This video by Dr. Jarrod Gardner provides a detailed microscopic and clinical overview of Epidermodysplasia Verruciformis (EDV), a rare skin disorder often abbreviated as Eevee or EDV. Classically an autosomal recessive genodermatosis, EDV presents with numerous thin plaques resembling pityriasis rosea, tinea versicolor, or verruca plana. The hallmark microscopic finding is the presence of huge, blue-grey, voluminous keratinocytes infected by specific human papillomavirus (HPV) types (commonly 5 and 8), alongside features of a flat wart. Dr. Gardner emphasizes the distinction between the rare syndromic, inherited form (associated with EVR1 and EVR2 gene mutations and increased risk of cutaneous squamous cell carcinoma) and the much more common incidental, focal findings of EDV in otherwise benign skin lesions, which typically carry no clinical significance. He also discusses a complex case in a transplant patient, where EDV changes were intermingled with squamous cell carcinoma due to immunosuppression and sun damage, making diagnosis challenging.
Epidermodysplasia Verruciformis (EDV): Microscopic Features and Clinical Significance
0:00 Introduction to EDV: Dr. Jarrod Gardner introduces Epidermodysplasia Verruciformis (EDV), also known as Eevee, an autosomal recessive genodermatosis.
0:25 Clinical Presentation: Patients classically develop numerous thin, pink or brown plaques resembling pityriasis rosea, tinea versicolor, or flat warts (verruca plana).
0:41 Microscopic Appearance - Flat Wart Features: Microscopically, EDV lesions show features of a flat wart: an acanthotic epidermis with gentle undulation and a thick granular layer containing large, clumpy, purple keratohyalin granules.
1:20 Key Diagnostic Feature - Blue-Grey Keratinocytes: The most distinctive feature of EDV is the presence of huge, ginormous blue-grey keratinocytes with voluminous cytoplasm, infected by specific human papillomavirus (HPV) types. The nuclei of these cells are also large and often have a hazy, ground-glass chromatin pattern.
2:13 Diagnostic Criteria: The combination of these unique cells in the epidermis with flat wart-like changes in the background is diagnostic of EDV.
2:21 Syndromic EDV (Rare Form): The classic, rare form is an autosomal recessive inherited disorder involving EVR1 and EVR2 genes. Patients acquire unique HPV infections (commonly types 5 and 8) and have a higher risk of developing cutaneous squamous cell carcinomas, especially with sun exposure.
3:21 Incidental EDV (Common Form): Much more common are incidental findings of EDV in solitary skin lesions or as a background feature in biopsies for other conditions (e.g., nevi, basal cell carcinoma). These focal areas typically have no clinical significance, and Dr. Gardner often does not include them in pathology reports.
5:54 Incidental Focus Example: A case illustrating a tiny, incidental focus of EDV within a nevus excision, highlighting its common presentation without clinical relevance.
8:10 Solitary Lesion EDV: When an entire biopsy primarily shows EDV, it may be diagnosed as such, potentially representing a solitary epidermal dysplasia of Verruciformis acanthoma, which also lacks the widespread significance of the syndromic form.
8:48 EDV in Sun-Damaged Skin: EDV can also be an incidental finding in older, sun-damaged patients, even alongside other lesions like actinic keratosis.
10:01 Importance for Pathologists: Recognizing EDV is crucial for pathologists to avoid misdiagnosing it as more serious conditions like Paget's disease, squamous cell carcinoma in situ, or melanoma due to the enlarged, atypical-looking keratinocytes.
11:19 EDV with Squamous Cell Carcinoma in a Transplant Patient: A complex case demonstrates EDV intermingled with squamous cell carcinoma in situ in an elderly transplant patient. Immunosuppression and chronic sun damage likely contributed to both conditions, and the large EDV cells can make assessing atypia challenging.
15:19 HPV Effect on Atypia Assessment: The viral changes from HPV infection can make it difficult to accurately assess nuclear atypia, similar to verruca vulgaris or condylomas.
15:30 "Tree Man" Phenomenon: Dr. Gardner briefly mentions the "tree man" condition, where patients develop huge, disfiguring verrucous overgrowths, which is often associated with EDV, but notes that this phenotype differs significantly from the typically flat lesions seen in most EDV cases.
16:56 Key Takeaway for EDV: The most important thing to remember about EDV is the microscopic appearance of the huge, blue-grey keratinocytes within an acanthotic epidermis, recognizing the distinction between the rare syndromic form and the common, clinically insignificant incidental foci.