Simultaneous development of COVID-19 pneumonia and pulmonary metastasis in a known case of chondrosarcoma: a case report.

<bold>Background: </bold>The outbreak of coronavirus disease 2019 (COVID-19) started in December 2020, and is a global problem now. There are several sets of established data regarding computed tomography (CT) findings in COVID-19 pneumonia with many differential diagnoses. During the early days of the pandemic, there was little data regarding lung CT features of COVID-19 in a cancer patient. In this paper, we described a rare case of simultaneous presentation of COVID-19 with pulmonary metastasis.<bold>Case Presentation: </bold>A Persian patient with a history of chondrosarcoma presented to our clinic during the COVID-19 pandemic with a new-onset cough. He had experienced no recurrence during previous follow-up visits. Chest CT scan revealed numerous bilateral small peripheral and perilymphatic pulmonary nodules, unilateral ground-glass patch, and nodular interlobular septal thickening. Biopsy of the pulmonary nodules established pulmonary metastasis of chondrosarcoma origin, and pharyngeal reverse transcription polymerase chain reaction (RT-PCR) was positive for COVID-19.<bold>Conclusion: </bold>Pulmonary metastasis should be considered as a differential diagnosis of COVID-19 features in cancer patients in the pandemic era. [ABSTRACT FROM AUTHOR]