Common wart pathology

Verruca vulgaris (common warts) are keratotic injuries caused by infection by various subtypes of DNA virus, human papillomavirus (HPV).

Histology vulgar wart

Histopathological examination of the verruca vulgaris reveals a marked and papillomatous epidermis with hypergranulomatosis and overlapping levels of parakeratosis (Figure 1).

The upper epidermis may contain a large pink inclusions (figure 2), particularly in cases that arise in acral fur. Other injuries show less basophilic granules (figure 3). Characteristic vacuolated keratinocytes (koilocytes), which have a little shrinkage core surrounded by a perinuclear halos, are seen in the upper epidermis (figure 3).

Special spots for verruca vulgaris

No special stains are required to make the diagnosis. PCR can be used to identify the type of HPV.

Differential diagnosis vulgar wart pathology

Seborrheic keratosis – The distinction may be difficult for old warts in which the viropathic effect is difficult to appreciate. Some pathologists use the term “verrugal keratosis” or similar in cases where a clear distinction cannot be made.

Molluscum contagiosum: The large viral inclusions of the mollusk should not be confused with the large basophilic inclusions that can be seen in some warts (Figure 2). Large HPV inclusions are usually seen in lesions that occur in the acral skin, an extremely rare site for molluscum contagiosum.