Pituitary Tutorial—Nonsecreting Tumors
AKA null-cell tumors, old name was "chromophobe andenomas."
Nonsecreting pituitary tumors are one of the most common of the known pituitary tumors. And, well, "nonsecreting" is a bit of a misnomer. A lot of these tumors DO secrete stuff like alpha-subuit, but it has no known hormonal function and has been difficult to assay for in the past.
We will discuss:
History and Physical Examination
Nonsecreting tumors typically present with two syndromes:
Laboratory and imaging studies
Laboratory studies of use include a prolactin level, which is often elevated in these patients. (Why?) So the question then arises whether this is a prolactinoma or a nonsecreting tumor. How to sort this out? Well, no one can tell you for sure, but it is hard to get your prolactin over 150 except with a prolactinoma. Also, you should get around 100 of prolactin for each cm of tumor diameter: a ratio of prolactin/tumor diameter significantly less that this makes one worry about a nonsecreting tumor.
Differential diagnosis of nonsecreting pituitary tumors
Unless clearly expanding the sella and pushing out from here, these tumors can mimic/be mimiced by suprasellar lesions such as:
Prolactin levels for all of these problems rarely exceed 150 ng/ml. Also, there is a (very) rough correlation between pituitary tumor size and expected prolactin level: a 10 mm tumor should produce a serum prolactin of around 100 ng/ml. This rule becomes useful when you have, e.g., a 30 mm tumor and a prolactin level of 50 ng/ml: think of a nonsecreting tumor here, not prolactinoma.
Treatment of nonsecreting tumors
The mainstay of treatment for nonsecreting tumors is surgical debulking followed by either close observation or RT.
Controversies in nonsecreting tumors
Among the controversies in the treatment of nonsecreting tumors are:
Such questions provide grist for controversies during endocrinological and neurosurgical meetings.