Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Psoriasiform and spongiotic dermatitis


Psoriasis

Key Features

  • Neutrophils above parakeratosis in stratum corneum

  • Little to no serum in stratum corneum

  • Alternating neutrophils and parakeratosis in the stratum corneum (sandwich sign)

  • Neutrophilic spongiform pustules

  • Little spongiosis in adjacent epidermis

  • Tortuous blood vessels in dermal papillae

The appearance of psoriasis depends on the stage of the lesion and type of lesion. Early guttate lesions demonstrate no acanthosis. Established plaques demonstrate a characteristic pattern of regular acanthosis. Pustular psoriasis may never demonstrate acanthosis. Acral and intertriginous lesions of psoriasis commonly demonstrate a background of spongiosis, but spongiosis is distinctly absent from the surrounding epidermis in most other locations. Reiter disease and geographic tongue histologically look like psoriasis.

Pearl

Collections of neutrophils within the stratum corneum:

  • Psoriasis, tinea, impetigo, Candida , seborrheic dermatitis, syphilis (PTICSS)

Plaque psoriasis

Key Features

  • Regular, bulbous, club-shaped acanthosis

  • Thin superpapillary plates

  • Alternating neutrophils and parakeratosis in the stratum corneum (sandwich sign)

  • Little to no serum in stratum corneum

  • Neutrophilic spongiform pustules

  • Little spongiosis in adjacent epidermis

Fig. 8.1, Plaque psoriasis

Pustular psoriasis

Key Features

  • Collections of neutrophils within stratum corneum

  • Subcorneal pustules

  • Spongiform pustules

Pearl

Subcorneal pustules: Candida, acropustulosis of infancy, transient neonatal pustular melanosis, Sneddon–Wilkinson (and IgA pemphigus), impetigo, pustular psoriasis, Staphylococcus scalded-skin syndrome (CAT SIPS, or an anagram of SIPS)

Fig. 8.2, Pustular psoriasis

Guttate psoriasis

Key Features

  • Neutrophils above parakeratosis

The key histologic feature of guttate psoriasis is a focus of neutrophils on top of parakeratosis (half of the sandwich sign, jelly up). The neutrophilic focus may be small and only visible in step sections. The focus often has a humplike configuration or resembles a child's drawing of a seagull.

Fig. 8.3, Guttate psoriasis

Inflammatory linear verrucous epidermal nevus (ILVEN)

Key Features

  • Alternating orthokeratosis and parakeratosis from left to right

  • Areas of orthokeratosis have a prominent granular layer

  • Areas of parakeratosis lack an underlying granular layer (see Chapter 2 )

Fig. 8.4, Inflammatory linear verrucous epidermal nevus (ILVEN)

Mycosis fungoides

Key Features

  • Epidermal collections of lymphocytes

  • Lymphocytes hyperchromatic and surrounded by white space (lump of coal on a pillow)

  • Epidermal lymphocytes larger, darker, and more angulated than lymphocytes in dermis

  • Little spongiosis in adjacent epidermis

  • Papillary dermal fibrosis

  • In areas, lymphocytes may also line up along the dermal epidermal junction

  • Bare underbelly sign (see Chapters 7 and 24 )

Fig. 8.5, Psoriasiform mycosis fungoides

Syphilis

Key Features

  • Vacuolar interface dermatitis together with elongated psoriasiform acanthosis

  • Vacuolar interface dermatitis together with interstitial dermal infiltrate (busy dermis)

  • Neutrophils in the stratum corneum

  • Plasma cells present in about two thirds of cases

  • Endothelial swelling obliterates the lumen of small vessels

  • Perivascular lymphocytes and histiocytes with visible cytoplasm (see Chapters 7 and 17 )

Fig. 8.6, Syphilis

Pearl

Plasma cells are commonly associated with:

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts