[Pancreas transplant pathology: clinicopathologic and experimental findings]

134 pancreas transplantations (113 simultaneous pancreas-kidney, 5 pancreas after kidney, 16 pancreas transplants alone) done in Rostock from VI/95 to III/04 were evaluated in respect to pancreas transplant lesions. Additionally, 36 pancreas specimen of Brown Norway rats experimentally transplanted into diabetic Lewis rats were examined. From 55 out of the 134 pancreas transplant patients, 122 partly repeated pancreas graft specimen examinations were carried out morphologically. The principal lesions in the human pancreas transplants were acute (enzymatic) necrotizing transplant pancreatitis (41 samples), acute (13) and chronic (14) transplant rejection specimen as well as primary or secondary graft thrombosis (12 probes). 23 probes were zero-hour biopsies and 2 showed normal tissue. From 69 out of the 118 pancreas transplant patients with an additional kidney graft, a total of 159 renal transplant probes were examined. They showed the following lesions: acute tubular damage or acute renal failure (23), acute (56) or chronic (22) kidney graft rejection, acute tubular cyclosporine or FK 506 toxicity (53), and histologically normal graft tissue (8 cases). As in other grafted organs, the changes occurring in the transplanted pancreas consist of varying lesions related and/or not related to pancreas transplant rejection. A concise classification and a reproduceable grading schedule are suggested for diagnostic, differential diagnostic, therapeutic, and prognostic purposes. Pancreatic rejection lesions can be classified according to a proposed Rostock '04 working classification of pancreas allograft rejection into three grades (I: mild, II: moderate, III: severe) both for acute and chronic pancreas rejection. There was no direct correlation of the findings in 21 patients with simultaneously studied pancreas and renal transplant biopsies. In contrast to renal grafts, pancreatic rejection signs were often superimposed by acute transplantation pancreatitis with or without secondary graft thrombosis, nonenzymatic necroses or infection. Experimental acute pancreas transplant rejection in rats showed quite similar findings to human grafts and was also graded into three different acute rejection stages.