Meningioma enlargement associated with luteinizing hormone-releasing hormone agonist therapy: two cases and supporting in vitro evidence.

Luteinizing hormone-releasing hormone (LHRH) agonists are widely used for androgen-deprivation therapy in prostate cancer. Recent reports have raised concern that LHRH may influence the biological behavior of LHRH receptor-expressing intracranial tumors, including meningiomas; however, clinical evidence remains limited. We describe two cases of rapidly progressive meningioma temporally associated with the initiation of leuprorelin acetate. Case 1 was a 67-year-old man with a left cerebellopontine angle meningioma that had demonstrated gradual enlargement over 26 months. Following the initiation of leuprorelin acetate, the tumor exhibited accelerated growth, necessitating surgical resection. Pathology confirmed a fibrous meningioma with LHRH and its receptor positive. Case 2 was a 72-year-old man previously treated with subtotal resection and radiotherapy for an atypical meningioma. After 6 years of radiographic stability, the tumor rapidly regrew soon after leuprorelin acetate initiation and required re-resection. Both the primary and recurrent tumors were LHRH- and LHRH receptor-positive. Freshly resected tumor tissue cultured ex vivo demonstrated a dose-dependent increase in cell viability following 7-day exposure to leuprorelin acetate. These findings suggest that LHRH agonists may be associated with increased cell viability in a subset of receptor-positive meningiomas. Caution is warranted when initiating LHRH agonist therapy in patients with known or suspected meningiomas.