An Unusual Case of a COVID19-Associated Solitary Pulmonary Nodule

Introduction: Solitary pulmonary nodules (SPN) are commonplace and often incidental findings on diagnostic imaging such as computed tomography (CT) of the thorax. A SPN is defined as a single lung opacity of less than 3cm in size. They present a diagnostic dilemma as differentials are broad and range from benign to malignant. Here, we present a case of a SPN in an patient with SARS-CoV-2 infection. Case Description: A 33 year-old female with history of recreational marijuana use presented to the hospital with right-sided flank pain, dysuria, fevers, and nausea for four days. Upon presentation, she was afebrile with stable vital signs and SpO2 97% on ambient air. Physical exam was remarkable only for flank and suprapubic tenderness. A diagnosis of pyelonephritis was made and confirmed with CT of the abdomen which also detected a left lower lobe subpleural nodular consolidation. Follow-up chest CT better characterized the lesion as a 2.2 x 1.2 cm ground glass opacity (GGO) in the posterior left lower lobe without effusion, pneumothorax, or regional lymphadenopathy. Coccidioides serology was negative, however, routine COVID-19 testing found the patient to be positive for SARS-CoV-2. She underwent successful treatment for pyelonephritis and was discharged with instructions to follow up in pulmonology clinic. At follow up, she denied any interval development of respiratory symptoms. Repeat chest CT four months later showed complete resolution of the lesion and she was discharged from pulmonology clinic. Discussion: Since the advent of COVID-19, a plethora of radiologic findings have been noted in patients with known infections. Chest CT offers insight into clinical staging of diseas e and temporal evolutions of CT findings correlate with disease severity. Typical features include bilateral peripheral GGO, crazy paving pattern, airspace consolidations, traction bronchiectasis, and bronchovascular thickening. Atypical findings include mediastinal lymphadenopathy, pleural effusions, multiple small nodules, tree-in-bud, pneumothorax, and cavitation. Though not typical and seemingly underreported, a SPN may also indicate a very early infectious stage in the absence of respiratory symptoms. For our patient, Fleischner guidelines suggest a follow-up CT at 6-12 months but such a strategy would surely fail to detect development of pneumonia given the speed at which COVID-19 progresses, and possibly miss the window on early outpatient interventions and infection prevention. Instead, this case highlights the importance of shorter interval repeat chest imaging in patients with incidental SPN and SARS-CoV-2 infection as a means to monitor for resolution or progression requiring further evaluation and treatment.