Cytological abnormalities of superficial horny cells from 266 patients with common parakeratotic and orthokeratotic diseases (psoriasis, seborrheic dermatitis, various types of dermatitis-eczema, mycosis fungoides, and several other dermatoses) were evaluated with an adhesive slide technique. Most patients showed orthokeratotic and parakeratotic (nucleated) corneocytes in varying frequency. Horny cells in different stages of nuclear decomposition (halo cells) and masses of leukocytes were observed in only some of these dermatoses. An analysis of the frequency of nucleated horny cells and halo cells yielded statistically significant differences between psoriasis and most other dermatoses; only seborrheic dermatitis of the head region and mycosis fungoides showed similar changes in some instances. These findings suggest a classification of cytological changes which may be useful in the differential diagnosis of these diseases, particularly in the cytodiagnosis of psoriasis.
Goldschmidt H, Thew MA. Exfoliative Cytology of Psoriasis and Other Common DermatosesQuantitative Analysis of Parakeratotic Horny Cells in 266 Patients. Arch Dermatol. 1972;106(4):476-483. doi:10.1001/archderm.1972.01620130008003