effect of endocrine cyst and hormonal secretion

Is there a general belief/understanding of if/how a cyst on a hormonal gland might effect secretion of the hormone?  More specifically, a cystic pineal gland and possible effect on melatonin secretion.  

[Godofredo MD]

Hi.

Melatonin has been considered as a possible marker of pineal tumors.  In true pineal tumors such as pineocytomas, there may be excessive secretion of melatonin, whereas low levels of melatonin favor benign pineal cystic lesions.

I came across a study which might help explain the compressive effects of pineal cysts or tumors on melatonin secretion. In as study by Mandera et al in 2003 with the title, "Melatonin secretion profile after experimental pineal gland compression in rats", it was concluded that "pineal gland compression (like in case of some tumors) results in decrease of the concentration of blood melatonin, that may possibly result in decreased protective action of the indoleamine."

You can find the study at this link:

http://www.nel.edu/pdf_/24_6/NEL240603A01_Mandera_.pdf

Hope this helps.