Sarcomatoid carcinoma of the lung
Encyclopedia
Sarcomatoid carcinoma of the lung is a term that encompasses five distinct histological subtypes of lung cancer
, including (1) pleomorphic carcinoma, (2) spindle cell carcinoma, (3) giant cell carcinoma, (4) carcinosarcoma, or (5) pulmonary blastoma.
(WHO) typing system ("WHO-2004"), currently the most widely used lung cancer classification scheme. Many of these entities are rare, recently described, and poorly understood. However, since different forms of malignant tumors generally exhibit diverse genetic, biological, and clinical properties, including response to treatment, accurate classification of lung cancer cases are critical to assuring that patients with lung cancer receive optimum management.
Approximately 98% of lung cancers are carcinoma
, a term for malignant neoplasms derived from cells of epithelial lineage, and/or that exhibit cytological or tissue architectural features characteristically found in epithelial cells. Under WHO-2004, lung carcinomas are divided into 8 major taxa:
Sarcomatoid carcinomas are unique among lung carcinomas in that, although they are considered carcinomas, they contain cytological and tissue architectural features that are usually characteristic of sarcoma
.
Overexpression of the EGFR
protein
occurs in nearly all cases (22/22).
Mutations of the EGFR gene are relatively rare (0/23).
K-ras mutations found in 8/22 cases (Gly12Cys in 6 cases and Gly12Val in 2 cases)
Very few histospecific studies of individual subtypes SCL have been published in the literature; most data has been small retrospective case series or case reports.
In many cases, SCL are generally treated like other NSCLC. However, as SCL are considered particularly aggressive non-small cell lung cancers, some experts recommend particularly aggressive treatment approach to these tumors.
Little is known about the effects of EGFR inhibitors in SC, although some evidence suggests that these tumors are not likely to be highly responsive.
Lung cancer
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...
, including (1) pleomorphic carcinoma, (2) spindle cell carcinoma, (3) giant cell carcinoma, (4) carcinosarcoma, or (5) pulmonary blastoma.
Lung Cancer Classification
Lung cancer is a large and exceptionally heterogeneous family of malignancies. Over 50 different histological variants are explicitly recognized within the 2004 revision of the World Health OrganizationWorld Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
(WHO) typing system ("WHO-2004"), currently the most widely used lung cancer classification scheme. Many of these entities are rare, recently described, and poorly understood. However, since different forms of malignant tumors generally exhibit diverse genetic, biological, and clinical properties, including response to treatment, accurate classification of lung cancer cases are critical to assuring that patients with lung cancer receive optimum management.
Approximately 98% of lung cancers are carcinoma
Carcinoma
Carcinoma is the medical term for the most common type of cancer occurring in humans. Put simply, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that generally arises from cells originating in the endodermal or ectodermal germ layer during...
, a term for malignant neoplasms derived from cells of epithelial lineage, and/or that exhibit cytological or tissue architectural features characteristically found in epithelial cells. Under WHO-2004, lung carcinomas are divided into 8 major taxa:
- Squamous Cell Carcinoma
- Small Cell Carcinoma
- Adenocarcinoma
- Large Cell Carcinoma
- Adenosquamous Carcinoma
- Sarcomatoid Carcinoma
- Carcinoid Tumor
- Salivary Gland-like Carcinoma
Sarcomatoid carcinomas are unique among lung carcinomas in that, although they are considered carcinomas, they contain cytological and tissue architectural features that are usually characteristic of sarcoma
Sarcoma
A sarcoma is a cancer that arises from transformed cells in one of a number of tissues that develop from embryonic mesoderm. Thus, sarcomas include tumors of bone, cartilage, fat, muscle, vascular, and hematopoietic tissues...
.
Histogenesis and Genetics
Abnormal duplication of the EGFR gene is a relatively infrequent phenomenon in SCL (>/= 4 copies in >/= 40% of cells in 5/22)Overexpression of the EGFR
Epidermal growth factor receptor
The epidermal growth factor receptor is the cell-surface receptor for members of the epidermal growth factor family of extracellular protein ligands...
protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
occurs in nearly all cases (22/22).
Mutations of the EGFR gene are relatively rare (0/23).
K-ras mutations found in 8/22 cases (Gly12Cys in 6 cases and Gly12Val in 2 cases)
Treatment
Because these tumors are so rare, there have been no randomized clinical trials yet conducted with respect to specific treatment regimens for any subtype.Very few histospecific studies of individual subtypes SCL have been published in the literature; most data has been small retrospective case series or case reports.
In many cases, SCL are generally treated like other NSCLC. However, as SCL are considered particularly aggressive non-small cell lung cancers, some experts recommend particularly aggressive treatment approach to these tumors.
Little is known about the effects of EGFR inhibitors in SC, although some evidence suggests that these tumors are not likely to be highly responsive.
External links
- Lung Cancer Home Page. The National Cancer InstituteNational Cancer InstituteThe National Cancer Institute is part of the National Institutes of Health , which is one of 11 agencies that are part of the U.S. Department of Health and Human Services. The NCI coordinates the U.S...
site containing further reading and resources about lung cancer. - http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf. World Health Organization Histological Classification of Lung and Pleural Tumours. 4th Edition.