Aggressive pituitary tumor growth.

Three cases with extrasellar extension from our material of 132 pituitary tumors are reported. One tumor secreted growth hormone, one secreted prolactin, and one secreted adrenocorticotropic hormone (ACTH). All three patients had a short case history. The tumors recurred rapidly after surgery. Light microscopy showed pleomorphic cells but no signs of morphologic malignancy. Ultrastructural analysis revealed intracellular filamentlike inclusions, with a cross-banded substructure in two cases. The DNA analysis of two of the cases showed aneuploidy. Our three cases of pituitary tumors are likely to represent a particularly aggressive type of tumor growth.