Track: Case Reports

Abstract:

Wnt/β-Catenin-Activated Nonpilomatrical Carcinoma (WANC) is a rare cutaneous tumor. We present two cases. Case 1 presented as a 1.7cm rapidly growing pink nodule on the buccal cheek of a 79-year-old male. Histology revealed a nodular dermal basaloid tumor with no epidermal component. This plus CDX2 positivity increased the concern for a gastrointestinal tumor metastasis. Further analysis showed the diagnosis to be a WANC. Case 2 presents as a 4.5cm rapidly growing exophytic friable nodule on the right dorsal hand of an 86-year-old male. Histology revealed a diffusely ulcerated and invasive basaloid tumor with islands, retraction artifact, and glandular/rosette formation. Again, with further analysis this tumor was found to represent a WANC. WANC is a rare high-grade cutaneous carcinoma with a biphasic appearance, rosettes, frequent squamous and neuroendocrine features, nuclear positivities for β-Catenin, CDX2 expression, and complete loss of Rb expression. Additional positive stains include EMA, BER-EP4, CDX2, and CK7. Tumors are mostly found on the head and neck and upper extremities but is also seen on the trunk and lower extremities. This is an interesting and unique condition due to its rarity, the lack of pilomatrical differentiation that would normally be expected in a Wnt/β-Catenin-activated cutaneous tumor, and as a mimicker of metastatic disease. Both of our patients were referred for definitive surgical management.