Abstract
Focal epithelial hyperplasia, or Heck’s disease, is a relatively rare virus-induced benign disease. To the best of the authors’ knowledge it has not been reported in an ethnic Chinese population. The authors report two cases of focal epithelial hyperplasia (FEH) in Chinese patients, which were clinically and histologically in accord with FEH. In particular, the lesions in one case were located on the gingival mucosa, which is rarely affected by FEH. DNA extracted from paraffin-embedded specimens from the two patients was tested for the presence of human papilloma virus followed by specific polymerase chain reaction testing for 16, 18, 13, and 32 subtypes in order to confirm the clinical diagnosis.
Focal epithelial hyperplasia (FEH), or Heck’s disease, is a rare disease that was first described in a Native American population in 1965 . Human papilloma virus (HPV) types 13 and 32 are strongly implicated in the aetiology of FEH . The occurrence of FEH varies from 0.002% to 35% depending on the population studied and the geographic region. FEH is characterised by multiple, asymptomatic, soft, small raised papules or nodules on the oral mucosa. The lesions are predominantly found on the lips, buccal mucosa and tongue . Histological findings include focal epithelial hyperplasia, widened and elongated rete ridges and occasional peri-nuclear vacuoles.
FEH is relatively rare in Asian populations . There has been no exact and complete report of FEH in an ethnic Chinese population. In this report, the authors describe two cases of Chinese patients with oral lesions that were clinically and histologically in accord with FEH. In particular, the lesions of one case were located on the gingival mucosa, which is rarely affected by FEH. To the best of the authors’ knowledge, FEH lesions on the gingiva of Asian people have not been reported before.
Case report 1
A 7-year-old Chinese girl came to the authors’ clinic in February 2009. She complained of painless lesions on the lips and buccal mucosa which had been present for about one year. She had no skin lesions or history of immunosuppressive and metabolic disease. She was otherwise healthy and had no history of allergy or any inherited disease. None of her family members had similar oral lesions.
Clinical examination revealed multiple slightly protruded, soft, asymptomatic papules on the lips and buccal mucosa. The papules were the same colour as the surrounding mucosa or whiter, ranging from 3 to 10 mm in diameter ( Fig. 1 A ).
Anti-human immunodeficiency virus (HIV) and anti-syphilis antibodies in serum were negative. Subtype-specific polymerase chain reaction (PCR) was performed to detect HPV 6, 11, 16 and 18 by the Department of Dermatology (West China Hospital, Sichuan University), and all results were negative. HPV 13 was detected in a DNA sample extracted from a paraffin-embedded block by PCR using HPV 13 specific primers. Histological examination showed parakeratosis and severe acanthosis with elongated and widened rete ridges. Epithelial dysplasia was not detected. The evidence of viral infection was that the nuclei of epithelial cells in the stratum spinosum were enlarged and hyperchromatic with very little nuclear degeneration resembling a mitotic figure (mitosoid cell) ( Fig. 2 A and B ).
These clinical manifestations and histopathological features, together with laboratory investigations, were consistent with a diagnosis of FEH. Considering the benign nature and spontaneous resolution of the disease , no treatment was attempted.
Case report 2
A 33-year-old Chinese woman with a history of painless lesions on the anterior labial gingiva for one month was referred to the authors’ clinic by her dentist. The medical history and family history were unremarkable. Clinical examination revealed a number of pale, protruded, soft, asymptomatic papules of 1–3 mm in diameter on the anterior labial gingiva.
The lesions were firm on palpation, covered by healthy, normal-appearing mucosa which was neither ulcerated nor inflamed. There were no other oral or extraoral lesions ( Fig. 1 B).
Histological examination showed parakeratosis and severe acanthosis of epithelium with elongated and widened rete ridges. Cellular swelling, oedema and peri-nuclear vacuoles were observed in the upper layers of the epithelium, indicating virus infection ( Fig. 3 A and B ).
A clinical diagnosis of FEH was proposed based on the clinical and histopathological features. Subtype-specific PCR was performed to confirm the diagnosis, and HPV 32 was detected in DNA samples extracted from the paraffin-embedded block of the lesion.
Considering the benign and spontaneously regressive nature of the disease, no treatment was attempted. The biopsy area showed no sign of recurrence and other lesions were not changed after 16 months follow up.
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