Verrucous carcinoma with dysplasia or minimal invasion: a variant of verrucous carcinoma with extremely favorable prognosis.

Verrucous carcinomas (VC) recur locally but do not metastasize in the absence of an invasive squamous cell carcinoma (SCC) component. Although excluded from the definition of pure VC, some tumors harbor only dysplasia or minimal invasion, findings of unknown clinical significance. Surgically resected VC cases from two institutions were collected and categorized into three types: VC, VC with dysplasia or minimal invasion (VCDMI), defined as SCC less than or equal to 2 mm in depth, and SCC arising in VC (SCC-VC) where the SCC was greater than 2 mm in depth. Cases were also matched with conventional SCC based on location and T and N-stages, and clinical follow up was obtained. Of the 58 total cases, 18 were VC, 26 VCDMI, and 14 SCC-VC. Only 1 of 18 (5.6 %) VC and 5 of 26 (19.2 %) VCDMI cases recurred locally (p = 0.37) versus 7 of 14 (50 %) SCC-VC (p = 0.01). All VC and VCDMI cases were node negative at presentation whereas SCC-VC had nodal metastases in 2 of 14 (14.3 %) cases. No patients with VC or VCDMI died from disease, whereas 5 of 14 (35.7 %) patients with SCC-VC died from disease. T-stage matched conventional SCC cases from institutional databases had worse outcomes than VC and VCDMI, but not after they were matched for both T and N-stages. Our findings suggest that dysplasia and/or minimal invasive SCC do not adversely affect outcomes in tumors otherwise showing diagnostic features of VC.