Plasma Cell Vulvitis: A Classification Into Two Clinical Phenotypes.

Objective: The etiology of plasma cell vulvitis (PCV) is debated. The authors aimed to test the hypothesis that PCV could be divided into 2 clinical phenotypes.

Methods: Patients with a clinico-pathological diagnosis of PCV and with available vulvar photos seen in a vulvar clinic were retrospectively studied. The cases of PCV were divided into 2 groups: non-lichen-associated (primary PCV) and lichen-associated (secondary PCV). The 2 groups were compared in terms of age, menopausal status, location of the PCV, and 12 histologic parameters (Fisher exact test, p < .05).

Results: Thirty-five patients (20 primary and 15 secondary PCV) were included. The 2 groups did not differ in terms of age (mean, 65; range, 50-85) or menopausal status. Primary PCV was located exclusively on the vestibule for 19/20 patients, whereas secondary PCV was extravestibular for 14 of 15 patients, either exclusively (2) or both extravestibular and vestibular (12). One patient with secondary PCV had solely vestibular involvement. Five histological features were observed significantly more often in case of secondary PCV: epidermal atrophy, parakeratosis, dermal and epidermal neutrophils, and dermal eosinophils.

Conclusions: Plasma cell vulvitis can be divided clinically into 2 phenotypes. Primary non-lichen-associated PCV is restricted to the vestibule and could be the vulvar counterpart of atrophic vaginitis. Secondary lichen-associated PCV is both extravestibular and vestibular, and its clinical and histological features should be looked for outside the PCV areas. This division of PCV into 2 clinical phenotypes could have therapeutic implications.