Focal Epithelial Hyperplasia    



Quick Summary
Introduction
References
Photos



Clinical Features
Histopathology
Treatment
Prognosis

Rete ridges of hyperplastic mass (to left) extend down to terminate
 at the same level as those of adjacent normal epithelium.

 

 


 

Quick Review

Focal epithelial hyperplasia is essentially an oral infection with the wart-producing papillomavirus, although from a different family of viruses.  Individual pink or whitish mucosal masses are typically multiple and often flat on top.  They are painless, very contagious and occur in children and adolescents, although some may remain into adulthood.  They cause no significant problem unless one occurs on the visible lip.  When desired, lesions can be removed by conservative surgery or laser destruction.


Introduction

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One of the most contagious of the oral papillary lesions is focal epithelial hyperplasia or Heck's disease, another HPV-induced epithelial proliferation first described in 1965 in Native Americans. The level of contagion is exemplified by the fact that in some isolated populations up to 40% of children have been affected. Today it is known to exist in numerous populations and ethnic groups and to be produced by one of the subtypes of the human papillomavirus, HPV-13, and possibly HPV-32. Where the infection is endemic among children, adults seem to have minimal evidence of residual oral lesions and so the lesions are presumed to eventually disappear on their own.

Focal epithelial hyperplasia is somewhat different from other HPV infections in that it is able to produce extreme acanthosis or hyperplasia of the prickle cell layer of the epithelium with minimal production of surface projections or induction of connective tissue proliferation. The mucosa may be 8-10 times thicker than normal.


Clinical Features

Heck's disease primarily occurs in children, but lesions may occur in young and middle-aged adults. There is no gender predilection. Sites of greatest involvement include the labial, buccal and lingual mucosa, but gingival and tonsillar lesions have also been reported.

Individual lesions are broad based or so slightly elevated as to present as well demarcated plaques (Figure 1). Lesions are frequently papillary in nature (Figure 2), but relatively smooth-surfaced, flat-topped lesions are more commonly seen. Papules and plaques are usually the color of normal mucosa, but may be pale or, rarely, white. Hyperplastic lesions are small (0.3-1.0 cm.), discrete, and well-demarcated, but they frequently cluster so closely together that the entire mucosal area takes on a cobblestone or fissured appearance (Figure 3).


Pathology and Differential Diagnosis

Epithelial hyperplasia in this disease presents microscopically as an abrupt and sometimes considerable focal acanthosis of the oral epithelium. The thickened mucosa extends upward, not down into underlying connective tissues, hence, the lesional rete ridges are at the same depth as the adjacent normal rete ridges. The ridges themselves are widened, often confluent and sometimes club-shaped; they are not long and thin as in psoriasis and other diseases. Some superficial keratinocytes show a koilocytic change similar to that seen in other HPV infections, while occasional others demonstrate a collapsed nucleus which resembles a mitotic figure (mitosoid cell). These presumably result from viral alteration of the cells. Virus-like particles have been noted ultrastructurally within both cytoplasm and nuclei of cells within the spinous layer, and this layer is positive for HPV antigen with in situ hybridization.

The lesion is usually easily differentiated from squamous papilloma, verruca vulgaris and condyloma by its lack of pronounced surface projections; the presence of mitosoid cells, and the lack of connective tissue cores in the surface projections, when present. The sessile nature of focal epithelial hyperplasia also serves to separate it from the former two lesions, although this is not a guaranteed distinction.

Focal epithelial hyperplasia also tends to lack the pronounced elongation of thin rete ridges seen in keratoacanthoma and pseudoepitheliomatous hyperplasia, and it lacks the central keratin-filled core of the keratoacanthoma. It also lacks the subepithelial foamy or granular histiocyte-like cells required for the diagnosis of verruciform xanthoma.


Treatment and Prognosis

Conservative excisional biopsy may be required to establish the proper diagnosis, but additional treatment is unnecessary, except perhaps for esthetic reasons relating to visible labial lesions. Spontaneous regression has been reported after months or years, and the disease is rather rare in adults. No case of focal epithelial hyperplasia has been reported to transform into carcinoma. It should be remembered that focal epithelial hyperplasia may be an oral manifestation of AIDS.


 

References (Chronologic Order)

Note: Click on underlined author's names for additional detail.

General references:

Neville BW, Damm DD, Allen CM, Bouquot JE. Oral and maxillofacial pathology. Philadelphia, W. B. Saunders; 1995.

Elder D, Elenitsas R, Jaworsky C, Johnson B Jr. Lever's Histopathology of the skin, 8th edition. Philadelphia; Lippincott-Raven, 1997.

Sapp JP, Eversole LR, Wysocki GP. Contemporary oral and maxillofacial pathology. Mosby; St. Louis, 1997.

Odell EW, Morgan PR. Biopsy pathology of the oral tissues. London; Chapman & hall Medical, 1998.

Specific references:

Archard HO, Heck JW, Stanley HR. Focal epithelial hyperplasia: an unusual and mucosal lesion found in Indian children. Oral Surg Oral Med Oral Pathol 1965; 20: 201-212.

Witkop CJ Jr, Niswander JD. Focal epithelial hyperplasia in Central and South American Indians and Latinos. Oral Surg Oral Med Oral Pathol 1965; 20: 213-217.

Starink TM, et al. Focal epithelial hyperplasia of the oral mucosa. Report of two cases from the Netherlands and review of the literature. Br J Dermatol 1977; 96:375-380.

Harris AM, van Wyk CW. Heck's disease (focal epithelial hyperplasia): a longitudinal study. Community Dent Oral Epidemiol 1993; 21: 82-85.

Padayachee A, van Wyk CW. Human papillomavirus (HPV) DNA in focal epithelial hyperplasia by in situ hybridization. J Oral Pathol Med 1991; 20: 210-214.

Carlos R, Sedano HO. Multifocal papilloma virus epithelial hyperplasia. Oral Surg Oral Med Oral Pathol 1994; 77:631-635.

Viraben R, et al. Focal epithelial hyperplasia (Heck disease) associated with AIDS. Dermatology 1996; 193:261-262.


Pictures

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