Relationship of lymphoplasmacytic infiltration of skin tumors to tumor ulceration.

The lymphoplasmacytic infiltrates of 400 benign, borderline, and malignant skin tumors were assessed by light microscopy to determine the relationship between the presence of tumor ulceration and the histologic character of the infiltrate. Squamous cell carcinomas had the highest overall number of infiltrating lymphoplasmacytic cells, while seborrheic keratoses had the lowest. Plasma cells in the infiltrates were related significantly to tumor ulceration (P less than .001). This suggests that the plasma cell infiltrates may be more related to tumor ulceration than to a tumor-specific response in these carcinomas. Small lymphocytes were most evident adjacent to areas of irregularity in the peripheral palisade or of squamous differentiation of the basal cell carcinomas. This suggests that the presence of small lymphocytes, not plasma cells, is a response by the immunocompetent host to areas of tumor invasion.