(042) IMMUNOSTAINING FOR MARKERS OF MAST CELLS AND NERVES IN BOTH EXCISED VESTIBULAR AND ENDOMETRIOSIS IMPLANT TISSUES IN A SINGLE PATIENT.

Introduction: Neuroproliferative vestibulodynia (NPV) is a chronic genital pain condition characterized by severe vestibular allodynia and hyperalgesia. The clinically suspected diagnosis of NPV is confirmed in excised vestibular tissue by immunohistochemical staining of > 8 cells per 100x magnification positively immunostained for CD 117, a mast cell marker, and 10 times the area compared to controls positively immunostained for PGP 9.5, a neuronal marker, Endometriosis, on the other hand, is a chronic pelvic pain condition associated with growth of ectopic endometrial-like tissue outside the uterus. The clinically suspected diagnosis is confirmed in excised endometriosis tissue revealing, in some patients, endometrial type glands and/or stroma. In patients with NPV and endometriosis, it is hypothesized that excess mast cells release cytokines and growth factors that promote neuroproliferation in their respective tissues, resulting in chronic genital and pelvic pain symptoms, respectively. In a study involving 65 patients with pathologically confirmed NPV, 63% reported having additional conditions associated with aberrant mast cell activity, including endometriosis. The conditions of NPV and endometriosis may both be focal to the vestibule and pelvis, respectively, but both may also share pathologies of aberrant mast cell activity with other systemic disorders. Objective: To perform immunostaining for markers of mast cells and nerves in excised vestibular and endometriosis implant tissues from a single patient. Methods: Fixed, paraffin-embedded vestibular tissue specimens from the 1:00-11:00 and 12:00 vestibule, and from excised endometriosis fibroadipose tissue on the rectosigmoid colon, were sectioned and immunostained for CD 117 (C-kit) and PGP 9.5. The immunostained slides were examined and digital photomicrographs taken. A minimum of 2 photomicrographs were examined at 100x magnification for each stained slide, identifying representative regions of the excised tissue. Manual counting of CD117 and PGP 9.5 immunopositive profiles, cells/nerves per 100x magnification, was performed for each photomicrograph. Results: A 23-year-old woman presented with a history marked by painful and prolonged menstrual periods, inability to insert tampons, and discomfort with both entry and deep thrusting during intercourse. After excluding other forms of vestibulodynia, she underwent complete 1:00-11:00 and 12:00 subepithelial vestibulectomy with vaginal advancement flap reconstruction. Post-operatively, she reported "very much better" symptoms, with a reduction of entrance dyspareunia, but continued to experience deep thrusting pain with penetrative sexual activity. She subsequently underwent endometriosis excision surgery with positive lesions identified in 12 locations in the pelvis and retroperitoneum. Tissue stained for CD117 and PGP9.5 analyzed by manual counting exhibited > 20 immunopositive cells and nerves per 100x microscopic field in the epithelial basement membrane and adjacent subepithelial regions of the 1:00-11:00 and 12:00 vestibule, as well as in the endometriosis fibroadipose tissue on the rectosigmoid colon. Conclusions: We report for the first time, in a single patient diagnosed with both NPV and endometriosis, immunostaining findings of high densities of mast cells and nerves in their respective tissues. These findings reinforce the hypothesis that NPV and endometriosis are linked to a broader condition associated with aberrant mast cell activity. Disclosure: No. [ABSTRACT FROM AUTHOR]