Squamous Cell Carcinoma with Mucinous Metaplasia

Abstract

Squamous cell carcinoma with mucinous metaplasia (SCCMM) is an invasive, atypical squamous cell proliferation containing mucin-producing, “signet-ring”-shaped cells. SCCMM differs from adenosquamous carcinoma and mucoepidermoid carcinoma by the absence of glandular structures and of a definite adenoid pattern. It is a very rare neoplasm with only three cases reported in the literature, one associated with high-risk HPV type 18. Mucin is not a normal product of adult keratinocytes. It has been argued that the influence of environmental factors, as HPV infection and viral genomic integration, could trigger a bipotent keratinocyte progenitor to differentiate along two different functional pathways, generating squamous or mucin-producing cells, progressively and irreversibly losing its original proliferative capacities and undergoing a sort of differentiative and replicative senescence with mucin production.