Vulvar squamous cell carcinomas (SCCs) arising in association with vulvar lichen planus (LP) are poorly documented.

We sought to present clinicopathological features of 38 patients (median age 61 years, range 39-90 years) with LP-associated vulvar SCCs.

Evaluated were location of vulvar SCC and metastases at presentation, recurrences, survival, precursor lesions, presence of human papillomavirus DNA, p16^ink4a, and p53 expression.

In all, 32 solitary (5 pT1a, 20 pT1b, 7 pT2) and 6 multifocal SCCs, located in the vestibulum (n = 20) and in nonhair-bearing modified and glycogenated mucosa (n = 18), arose in erosive (n = 13) and nonerosive (n = 25) LP. All SCCs were human papillomavirus DNA and p16^ink4a negative. Sixteen of 38 (42%) women had inguinal metastases at presentation. Treatment was surgery with clear margins (36/38) and chemoradiation (2/38). Fourteen of 36 (39%) surgically treated patients developed between 1 and 5 new SCCs in the residual diseased mucosa. Of all recurrences, 68% developed within 12 months via precursors revealing various histologic features including elongated, but also flat rete ridges, basaloid and hypertrophic differentiation with inconsistent p53 expression. Fourteen of 38 (37%) patients died of SCCs.

Retrospective study and lack of a standardized treatment protocols are limitations.

LP-associated SCCs were located in nonhair-bearing vulvar mucosa. Patients had a high rate of inguinal metastases, recurrent vulvar cancers in diseased mucosa, and disease-related death.