Panhypopituitarism secondary to a macroprolactinoma manifesting with pancytopenia: case report and literature review.

OBJECTIVE: To present a case of pancytopenia associated with hypopituitarism secondary to a macroprolactinoma.
METHODS: We report the clinical features on presentation and results of laboratory investigation. Findings on magnetic resonance imaging are illustrated. The response to hormone replacement therapy is summarized.
RESULTS: A 46-year-old man was referred with pancytopenia and secondary hypothyroidism. Laboratory investigation revealed hypopituitarism and a substantially increased prolactin level. Magnetic resonance imaging of the head demonstrated a macroprolactinoma. Hematologic investigation disclosed no other cause for the pancytopenia. Hormone replacement therapy was initiated with hydrocortisone, levothyroxine, and testosterone. Cabergoline was used to induce regression of the prolactinoma. A rapid improvement was seen in the cytopenias, with normalization of the blood cell counts after 8 months of treatment. This result has been sustained during 29 months of follow-up.
CONCLUSION: Pancytopenia associated with hypopituitarism has been reported in the literature as a rare occurrence limited to isolated case reports, predominantly associated with Sheehan syndrome. To our knowledge, this is the first reported case of pancytopenia associated with a macroprolactinoma. This finding is noteworthy because prolactin alone has been reported to support hematopoiesis in animal studies.