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Giant cell carcinoma of the lung (GCCL) is a rare histological form of large-cell lung carcinoma, a subtype of undifferentiated lung cancer, traditionally classified within the non-small cell lung carcinomas (NSCLC). The characteristic feature of this highly lethal malignancy is the distinctive light microscopic appearance of its extremely large cells, which are bizarre and highly pleomorphic, and which often contain more than one huge, misshapen, pleomorphic nucleus ("syncytia"), which result from cell fusion. Although it is common in the lung cancer literature to refer to histologically mixed tumors containing significant numbers of malignant giant cells as "giant cell carcinomas", technically a diagnosis of "giant cell carcinoma" should be limited strictly to neoplasms containing ''only'' malignant giant cells (i.e. "pure" giant cell carcinoma).〔 Aside from the great heterogeneity seen in lung cancers (especially those occurring among tobacco smokers), the considerable variability in diagnostic and sampling techniques used in medical practice, the high relative proportion of individuals with suspected GCCL who do not undergo complete surgical resection, and the near-universal lack of complete sectioning and pathological examination of resected tumor specimens prevent high levels of quantitative accuracy. ==Epidemiology== The true incidence, prevalence, and mortality of GCCL is generally unknown due to a lack of accurate cancer data on a national level. It is known to be a very rare tumor variant in all populations examined, however. In an American study of a database of over 60,000 lung cancers, GCCL comprised between 0.3% and 0.4% of primary pulmonary malignancies, with an age-adjusted incidence rate of about 3 new cases per million persons per year. Wit h approximately 220,000 total lung cancers diagnosed in the US each year,〔(【引用サイトリンク】title=Fact Sheet: Cancer of the Lung and Bronchus )〕 the proportion suggests that approximately 660 and 880 new cases are diagnosed in Americans annually.〔〔 〕 However, in a more recent series of 4,212 consecutive lung cancer cases, only one (0.024%) lesion was determined to be a "pure" giant cell carcinoma after complete sectioning of all available tumor tissue. While some evidence suggests GCCL may have been considerably more common several decades ago, with one series identifying 3.4% of all lung carcinomas as giant cell malignancies, it is possible that this number reflect Most published case series and reports on giant cell-containing lung cancers show that they are diagnosed much more frequently in men than they are in women,〔 ((Chinese text) )〕 with some studies showing extremely high male-to-female ratios (12:1 or more). In a study of over 150,000 lung cancer victims in the US, however, the gender ratio was just over 2:1, with women actually having a higher relative proportion of giant cell cancers (0.4%) than men (0.3%).〔 Giant cell carcinomas have been reported to be diagnosed in a significantly younger population than all non-small cell carcinomas considered as a group.〔 Like nearly all lung carcinomas, however, GCC's are exceedingly rare in very young people: in the US SEER program, only 2 cases were recorded to occur in persons younger than 30 years of age between 1983 and 1987.〔 The average age at diagnosis of these tumors has been estimated at 60 years.〔 The vast majority of individuals with GCCL are heavy smokers,〔 Although the definitions of "central" and "peripheral" can vary〔 between studies, GCCL are consistently diagnosed much more frequently in the lung periphery.〔 In a review of literature compiled by Kallenburg and co-workers, less than 30% of GCCL's arose in the hilum or other parts of the "central" pulmonary tree.〔 A significant predilection for genesis of GCCL in the upper lobes of victims has also been postulated.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Giant-cell carcinoma of the lung」の詳細全文を読む スポンサード リンク
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