Author: Assoc Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2013.
Epidermodysplasia verruciformis (EV) is a rare autosomal recessive genodermatosis due to mutations of the EVER1/TMC6 or EVER2/TMC8 genes which results in an intrinsic immunodeficiency against certain human papillomavirus (HPV) types. EV is also seen in patients infected with human immunodeficiency virus (HIV), and with CD8 T-cell lymphocytopenia or graft versus host disease (GVHD).
Histology of epidermodysplasia verruciformis
Histopathology of EV lesions shows enlarged cells in the granular or spinous layer. These have a quite distinctive blue-gray swollen cytoplasm. (figure 1) which reflects HPV infection by the unusual HPV types seen in this disorder. There may be enlarged keratohyaline granules and koilocytes.
Special studies for epidermodysplasia verruciformis
PCR may be used to identify the EV-HPV subtypes. HPV-3,5,8,9,10,13,14,15,17,19-25,28,29,36-38,46,47,49,50,59 have been isolated.
Differential diagnosis of epidermodysplasia verruciformis pathology
EV-like changes – Foci of EV changes may rarely be seen incidentally on actinically damaged skin, or as part of an acanthoma (“EV-acanthoma”).
Squamous cell carcinomain situ (Bowen disease) – Sometimes the cytoplasm in a non-HPV induced dysplastic epithelium can be pale or clear similar to that seen in figure 1. EV lesions may also harbour dysplasia or carcinoma.
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