PEComa of the colon resistant to sirolimus but responsive to doxorubicin/ifosfamide.

A 23-year-old male presented with a three-week-history of crampy abdominal pain and melaena. Colonoscopy revealed a friable mass filling the entire lumen of the cecum; histologically, it was classified as perivascular epithelioid cell tumor (PEComa). An magnetic resonance imaging scan showed, in addition to the primary tumor, two large mesenteric lymph node metastases and four metastatic lesions in the liver.

Defense mechanisms in Peyer's patches and mesenteric lymph nodes against Yersinia enterocolitica involve integrins and cytokines.

Adhesion molecules and cytokines are involved in regulation of cellular host responses in infection processes. In this study the roles of the integrins Mac-1 and VLA-4, as well as those of the cytokines tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma), in defense mechanisms against Yersinia enterocolitica in Peyer's patches (PP) and mesenteric lymph nodes (MLN) were investigated by blocking these molecules with antibodies in vivo prior to orogastric Yersinia infection. Intestinal Yersinia infection caused abscesses composed of polymorphonuclear (Mac-1+ VLA-4+ Pgp-1+ ICAM-1-) and mononuclear (Mac-1+ VLA-4+ Pgp-1+ ICAM-inhibited phagocytosis of yersiniae by macrophages, (ii) reduced Yersinia-specific proliferation and IFN-gamma production of T cells from PP and MLN, and (iii) caused increased bacterial growth in PP and MLN followed by profound tissue destruction.