小児患者における気管支内ポリープとして現れたALK陽性未分化大細胞型リンパ腫

Anaplastic large cell lymphoma (ALCL) accounts for 10-15% of pediatric and adolescent non-Hodgkin lymphoma cases, with lung involvement observed in 14% of cases. We present a case of primary isolated ALCL in the endobronchial region of a 14-year-old boy. He presented with fever, dyspnea on exertion, cough, and left chest pain. A chest X-ray revealed a complete cut-off of the left main bronchus, which was further evaluated by bronchoscopy, showing complete occlusion of the left main bronchus by an endoluminal mass. Bronchoscopy with electrocautery snaring was performed, and immunomorphological findings confirmed the diagnosis of primary ALCL of the left main bronchus. Clinical and radiological evaluation revealed no evidence of extra-thoracic disease. A standard chemotherapy protocol was initiated. ALCL is an uncommon neoplasm in the pediatric population and rarely presents as a primary lung tumor. However, when unusual pulmonary lesions are encountered, especially in children, ALCL should be part of the differential diagnosis.