Munro's microabscess is an abscess (collection of neutrophils) in the stratum corneum of the epidermis due to the infiltration of neutrophils from papillary dermis into the epidermal stratum corneum. They are a cardinal sign of psoriasis[1] where they are seen in the hyperkeratotic and parakeratotic areas of the stratum corneum.[2] Munro microabscesses are not seen in seborrheic dermatitis.[3]