Oral tonsils: Location, distribution, and histology

Oral tonsils: Location, distribution, and histology Milton J. Kmpp,

Lieutmant

Colonel, DC, USA*

T

he purpose of this article is to describe the existence of a number of structures in the oral mucosa which histologically resemble the palatine, pharyngeal, and lingual tonsils. Because of this similarity, they will be termed oral tonsils, and this report will deal with their clinical, gross, and histologic features. METHODS

AND

MATERIALS

This study is based on clinical observation of 503 randomly selected male patients who had reported to a dental clinic for routine oral examination. In six cases tissue biopsy specimens were taken, fixed in 10 per cent formalin, embedded in paraffin, sectioned at 5 microns, and stained with hematoxylin and eosin. FINDINGS Clinical findings

Routine oral examination of the 503 patients, whose average age was 24 years, revealed that the soft palate, the floor of the mouth, and the ventral surface of the tongue showed small, round, elevated, nodular, smooth, pink, freely moveable structures which ranged from 1 to 3 mm. in diameter. Of the 503 patients, 105 had one to twenty-five of these structures in random distribution over the posterior soft palate (Figs, 1 and 2). Twenty-five of the patients had one to six of these structures in random distribution on the ventral surface of the tongue in the area just above the reflection of the mucosa of the floor of the mouth (Fig. 3). Sixty-two of the patients had from one to sixteen structures randomly distributed over the right and left sides of the floor of the mouth (Figs. 5 and 6). The clinical appearance of the nodular structures was similar in all three locations. The ora tonsils must be distinguished from the opening of certain minor salivary gland ducts which have a somewhat similar clinical *Chief, Dental Research Division, United States Army Command, Department of the Army, Washington, D. C.

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appearance. These duct openings are seen on either side of the midline of the anterior part of the ventral aspect of the tongue (Fig. 4). During surgical excision the oral tonsils were found to be circumscribed and superficially located, and they appeared to be attached to the overlying mucosa. The cut surface of the gross specimen showed a firm, smooth, solid, gray-white appearance. Microscopic

findings

Of the six specimens, two were removed from the soft palate, two from the floor of the mouth, and two from the ventral surface of the tongue. Microscopically, there was no difference between the oral tonsils removed from different oral sites. These structures contained a central crypt lined with stratified squamous epithelium (Figs. 7, 8, and 9), which was continuous with the surface epithelium of the overlying oral mucosa. In one case, however, a part of the crypt lining consisted of pseudostratified columnar epithelium, and in another case the duct of a mixed salivary gland opened into the bottom of the crypt (Fig. 8). The orifice of the crypts was very small, so that it was difficult to demonstrate unless serial sections were cut and examined. In most of the seetions, therefore, the crypt of the oral tonsil appears only as an epitheliumlined cleft (Fig. 10). On the periphery of the epithelium-lined cleft crypt, the oral tonsil consists of a circumscribed mass of diffuse and nodular lymphoid tissue. This lymphoid tissue shows no differences from similar tissue found in other tonsils. DISCUSSION

The purpose of this report is to describe the existence of lymphoepithelial structures in the oral mucosa which are called ora tonsil. In the current series, 21 per cent of the patients had aggregates on the soft palate, 5 per cent had them on the ventral surface of the tongue, and 12 per cent had them on the floor of the mouth. These occurrence rates are most likely understated, since only clinically well-defined nodules were included in the study. Many less welldelineated nodular elevations, suggestive of oral tonsils, were not included. The great frequency with which the oral tonsils present clinically as circumscribed nodules has often led to misdiagnosis and excision. These structures, however, are normal for the oral mucosa and, unless they become large, symptomatic, or exude purulent discharge, do not require excision.

Fig. 2. Oral tonsil nodules of the soft palate. Note variation in size. The palatine tonsils are clearly distinguishable from the oral tonsils. Fig. 8. Random distribution of oral tonsils on soft palate. Fig. 3. Oral tonsil nodules on ventral surface of tongue. Fig. 4. Minor salivary gland ducts and plica fimbriata which may be confused with oral tonsil nodules. Fig. 5. Oral tonsil nodule on right and left floor of mouth. Fig. 6. Oral tonsils occur in random distribution over floor of mouth.

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Oral

29 1

Pig. 7. Oral tonsil

from

soft

palate.

Fig. 8. Oral tonsil into bottom of crypt.

from

ventral

Crypt

surface

linin g is continuous

of tongue.

Note

with

tonsils

epitlielial

duct, of salivary

159

surfarcs.

gland

opening

Since the presence of oral tonsils is not well known, it is possible that some of the lesions described in the literature as lymphoepithelial cysts or branchial cysts of the oral cavity,1-5 in reality, represent oral tonsils. The dentist and the physician, therefore, must recognize the existence of these structures and avoid their surgical removal. SUMMARY This report deals with the routine oral examination of 503 randomly male patients. In 21 per cent of these patients, small, circumscribed,

selected nodular

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Surg. 1970

Fig. 9. Oral tonsil from floor of mouth. Note epithelial connection between surface and crypt. This is not a midplane section; therefore, crypt opening onto surface epithelium is not demonstrated.

Fig. 10. Crypt appears M epithelium-lined cleft. Serial strate continuity of surface epithelium and crypt lining.

sections were necessary

to demon-

structures, 1 to 3 mm. in diameter, were observed on the mucosa of the soft palate ; 5 per cent of the patients had similar structures on the ventral surface of the tongue; and 12 per cent had them on the floor of the mouth. These structures, which histologically resemble the tonsils of Waldeyer’s ring, should be called oral tomiZs. They ranged in number from one to twenty-five and were randomly located on the soft palate. Similar structures occurred on the ventral surface of the tongue ranging in number from one to six, and on the floor of

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the mouth, where they ranged in number from one to sixteen. They were asymptomatic, and in six cases biopsies revealed a central crypt, continuous with t.he surface epithelium, which was lined with stratified squamous epithelium around which a circumscribed mass of nodular and d%use lymphoid tissue could bl) seen. It has been suggested that the oral tonsils are normal in the oral mucosa and, unless they become large, infected, or symptomatic, require no excision. Oral tonsils on the ventral surface of the tongue should be distinguished from salivary gland duct orifices. It is possible that some of the lymphoepithelial lesions described in the literature in reality represent normal oral tonsils. REFERENCES

1. Gold,

C.:

Branchial

Cleft

Cyst

Located

MED. & ORAL PATH. 15: 11X%1120,.1962.

in the Floor

of the Mouth,

ORAL STJRG.,ORAL

H. I.: Sublingual Branchlogenic Cyst; Report of a Case, ORAL SURG.,ORAL MED. & ORAL PATH. 16: 333-338, 1963. 3. Vickers, R. A., Gorlin, R. J., and Smart, E. A.: Lymphoepithelial Lesions of the Oral Cavity; Report of Four Cases, ORAL SURG.,ORAL MED. & ORAL PATH. 16: 1214-1221, 1963.

2. Calman,

4. Bhaskar,

S. N.:

Lymphoepithelial

Cysts of the Oral Cavity;

Report

of Twenty-Four

Cases:

ORAL SURG.,ORAL MED. &ORAL PATH. 21: 120-128,1966. 5. Young,

W. G., and Claman,

8. M.:

A Lymphoepithelial

SURCL,ORAL MED.& ORAL PATH.~~: 62.70,1967.

Cyst

of the Oral

Cavity,

ORAI.