Mixed inflammation


In this aspirate of a skin lesion, there is a mixture of neutrophils and macrophages, with low numbers of lymphocytes, plasma cells and eosinophils. Macrophages are leukophagocytic and vacuolated (“reactive”). Neutrophils are mildly degenerate (swollen nuclei and cytoplasm), however the inflammation was not due to sepsis but was secondary to a ruptured follicular cyst, releasing keratin into the subcutaneous tissue. Keratin is an “endogenous” foreign body and incites a mixed or pyogranulomatous inflammatory response, which may have eosinophils and lymphocytes (including plasma cells) (Wright’s stain, 100x objective).