Isolated Subcarinal Lymph Node Recurrence 24 Years After Treatment for Primary Tracheal Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) is a slow-growing malignancy characterised by late recurrence, making long-term follow-up essential. We report a case of 55-year-old woman who presented with exudative right pleural effusion and subcarinal lymphadenopathy after haematopoietic stem cell transplantation for myelofibrosis. She had undergone surgery and radiotherapy for primary tracheal ACC 24 years prior. Although haematologic disease-related conditions were initially suspected, endobronchial ultrasound-guided transbronchial needle aspiration of the subcarinal lymph node revealed isolated recurrence of ACC, with no evidence of pleural malignancy on pleural biopsy results. Because ACC progresses more slowly than many other malignancies, the growth rate alone does not reliably distinguish benign from malignant lesions. Therefore, a history of ACC should always be considered, and a tissue diagnosis should be pursued when clinically indicated.