[Morphological aspects of parathyroid gland transplantation. Contribution on the clinical relevance of induced, invasive tissue growth].

The results of morphologic studies performed in 18 patients who had total parathyroidectomy and autotransplantation of parathyroid tissue into the forearm muscle are presented. All patients had long-standing renal disease with azotemia, hyperphosphatemia and high levels of parathyroid hormone. The histologic findings after total parathyroidectomy, before gland transplantation, are important for selection of parathyroid tissue for surgery. Diffuse hyperplasia with the development of multiple nodules of the parathyroids can possibly be adverse for the transplant. In one case, nine month after autotransplantation we found a tumor in the forearm, measuring 2.0 X 3.0 X 2.2 cm in diameter. Morphologic findings in this case before implantation showed diffuse hyperplasia with adenomatous nodules but no signs of carcinoma. The grafted parathyroid tissue after excision was seen with blood vessel invasion in the normal skeletal muscle. In the case of primary renal disease with secondary parathyroid hyperplasia, the light microscopic examination revealed an autonomous tumorlike adenomatous formation in the autografted parathyroid tissue, with graft-dependent hypercalcemia. The invasive growth with some signs of neoplasia following autotransplantation raises the question of the development of certain neoplasia.