Posters— Diagnostic Imaging/Pathology

A CASE OF GASTROINTESINAL SARCOMA TUMOR (GIST) REVEALED BY A MEDITERRANEAN KAPOSI’S SARCOMA IN AN HIV-NEGATIVE PATIENT: CASUAL ASSOCIATION OR NOT?

Vincent Baty⁽¹⁾, Isabelle Ray-Coquard⁽¹⁾, Eric Fontaumard⁽¹⁾, Dominique Ranchere-Vince⁽²⁾, David Tavan⁽²⁾, Jean-Yves Blay⁽²⁾.(1): Clinique Eugene Andre, (2): Centre Leon Berard, LYON, France

Mediterranean Kaposi’s sarcoma (KS) typically runs a chronic course in elderly patients and may be associated with secondary malignancies. HHV-8 has been well documented to be associated with all forms of KS. Gastrointestinal stromal tumors (GIST) are a recently described entity whose etiology remains unknown. The possible role of Human Herpes-Virus 8 (HHV-8) in this disease has not been reported. We hereafter report the first case of an association of a colonic GIST with KS in an HIV-negative patient. A 72-year old Spanish woman was admitted with a few months history of flat skin lesions and nodules on her left knee. The histopathological study of skin biopsies demonstrated Cutaneous Kaposi’s sarcoma (CKS). Endoscopic explorations of the gastrointestinal tract were performed as a standard staging procedure and revealed a stenotic tumor on the transverse colon. The histopathological and immunochemistry studies of colonic tumor enabled to identify a GIST. A segmental surgical resection was subsequently performed. The tumor size was 4x1,5x1,5cm. The association of Kaposi’s sarcoma and smooth muscle tumors of the gastrointestinal tract is extremely rare since only one case has been reported in a HIV-positive patient. Infection with HHV8, is identified in more than 95% of KS and has been demonstrated in other skin cancer in immunosuppressed patients, and for angiosarcoma in HIV-negative patient. Conversely, latent EBV infection has been demonstrated in low-grade leiomyosarcoma (LS) in HIV-positive patients but neither in adjacent Kaposi s sarcoma lesions nor in LS occuring in immunocompetent hosts. Thus our case is remarkable since the association of LS and CKS has not been reported previously in non-HIV patient and suggest a possible association between HHV-8 infection and GIST. The presence of Epstein-Barr virus (EBV) and HHV8 DNA sequences is investigated on CKS both and GIST tissue specimens and the results will be available for presentation at CTOS.