PSORIASIS VULGARIS OF THE SKIN AND MUCOUS MEMBRANE, ITS PATHOLOGICAL
POSITION AND ÆTIOLOGY. P. THIMM. (_Monatsh. f. prakt. Derm._, July
1st, 1904, p. 1.)
Dr. Thimm gives the history of a patient, a man aged 36 years, who had
been under his care for five years. He had an obstinate recurring
extensive psoriasis eruption of the skin of the trunk and limbs, typical
psoriasis lesions of the upper and lower lips, extending on to the
mucous membranes of the mouth and nasal cavities. In addition, the
mucous membrane of the mouth showed, while he was under observation,
various circumscribed diseased patches, setting in synchronously with
the eruption on the skin, which also disappeared at the same time after
general treatment with arsenic. Schimmer’s typical leucoplakia was also
present, the patient being an immoderate smoker, and this continued in
spite of all treatment. There were no signs of syphilis.
Microscopical examination of two mucous membrane lesions showed great
œdema, enlarged intercellular spaces, thickening of the epidermal
covering _in toto_, but a thinning of the rete over the elongated,
high-reaching papillæ. Small-celled infiltration of the upper layers of
the corium, extending even up into the epithelium, was also present.
But what was not visible, nor present in any of the sections, was the
parakeratotic heaping up of scales of the psoriasis lesions.
Exceptionally this may be wanting in cutaneous psoriasis patches, but
its absence is, as a rule, or even always, characteristic, in psoriasis
of mucous membranes. In certain sections, however, the uppermost
epithelial layers, one found, to a depth of three cell layers, were
pressed together to form a dark-coloured narrow band, but having regard
to the smooth contour of the surface this could hardly be looked upon as
a partly developed scale. The pathological characters of any lesions are
to a certain extent altered according to the position in which they
occur. By the word “parakeratosis” is understood, apart from the heaping
up of dry, scaly formations, a condition in which we find the following
changes of the epithelium: parenchymatous œdema, extension of the basal
horny layer, abnormally scanty fat contents of the same, want of
keratohyalin, and abnormally good preservation of the nuclei. Such are,
however, pathological changes of the external epithelium, but normal
conditions of the mucous membranes. Parakeratotic changes of the mucous
membranes of the mouth cannot be considered diagnostic of psoriasis. But
the changes in the papillæ, the infiltration of the upper layer of the
corium, the widening of the blood-vessels, the dilatation of the
lymph-channels, taken in conjunction with the clinical symptoms and the
results of treatment, leave no doubt that the case was one of true
psoriasis vulgaris of the mucous membrane of the mouth. Previously, very
few cases of scaly lesions of the mucous membranes had been described,
and in psoriasis of the skin the extensive and destructive infiltration
seen in these lesions of mucous membranes is unknown.
The ætiology of psoriasis, whether of the skin or mucous membrane, has
been, and is still so hotly discussed, that the translator can but
mention the author’s conclusion that the pathological picture of his
case points anatomically to an inflammatory origin, and ætiologically to
a parasitic origin of psoriasis.