Hairy Leukoplakia Workup

Updated: Aug 05, 2019
  • Author: James E Cade, DDS; Chief Editor: Jeff Burgess, DDS, MSD  more...
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Workup

Laboratory Studies

In most cases of oral hairy leukoplakia (OHL), the diagnosis is established on clinical basis, while a definitive diagnosis requires both an appropriate histopathological appearance and the demonstration of Epstein-Barr virus (EBV) DNA, RNA, or protein within the epithelial cells of the lesion.

Several immunohistochemical and in situ hybridization kits are commercially available for this purpose. [23] Tissue biopsy is indicated only if the lesions are unusual in appearance or ulcerated and suggest cancer.

Oral hairy leukoplakia may occur when CD4 counts are 200-300 cells/µL or lower. [24]

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Procedures

It is important to differentiate hairy leukoplakia from other, more serious, oral lesions that may have a similar clinical appearance. In some cases, biopsy and histologic examination are required to exclude cancer.

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Histologic Findings

The histopathology of oral hairy leukoplakia (OHL) is characterized by the following five major features:

  • Hyperkeratosis of the upper epithelial layer that represents an altered pattern of keratin expression in the squamous epithelial cells: This hyperkeratosis is largely responsible for the characteristic shaggy or "hairy" gross appearance of the lesion. Superficial infections of the hyperkeratinized epithelium with bacteria or Candida may also be seen.

  • Parakeratosis of the superficial epithelial layer: This abnormal persistence of cell nuclei in the superficial epithelial layers may represent incomplete squamous differentiation.

  • Acanthosis of the stratum spinosum in the epithelial mid layer: This abnormal expansion of cells occurs with foci or layers of ballooning koilocyte-like cells. The nuclei have a homogenous ground-glass appearance and may contain Cowdry type A intranuclear inclusions.

  • Minimal or no inflammation in the epithelial and subepithelial tissues

  • Histologically normal basal epithelial layer

Although these characteristic histologic features of hairy leukoplakia are highly suggestive of the diagnosis, none is unique to the lesion. Thus, a definitive diagnosis of hairy leukoplakia requires both an appropriate histologic/cytologic appearance and demonstration of Epstein-Barr virus (EBV) DNA, RNA, or protein within the epithelial cells of the lesion.

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