Porokeratosis with large skin lesions. Histologic, cytologic and cytogenetic study of three cases.
Otsuka F, Watanabe R, Kawashima M, Tomita Y, Ohara K, Ishibashi Y
Three porokeratosis patients with large skin lesion(s) are reported. The histopathology of the large lesions revealed that the epidermis 1) frequently presented slight or marked acanthosis and/or elongation of the rete ridge, and 2) contained abnormal cells, e.g. hyperchromatic, large, multinucleated, and/or irregular shaped nuclei. The DAPI-DNA microfluorometric study revealed DNA polyploidy and/or an increased population of epidermal cells with hyperdiploid and/or tetraploid DNA content. These results indicate the proliferating potential of the epidermis and the existence of a neoplastic clone or clones therein. This finding may explain the enlargement of skin lesions and possibly the development of malignancy, as sometimes occurs in large skin lesions. Furthermore, cultured skin fibroblasts from a patient's skin lesion or its surrounding skin revealed various kinds of chromosomal structural abnormalities, which may serve as a basis for the development of abnormal neoplastic clones in the porokeratotic epidermis.