Diaphragmatic Eventration Masquerading as Lobar Collapse in Severe ABPA.

Allergic bronchopulmonary aspergillosis (ABPA) characteristically causes transient mucus plugging and lung collapse. We present a 62-year-old asthmatic with acute ABPA whose severe right-sided diaphragmatic elevation initially mimicked mucus-induced atelectasis. High-resolution CT and positional spirometry unmasked a massive diaphragmatic eventration, highlighting a rare structural mimic of lobar collapse.