[Not all cases of groundglas opacity are COVID-19 - Pneumocystis-jirovecii-pneumonia as a differential diagnosis].

History and clinical findings A 68-year-old male patient with psorias and a bullous pemphigoid as an underlying disease developed bilateral groundglass opacities on chest CT under longer-term, higher-dose immunosuppressive therapy with methylprednisolone with clinical symptoms of dry cough, progressive dyspnea and fever. Diagnosis and therapy After the exclusion of COVID-19, Pneumocystis jirovecii pneumonia (PCP) was detected and a corresponding high-dose therapy with trimethoprim-sulfamethoxazole was initiated promptly. Course Nonetheless, a complicated course with bacterial superinfection and pulmonary aspergillosis as well as ARDS developed. Discussion and conclusion In contrast to COVID-19, the typical course, diagnosis and therapy of Pneumocystitis jirovecii pneumonia are discussed. It is particularly emphasized that not all ground glass infiltrates in the CT chest image can be traced back to a COVID-19, even in a pandemic situation. Possible differential diagnoses should always be considered and taken into account in the diagnosis.