary pleural hydatidosis is, as well as the shortcomings of serologic testing. The review of comparative literature shows just 12 documented instances, with our case being the first to exhibit rib erosion without hepatic or pulmonary involvement (Sudan et al., 2025 [2], Soner Gürsoy et al., 2009 [3], Brunetti et al., 2010 [7]). It encompasses radiological, pathological, and therapeutic nuances, promoting biopsy in equivocal cases (Santivanez et al., 2010 [1], Mardani et al., 2017 [6]). Conclusion: Even though primary pleural hydatid cysts are uncommon, they should be considered in the differential diagnoses of pleural masses, especially in areas where they are endemic. For an accurate diagnosis, histopathology and collaboration across disciplines are essential. For isolated cysts, albendazole monotherapy may be adequate; however, long-term monitoring is crucial (Mardani et al., 2017 [6], Qian, 1988 [9]).