Which histologic findings are characteristic of epidermolytic ichthyosis (EI)?

Updated: Aug 23, 2019
  • Author: Brittany G Craiglow, MD; Chief Editor: Dirk M Elston, MD  more...
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Answer

In epidermolytic ichthyosis, hematoxylin and eosin findings are distinctive but not unique to epidermolytic ichthyosis. Typical findings include marked hyperkeratosis, a thick granular layer, coarse keratohyaline granules, and vacuolar degeneration of the upper epidermis. Occasionally, deeper granular cells become dense, enlarged, and irregular, and the shaped masses appear to be keratohyaline granules. In addition, dyskeratosis is frequently present to varying degrees. [16] Patients whose pathologic slides demonstrate continuous involvement of the entire horizontal epidermis with these distinctive findings are more likely to have generalized disease; those with focal involvement revealing skip areas of normal epidermis are more likely to have a mosaic form of epidermolytic ichthyosis. [17]

On electron microscopy, large, round-to-oval, dense clumps of keratin tonofilaments can be seen in the lower epidermal layers.

Hematoxylin and eosin staining of epidermolytic ichthyosis is shown in the images below.

Pathology of epidermolytic ichthyosis (hematoxylin Pathology of epidermolytic ichthyosis (hematoxylin and eosin stain).
Pathology of epidermolytic ichthyosis (hematoxylin Pathology of epidermolytic ichthyosis (hematoxylin and eosin stain).

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