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Kaposi's sarcoma: An unexpected story
HUMAN PATHOLOGY
V o l u m e 13 N u m b e r 10 October 1 9 8 2
Editorial
KAPOSI'S SARCOMA: An Unexpected Story In tile last part of the 19th century, Kaposi described a rare, multifocal sarcoma occurring primarily in men over the age of 50 years. Developing on the lower extremities first, it can then invoh'e the upper extremities and even tile viscera. O f interest, Kaposi's sarcoma may account for up to 9 per cent of all neoplasms in black African men. In the United States, the disease is more common in persons of Jewish and Mediterranean descent. Since 1979, Kaposi's sarcoma has emerged in a totally unexpected population--young homosexual men. Why shonld a relatively rare neoplasm, previously seen in middle-aged men, suddenly emerge in a new group? What is the relationship, if any, between homosexual activity and increased susceptibility to Kaposi's sarcoma? As Gottlieb and Ackerman point out in their paper in this issue, more than 68 cases Imve been reported since January 1979. All these cases have been in relatively young homosexual men. These authors clearly establish the validity o f the tissue diagnosis. The most popular explanation for.this strange and unique phenomenon centers on the immune status o f the patient and the role of infectious agents. Gottlieb and Ackerman carefully review the evidence linking tim cytomegalovirus (CMV) to rite pathogenesis of Kaposi's sarcoma. Although this is quite attractive as a plausible hypothesis, the evidence is largely circumstantial. Patients with Kaposi's sarcoma have been reported to have a broad spectrum of abnormal i m m u n e responses. I m m u n o s u p p r e s s i o n b r o u g h t about by drugs may result in the development of the neoplasm. Fenoglio and her associates have had tile opportunity to study tumor cells from a young homosexual man who developed Kaposi's sarcoma after receiving chemotherapy for testicular cancer. Using the techiaique of in situ hybridization for the detection of viral RNA transcripts, these investigators, whose case report also appears in this issue, were able to localize CMV-specific mRNA in Kaposi's sarcoma cells. Their
report provides more direct evidence suggesting a link between CMV infection and Kaposi's sarcoma. The literature accnmulating worldwide snggests tlmt certain htnnan malignancies may develop as a consequence of CMV infection. Add to this tile established high incidence o f lymphomas in patients with Kaposi's sarcoma and the picture begins to come into focus. As I read these two papers in tiffs issue o f Hu~lar~ PAXnOLOGV,tim notion that we may have identified a true lmman oncogenic virus seems most attractive. Since a state of immunodeficiency appears necessary for the CMV to perhaps function as a cancer "promoter," the syndrome has been named "gay-related imnmnodeficiency disease," or GRID. Recently, scientists at the Centers for Disease Control in Atlanta have studied a cluster of 19 cases in Los Angeles and Orange Counties in California. This represents the first intensive medical investigation of the GRID syndrome in a cluster. Within five years prior to tile onset of symptoms, nine patients had trod sexual contact with other patients diagnosed as having Kaposi's sarcoma. Detailed epidemiologic studies demonstrated that the nine patients from Los Angeles and Orange Counties could be linked to other patients and were part o f an interconnected series of cases that included 16 patients from eight other cities. Unequivocal identification o f tlte presumed infectious agent ires not been accomplished. One hypotltesis under consideration by the Atlanta scientists is timt within the gay population tltere is a smaller subset of patients who, for whatever reasons, are immunodeficient and susceptible to the oncogenic potential of CMV. The other factors to be considered in clinical characterization of this group are life-style, drug use, diet and nutrition, and genetic features of the immune system. Obviously, there are tantalizing clues, but many more data are needed. Pathologists making the tissue diagnosis of Kaposi's sarcoma in young men should be alert to the GRID syndrome.-BERNARD l~,I. WAGNER, MD, Editor
0046-8177/8211000/0873 $00.20 9 W. B. Saunders Co.
873
V o l u m e 13 N u m b e r 10 October 1 9 8 2
Editorial
KAPOSI'S SARCOMA: An Unexpected Story In tile last part of the 19th century, Kaposi described a rare, multifocal sarcoma occurring primarily in men over the age of 50 years. Developing on the lower extremities first, it can then invoh'e the upper extremities and even tile viscera. O f interest, Kaposi's sarcoma may account for up to 9 per cent of all neoplasms in black African men. In the United States, the disease is more common in persons of Jewish and Mediterranean descent. Since 1979, Kaposi's sarcoma has emerged in a totally unexpected population--young homosexual men. Why shonld a relatively rare neoplasm, previously seen in middle-aged men, suddenly emerge in a new group? What is the relationship, if any, between homosexual activity and increased susceptibility to Kaposi's sarcoma? As Gottlieb and Ackerman point out in their paper in this issue, more than 68 cases Imve been reported since January 1979. All these cases have been in relatively young homosexual men. These authors clearly establish the validity o f the tissue diagnosis. The most popular explanation for.this strange and unique phenomenon centers on the immune status o f the patient and the role of infectious agents. Gottlieb and Ackerman carefully review the evidence linking tim cytomegalovirus (CMV) to rite pathogenesis of Kaposi's sarcoma. Although this is quite attractive as a plausible hypothesis, the evidence is largely circumstantial. Patients with Kaposi's sarcoma have been reported to have a broad spectrum of abnormal i m m u n e responses. I m m u n o s u p p r e s s i o n b r o u g h t about by drugs may result in the development of the neoplasm. Fenoglio and her associates have had tile opportunity to study tumor cells from a young homosexual man who developed Kaposi's sarcoma after receiving chemotherapy for testicular cancer. Using the techiaique of in situ hybridization for the detection of viral RNA transcripts, these investigators, whose case report also appears in this issue, were able to localize CMV-specific mRNA in Kaposi's sarcoma cells. Their
report provides more direct evidence suggesting a link between CMV infection and Kaposi's sarcoma. The literature accnmulating worldwide snggests tlmt certain htnnan malignancies may develop as a consequence of CMV infection. Add to this tile established high incidence o f lymphomas in patients with Kaposi's sarcoma and the picture begins to come into focus. As I read these two papers in tiffs issue o f Hu~lar~ PAXnOLOGV,tim notion that we may have identified a true lmman oncogenic virus seems most attractive. Since a state of immunodeficiency appears necessary for the CMV to perhaps function as a cancer "promoter," the syndrome has been named "gay-related imnmnodeficiency disease," or GRID. Recently, scientists at the Centers for Disease Control in Atlanta have studied a cluster of 19 cases in Los Angeles and Orange Counties in California. This represents the first intensive medical investigation of the GRID syndrome in a cluster. Within five years prior to tile onset of symptoms, nine patients had trod sexual contact with other patients diagnosed as having Kaposi's sarcoma. Detailed epidemiologic studies demonstrated that the nine patients from Los Angeles and Orange Counties could be linked to other patients and were part o f an interconnected series of cases that included 16 patients from eight other cities. Unequivocal identification o f tlte presumed infectious agent ires not been accomplished. One hypotltesis under consideration by the Atlanta scientists is timt within the gay population tltere is a smaller subset of patients who, for whatever reasons, are immunodeficient and susceptible to the oncogenic potential of CMV. The other factors to be considered in clinical characterization of this group are life-style, drug use, diet and nutrition, and genetic features of the immune system. Obviously, there are tantalizing clues, but many more data are needed. Pathologists making the tissue diagnosis of Kaposi's sarcoma in young men should be alert to the GRID syndrome.-BERNARD l~,I. WAGNER, MD, Editor
0046-8177/8211000/0873 $00.20 9 W. B. Saunders Co.
873