RESUMO
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of gastrointestinal tract, and bleeding is among the primary symptoms. If the tumor is located in the small intestine, diagnosis might be difficult because of its inaccessibility by endoscope. This report presents a case of duodenal GIST diagnosed with the aid of diffusion-weighted (DW) magnetic resonance imaging (MRI). A 66-year-old male was admitted to the hospital because of shortness of breath and melena. The patient demonstrated marked anemia. Esophagogastroduodenoscopy and colonoscopy revealed no involvement of the mucosa of the gastrointestinal tract in regard to the observed bleeding. Thereafter, computed tomography was done and showed a tumorous lesion 4.2 cm in diameter located around the ligament of Treitz. The area showed significant high intensity by DW-MRI, strongly suggesting malignant character. Examination with a long endoscope demonstrated a large submucosal tumor with wide ulceration located at the third portion of the duodenum. The biopsy sample contained spindle-shaped cells that were positive for CD34 and c-kit on histochemistry, and the tumor was diagnosed as GIST. The patient underwent surgery and survived for 16 months without any recurrence.
RESUMO
BACKGROUND: A regimen consisting of polyclonal anti-T-cell antibody, sirolimus (SRL), and donor bone marrow (DBM) infusion induces robust transplantation tolerance to skin allografts in mice. We investigated the effect of a similar regimen in a nonhuman primate (NHP) model. METHODS: Cynomolgus macaques (Macaca fascicularis) were transplanted with mismatched kidney allografts. Recipients were treated with 7 doses of antithymocyte globulin (Thymoglobulin, day 1 to 9), sirolimus, and DBM infusion (day 14). Anti-CD20 antibody, rituximab, was given on days 0 and 5. RESULTS: A regimen of Thymoglobulin, 30 days of SRL, and DBM infusion induced significantly greater prolongation of graft survival with a mean survival time of 88 days compared with the control regimen (no DBM) with an mean survival time of 53 days (P=0.022). Unlike the murine skin allograft model, all grafts were rejected within 111 days. A combination of Thymoglobulin, continuous SRL, and rituximab caused graft and systemic SV40 infection and failed to achieve further extension of graft survival. C4d deposition was observed in 50% of recipients as early as 18 days, suggesting antidonor antibody production. A transient, low-to-moderate degrees of multilineage chimerism was observed after DBM infusion. Treatment with Thymoglobulin resulted in profound depletion of CD4+ and CD8+ T cells, whereas addition of rituximab achieved prolonged (up to 3 months) depletion of CD20+ B cells. CONCLUSION: The Thymoglobulin, SRL, and DBM protocol is simple and produces long-term kidney allograft survival in NHP although additional treatment modalities may be necessary for induction of long-term tolerance.
