CASE
A 53-year-old white male came to our ear, nose, and throat office with a 2- month history of a localized, partially flattened, erythematous lesion on the dorsum of his tongue (see Figure 1). Topical triamcinolone in dental paste (Kenalog in Orabase) prescribed by his primary care physician had not been beneficial. The patient denied any associated pain, dysphagia, odynophagia, other lesions in his mouth, or changes in his voice. His medical history was significant only for mild hypertension; family history was noncontributory. The patient denied any alcohol or tobacco abuse.
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DISCUSSION
This is a classic case of median rhomboid glossitis (MRG), also known as central papillary atrophy. MRG is a fairly common entity that occurs in up to 1% of adults, with more men affected than women in a ratio of 3 to 1. MRG is remarkable in that it is confined to the midline dorsal aspect of the tongue. The origin of MRG was once attributed to residual elements of the fetal tuberculum impar that were subsequently susceptible to fungal infection. While the embryonic origin is still mentioned by many sources, most authors feel that infection with Candida albicans is the sole etiology. Candida, which is found in up to 50% of the population, is the most common oral cavity fungal organism. While oral candidiasis, or thrush, is often associated with infants and immunocompromised patients, most infected adults may be asymptomatic and have no predisposing factors, as was the case in our patient.
MRG typically manifests as a welldefined area of erythema on the midline dorsal tongue directly anterior to the circumvallate papillae. Figure 1 demonstrates the classic MRG location, as well as the typical sessile appearance consistent with denuded papillae; note the focal areas of residual papillae. While MRG can take on a multitude of shapes, the classic rhomboid appearance is most common.
Biopsy typically reveals absence of papillae with epithelium that can range from atrophic to hyperplastic. The underlying stroma usually contains an inflammatory infiltrate. Fungal stains, such as Gomori's methenamine silver, may be used to demonstrate Candida, but they are often unnecessary, as the organisms can frequently be seen with hematoxylin and eosin stain.
The differential diagnosis of oral lesions in general and tongue lesions specifically can be extensive and challenging. The midline presentation and often asymptomatic nature of MRG helps to narrow the differential.
Aphthous ulcer is unlikely in this situation, given the appearance and location of the lesion. Most aphthous ulcers manifest as painful sores, typically less than 1 cm in diameter, and usually have an overlying fibrinous exudate. Aphthous ulcers are also rarely found on the dorsum of the tongue and would be more likely on the labial/buccal mucosa, floor of the mouth, and gingiva. Aphthous ulcers occur in about 20% of the population.
Erythroplakia is a clinical term used to describe well-circumscribed, erythematous plaques or lesions that cannot be rubbed off. Upward of 90% of all cases of erythroplakia will harbor some degree of atypia, carcinoma in situ, or squamous cell carcinoma. The floor of the mouth, ventral tongue, and mandibular gingiva are the most common sites. In this case, the poorly circumscribed appearance, combined with location, would argue against a diagnosis of erythroplakia.
Oral squamous cell carcinoma would be highly unlikely in this patient, given his lack of symptoms, appearance of the lesion, and absence of risk factors.
Treatment The typical treatment for MRG is the same as for thrush or other manifestations of oral candidiasis. Topical antifungals, such as nystatin (Mycostatin, generics) or clotrimazole (Mycelex, generics), are the mainstays of treatment. In asymptomatic MRG, an argument can be made for observation. This is particularly true given the fact that a large portion of the general population harbors oral Candida. Patients who present with such symptoms as tongue pain, otalgia, or dysphagia warrant further investigation with excisional biopsy to rule out an occult malignancy or more invasive process.
Given the asymptomatic nature of our patient's lesion and the classic appearance, a biopsy was not performed. The patient was placed on 10-mg clotrimazole troches 5 times a day for 10 days. We reassured him that his lesion represented a benign process and instructed him to follow up if the lesion failed to resolve or if he experienced any severe pain or discomfort. JAAPA
Jason Fowler practices in otolaryngology with Peter White in Meadville, Pennsylvania. They have indicated no relationships to disclose relating to the content of this article.
Erich Fogg, PA-C, MMSc, department editor