Histologic examination of the punch biopsy specimen from an affected area showed a clearly thickened and compact stratum corneum above a typically differentiated and stratified epidermis. There was a clear retention of nuclei, with nuclear parakeratosis, in the corneocytes, and a number of intact keratohyaline granules were evident within the cytoplasm. These granules imparted basophilic properties to the compact horny layer. The epidermis was mildly acanthotic, with some hyperplasia of the rete ridges. In general, the keratinocytes appeared normal. A superficial perivascular lymphocytic inflammation was present in the dermis. No evidence of fungal infection was found on periodic acid–Schiff staining.
Scaling Lesions on the Axillary Skin of a 52-Year-Old Man—Diagnosis. Arch Dermatol. 2004;140(9):1161-1166. doi:10.1001/archderm.140.9.1161-f