METASTATIC PROLACTINOMA - EFFECT OF OCTREOTIDE, CABERGOLINE, CARBOPLATIN AND ETOPOSIDE - IMMUNOCYTOCHEMICAL ANALYSIS OF PROTOONCOGENE EXPRESSION

A 49-yr-old woman presented with an extensive prolactinoma (serum PRL > 10,000 mU/L, normal range <450 mU/L). Over a 5-yr period following t ranssphenoidal surgery and pituitary irradiation, she became increasin gly resistant to high doses of bromocriptine and underwent transfronta l surgery followed by stereotactic radiotherapy. In spite of these tre atments, serum prolactin estimations rose progressively to >100,000 mU /L. Magnetic resonance imaging scanning demonstrated a massive cystic tumor invading the temporal lobes, extending into the cervical and tho racic spine, with metastases to cervical lymph nodes. High-dose caberg oline administration resulted in a 30% decrease in serum PRL. Octreoti de was administered as a continuous sc infusion with a profound analge sic effect on facial pain but with no effect on tumor progression. She was treated with a course of chemotherapy consisting of carboplatin a nd etoposide without any noticeable effect. The patient died 6 months following chemotherapy. Immunocytochemical analysis demonstrated posit ive nuclear staining for WAF-1, Rb protein, c-myc, and p53 both in the original and metastatic tumors. The metastases but not the primary tu mor stained for c-jun. Metastatic prolactinoma remains a therapeutic c hallenge. It is associated with a variable proto-oncogene expression, which may be coincidental or causal. Cabergoline had no advantage over bromocriptine. Octieotide relieved facial pain but did not alter tumo r progression. An effective therapy for metastatic prolactinoma remain s to be identified.