Histological study #03129/2017
The submitted tissue sample consists of epidermis and superficial dermis of the oral mucosa. Nodular, multifocal to coalescent, densely cellular, poorly demarcated lesions are observed in the superficial dermis, with expansive and infiltrative growth in laces and nests from the squamous stratum of the epidermis.
Lesions are not encapsulated. These lesions are arranged in nests surrounding a hypereosinophilic, acellular and laminated material (keratin pearls). The cells are polygonal and densely-packed, with abundant, eosinophilic and homogeneous cytoplasm. The nucleus is round, paracentral and the chromatin is partially packaged. The cells present anisocariosis, anisocytosis and cariomegaly. The number of mitosis is high (more than 22 mitotic figures/10 field/HPF). Multifocally, areas with cellular debris and fragmented eosinophilic material (necrosis) are observed, as well as extravasation of erythrocytes from the vessels (hemorrhage). The stroma is moderate to abundant, and is composed by a large number of immature fibroblasts immersed in a collagen matrix arranged in an haphazard distributed (desmoplasia), a moderate number of blood vessels and an inflammatory infiltrate composed by lymphocytes.
A complete loss of the superficial epidermis (ulcer) is observed, along with surrounding areas in which there is an subacute inflammatory infiltrate composed of neutrophils and lymphocytes in less proportion. In section view, the margins are affected by the main lesion described.