Precursor T-lymphoblastic lymphoma within a recurrent pituitary adenoma.

Only single examples of lymphoma associated with pituitary adenoma have been reported. In our patient, a precursor T-lymphoblastic lymphoma developed within a recurrent pituitary adenoma 17 years after the first resection. Histomorphologically, lymphoma and adenoma components were tightly admixed. The features harbour remarkable similarity to the previous report by Kuhn et al.. In both patients the lymphomas were composed of T-cells, there was no evidence of further sites involved, and both adenomas expressed follicle-stimulating hormone. The hormone may have posed a proliferative and transforming effect on lymphatic cells and could have played a crucial role in "lymphomagenesis" as an exceptional phenomenon.