Median Rhomboid Glossitis

§ overviewOverview

A localised area of atrophic filiform papillae on the midline posterior dorsum of the tongue, chronically associated with Candida infection rather than the previously proposed developmental origin.

§ icdICD Classification

ICD-10 K14.2

§ etiologyEtiology

• 01Chronic Candida albicans infection (currently accepted view)
• 02Historically considered developmental — persistence of the tuberculum impar — now largely rejected

§ riskRisk Factors

• 01Smoking
• 02Denture wear
• 03Diabetes mellitus
• 04HIV infection
• 05Inhaled/topical corticosteroids
• 06Immunosuppression

§ geneticsGenetics & Molecular Biology

• 01No specific genetic association

§ epidemiologyEpidemiology

Prevalence < 1%; M > F; adults; increases in smokers, diabetics and HIV patients.

§ pathogenesisPathogenesis

Chronic candidal colonisation induces atrophy of filiform papillae in a warm, moist midline zone of the posterior tongue, producing a well-demarcated rhomboidal red patch. Occasionally an opposing red 'kissing lesion' develops on the palate.

§ clinicalClinical Features

• 01Well-demarcated, oval or rhomboidal red or pink patch
• 02Located in the midline of the posterior dorsum of the tongue, immediately anterior to the circumvallate papillae
• 03Smooth or slightly nodular / lobulated surface
• 04Usually asymptomatic; occasionally burning or altered taste
• 05Kissing lesion on palate in HIV / immunocompromised

§ signsSigns & Symptoms

• 01Usually asymptomatic; incidental finding
• 02Occasional burning or foreign body sensation

§ differentialDifferential Diagnosis

• 01Geographic tongue (migrating)
• 02Erythematous candidiasis (diffuse)
• 03Erythroplakia (biopsy)
• 04Granular cell tumour of tongue (submucosal mass)
• 05Lymphangioma
• 06Median rhomboid tongue variant (developmental — now rare diagnosis)

§ criteriaDiagnostic Criteria

• 01Clinical: midline posterior dorsum tongue red patch. Confirmed by response to antifungal therapy or Candida on KOH/culture.

§ histopathHistopathology

• 01Atrophy of filiform papillae with parakeratosis
• 02PAS-positive hyphae in parakeratin layer (in most cases)
• 03Elongated rete ridges (pseudo-epitheliomatous hyperplasia) — may mimic well-differentiated SCC — beware in shallow biopsies
• 04Chronic inflammatory infiltrate with lymphocytes, plasma cells

§ investigationsInvestigations

• 01Clinical + KOH mount / culture for Candida
• 02HbA1c, HIV screen in extensive / non-responding cases
• 03Biopsy if clinical suspicion of neoplasm — but interpret cautiously due to pseudo-epitheliomatous hyperplasia

§ ihcIHC / Special Stains

• 01Not required routinely

§ classificationClassification

• 01Flat (atrophic) MRG
• 02Nodular / hyperplastic MRG
• 03MRG with palatal kissing lesion (multifocal chronic erythematous candidiasis)

§ planTreatment Planning

• 01Identify predisposing factors (smoking, diabetes, HIV, denture)
• 02Antifungal therapy first line; monitor response

§ treatmentTreatment

• 01Systemic fluconazole 100–200 mg once daily × 14 days (extensive/nodular)
• 02Topical nystatin or miconazole gel for milder cases
• 03Smoking cessation
• 04Address underlying immunosuppression / diabetes
• 05Surgical excision reserved for persistent nodular lesion or when malignancy cannot be excluded

§ medicalMedical Management

• 01Fluconazole, nystatin, miconazole

§ surgicalSurgical Management

• 01Excision of persistent nodular lesion after failed medical therapy — mainly to exclude neoplasm

§ complicationsComplications

• 01Persistent lesion
• 02Rare pseudo-epitheliomatous hyperplasia mistaken for SCC

§ recurrenceRecurrence Rate

Common if predisposing factors not addressed.

§ followupFollow-up Protocol

• 01Review at 4 weeks after antifungal course; re-biopsy if persists

§ prognosisPrognosis

Excellent — benign; not premalignant.

§ preventionPrevention

• 01Smoking cessation
• 02Glycaemic and immune control

§ examKey Examination Points

• 01Midline location anterior to circumvallate papillae
• 02Well-demarcated rhomboidal shape
• 03Palatal kissing lesion?

§ revisionQuick Revision Summary

• 01Midline posterior dorsum tongue
• 02Rhomboidal red patch
• 03Candida-associated
• 04Fluconazole responds
• 05Beware pseudo-epitheliomatous hyperplasia

§ vivaBDS Viva Questions

• 01Define MRG and give its site.
• 02Current understanding of aetiology?
• 03Why was it previously thought developmental?
• 04What is a kissing lesion?
• 05Histopathological pitfalls?
• 06Treatment of choice.

§ bdsBDS Professional Examination

• 01Short note: Median rhomboid glossitis.

§ fcpsFCPS Residency Questions

• 01Discuss the histopathological differential of a midline dorsal tongue lesion, including pseudo-epitheliomatous hyperplasia mimicking SCC.

§ pearlsClinical Pearls

• 01Any midline red patch of the tongue in a smoker / diabetic — think MRG.
• 02Palatal kissing lesion — screen for HIV.
• 03Do not diagnose SCC from a superficial biopsy of MRG — beware pseudo-epitheliomatous hyperplasia.

§ mnemonicsMnemonics

• 01MRG = Midline Rhomboid, Grows on Candida

§ readingSuggested Reading

• 01Wright BA. Median rhomboid glossitis — not a misnomer. OOOOE 1978.
• 02Nelson BL, Thompson LDR. Median rhomboid glossitis. Ear Nose Throat J 2007.

§ differentialDifferential Comparison

§ mcqsMCQs — Assessment (5)

§ relatedRelated Diseases

References

1. Neville BW. Oral & Maxillofacial Pathology, 4e
2. Regezi JA. Oral Pathology, 7e