COVID19 pneumonia with cavitation and cystic lung changes: multi-detector computed tomography spectrum of a gamut of etiologies

The COVID19 pandemic since its beginning in March 2020, continues to wreak havoc causing great morbidity and mortality with each passing day. Ample literature is now available describing the imaging features of COVID19 infection; however, there is still a paucity of knowledge on the various causes of pulmonary cavitation and cystic lesions which can be associated with the virus albeit uncommonly. Cavitation in a COVID19 positive patient could be a consequence of the infection itself or a manifestation of sinister etiologies like coinfection with bacterial, fungal or mycobacterial pathogens, or incidental malignancy/metastasis. It could also be a result of multiple cavitating pulmonary nodules as a manifestation of septic emboli and infarct, Granulomatosis with polyangiitis or rheumatoid arthritis creating a diagnostic dilemma. Similarly, the causes of cystic air spaces on chest CT in COVID19 patient can be varied, either primarily due to the infection itself or secondary to coexistent cystic bronchiectasis, emphysema, interstitial lung disease or mechanical ventilation-associated barotrauma as well as complicated pulmonary cysts. Through this pictorial review, we aim to highlight these uncommon imaging manifestations of COVID19 and educate the reader regarding the various causes, MDCT features and differentials to be considered while approaching a cavity/cystic lesion amidst this pandemic.