Skip to content

Lung Cancer Health Center

Font Size

Small Cell Lung Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Cellular Classification of Small Cell Lung Cancer

Before initiating treatment of a patient with small cell lung cancer (SCLC), an experienced lung cancer pathologist should review the pathologic material.

Pathologic Classification

Recommended Related to Lung Cancer

What Is Lung Cancer?

Although lung cancer is the leading cause of cancer death in the U.S. in both men and women, both the occurrence of lung cancer and the deaths related to it can be reduced. More than four out of every five cases of lung cancer are associated with cigarette smoking. The cause-and-effect relationship has been extensively documented. During the 1920s, large numbers of men began to smoke cigarettes, presumably in response to increased advertising. Twenty years later, the frequency of lung cancer in men...

Read the What Is Lung Cancer? article > >

The current classification of subtypes of SCLC includes the following:[1]

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

SCLC arising from neuroendocrine cells forms one extreme of the spectrum of neuroendocrine carcinomas of the lung.

Neuroendocrine tumors include the following:

  • Low-grade typical carcinoid.
  • Intermediate-grade atypical carcinoid.
  • High-grade neuroendocrine tumors including large-cell neuroendocrine carcinoma (LCNEC) and SCLC.

Because of differences in clinical behavior, therapy, and epidemiology, these tumors are classified separately in the World Health Organization (WHO) revised classification. The variant form of SCLC called mixed small cell/large cell carcinoma was not retained in the revised WHO classification. Instead, SCLC is now described with only one variant, SCLC combined, when at least 10% of the tumor bulk is made of an associated non-small cell component.

SCLC presents as a proliferation of small cells with the following morphological features:[2]

  • Scant cytoplasm.
  • Ill-defined borders.
  • Finely granular "salt and pepper" chromatin.
  • Absent or inconspicuous nucleoli.
  • Frequent nuclear molding.
  • A high mitotic count.

Combined small cell carcinoma includes a mixture of small cell and large cell or any other non-small cell component. Any cases showing at least 10% of SCLC are diagnosed as combined SCLC, and SCLC is limited to tumors with pure SCLC histology. SCLC associated with LCNEC is diagnosed as SCLC combined with LCNEC.

Nearly all SCLC are immunoreactive for keratin, thyroid transcription factor 1, and epithelial membrane antigen. Neuroendocrine and neural differentiation result in the expression of dopa decarboxylase, calcitonin, neuron-specific enolase, chromogranin A, CD56 (also known as nucleosomal histone kinase 1 or neural-cell adhesion molecule), gastrin-releasing peptide, and insulin-like growth factor 1. One or more markers of neuroendocrine differentiation can be found in approximately 75% of SCLC.[3]

Although preinvasive and in situ malignant changes are frequently found in patients with non-small cell lung cancer, these findings are rare in patients with SCLC.[4]

References:

  1. Travis WD, Colby TV, Corrin B, et al.: Histological typing of lung and pleural tumours. 3rd ed. Berlin: Springer-Verlag, 1999.
  2. Brambilla E, Travis WD, Colby TV, et al.: The new World Health Organization classification of lung tumours. Eur Respir J 18 (6): 1059-68, 2001.
  3. Guinee DG Jr, Fishback NF, Koss MN, et al.: The spectrum of immunohistochemical staining of small-cell lung carcinoma in specimens from transbronchial and open-lung biopsies. Am J Clin Pathol 102 (4): 406-14, 1994.
  4. Kumar V, Abbas A, Fausto N, eds.: Robins and Cotran Pathologic Basis of Disease. 7th ed. Philadelphia, Pa: Elsevier Inc, 2005.

    This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http:// cancer .gov or call 1-800-4-CANCER.

    WebMD Public Information from the National Cancer Institute

    Last Updated: September 04, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
    1
    Next Article:

    Today on WebMD

    Broken cigarette
    Do you know the myths from the facts?
    man with a doctor
    Our health check will steer you in the right direction.
     
    sauteed cherry tomatoes
    Fight cancer one plate at a time.
    Lung cancer xray
    See it in pictures, plus read the facts.
     
    15 Cancer Symptoms Men Ignore
    FEATURE
    Lung Cancer Risks Myths and Facts
    SLIDESHOW
     
    cancer fighting foods
    SLIDESHOW
    Improving Lung Cancer Survival Targeted Therapy
    VIDEO
     
    Lung Cancer Surprising Differences Between Sexes
    VIDEO
    Pets Improve Your Health
    SLIDESHOW
     
    Vitamin D
    SLIDESHOW
    Lung Cancer Surgery Options
    VIDEO
     

    WebMD Special Sections