Tongue - Hyperkeratosis
comment:Hyperkeratotic lesions, although very common in the forestomach, are rare on the tongue in NTP studies. Hyperkeratosis (thickening of the stratum corneum) occurs in two forms: orthokeratotic ( Figure 1 and Figure 2 ) or parakeratotic hyperkeratosis. In orthokeratotic hyperkeratosis (sometimes referred to as orthokeratosis), the dead keratinocytes are anuclear, whereas in parakeratotic hyperkeratosis (sometimes referred to as parakeratosis), the dead keratinocytes have retained pyknotic nuclei. Hyperkeratosis often accompanies squamous epithelial hyperplasia.
recommendation:In general, hyperkeratosis associated with hyperplasia of the underlying squamous epithelium is not diagnosed separately but is described in the pathology narrative as a component of the hyperplasia. However, if the hyperkeratosis is prominent or is disproportionately increased compared with the degree of hyperplasia, or if it occurs in the absence of epithelial hyperplasia, then it should be diagnosed and graded. Grading should be based on the thickness of the keratin and the amount of tongue surface affected. The pathologist should use his or her judgment in determining whether or not the hyperkeratosis should be diagnosed separately. When diagnosed, the term "hyperkeratosis" should be used for both the ortho- and parakeratotic forms (i.e., do not use the term parakeratosis).
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