Diagnostic utility of Ki-67 and Cyclin D1 immunostaining in differentiation of psoriasis vs. other psoriasiform dermatitis

Engin Sezer; Almut Böer-Auer; Emel Cetin; Fatma Tokat; Emel Durmaz; Sedef Sahin; Umit Ince

doi:10.5826/dpc.0503a02

Diagnostic utility of Ki-67 and Cyclin D1 immunostaining in differentiation of psoriasis vs. other psoriasiform dermatitis

Authors

Engin Sezer Department of Dermatology, Acibadem University School of Medicine, Istanbul, Turkey
Almut Böer-Auer Department of Dermatology, Dermatologikum, Hamburg, Germany
Emel Cetin Department of Pathology, Acibadem University School of Medicine, Istanbul, Turkey
Fatma Tokat Department of Pathology, Acibadem University School of Medicine, Istanbul, Turkey
Emel Durmaz Department of Dermatology, Acibadem University School of Medicine, Istanbul, Turkey
Sedef Sahin Department of Dermatology, Acibadem University School of Medicine, Istanbul, Turkey
Umit Ince Department of Pathology, Acibadem University School of Medicine, Istanbul, Turkey

Keywords:

psoriasis, psoriasiform dermatitis, proliferation, Ki-67, Cyclin D1

Abstract

Background: Differentiation of psoriasis from non-psoriasis psoriasiform dermatitis (NPPD) may be difficult for dermatopathologists, as lack of distinctive histopathological features in a subset of cases may cause confusion in diagnosis.

Objective: As the prototype of psoriasiform dermatitis, psoriasis is a hyperproliferative skin disorder with increased epidermal turnover compared with NPPD, we investigated the role of proliferation markers, Ki-67 and Cyclin D1 as diagnostic tools to differentiate psoriasis from other psoriasiform dermatitis.

Methods: Histopathological specimens of psoriasis (n = 35) and NPPD (n = 36, 14 pityriasis rubra pilaris, 12 pityriasis rosea and 10 lichen simplex) cases were reviewed and immunohistochemically stained for Ki-67 and Cyclin D1. Ki-67 and Cyclin D1 positive cells were counted for suprabasal, and total epidermal immunostaining per mm².

Results: Suprabasal and total epidermal cell counts for Ki-67 were found to be significantly higher in the psoriasis group compared with the NPPD group (p < 0.05). An important and interesting feature was the presence of a cut-off value for the suprabasal/total epidermal cell count ratio of 75% for Ki-67 immunostaining, which was higher in all patients having psoriasis (range, 77.1% – 92.4%) and lower in all NPPD cases (range, 21.0% – 73.3%). However, suprabasal Cyclin D1 cell counts were higher in the psoriasis group compared with the NPPD group (p < 0.05), total epidermal Cyclin D1 cell counts were not statistically significant in either group (p = 0.167), and a cut-off value for suprabasal/total epidermal cell count ratio to distinguish these two entities was not detected using this immunostain.

Conclusions: We suggest that Ki-67 is a more sensitive marker than Cyclin D1 in terms of having a cut-off value of 75% for the suprabasal/total epidermal immunoreactive cell count ratio, which we believe could be useful for dermatopathologists in differentiating psoriasis from other psoriasiform dermatitis.