No abstract

The structure and distribution of lymphoglandular complexes of the colon are described. The cellular composition of these complexes, as detailed by immunohistochemistry and electron microscopy, suggests that they are sites of antigen processing. Variations in structure and in the number of complexes that are found in certain colonic diseases are documented.

Activation of ret/PTC-1 has been documented in a minority of papillary thyroid carcinomas (PTC). In a recent study, the authors' group detected the presence of ret/PTC-1 in association with a background of florid lymphocytic thyroiditis (LT) in 58% of cases of PTC studied, which prompted them to examine the incidence of RET/PTC-1 expression in 27 examples of various forms of nonlymphomatous lymphoid infiltration of the thyroid by using TaqMan RT-PCR. Overall, 21 cases (78%) were found to express the chimeric transcript of ret/PTC-1. Eighteen cases of Hashimoto thyroiditis were positive (95%), and, of these, three had concomitant PTC while the remainder had no histologic evidence of associated malignancy. Three cases of lymphocytic thyroiditis demonstrated activated ret/PTC-1 (43%), two having associated PTC. These data suggest either that ret/PTC-1 is an indicator of follicular thyroid cell activation or that ret/PTC-1 activation is an early event in malignant transformation. If the latter is the case, it may be that, in a defined subset of the cell population, ret/PTC-1 activation elicits an autoimmune response, which, while possibly curtailing the development of PTC in the majority of cases, results in destruction of the thyroid parenchyma. Int J Surg Pathol 8(3):185-189, 2000