Origin of undifferentiated neoplasm from verrucous epidermal carcinoma of oral cavity following irradiation

Abstract

Apparent anaplastic transformation of an x-irradiated verrucous carcinoma of the oral cavity is described in detail, including ultrastructural observations. The anaplastic lesion had definite epidermoid differentiation in the form of tonofibrils and tonofilaments, demonstrable only with electron microscopy. It and the well-differentiated one coexisted discretely and metastasized independently. It is proposed that the former arose as a new carcinoma from the cells of the latter, rather than through a transformative dedifferentiation.