INTRODUCTION

Focal epithelial hyperplasia is a benign, chronic illness, mainly affecting children. It manifests in the oral mucosa and is caused by human papilloma virus. It is related to subtypes 13 and 32;^1,2 it is common in North American native subjects. In Colombia it is mostly found in the Antioquìa and Chocó districts.^3,4 It is clinically characterized by presence of multiple papules involving the whole of the oral mucosa. Lesions can be found in the gums, labial and buccal mucosa and the tongue. Lesions are asymptomatic and of variable size^5,6

Histopathological study of lesions reveals formation of parakeratin layers and extensive acanthosis. Epithelial cells of the stratum spinosum show large nuclei with vacuolated cytoplasm indicating koilocyte degeneration.^7,8

From a therapeutics perspective, the disease tends to exhibit spontaneous regression, and this regression can persist for 10 up to 30 years, which implies that patients will exhibit lesions during all their childhood, adolescence and part of their adult life. This situation might generate oral problems as well as psychosocial issues such as rejection.^9,10 Treatment alternatives can be surgical excision, cryosurgery, 5% imiquimod and laser ablation. Nevertheless, all the aforementioned are trauma-inducing techniques, some are immunemodulating techniques, and might cause anguish, anxiety and fear in the patient.^11,12

Trichloroacetic acid (TAA) is a favorable therapeutic option, it elicits little trauma or negative emotional reactions, nevertheless its use requires further study.¹³ TAA is chemically composed of carbon, chloride, oxygen and hydrogen. It causes denaturalization, precipitation and destruction of lesions by means of chemical coagulation of affected tissue. Clinically, certain flattening of the lesions can be observed.¹⁴ It is used for the treatment of vaginal infections caused by human papilloma virus in conditions such as papilloma, condyloma and common warts (verruca vulgaris). Suitable results are obtained when this acid is used at concentrations higher than 80%.^15,16 Harris et al applied TAA in oral lesions of two pediatric patients; they observed lesion resolution with two topical applications.¹⁷ Leon et al reported two cases of patients affl icted with FEH (focal epithelial hyperplasia), who showed satisfactory results after being treated with TAA.¹⁸

The aim of the present study was to assess effectiveness of trichloroacetic acid therapy in treatment of focal epithelial hyperplasia.

MATERIAL AND METHODS

A prospective analytical study was conducted with an intervention component. Eleven patients were included in the study, according to population. Patients exhibited clinical and histopathological characteristics of focal epithelial hyperplasia and had previously signed informed consent forms. Convenience sampling was applied to patients attending dental services at the clinics of the Rafael Nuñez University Corporation and the University of Cartagena. Initially, an intraoral examination was conducted in subjects showing clinical impression of focal epithelial hyperplasia (Figure 1). Patients were subjected to incision biopsy in one of the lesions so as to establish anatomical and pathological diagnosis. At a later point, and following Beutner et al protocolol,¹⁹ 80% trichloroacetic acid was applied.

Figure 1 Multiple papules located in the right oral mucosa, lower lip and tongue. 

To begin with, the area was cleansed with abundant water supply and the lesion surface was dried. After this, TAA was applied over the lesions with a hyssop; after 90 seconds the lesion acquired an intense white coloration due to the chemical burn caused by the acid (Figure 2). After this, a buffering substance was applied in the mouth, this substance was composed of water and sodium bicarbonate powder (soda) so as to neutralize the acid´s ph and to eliminate residues which might affect adjacent tissues. The process was repeated in all lesions every two weeks, until lesion disappearance (Figure 3).

Figure 2 Application of 80% trichloroacetic acid on the lesions. 

Figure 3 Lesion resolution after trichloroacetic acid application. 

The present work was adapted to the World Medical Association Helsinki recommendations for biomedical research, (Number 008430 (1993) resolution of technical, scientific and administrative norms) and was approved by the ethics research committee of the Rafael Nuñez University Corporation and the University of Cartagena.

Data statistical analysis was conducted using Strata^TM version 12 for Windows statistical package. Description was made of treated patients’ data, central tendency and dispersion measures were used for quantitative variables and frequency distribution and qualitative variables proportions. Lesion resolution time was defined as main outcome (dependent variable).

RESULTS

Out of a total of 11 patients, 63.64% were female. Average age was 9.0 ± (SD:3.41). Most affected sites in the mouth were upper and lower labial mucosa in 100% cases, right and left oral mucosa in 63.64% cases, dorsal side of the tongue in 45.45% cases and lateral border of the tongue in 27.27% cases (Table I). Anatomical and pathological study revealed presence of epithelial acanthosis, papillomatosis and koilocytosis in 100% of cases.

Table I Case distribution according to gender, age, lesion location and evolution time. 

ULM = Upper labial mucosa, LLM = Lower labial mucosa, RBM = Right buccal mucosa, LBM = Left buccal mucosa, TD = Tongue dorsum, TB = Tongue border.

The greatest number of acid application was three and four times per case, representing 27%, with average of 4.0 ± (SD:2.0), lesion disappearance average was 61.3 days ± (SD:28.8) and relapse was not present in 100% of all cases (Table II).

Table II Lesion behavior with respect to number of applications, time of disappearance and recurrence. 

With respect to symptoms, two patients manifested burning sensation after acid application during the first session, no complications such as ulcerative lesions, blisters or burns were observed.

DISCUSSION

Gonzalez et al and Hall et al described in their studies that FEH is characterized by the presence of multiple papules, which are commonly located in the labial and oral mucosa; they describe these lesions as asymptomatic, of variable size and matching the color of adjacent mucosa.^19,20,21 Villanueva et al state that FEH frequently affects child population, and exhibits preference for the female gender;²² this concurs with the clinical characteristics exhibited in 100% of cases examined in the present study: 63.64% of total population was female, and age average was 9.0 years. Lopez et al and Gonzalez et al stated that in the histological study, the condition was characterized by presence of acanthosis, epithelial projections, papillomatosis, ovoid-shaped cells with increased cytoplasm and displaced nuclei also called koliocytes;^23,24 all the aforementioned fully concurs with 100% of cases studied in the present report.

Leon et al reported two cases of patients affl icted with FEH in the upper and lower labial mucosa as well as the oral mucosa. Lesions were treated with 70% TAA in several sessions, favorable results were obtained.¹⁸ Little et al reported that FAA application in FEH cases was a therapeutic alternative offering suitable results; they recommend concentrations of 80 and 90%.²⁵ The present study concurred with these appreciations since topical applications were performed with 80% TAA and favorable results were obtained. Average time for lesion disappearance was 61.3 days; only two patients experimented burning sensation after acid application in the first visit. No relapse was observed in 100% of all cases.

Mata et al applied TAA and cryotherapy to patients affl icted with FEH. They reported full lesion resolution after a two year follow-up,²⁶ differing from the present study where average time for lesion resolution was 61.3 days with only 80% TAA topical applications.

CONCLUSIONS

Application of trichloroacetic acid as therapeutic method in focal epithelial hyperplasia was an effective technique, lesions were resolved in a rapid and atraumatic manner, without generating anxiety or fear. Lesions exhibiting greater diameter and height required more applications than those of smaller size.