Unveiling a Hidden Diaphragmatic Hernia Underlying a Spontaneous Hydropneumothorax: A Diagnostic Surprise.

Right-sided diaphragmatic hernias in adults are rare and often pose diagnostic challenges due to their atypical clinical and radiological presentations. The coexistence of a spontaneous hydropneumothorax can obscure the underlying pathology, initially diverting attention toward pleural management. We report a rare case of a spontaneous right-sided diaphragmatic hernia discovered incidentally beneath a spontaneous hydropneumothorax in an elderly patient presenting with chest pain, respiratory distress, and abdominal discomfort. Clinical examination revealed decreased breath sounds on the right side with mild abdominal tenderness, and computed tomography of the chest confirmed herniation of abdominal contents into the thoracic cavity, clarifying the dual pathology and guiding definitive surgical management. This case highlights the importance of maintaining a high index of suspicion for diaphragmatic hernia in atypical presentations of hydropneumothorax, emphasizing the role of multimodal imaging, early multidisciplinary collaboration, and adherence to safe chest drain insertion protocols to prevent iatrogenic injury and optimize outcomes.