Introduction: Currently, cabergoline therapy is the main treatment for prolactinomas. The use of
the drug in most cases leads to regression of the tumor, normalization of prolactin
(PRL) levels, and restoration of gonadotropic function. The mechanism of its action
in tumor cells “in vivo” tracked in dynamics in the same human tumor is of considerable
interest. Materials and Methods: A 30-year-old male was admitted to N.N. Burdenko National Medical Research Center
of Neurosurgery. An magnetic resonance imaging (MRI) revealed a giant pituitary adenoma.
The level of PRL was more than 5000 mU/l (30-360) (serum dilution was not used to
determine PRL). Transcranial microsurgical removal of the tumor was performed. He
was treated by cabergoline after surgery. Endoscopic transsphenoidal approach was
repeated with subtotal removal of the rest of the tumor. Morphological and immunohistochemical
studies of the tumor were done. Results: A morphological study revealed PRL-positive tumor with a Ki-67 LI of 8% with a distinctive
expression of D2R, CD31, and CD34 markers. Control MRI in 3 months after surgery revealed
remnants of a tumor of endoinfrasellar localization, the tumor remainders were found
in endoinfrasellar localization. The tumor retained pronounced immunopositivity to
PRL and D2R and a decrease in the Ki-67 to 2% and in the expression of CD31 and CD34.
Subsequent therapy with cabergoline resulted in persistent normoprolactinemia, restoration
of androgenic function, and absence of tumor recurrence during the 10-year follow-up
period. Conclusions: Cabergoline is an effective treatment for prolactinoma, which leads to tumor regression.
One of its mechanisms is the reduction of the proliferative index and tumor angiogenesis.
Key-words:
Aggressive pituitary adenoma - cabergoline - giant prolactinoma - Ki-67 - male prolactinoma
- proliferative potential
