COVID-19 pneumonia and an indelible ground-glass nodule Respirology Case Reports

A 59-year-old man who complained of fever, general malaise, and olfactory and taste disorders was admitted to hospital five days after onset. Coronavirus disease 2019 (COVID-19) pneumonia was diagnosed from the results of chest computed tomography (CT) and reverse transcription polymerase chain reaction test. Chest CT showed multiple patchy ground-glass nodules (GGNs), mainly in the peripheral lung parenchyma beneath the pleura (Fig. 1A). A GGN in the right upper lobe seemed to show characteristics differing from other GGNs on chest CT, so follow-up CT was scheduled after his recovery. He was discharged without sequelae after 19 days of treatment, and follow-up CT was performed three months later (Fig. 1B). Only the GGN (Fig. 1B, arrow) in the right upper lobe remained, although the other pneumonia shadows had disappeared. Based on these imaging findings, primary pulmonary adenocarcinoma was suspected. Thoracic surgery was performed to obtain a definitive diagnosis, and adenocarcinoma in situ (AIS) was histopathologically diagnosed. Although follow-up CT is not cost-effective for all COVID-19 pneumonia patients, the possibility of lung neoplasm should be kept in mind if the GGN shows characteristics non-specific for viral infection, such as solitary nature, relative roundness, well-defined borders, and distance from the pleura. If the clinician has such a suspicion, a follow-up CT at low dose is recommended after one to three months according to the guidelines for pulmonary nodules with suspected infection [1].