The Carcinoid tumor


A 56-year-old man presents with increasing chest pain, bloody sputum, and weight loss over the past 3 months. A highresolution CT scan reveals a mass circumscribing the right main bronchus, extending into its lumen. Histologic examination of an open-lung biopsy is shown in the figure. Electron microscopy shows numerous neuroendocrine granules within tumor cells. What is the appropriate diagnosis?

  1. Adenocarcinoma
  2. Bronchioloalveolar carcinoma
  3. Carcinoid tumor
  4. Large cell carcinoma
  5. Squamous cell carcinoma