Thanks for the query, as I believe more information is the key to making accurate diagnosis. Zoladex
is a GNRH agonist injection, I feel the cyst
you are having is ENDOMETRIOTIC cyst. Its useful to suppress the other endometriotic lesions. I am not able to understand why a PCR test advised, it needs further history and complete examinations done on you.
Hope I answered your question, Kindly reply me if you have any further queries or any comments. I will be very happy to help you.