Psoriasis is an autoimmune disease of the skin characterized by hyperkeratosis, hyperproliferation of the epidermis,
inflammatory cell accumulation and increased dilatation of dermal papillary blood vessels. Cases of psoriasis were
investigated in vivo with optical means in order to evaluate the potential of in vivo optical biopsy. A Polarization
Multispectral Dermoscope was employed for the macroscopic observation. Features such as the 'dotted' blood vessels
pattern was observed with high contrast. High resolution image sections of the epidermis and the dermis were produced
with a custom made Multiphoton Microscope. Imaging extended from the surface of the lesion down to the papillary
dermis, at a depth of 200 μm. In the epidermis, a characteristic morphology of the stratum corneum found only in
Psoriasis was revealed. Additionally, the cytoplasmic area of the cells in the stratum spinosum layer was found to be
smaller than normal. In the dermis the morphological features were more pronounced, where the elongated dermal
papillae dominated the papillary layer. Their length exceeds 100μm, which is a far greater value compared to that of
healthy skin. These in vivo observations are consistent with the ex vivo histopathological observations, supporting both
the applicability and potentiality of multispectral dermoscopy and multiphoton microscopy in the field of in vivo optical
investigation and biopsy of skin.
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