Warty–basaloid carcinoma: clinicopathological features of a distinctive penile neoplasm. Report of 45 cases

Abstract

Most penile cancers are squamous cell carcinomas, but there are several subtypes with different clinicopathologic, viral, and outcome features. We are presenting 45 cases of a distinctive morphological variant of penile squamous cell carcinoma composed of mixed features of warty and basaloid carcinomas. This tumor was earlier recognized in a recent viral study and showed a high association with human papillomavirus infection. However, clinicopathologic features are not well known. In this multi-institutional study, patients' mean age was 62 years. Most tumors (64%) invaded multiple anatomical compartments, including glans, coronal sulcus, and, especially, inner foreskin mucosa. Tumor size ranged from 2 to 12 cm (mean 5.5 cm). Three morphological patterns were recognized: (1) the most common, observed in two-thirds of the cases was that of a typical condylomatous tumor on surface and basaloid features in deep infiltrative nests; (2) in 15% of the cases, there were non-papillomatous invasive carcinoma nests with mixed basaloid and warty features; and (3) unusually, predominantly papillomatous. Invasion of penile erectile tissues was frequent, either corpus spongiosum or cavernosum (47% each). Tumors limited to lamina propria were rare. Most tumors were of high grade (89%). Vascular and perineural invasion were found in about one-half and one-quarter of cases, respectively. Associated penile intraepithelial neoplasia was identified in 19 cases and mostly showed basaloid, warty–basaloid, or warty features. Inguinal nodal metastases were found in 11/21 patients with groin dissections. Invasion of corpora cavernosa, high histological grade, and presence of vascular/perineural invasion were more prevalent in metastatic cases. In 21 patients followed, the cancer-specific mortality rate was 33% with a mean survival time of 2.8 years. Warty–basaloid carcinomas are morphologically distinctive human papillomavirus-related penile neoplasms that, such as basaloid carcinomas, are biologically more aggressive than typical warty carcinoma from which they should be distinguished.