Problems in the diagnosis of small cell carcinoma of the lungs by fiberoptic bronchoscopy.

Fiberoptic bronchoscopy (FOB) with the aid of endoscopic biopsies and brush cytology is recognized as a valuable approach in the diagnosis of lung cancer. However, histologic classification of lung cancer based on tiny specimens obtained from FOB can be difficult. Correct identification of small cell carcinoma of the lung is especially important because its recognition usually precludes surgery. In a review of 770 patients who underwent FOB biopsies at The Mount Sinai Hospital, New York, in individuals with proven lung cancer 150 instances of small cell carcinoma were encountered. In four of these instances subsequent surgery, such as scalene node biopsy, mediastinoscopy, or thoracotomy, was performed because clinically and radiologically the tumors did not behave as small cell carcinomas. Pathologic examination of larger tissue samples from these neoplasms provided the following final diagnoses: bronchial carcinoid, adenocarcinoma, squamous cell carcinoma, and small cell carcinomas-combined type. Analysis of the FOB biopsies and brush cytology usually permit diagnosis of small cell carcinoma of the lung. However, in instances where the biologic behavior of a tumor casts doubt on the diagnosis of small cell carcinoma, further studies should be performed, including radionuclide scans, and bone marrow and other biopsies before denying the patient a chance of surgical cure.