Diagnosis and management of a severe ALK-positive pneumonia-type lung adenocarcinoma: a case report.

Pneumonia-type lung adenocarcinoma (PLADC) exhibits clinical symptoms and radiographic features that mimic those of pneumonia. This often leads to misdiagnosis, which can delay appropriate treatment and result in poor outcomes, particularly in severe cases. Effective management of PLADC requires a timely and accurate diagnosis through tissue biopsy, allowing for detailed pathological examination and genetic profiling, followed by targeted therapy tailored to the patient's condition. While mutations in EGFR are commonly associated with PLADC, ALK fusions are rare and typically detected at advanced stages, with limited reports on treatment effectiveness. In this report, we present a case involving a young female patient with severe stage IV ALK-positive PLADC. Prior to receiving the accurate diagnosis, the patient suffered from severe complications, including respiratory failure, cardiac tamponade, invasive mechanical ventilation, and disseminated intravascular coagulation, all posing a high risk of mortality. Remarkably, within five days of initiating alectinib therapy, the patient's condition significantly recovered. She was successfully weaned from mechanical ventilation, and her Eastern Cooperative Oncology Group Performance Status score improved from 4 to 2 within eight days, leading to her discharge in much stabilized state. This case highlights the importance of genetic profiling and rapid and substantial efficacy of alectinib in treating ALK-positive PLADC, reinforcing the role of ALK inhibitors in managing severe cases and offering valuable insights for clinical strategies.