MRG is a common condition and it has been estimated that up 1% of the population show some degree of central papillary atrophy [1]. Men are affected about three times as often as women.

MRG appears as a well-demarcated, roughly rhomboid, erythematous and thus bright red lesion directly anterior to the vallate papillae [2]. Commonly, it seems patchy as the rhomboid area still includes papilla-carrying spots that bear an off-white color. Its surface is smooth or lobulated, and rarely bears erosions [1]. It may be slightly elevated above the surrounding tongue surface. While an MRG lesion is most commonly located in the midline of the dorsum of the tongue, paramedian occurrences have also been described [3]. Usually, patients don't claim any other symptoms. In few cases only, they describe pruritus or pain in the affected area.

There may be a similar lesion in the opposing area of the palate. Such an anomaly is sometimes referred to as "kissing lesion". It may imply an infectious pathogenesis of MRG in an immunodeficient patient. Accordingly, diagnostic measures should be taken to assess their immune system. Diabetes mellitus should be considered in this context, but this variant of MRG is more commonly associated with an HIV infection and an acquired immunodeficiency syndrome [4].

• Chronic Infection

  Median rhomboid glossitis median rhomboid glossitis A usually midline rugosity on the tongue, which is more common in men age 30 to 50 and caused by chronic infection, especially by Candida albicans, but also by actinomycosis. [medical-dictionary.thefreedictionary.com]

  Clinical features of oral candida infection Candida may arise suddenly as an acute infection or persist for long periods as a chronic infection. Classification of oral candida infection Acute pseudomembranous candidiasis. [dermnetnz.org]

  Sometimes Candida lesions disappear spontaneously or with minimal therapy. 1,3, 6,10 The clinical presentation of oral candidiasis includes both acute and chronic infections. [dentistrytoday.com]

• Pathologist

  All clinicians and scientists interested in birth defects, including pediatricians, geneticists, genetic counselors, obstetricians, and pediatric pathologists, will find this book to be an invaluable source of information. [books.google.com]

• Rigor

  By condensing much of the information presented in the first volume of the previous edition, and exercising rigorous editorial control, Drs. [books.google.com]

• Dysphagia

  She reported no tongue pain, dysphagia, dysarthria, or bleeding. There was no evidence of candidiasis on the tongue or adjacent structures. [nejm.org]

  Referral Admit to hospital if there are systemic symptoms, the patient is unwell or if there are oesophageal symptoms (dysphagia or retrosternal pain) - particularly if there is immunocompromise. [patient.info]

  Disorders Other associated disorders such as pernicious anaemia, erythema multiform, pemphigus vulgaris, oral lichen planus, aphthous ulcers, Plummer-Vinson syndrome, dysphagia, psoriasis may also lead to glossitis. [primehealthchannel.com]

• Lesion of the Tongue

  Median rhomboid glossitis is an inflammatory lesion of the tongue, now believed to be secondary to candidiasis. We document a case of median rhomboid glossitis with heavy colonisation by Actinomyces in a 60-year-old male. [ncbi.nlm.nih.gov]

  Median rhomboid glossitis is a condition characterized by an area of redness and loss of lingual papillae on the central dorsum of the tongue, sometimes including lesions of the tongue and palate. [en.wikipedia.org]

  The main sign of median rhomboid glossitis is a lesion on your tongue. This lesion is erythematous (red) and is located either in the middle of your tongue or at the back of your tongue. [aupairargentina.com]

  J Postgrad Med 1991 Oct;37(4):238-40 Abstract quote Median rhomboid glossitis is an inflammatory lesion of the tongue, now believed to be secondary to candidiasis. [thedoctorsdoctor.com]

• Pruritus

  Most of these lesions are asymptomatic, although some patients may complain of persistent pain, irritation, or pruritus. Despite the relative frequency of MRG, little is known about its etiology. [link.springer.com]

  In few cases only, they describe pruritus or pain in the affected area. There may be a similar lesion in the opposing area of the palate. Such an anomaly is sometimes referred to as "kissing lesion". [symptoma.com]

  Generalised cutaneous candidiasis (rare): a widespread rash, worse in skin folds and extremities, with pruritus. Skin lesions in patients with invasive candidiasis - see 'Invasive candidal infections', below. [patient.info]

• Pachyonychia

  The patient's clinical presentation and history were compatible with a diagnosis of pachyonychia congenita, a rare heritable disease that affects the nails, skin, oral and laryngeal mucosae, teeth, and hair. [ncbi.nlm.nih.gov]

  […] median rhomboid glossitis. ( 19601454 ) Fowler J.C....White P. 2009 9 Partial atrophic tongue other than median rhomboid glossitis. ( 17441970 ) Terai H....Shimahara M. 2007 10 Median rhomboid glossitis. ( 17990677 ) Nelson B.L....Thompson L. 2007 11 Pachyonychia [malacards.org]

• Hyperhidrosis

  The patient's mother had similar nail changes, which had been present since infancy as well as a focal plantar keratoderma and hyperhidrosis. [ncbi.nlm.nih.gov]

MRG is usually diagnosed clinically. However, it may not always be feasible to distinguish an uncomplicated MRG from aphthous stomatitis, granuloma, precancerous erythroplakia or neoplasms like hemangioma, squamous cell carcinoma or granular cell tumor [3]. In order to do so, a biopsy and subsequent analysis of the tissue sample is required. During a microscopic examination, the absence of papillae can be confirmed. Also, epithelial anomalies ranging from atrophic to hyperplastic changes are most commonly revealed [5]. Atypical nuclei and numerous mitotic figures are not characteristic of MRG and may indicate a neoplasm, though. In underlying layers of tissue, infiltrating inflammatory cells may be visible. Immunohistochemical stains may be applied to further evaluate the cells' characteristics if deemed necessary.

Additionally, characteristic spores and yeast buds forming pseudohyphae can be recognized microscopically and reveal the presence of Candida spp. If doubts remain as to the presence of yeasts, samples can be subjected to fungal stains. Fungal cultures are rarely required, but may provide interesting epidemiological data. In general, MRG has been associated with chronic Candida infections: A recent microbiological study found Candida albicans to account for the majority of cases, while Candida kefyr, tropicalis, krusei and glabrata have also been isolated [2]. However, one out of ten MRG patients tested negative for Candida spp. Non-Candida pathogens have occasionally been implicated in the development of MRG and may serve as an explanation in this regards [6].

As has been implied in the previous paragraph, if a kissing lesion is present or additional symptoms hint at a dysfunction of the immune system, this suspicion should be followed up.

• Foam Cell

  الصفحة 48 - Reactive oxygen species produced by macrophage-derived foam cells regulate the activity of vascular matrix metalloproteinases in vitro. Implications for atherosclerotic plaque stability. J Clin Invest 1996; 98:2572-2579. ‏ [books.google.com]

1. Joseph BK, Savage NW. Tongue pathology. Clin Dermatol. 2000; 18(5):613-618.
2. Goregen M, Miloglu O, Buyukkurt MC, Caglayan F, Aktas AE. Median rhomboid glossitis: a clinical and microbiological study. Eur J Dent. 2011; 5(4):367-372.
3. Lago-Mendez L, Blanco-Carrion A, Diniz-Freitas M, Gandara-Vila P, Garcia-Garcia A, Gandara-Rey JM. Rhomboid glossitis in atypical location: case report and differential diagnosis. Med Oral Patol Oral Cir Bucal. 2005; 10(2):123-127.
4. Fine DH, Tofsky N, Nelson EM, Schoen D, Barasch A. Clinical implications of the oral manifestations of HIV infection in children. Dent Clin North Am. 2003; 47(1):159-174, xi-xii.
5. Fowler JC, White P. A classic case of median rhomboid glossitis. Jaapa. 2009; 22(6):70.
6. Deshpande RB, Bharucha MA. Median rhomboid glossitis: secondary to colonisation of the tongue by Actinomyces (a case report). J Postgrad Med. 1991; 37(4):238-240.