Warty dyskeratoma is a cup-shaped, invaginated, epidermal lesion. The crater-like center is filled with keratin. The epidermis is hyperkeratotic and acantholytic, with a verrucoid appearing; dermal papillae lined by keratinocytes form villi that protrude into the crater. Although it may resemble a wart, it has no relationship to HPV.
Suprabasilar clefts are formed due to acantholysis. Dyskeratosis is also a prominent feature with "corps ronds" (large acantholytic cells with perinuclear halos in the spinous latery) and "corps grains" (pyknotic keratinoctyes with elongated dark nuclei and brightly eosinophilic cytoplasm in the corneal or upper granular layer)(Busam).
Note the corps ronds and corps grains in the dyskeratotic epithelium.
Warty dyskeratoma is a benign epidermal neoplasm that may be the sporadic counterpart of Darier disease (an autosomal dominant genodermatosis also known as keratosis follicularis). Dr. Fitzpatrick has demonstrated that warty dyskeratomas lose SERCA2 staining by IHC; SERCA2 is a calcium-ATP pump that is encoded by ATP2A2, a gene that is mutated in Darier disease (Hinshaw).
The differential diagnosis includes Darier disease (clinical history, but the lesions are histologically identical) and other acantholytic epidermal lesions (e.g. acantholyic actinic keratosis
Clinically presents as an umbilicated skin lesion with a central keratotic plug (similar to a keratoacanthoma), usually limited to the head, neck or face. It may be mistaken for a verruca vulgaris (common wart). Most lesions are solitary and sporadic (Busam).
→There is an outward exophytic component (verrucoid, hyperplastic epithelium) and an endophytic component (suprabasilar clefting, dyskeratosis, acantholysis). The crater-like center is filled with keratin.
→May be related (i.e. a sporadic form) to Darier disease.
Busam KJ. Dermatopathology: Foundations in Diagnostic Pathology 1st Ed. Philadelphia, PA: Elsevier; 2010: 345-6.
Hinshaw M, et al. Warty Dyskeratoma: eMedicine. Last updated on Jan 13 2010. Available at: emedicine.medscape.com/article/1060224