Immunocytochemical characterization of pacinian-like corpuscles in the labia minora of prepubertal girls.

STUDY OBJECTIVE: To better understand the precise role of sensory corpuscles within the female external genitalia.

DESIGN: After IRB approval, waste tissue samples were obtained from 10 normal girls (aged 2-9 years) who underwent surgery for labial fusion. Immunocytochemistry against protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), vasoactive intestinal peptide (VIP), 5-hydroxytryptamine transporter (5HTT), 5-hydroxytryptamine receptor 1A (5HT1A), Neuronal Peptide Y (NPY), neuronal nitric oxide synthase (nNOS), and estrogen receptors (ER) α and β was performed.

RESULTS: Pacinian-like corpuscles were identified in epithelium of labia minora of prepubertal girls. A central structure composed of an axon surrounded by a central core, outer core, external capsule, surrounded by encapsulated stroma, and a subsidiary innervation in the outer aspect of the corpuscle stroma stained for PGP 9.5 in the outer core and layers of the external capsule, NSE positive cells in layers of the outer core, 5HTT in stroma of the corpuscle and cells located in layers of the outer core, 5HT1A in cells of outer core, NPY in stroma of the corpuscle, and nNOS in external core and external capsule of the central structure. ERα was present in stroma, external core, and external capsule, and ERβ in stroma of the corpuscle with subsidiary innervation in the stroma positive to PGP 9.5, VIP, and NPY.

CONCLUSION: PGP 9.5, NSE, ERα, nNOS, and 5HTT immunoreaction detected in the outer core and external capsule could indicate these areas may play an important role in the functional aspects of the Pacinian-like corpuscle.