ORIGINAL ARTICLES   

Giornale Italiano di Dermatologia e Venereologia 2002 February;137(1):3-7

Copyright © 2002 EDIZIONI MINERVA MEDICA

language: Italian

Comparative SEM study of psoriasic cutis and chronic palmoplantar dermatitis

Mazzarello V., Ena P.

Università degli Studi - Sassari Dipartimento di Scienze Biomediche e *Istituto di Clinica Dermatologica

Background. It is often difficult to make a differential diagnosis of psoriasis and chronic palmoplantar dermatitis both in clinical terms and histopathologically. In order to distinguish between these two forms of acrodermatitis we assessed a number of differences observable using a scanning electron microscope (SEM) at the level of the dermoepidermal interface.
Methods. Skin samples were collected using a biopsy punch from 10 patients (6 F, 4 M), half of which underwent routine histological analysis. They were treated for SEM examination using the split skin technique according to Yamada. This method allows a rapid and selective separation of the epidermis from the derma using NaOH and ultrasound.
Results. In psoriasis, the expansion of the dermoepidermal surface due to hyperproliferation and anomalous differentiation (acanthosis and papillomatosis) leads to a reduced distance both between the dermal papillae and between the crests, resulting in a disordered and peculiar 3D alteration of the interface. In chronic dermatitis, acanthosis and lymphocyte phlogosis results in a less striking deformation of the dermoepidermal interface because there is less distance between the interpapillary crests and the layout is more regular and orderly. This means that the interface has an anfractuous but much more even profile compared to psoriasis. In chronic dermatitis dermal papillae are found with “honeycomb” apical thickening and degenerated basal cells. This ultrastructural difference reflects the different pathogenetic interactions peculiar to the two pathologies at the level of the dermoepidermal junction and derma.
Conclusions. The split skin method offers an important tool for the differentiated diagnosis of psoriasis and chronic palmoplantar dermatitis.