Abstract

Histologic distinction between lichen sclerosus (LS) and differentiated vulvar intraepithelial neoplasia (dVIN) can be difficult.  We present a case wherein reliance on histopathology alone could lead to misdiagnosis. Our patient is a 17-year-old female with clinical features of vulvar dermatitis and LS for two years. The patient was counseled to apply Clobetasol 0.05% to the affected area daily but reported no improvement after six months. A biopsy of the right labia majora revealed interface changes, hyalinization, some acanthosis, and foci of parakeratosis. Importantly, there was some basal atypia, particularly in a bulbous area of the epidermis, and near-contiguous p53 expression. A biopsy of the left labia minora revealed similar findings, with a lesser degree of atypia. These features, in isolation, are characteristic of dVIN.  However, dVIN is exceedingly rare in young patients. The case was reviewed by 6 dermatopathologists and gynecologic pathologists. It was observed that the degree of inflammation would be unusual post-clobetasol therapy and could be due to non-compliance. A review of the patient’s chart revealed that she “does not always remember to apply” Clobetasol. The case was signed out as LS, with a note describing the above, and to rebiopsy if concern persisted.  We conjecture that inflammatory infiltrates in the biopsied area caused reactive atypia due to lack of adherence to treatment. Although the patient’s age helped to rule out dVIN, similar cases in elderly patients may be occurring. Pathologists must be aware that reactive forms of untreated LS can mimic dVIN, to avoid misdiagnosis.