Review of pathologic material by an experienced lung cancer pathologist is important prior to initiating treatment of any patient with small cell lung cancer (SCLC). The intermediate subtype of SCLC and the more readily recognized lymphocyte-like or oat cell subtype are equally responsive to treatment.

The current classification of subtypes of SCLC is:[1]

• Small cell carcinoma.
• Mixed small cell/large cell carcinoma.
• Combined small cell carcinoma (i.e., SCLC combined with neoplastic squamous and/or glandular components).

Neuroendocrine carcinomas of the lung represent a spectrum of disease. At one extreme is SCLC, which has a poor prognosis. At the other extreme are bronchial carcinoids, which have an excellent prognosis after surgical excision.[2] Between these extremes is an unusual entity called well-differentiated neuroendocrine carcinoma of the lung.[3] It has been referred to as malignant carcinoid, metastasizing bronchial adenoma, pleomorphic carcinoid, nonbenign carcinoid tumor, and atypical carcinoid. Like SCLC, it occurs primarily in cigarette smokers, but it metastasizes less frequently. The 5-year survival rate is more than 50% in some series, and surgical cure appears possible in most stage I patients. Careful diagnosis is important, however, since the differential pathologic diagnosis from SCLC may be difficult.

References

1. Hirsch FR, Matthews MJ, Aisner S, et al.: Histopathologic classification of small cell lung cancer. Changing concepts and terminology. Cancer 62 (5): 973-7, 1988.  [PUBMED Abstract]
   
   
2. Harpole DH Jr, Feldman JM, Buchanan S, et al.: Bronchial carcinoid tumors: a retrospective analysis of 126 patients. Ann Thorac Surg 54 (1): 50-4; discussion 54-5, 1992.  [PUBMED Abstract]
   
   
3. Lequaglie C, Patriarca C, Cataldo I, et al.: Prognosis of resected well-differentiated neuroendocrine carcinoma of the lung. Chest 100 (4): 1053-6, 1991.  [PUBMED Abstract]