Portal versus systemic transplantation of dispersed neonatal pancreas.

It is not known whether the advantage of the portal vein as a transplant site for islet transplantation is caused by the immediate availability of a blood supply or by the localization of the islets in the portal circulation. We transplanted minimal quantities of islet tissue from neonatal rat donors to isogeneic adult rats with streptozotocin-induced diabetes. Transplants were performed to three sites, i.p., portal vein, and systemic vein (i.v.). When four neonatal donors were used for each recipient there were no i.p. cures but 90% i.v. and 100% portal vein cures, which suggests that access to a blood supply is important. As the amount of tissue transplanted was decreased, there were significantly more cures with the portal vein route, which suggests that localization of the islets in the portal circulation is also important to graft survival.

Ovarian sex cord tumors with annular tubules: an ultrastructural study.

The ultrastructural features of two "sex cord tumors with annular tubules" are presented. The findings are compared with the reported fine structure of ovarian and testicular stromal cells and the cells of gonadal stromal neoplasms. The predominant cell in the "sex cord tumor with annular tubules" has some of the ultrastructural features found in gonadal stromal cells of either ovarian or testicular type; however, no Charcot-Bottcher crystals, lamellar bodies, crystalloids of Reinke, abundant smooth endoplasmic reticulum or complex plasma membrane interdigitations are observed in the tumor cells to suggest wither Sertoli or Leydig cell origin. The striking similarity between the predominant cell type and granulosa cells, as well as the presence of fibrillary material of the type seen in Call-Exner bodies, suggests a granulosa cell origin for these neoplasms. However, the presence of a sparsely distributed second cell type which closely resembles the dark cells in normal nonluteinized ovarian stroma indicates these tumors may arise from the nonspecialized ovarian stroma.

Post-transplant malignant lymphoma. Distinctive morphologic features related to its pathogenesis.

Malignant lymphoma developed in two patients after renal transplantation. In both, the central nervous system was involved. Histologic study of the tumors showed that they were composed of a monomorphous proliferation of cells characterized by a large vesicular nucleus, prominent basophilic nucleolus and strongly pyroninophilic cytoplasm. The tumors thus would be classified as "diffuse large lymphoid lymphomas with pyroninophilia" or "immunoblastic sarcomas" as described in the literature. Tumor cells resembled cells observed in the paracortex of antigenically stimulated lymph nodes, cells from malignant lymphomas in mice that were antigenically stimulated and from malignant lymphomas in patients with immunodeficiency diseases or autoimmune disorders. The distinctive morphologic features of the tumors in the transplant recipients described provide further evidence that long-term antigenic stimulation may be important in their pathogenesis.

Breast adenomas.

True adenomas of the breast are cellular epithelial lesions, which may be confused with carcinoma and are difficult to classify. We have reviewed 28 adenomas of the breast and have developed specific diagnostic criteria, as well as a classification of breast adenomas based on histologic features. Electron microscopic studies confirm that adenomas have ultrastructural features similar to normal breast epithelium and are not variants of fibroadenomas. The association between lactating adenomas and pregnancy has been confirmed; however, clinicopathologic correlation does not suggest a relationship between adenomas and oral hormonal medication. Although adenomas are benign, this study includes the third reported case of an infiltrating carcinoma associated with a lactating adenoma.