Colloid-amyloid bodies in PUVA-treated human psoriatic patients.

In 4 cases of PUVA-treated psoriatic patients a number of colloid bodies and amyloid-like deposits were seen at the dermo-epidermal junction, in a very similar fashion the colloid bodies and the amyloid substances are deposited in lichen planus and in primary cutaneous anyloidoses respectively. In some instances such a deposition was found within the epidermis and contained remnants of cellular debris. Serial sections revealed that a part of the intraepidermal deposit is located in the dermis. Some deposition is partially composed of typical amyloid filaments and partially of nonamyloidal filaments. The latter were identical to those found in colloid or Civatte bodies of lichen planus and other conditions. Follow-up biopsies done in 1 patient several months after the cessation of the treatment still showed these substances. It was suggested that the amyloid-like substances are the product of special degeneration (apoptosis) of epidermal cells as colloid substances: Initally these cells undergo filamentous or colloid degeneration and they drop off into the dermis; where some of the characteristics of filaments are modified and connective tissue elements are added to produce such filamentous and amorphous components as seen in the amyloid island, whereas others remain as colloid bodies. Absorption or elimination of these substances seem to be extremely slow.