[796] Luteinizing Hormone-Releasing Hormone (LHRH) Expression in Male Meningiomas (MM)-Implications for Treatment of Coexisting Prostate Cancer with LHRH Agonists

RS Kulkarni, MD Reid-Nicholson, MK Terris, S Sharma, P Ramalingam. Medical College of Georgia, Augusta, GA; Charlie Norwood Veterans Affairs Hospital, Augusta, GA

Background: Meningiomas are mostly benign tumors accounting for approximately 20% of intracranial neoplasms in adults and have a female predominance. Both MMs and female meningiomas (FM) are hormonally sensitive and express predominantly progesterone receptor (PR) therefore, PR-blocking agents have been used in their treatment. LHRH has also been reported to be associated with meningioma proliferation in vitro. There have been reports of patients with prostate cancer who had progression of their coexisting meningiomas while on LHRH agonist treatment. Our aim was to evaluate LHRH expression in MMs and correlate this with PR and Ki-67 staining. To our knowledge no such study has been performed thus far.
Design: Twenty-four MMs were retrieved from our pathology files from 1991-2008 and compared with 24 FMs. Normal pituitary was used as control. MM and FM of all grades and histologic subtypes were included. Sections from the paraffin blocks of study cases and controls were stained with mouse monoclonal GnRH/LHRH, Ki-67 and PR. LHRH staining was cytoplasmic and its distribution was interpreted as being either focal or diffuse and staining intensity was graded as weak (1+) or strong (2-3+). More than 10% staining with PR was considered positive and the percentage of Ki-67 positivity was recorded in all cases. All stains were reviewed and graded by 3 reference pathologists.
Results: The distribution and intensity of LHRH staining in MM and FM is summarized in the table below. LHRH was diffusely positive in 92% of MM and 88% of FM, with both showing strong intensity (67% and 79% respectively).

LHRH- Distribution and Intensity of Staining

	Diffuse	Focal	Strong Intensity	Weak Intensity
Male	22 (92%)	2 (8%)	16 (67%)	8 (33%)
Female	21 (88%)	3 (12%)	19 (79%)	5 (21%)

Ki-67 positivity ranged from 1- 20% in both MMs (mean 5.4%) and FMs (mean 6.4%). PR was positive in 20 of 24 (83%) MMs and 23 of 24 (96%) FMs.
Conclusions: Our study shows that the majority of MM and FM are strongly and diffusely positive for LHRH in addition to PR and have a low proliferation index. LHRH expression in MM may have significant implications for the treatment of coexisting prostate cancer with LHRH agonists. Therefore, newer LHRH antagonists need to be evaluated as an alternative for the treatment of prostate cancer in this unique group of patients.
Category: Genitourinary (including renal tumors)

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 208, Tuesday Morning