Human Papillomavirus-related Carcinoma with Adenoid Cystic-like Features: A Series of 5 Cases Expanding the Pathologic Spectrum

Abstract

Aims

Human papillomavirus (HPV)-related carcinoma with adenoid cystic-like features is a newly described entity of the sinonasal tract. In this study, we evaluated histomorphology, immunophenotype, and molecular testing to identify potentially helpful features in distinguishing it from classical adenoid cystic carcinoma (AdCC).

Methods and Results

We retrospectively collected 5 HPV-related carcinomas with adenoid cystic-like features and 14 AdCCs of the sinonasal tract. All histologic slides were retrieved for morphological evaluation. Comparing to AdCC, HPV-related carcinomas with adenoid cystic-like features were associated with squamous dysplasia of surface epithelium (80% vs 0%, P<0.01) and presence of solid growth pattern (100% vs 29%, P=0.01), but less densely hyalinized tumor stroma (20% vs 86%, P=0.02). Squamous differentiation in the invasive tumor was seen in 3 HPV-related carcinomas with adenoid cystic-like features, 2 of them showing abrupt keratinization and 1 with scattered non-keratinizing squamous nests. Diffuse p16 staining in ≧75% of tumor cells was noted in all HPV-related carcinomas with adenoid cystic-like features but only in 1 AdCC (100% vs 7%, P<0.01). High-risk HPV testing was positive in all HPV-related carcinomas with adenoid cystic-like features (4 associated with type 33 and 1 type 16) but not AdCCs. MYB rearrangement was tested in 4 HPV-related carcinomas with adenoid cystic-like features and all showed negative.

Conclusions

This study further clarified the histologic spectrum of this tumor type and reported the first HPV type 16-related case. Diffuse p16 staining followed by HPV molecular testing is useful in distinguishing HPV-related carcinomas with adenoid cystic features from classical AdCCs.

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