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病例漫谈8:银屑病与钱币状皮炎 [复制链接]

Differential Diagnosis



        Psoriasis and nummular dermatitis share several attributes histopathologic, namely, parakeratosis that often is accompanied by serum, psoriasiform acanthosis, spongiosis, edema of the papillary dermis, and an infiltrate of lymphocytes mostly around dilated venules of the superficial plexus.

        The changes histopathologic enumerated here apply only to fully developed, active lesions of psoriasis and nummular dermatitis, i.e., scaly, reddish plaques in the case of psoriasis and papulovesicles affiliated with reddish, crusted, coin-shaped plaques in the case of nummular dermatitis. Both diseases have a wide spectrum of findings pathologic, grossly and microscopically, as would be expected for conditions whose lesions last for weeks or months (and even years in the case of some lesions of psoriasis).

        Clinically, psoriasis begins as tiny, red macules that soon enlarge to become slightly elevated and scaly. Early guttate (drop-sized) psoriatic lesions gradually enlarge centrifugally and, in time, may become extensive plaques. Nummular dermatitis starts as red macules that soon become papules which are scratched because of intense pruritus that accompanies them. In time, papules become vesicles that are eroded and crusted in lesions that are coin-shaped plaques. When rubbed persistently, lesions of nummular dermatitis become lichenified (by imposition of lichen simplex chronicus). When lesions of psoriasis and of nummular dermatitis resolve, hyperpigmentation tends to be residual. In some patients, hyperpigmentation persists for years.

        Salient findings histopathologic of early guttate lesions of psoriasis are:

        1.    Mounds of parakeratosis that at their summit contain neutrophils and a tad of serum

        2.    Neutrophils in discrete (Munro) or spongiform (Kogoj) pustules in the epidermis

        3.    Normal granular zone, except beneath parakeratotic foci

        4.    Normal suprapapillary plates

        5.    Slight acanthosis

        6.    Slight spongiosis

        7.    Marked edema of the papillary dermis

        8.    Superficial perivascular infiltrate of lymphocytes, and neutrophils, accompanied by extravasated erythrocytes around widely dilated capillaries and venules, and scatter of neutrophils in dermal papillae; a few erythrocytes may be present focally in the epidermis.

        Early lesions of nummular dermatitis are characterized histopathologically by:

        1.    Normal or focally parakeratotic cornified layer that contains serum

        2.    Spongiosis in foci; sometimes spongiosis more diffuse

        3.    Slight acanthosis

        4.    Edema of the papillary dermis

        5.    Superficial infiltrate of lymphocytes and often many eosinophils in perivascular and interstitial locale; those cells also present in the papillary dermis.

        Sections from a biopsy specimen from the center of a longstanding resolving plaque of psoriasis show the following:

        1.    Confluent compact orthokeratosis with only focal parakeratosis

        2.    Granular zone mostly of normal thickness

        3.    Supra-papillary plates of normal thickness

        4.    Psoriasiform acanthosis with rete ridges of approximately equal length and breadth

        5.    Tortuous capillaries in dermal papillae

        6.    Sparse to moderately dense superficial perivascular infiltrate of lymphocytes.

        Late lesions of nummular dermatitis are marked histopathologically by these changes:

        1.    Compact orthokeratosis with focal parakeratosis

        2.    Uneven psoriasiform acanthosis

        3.    Papillary dermis thickened by coarse bundles of collagen arranged in vertical streaks parallel to elongated rete ridges, i.e., signs of lichen simplex chronicus

        4.    Moderately dense superficial perivascular mixed-cell infiltrate of lymphocytes, histiocytes (including melanophages), plasma cells, and eosinophils.

        Lichen simplex chronicus often is imposed on longstanding lesions of nummular dermatitis and less often on those of psoriasis. In those instances, the evidence histopathologic of persistent rubbing, namely, a papillary dermis thickened markedly by coarse bundles of collagen arrayed in vertical streaks, may obscure the findings fundamental of nummular dermatitis or psoriasis. Clues helpful to recognizing the underlying process as nummular dermatitis are slight spongiosis in the unevenly psoriasiform epidermis, crusts as well as scales, and some eosinophils in the infiltrate in the dermis. Clues to the fundamental nature of the psoriatic process are neutrophils in parakeratotic foci, tortuous capillaries in dermal papillae, and some thin rete ridges.

        A few lines should be devoted to two interesting expressions morphologic of psoriasis, namely, the pustular and the erythrodermic. Pustular psoriasis is merely explosive psoriasis in which the process is accelerated so greatly that it bypasses guttate macules and papules and proceeds directly to pustules. Erythrodermic psoriasis is universal, exhibiting redness and scaling over the entire integument. The findings histopathologic in the erythroderma are just like those of a lesion of psoriasis developed fully, except that there is little, if any, scale as a consequence of exfoliation of clumps of parakeratosis.

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