Pituitary Adenomas without Signs of Endocrine Activity: The So-called “Chromophobe Adenomas”

Abstract

The vast majority of pituitary adenomas do not show clinical signs of hormone production but rather manifest their presence by production of hypopituitarism and signs of compression of the visual pathways. Different patient series show a wide range in the frequency of the various symptoms. Vision is affected in 57–98%, menstrual disturbances occur in 17–85%, impotency and loss of libido are reported in 39–73%, the basal metabolism is decreased in 26–80%, and adrenal insufficiency is seen in 39–70% of the cases (Bakay, 1950; Davidoff and Feiring, 1948; Heimbach, 1959; Michard, 1958; Mundinger and Riechert, 1967). The variations in reported symptoms usually are interpreted as manifestations of the tumor size with variable compression of the optic system and destruction of the normal pituitary function.—These tumors usually are reported as “chromophobe adenomas” because routine histology fails to demonstrate stainable secretory granules. The term “chromophobe” therefore has been used as equivalent to “without signs of endocrine activity”. This conclusion is not correct. We have demonstrated that HGH producing adenomas can contain only few granules in the case of rapid hormone discharge. Prolactin producing adenomas need special staining techniques for the demonstration of their granule content. We will show in the following chapter that the eosinophilic oncocytomas do not show any signs of hormone production. We suggest therefore that the term “chromophobe adenoma” should not be used in the description of clinical and pathological conditions. It should be replaced by “endocrine inactive adenoma”. This term has the minor disadvantage of consisting of two words, but it fits the clinical entity much better. The following chapters will describe the ultrastructural types of endocrine inactive pituitary adenomas which can be differentiated.