TSH-secreting pituitary tumor. A case report.

A pituitary tumor secreting thyroid-stimulating hormone (TSH) only was diagnosed in a 43-year-old man who originally showed signs and symptoms of thyrotoxicosis which recurred twice. Despite normal serum levels of T3 and T4, increased levels of TSH were diagnosed. The pituitary tumor was operated by the transsphenoidal approach. Morphological analysis of tumor tissue showed cellular pleomorphism and regressive changes. Nuclear DNA analysis showed that the tumor had only one cell line and an aneuploid DNA pattern. In vitro culture of tumor tissue confirmed that the tumor secreted TSH only.