Section 1 -

Psoriasiform Dermatitis Clifton R. White, Jr. Professor of Dermatology and Pathology Oregon Health and Sciences University Portland, Oregon

Psoriasiform Dermatitis Case Histories Case 1: A 36-year old women presented for a generalized eruption on the central abdomen. The clinician considered psoriasis versus pityriasis lichenoides et varioliformis acuta. Case 1 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 2: A 62-year old man presented for a generalized pruritic plaque-like eruption. The biopsy was taken from his left upper back where the clinician considered nummular dermatitis, mycosis fungoides, and sarcoidosis. Case 2 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 3: A 52-year old women presented with erythroderma (total body erythema). In addition, she had discrete papules in some areas. Several biopsies were taken. Case 3 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 4: A 44-year old man developed a whitish change at both the left and right oral comissure. Case 4 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 5: A 44-year old woman presented for a pruritic eruption. A biopsy from her left arm was submitted to rule out folliculitis versus eczema versus ? Case 5 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 6: A 42-year old woman developed multiple pruritic nodules. A biopsy was taken from the left upper back where the clinician considered excoriated prurigo nodule, lichen simplex chronicus, or deep fungal infection. Case 6 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 7: A 5-year old boy presented with a two year history of increasing pigmentation of a plaque on his right thigh extending to his knee. Case 7 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer I: Psoriasiform Only Psoriasis Allergic contact dermatitis Nummular dermatitis Dyshidrotic dermatitis, late Pityriasis rubra pilaris Seborrheic dermatitis Dermatophytosis Candidiasis Lichen simplex chronicus/ Prurigo nodularis/ Acanthoma fissuratum/ Pressure papule from prosthesis/ Surfer's nodules Chondrodermatitis nodularis chronica helicis II: Psoriasiform Lichenoid Lichen striatus Mycosis fungoides, plaque Inflammatory linear verrucous epidermal nevus Syphilis, secondary Psoriasiform Dermatitis Applying a pattern approach and algorithmic method for diagnosing inflammatory skin diseases has numerous advantages over other, less structured diagnostic methods. Inflammation in the skin can usually, at scanning power (2.5x), be easily categorized into one of nine patterns, the most common and extensive of which is superficial perivascular dermatitis in which inflammatory cells are present around the superficial dermal vascular plexus. In utilizing Ackerman's algorithmic approach, at certain points, key questions should be asked in order to determine the next appropriate branch in the outline to follow. For example, if one is confronted by a superficial perivascular infiltrate, the next key question is: ARE THERE EPIDERMAL CHANGES? A number of superficial perivascular dermatitides have no epidermal changes, such as tinea versicolor, Schamberg's disease, and urticaria. If epidermal changes are present, the next key question is: WHICH OF FOUR POSSIBLE EPIDERMAL CHANGES ARE PRESENT: INTERFACE, BALLOONING, SPONGIOTIC, OR PSORIASIFORM? Interface dermatitides are those in which there is alteration along the dermal epidermal junction, or interface, such as erythema multiforme or lichen planus. Ballooning dermatitides are characterized by intracellular edema within keratinocytes such as viral infections, fixed drug eruption, etc. Spongiotic dermatitides are characterized by intracellular edema between keratinocytes and is the largest category in the superficial perivascular pattern. Finally, psoriasiform dermatitides are characterized by epidermal hyperplasia, and are our subject for this session. Psoriasiform dermatitides may be subdivided into those diseases which are psoriasiform only and those accompanied by a lichenoid infiltrate (psoriasiform lichenoid). Every major division and subdivision in the algorithm, in general, has a prototype which is usually the most common example of that inflammatory pattern. The prototype for psoriasiform dermatitis, as the name indicates, is psoriasis. I. Psoriasiform Only Psoriasis Histologic features: Mounds of parakeratosis containing neutrophils Neutrophils in spongiform distribution in the upper spinous layer Diminished granular layer Thinning of the suprapapillary plate Uniform epidermal hyperplasia Anastomoses at the bases of the rete ridges Increased numbers of mitoses Dilated and tortuous blood vessels in the dermal papillae A superficial perivascular lymphocytic infiltrate Allergic Contact Dermatitis / Nummular Dermatitis / Dyshidrotic Dermatitis, Late (Chronic) Histologic features: Scale crust (plasma, neutrophils, and parakeratosis) or hyper- and parakeratosis Irregular hypergranulosis, irregular epidermal hyperplasia A superficial perivascular infiltrate often with a mixture of eosinophils. Pityriasis Rubra Pilaris Histologic features: Parakeratosis alternating with orthokeratosis in both a horizontal and vertical direction Occasionally collections of neutrophils within the stratum corneum Follicular plugging Intact granular layer Less epidermal hyperplasia than psoriasis A superficial perivascular predominately lymphocytic infiltrate. Seborrheic Dermatitis Histologic features: Irregular epidermal hyperplasia Mounds of scale-crust accentuated at the edges of follicular ostia Superficial perivascular predominantly lymphocytic infiltrate Dermatophytosis and Candidiasis Histologic features: Similar changes to those seen in chronic allergic contact dermatitis Often times neutrophils in the stratum corneum which are a clue to the presence of organisms Lichen Simplex Chronicus / Prurigo Nodularis / Picker's Nodule / Acanthoma Fissuratum / Pressure Papules from Prostheses / Surfer's Nodules Histologic features: Compact hyperkeratosis, parakeratosis, or crust Irregular hypergranulosis Irregular epidermal hyperplasia Prominent fibrosis in the dermal papillae where there are thickened collagen bundles, mainly arranged perpendicular to the surface A superficial perivascular lymphocytic infiltrate often mixed with eosinophils Chondrodermatitis Nodularis Chronica Helicis Histologic features: Prurigo nodule-like features with a central horn-filled plug or crusted ulceration overlying fibrin deposition Features of granulation tissue laterally "Chondroid" alteration of the dermis as it merges with the underlying cartilage Analogous to a clavus (corn); no evidence of a perforating disease II. Psoriasiform Lichenoid Occasionally, epidermal hyperplasia may be accompanied by a band-like rather than perivascular infiltrate. Lichen Striatus Histologic features: Small mounds of scale-crust and hyperkeratosis Irregular epidermal hyperplasia, often containing some spongiosis as well Dyskeratotic keratinocytes A superficial perivascular band-like infiltrate of lymphocytes which often contains collections of epithelioid histiocytes (granulomatous). Mycosis Fungoides, Plaque Histologic features: Hyper- and parakeratosis, sometimes containing collections of neutrophils Fairly regular epidermal hyperplasia with increased numbers of lymphocytes in all areas of the epidermis (per unit area) Band-like infiltrate of lymphocytes in the thickened, fibrotic, papillary dermis Many lymphocytes with folded ("cerebriform"), hyperchromatic nuclear membranes. Inflammatory Linear Verrucous Epidermal Nevus (Ilven) Histologic features: Alternation of ortho- and parakeratosis in the thickened stratum corneum Fairly regular epidermal hyperplasia A superficial perivascular predominantly lymphocytic infiltrate Syphilis, Secondary Histologic features: Parakeratosis containing neutrophils Irregular epidermal hyperplasia also containing neutrophils A superficial to superficial and deep perivascular and lichenoid infiltrate of lymphocytes, numerous plasma cells, and histiocytes Treponemal spirochetes may often be demonstrated with endothelial cells in the superficial dermis as well as within epidermal keratinocytes (Warthin-Starry, Dieterle).