Case 180. HPV-3 infection (verruca plana) (18 y-o M)
Biopsy from multiple, mildly pigmented flat elevasions on the perioral skin
Key words : human papillomavirus, verruca plana, verruca vulgaris
Verruca plana is often encountered on the face of the young, and HPV, types 3 or 10 is the causative agent.   Histologically, the koilocytic keratinocytes contain nuclear inclusions and "basket weave" appearance is seen in the cornified layer (HE).
Immunostaining for human papillomavirus antigen. Positivity is seen in the koilocytic nuclei and vacuolated cornified layer component.   Reference case 180A
Verruca vulgaris seen in the forearm of 13 y-o male, showing papillomatosis and hyperparakeratosis with koilocytosis (HE). Hypergranulosis with nuclear inclusions and perinuclear koilocytic changes is evident. Vacuoles remaining in the cornified layer are suggestive of HPV infeciton.
Reference case 180A
Immunostaining for HPV antigen, demonstrating positive nuclear signals in the granular and parakeratotic layers. The nuclei and vacuolated cytoplasm of the parakeratotic layer are positively stained. Verruca vulgaris is caused by HPV, type 2, 4 or 7.
  Reference case 180B
Another case of verruca vulgaris (18 y-o F), showing numerous intranuclear groundglass inclusions in the granular and keratinocyte layers (HE). Varied subtypes of HPV provoke verruca vulgaris. Common types of benign HPV infection are caused by HPV, types 1, 2, 3, 4, 7 and 10.
Reference case 180B
Electron micrograph of verruca vulgaris, showing small-sized 40 nm viral particles in the nuclear matrix. HPV antigen was undetectable in this case. EM features are consistent with production of viral virions, while immunostaining using HPV antiserum failed to identify positive signals.