Metastatic epidermotropic squamous carcinoma histologically simulating primary carcinoma

We present a case of a patient with penile squamous carcinoma and unilateral inguinal nodal involvement. Histological sections of the inguinal tumor demonstrated a basaloid (small-cell) squamous carcinoma of the type that arises from modified skin or mucosa. Multiple cutaneous lesions subsequently developed in the ipsilateral lower extremity. Biopsies revealed tumor that had the same histologic appearance as the nodal metastasis but that also showed a smooth and continuous connection with the overlying epidermis. We discuss the significance of this finding and review the pertinent literature.