Black pleural effusion caused by a pancreaticopleural fistula secondary to chronic alcoholic pancreatitis exacerbation accompanying COVID-19.

Pancreaticopleural fistula should be considered in alcohol abusers with pleural effusion, which can exhibit a black color.

Acute respiratory distress syndrome relapsing in 10 months with an initial manifestation of polymyositis.

Autoimmune disorders are an important cause of acute respiratory distress syndrome (ARDS). We report a case of a patient with steroid-responsive ARDS that relapsed in 10 months with an initial manifestation of seronegative polymyositis. ARDS associated with polymyositis may develop earlier than myopathy and may relapse later.

A case of humidifier lung with a difficult differential diagnosis from COVID-19.

Acute respiratory illnesses that presented with diffuse ground-glass opacities (GGOs) on chest computed tomography (CT) scan suggest the diagnosis of coronavirus disease 2019 (COVID-19). However, many other diseases show similar CT findings, which often offer a difficult differential diagnosis. Here, we report a case of humidifier lung, a rare phenotype of hypersensitivity pneumonitis (HP), which mimicked COVID-19. A 71-year-old man was admitted because of dyspnea and diffuse GGOs found on chest CT scan. Although COVID-19 was initially suspected, his symptoms rapidly improved by the next day. A medical interview revealed that he had started using an ultrasonic humidifier 1 month ago. A high-resolution CT (HRCT) scan showed ill-defined centrilobular nodules and mosaic attenuation, which are typical of HP but atypical of COVID-19. The inhalation challenge test confirmed the diagnosis of humidifier lung. History-taking of humidifier use and a precise HRCT interpretation are helpful to differentiate it from COVID-19.