Flat warts, technically known as Verruca plana, are reddish-brown or flesh-colored, slightly raised, flat-surfaced, well-demarcated

papule A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...

of 2 to 5 mm in diameter. Upon close inspection, these

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

s have a surface that is "finely verrucous".Lookingbill, Donald, et al. ''Principles of Dermatology''. Saunders. 2000. Pages 68-69. . Most often, these lesions affect the hands, legs, or face, and a linear arrangement is not uncommon. At

histopathology Histopathology (compound of three Greek words: ''histos'' "tissue", πάθος ''pathos'' "suffering", and -λογία '' -logia'' "study of") refers to the microscopic examination of tissue in order to study the manifestations of disease. Spe ...

, flat warts have cells with prominent

perinuclear vacuolization Vacuolization is the formation of vacuoles or vacuole-like structures, within or adjacent to cells. Perinuclear vacuolization of epidermal keratinocytes is most likely inconsequential when not observed in combination with other pathologic findi ...

around

pyknotic Pyknosis, or karyopyknosis, is the irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis. It is followed by karyorrhexis, or fragmentation of the nucleus. Pyknosis (from Ancient Greek meaning "thick, clo ...

basophilic Basophilic is a technical term used by pathologists. It describes the appearance of cells, tissues and cellular structures as seen through the microscope after a histological section has been stained with a basic dye. The most common such dye is ...

, centrally located nuclei that may be located in the granular layer. Last Update: May 13, 2019. These are referred to as "owl's eye cells."

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Virus-related cutaneous conditions Papillomavirus-associated diseases {{Cutaneous-infection-stub