Background: Hydatidosis is a parasitic infection that is still frequent in the world, especially in the Mediterranean area and in breeding regions such as Morocco. The management of complicated hydatid cysts remains delicate, especially in the case of intrapleural rupture, with a high risk of intraoperative swarming and of local, regional and distant recurrence, which modifies the prognosis. This case of dissemination by contiguity is one of the rarest presentations. Case presentation: This is a case report of a 29-year-old Moroccan patient, operated 8 years before for a left pulmonary hydatid cyst ruptured in the pleura and bronchi without immediate postoperative complications who presented with respiratory symptomatology revealing an almost exclusive left thoracoabdominal hydatidosis with diaphragmatic involvement The diagnosis was retained on several clinical, biological and radiological grounds. The almost exclusive left involvement pleads for a dissemination by contiguity entering the case of a diffuse hydatidosis whose treatment is medical. The evolution is marked few months later by the death of the patient by respiratory distress. Conclusion: Contiguous dissemination of the pulmonary hydatid cyst is a rare but possible situation which requires careful peroperatory manipulation of the hydatid cyst content, the adoption of surgical methods with the lowest risk of recurrence and complications, and an adjuvant medical treatment with albendazole. Patients education on the importance of adherence to treatment and follow-up is fundamental.