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Histopathologic diagnosis of dermatitis

From Wikipedia, the free encyclopedia

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Histopathology of dermatitis can be performed in uncertain cases of inflammatory skin condition that remain uncertain after history and physical examination.[1]

Sampling

Generally a skin biopsy:

  • For punch biopsies, a size of 4 mm is preferred for most inflammatory dermatoses.[2]
  • Panniculitis or cutaneous lymphoproliferative disorders: 6 mm punch biopsy or skin excision.[2]

A superficial or shave biopsy is regarded as insufficient.[2]

Fixation

  • Generally: Buffered 4% formaldehyde.[3]
  • In suspected immunologic disease:[4] Fixation for immunofluorescence, with for example Michel's solution.[3] For details, see immunofluorescense of skin tissues

Staining

Generally 3 sections for H&E staining and one section with periodic acid Schiff (PAS)[notes 1][2]

  • If suspected bacterial and fungal microorganisms, consider Gram stain and Gomori methenamine silver stain.[2]

Microscopic evaluation

Summarize
Perspective

One approach is to classify into mainly either of the following, primarily based on depth of involvement:[2]

  • Epidermis, papillary dermis, and superficial vascular plexus:
  • Vesiculobullous lesions
  • Pustular dermatosis
  • Non vesicullobullous, non-pustular
  • With epidermal changes
  • Without epidermal changes. These characteristically have a superficial perivascular inflammatory infiltrate, and can be classified by type of cell infiltrate:[2]
  • Lymphocytic (most common)
  • Lymphoeosinophilic
  • Lymphoplasmacytic
  • Mast cell
  • Lymphohistiocytic
  • Neutrophilic

Continue in corresponding section:

Non vesicullobullous, non-pustular lesions with epidermal changes

Spongiotic dermatitis

It is characterized by epithelial intercellular edema.[2]

More information Characteristics, Micrograph ...

In addition to above, an unspecific spongiotic dermatitis can be consistent with nummular dermatitis, dyshidrotic dermatitis, Id reaction, dermatophytosis, miliaria, Gianotti-Crosti syndrome and pityriasis rosea.[2][notes 2]

Interface dermatitis

These are sorted into either:[2]

  • Interface dermatitis with vacuolar change
  • Interface dermatitis with lichenoid inflammation
Interface dermatitis with vacuolar change
More information Main conditions, Characteristics ...

An interface dermatitis with vacuolar alteration, not otherwise specified, may be caused by viral exanthems, phototoxic dermatitis, acute radiation dermatitis, erythema dyschromicum perstans, lupus erythematosus and dermatomyositis.[2]

Interface dermatitis with lichenoid inflammation
More information Main conditions, Characteristics ...

Interface dermatitis with lichenoid inflammation, not otherwise specified, can be caused by lichen planus-like keratosis, lichenoid actinic keratosis, lichenoid lupus erythematosus, lichenoid GVHD (chronic GVHD), pigmented purpuric dermatosis, pityriasis rosea, and pityriasis lichenoides chronica.[2] Unusual conditions that can be associated with a lichenoid inflammatory cell infiltrate are HIV dermatitis, syphilis, mycosis fungoides, urticaria pigmentosa, and post-inflammatory hyperpigmentation.[2] In cases of post-inflammatory hyperpigmentation, it is important to exclude potentially harmful mimics such as a regressed melanocytic lesion or lichenoid pigmented actinic keratosis.[2]

Psoriaform dermatitis

Examining multiple deeper levels is recommended if initial cuts do not correlate well with the clinical history.[2]

Psoriaform dermatitis typically displays:[2]

  • Regular epidermal hyperplasia, elongation of the rete ridges, hyperkeratosis, and parakeratosis.
  • Usually:A superficial perivascular inflammatory infiltrate
  • Often: Thinning of epidermal cells overlying the tips of dermal papillae (suprapapillary plates), and dilated, tortuous blood vessels within these papillae

Further histopathologic diagnosis is performed by the following parameters:

More information Condition, Hyperkeratosis ...

Non vesicullobullous, non-pustular lesions without epidermal changes

Lymphocytic infiltrate

More information Main conditions, Characteristics ...

Lymphoeosinophilic infiltrate

More information Main conditions, Characteristics ...

Lymphoplasmacytic infiltrate

More information Main conditions, Characteristics ...

Mastocytosis

More information Main conditions, Characteristics ...

Lymphohistiocytic infiltrate

Thumb
Leprosy

These include bacterial infections including leprosy, and the sample should therefore be stained with Ziel-Neelsen, acid fast stains, Gomori methenamine silver, PAS, and Fite stains.[2] If negative, an unspecific lymphohistocytic dermatosis may be caused by drug reactions and viral infections.[2][notes 2]

Neutrophilic infiltrate

More information Main conditions, Characteristics ...

Multinucleated giant cells

Thumb
Suture granuloma, with multinucleated giant cells surrounding (grey) suture material.
  • Foreign bodies indicate a foreign body granuloma.
  • Specific forms of multinucleated giant cells include the Touton giant cell, which contains a ring of nuclei surrounding a central homogeneous cytoplasm, with foamy cytoplasm surrounding the nuclei.[29][30] The central cytoplasm (surrounded by the nuclei) may be both amphophilic and eosinophilic.[31]
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Notes

  1. PAS is for evaluation of the epidermal basement membrane, blood vessels, and the presence of fungal organisms
  2. In "not otherwise specified" cases, a diagnosis may be reached by a review of the medical history and physical examination, based upon the potential conditions at hand.
  3. Parakeratotic mounds at the edge of follicular ostia.
  4. Pigmented purpuric dermatitis of Gougerot and Blum particularly have a tendency for lichenoid infiltrate.
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Reference list

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