[471] Non-Infectious Vulvitis: A Histopathologic Review and Classification of 183 Cases

May P Chan, Mary Jane Zimarowski. University of Michigan, Ann Arbor, MI; Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA

Background: The vulva is susceptible to a variety of cutaneous and mucosal inflammatory disorders. While well-developed lesions are easy to recognize, most inflammatory vulvar biopsies are challenging due to histologic overlap among early lesions and under-recognition of rare entities. We aim to identify subtle features that help in classifying these cases.
Design: BIDMC archive was searched for non-neoplastic and non-infectious vulvar biopsies. A total of 188 cases were reviewed by the authors blinded to the original diagnoses. Final diagnoses were based on consensus among the authors' and the original pathologist's impressions, and clinical correlation where available. Associations between histologic features and diagnoses were analyzed by χ2 test.
Results: Five cases were excluded due to presence of Corynebacteria (4 cases) and Herpesvirus (1 case) upon review. Twenty-two cases (12.0%) show evidence of two concurrent processes. A limited differential diagnosis is rendered in 15 cases (8.2%). Conditions encountered include: Eczema (22.4%), lichen sclerosus (LS) (38.8%), lichen simplex chronicus (LSC) (29.0%), Zoon's vulvitis (7.7%), Behcet's (2.7%), hidradenitis (2.2%), ruptured cyst (1.6%), psoriasis (1.1%), radiation dermatitis (1.1%), sebopsoriasis (1.1%), seborrheic dermatitis (1.1%), ulcer NOS (1.1%), and lichen planus (0.5%) (Total>100% due to multiple diagnoses in some cases). Early LS and Zoon's vulvitis are commonly part of a differential diagnosis (6 cases each). LS is significantly associated with subepithelial wiry fibrosis with lymphocyte entrapment (p<0.0001). Eosinophils are seen in 44.7% of LS. LSC is associated with zones of pale epithelium (p<0.0001) and prominent stromal fibroblasts (p=0.0004). Fifty percent of Zoon's vulvitis were originally misdiagnosed. Basal keratinocytic crowding with increased N:C ratio is a common finding (92.9%) in Zoon's vulvitis.
Conclusions: Early LS may be confused with LSC, eczema, and Zoon's vulvitis; a useful feature is subepithelial wiry fibrosis with lymphocyte entrapment. The frequent finding of eosinophils in LS suggests a component of hypersensitivity. Zones of pale epithelium and prominent stromal cells help in diagnosing subtle LSC. Zoon's vulvitis tends to be underdiagnosed; while the number of plasma cells may vary, the finding of basal crowding, in combination with more typical features such as intraepithelial neutrophils and mild spongiosis, aids in its diagnosis. We also propose an algorithm to help in classifying vulvitis.
Category: Dermatopathology

Monday, March 19, 2012 11:15 AM

Platform Session: Section F, Monday Morning


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