(001) Excess Density of Mast Cells and Nerves with Neuroproliferative Vestibulodynia: Defining the Extent of the Vestibulectomy Surgical Excision
Authors: Goldstein I , Uloko M , Stearns H 
Published: June 2023

Abstract

Introduction
Congenital neuroproliferative vestibulodynia (NPV) is associated with lifelong entrance dyspareunia, starting with initial tampon insertion. Acquired NPV is associated with pain-free penetration until after a severe candidiasis infection and/or allergic reaction to a locally applied agent. NPV is diagnosed by ruling out other forms of vestibulodynia. Based on immunohistochemical examination of excised vestibular tissue specimens from women with NPV, the pathophysiology is related to high density of mast cells and nerves throughout the entire surgical specimen If conservative, non-operative strategies fail, or are not appropriate, surgical excision may be considered as vestibulectomy has a high success rate. The extent of surgical excision, however, varies by surgeon, from an excision of the posterior vestibule to a wider excision involving posterior vestibule along with left and right anterior vestibule, millimeters next to the urethral meatus. Few providers perform an even wider excision when appropriate including vestibular tissue inferior to the clitoris/right and left frenulum, and superior to the urethral meatus, the “12:00” vestibule. The extent of vestibular tissue excision related to patient outcome in NPV has not been studied.

Objectives
This study compares the density of mast cells and nerves from the 12:00 vestibule to the posterior and left and right anterior vestibule using immunohistochemistry.

Methods
Surgical specimens (12:00 vestibule; posterior and left and right anterior vestibule) from 6 women (mean age 27 +/− 11 years) were fixed in formalin, paraffin embedded blocks and labelled. 5 um sections from each block were stained with hematoxylin and eosin and slides analyzed by light microscopy. Antibodies to CD117 and PGP 9.5 were used for immunostaining. Multiple regions were examined and photographed using a Zeiss AxioCam HR high resolution digital microscope. Density of CD117 and PGP9.5 positive cells were determined by counting the number of dark brown stained cells per high-power field (hpf = x 20 magnification). Specimens from control subjects have values of 8 mast cells or less per hpf, as reported by Bornstein.

Results
High densities of CD117-positive cells in vestibular epithelium and stroma were noted in the 12:00 vestibule (mean density of 43 +/− 18 per hpf) versus in the posterior and left and right anterior vestibule (mean density of 38 +/− 14 per hpf). High densities of PGP9.5-positive cells were noted in vestibular stroma in the 12:00 vestibule (mean density of 31 +/− 20 per hpf) versus the posterior and left and right anterior vestibule (mean density of 33 +/− 18p er hpf). Figures 1 and 2 show CD117-positive cells and PGP9.5 positive cells, consistent with excess mast cells and nerves, respectively at the 12:00 vestibule and from the posterior and left and right anterior vestibule.

Conclusions
We demonstrate, for the first time, that the 12:00 vestibule contains the same increased number of mast cells and nerves as the rest of the vestibule. If anesthetizing that region pre-operatively provides pain relief, excision during surgery should be considered. In patients with NPV, excising the 12 o’clock region at the top of the vestibule may result in improved post-operative success rate.

Disclosure
No.