| Abstract|| |
Nevus of Ota, a benign melanocytic pigmentary disorder with rare malignant transformation potential, affects 0.014-0.034% of the Asian and Black population and has a strong predilection for females. It occurs in the area innervated by the first and second division of the trigeminal nerve. Oral manifestation is rarely noted with only 14 cases reported till date. This report documents a case of Nevus of Ota with the infrequently noted oral involvement, in an Indian lady. Since oral manifestation is not acknowledged in Tanino's classification, the authors propose a modification to the same.
Keywords: Congenital, Nevus of Ota, oral, palate, unilateral
|How to cite this article:|
Guledgud MV, Patil K, Srivathsa SH, Malleshi SN. Report of rare palatal expression of Nevus of Ota with amendment of Tanino's classification. Indian J Dent Res 2011;22:850-2
Oculodermal melanocytosis/nevus fuscoceruleus ophthalmomaxillaris/Nevus of Ota is a frequently benign, congenital and unilateral melanocytic pigmentary disorder, generally involving the area innervated by the first and second divisions of the trigeminal nerve. , In 1916, Pusey described the case of a Chinese student with both sclera and facial pigmentation, but it was only in 1939 this melanocytic nevi was identified as a definitive entity by Japanese dermatologist M. T. Ota. ,,
|How to cite this URL:|
Guledgud MV, Patil K, Srivathsa SH, Malleshi SN. Report of rare palatal expression of Nevus of Ota with amendment of Tanino's classification. Indian J Dent Res [serial online] 2011 [cited 2014 Jul 30];22:850-2. Available from: http://www.ijdr.in/text.asp?2011/22/6/850/94684
Nevus of Ota affects mostly the Asians and the Blacks. On the contrary, in Japan, the incidence is about 1 to 2 per 1000 of the general population. ,, Extracutaneous association, especially ocular involvement of this entity, has been reported.  However, oral involvement is rarely noted.
| Case Report|| |
A 36-year-old Indian lady presented to the Oral Diagnostic Clinic for evaluation of her oral health status. Incidentally, she also presented with asymptomatic hyperpigmented macular bluish-black extensive lesion involving the right side of the scalp, forehead, temple, zygomatic arch, periorbital area, sclera, lower palpebra, and radix of the nose with interspersed pinpoint lentigo-like spots [Figure 1], [Figure 2] and [Figure 3]. On intraoral evaluation, a similar well-defined lesion with uniform bluish-black appearance measuring approximately 1.5 × 2 cm on the right side of the posterior part of the hard palate bordering the midline was observed [Figure 4]. These pigmentations were congenital in origin, with no history of any deleterious habits or positive family history for similar lesions.
|Figure 2: Profile view showing facial pigmentation on right side of face|
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Tympanic membrane involvement was not noted and ophthalmic investigation did not reveal any evidence of cataract or glaucoma. The clinical status did not suggest any underlying systemic disorder.
A diagnosis of Nevus of Ota was established as evidenced by the clinical findings. The need for regular follow-up has been impressed upon the patient owing to the lesions' malignant transformation potential.
| Discussion|| |
Nevus of Ota, or nevus fuscoceruleus ophthalmomaxillaris, is a dermal melanocytic hamartoma that demonstrates bluish hyperpigmentation along the ophthalmic and maxillary divisions of the trigeminal nerve.  It can be either congenital or acquired during adolescence. , Most patients have no positive family history. 
It has been hypothesized that the nevoid cells originate from Schwann cells or other neural elements, and that abnormalities of neural crest migration lead to these congenital dermal melanoses.  Due to female preponderance, female sex hormones have been suggested as potent stimuli. Other implicated stimuli include infection, trauma, or ultraviolet light exposure. 
Nevus of Ota mostly appears as an unilateral, macular, rarely papular or nodular, patchy brown, slate-blue or blue-black pigmentation, with deeper lesions appearing blue due to Tyndall effect. ,, Intermingling of lentigo-like spots also may be noted. About 11% lesions are bilateral. The eyelids, sclera, bulbar and palpebral conjunctiva, cornea, iris, retina, optic nerve, extraocular muscles, retrobulbar fat, the cheeks, forehead, scalp, the pharynx, the nasal mucosa, the tympanic membrane, and leptomeninges may be involved. , Oral mucosal association, though common in Japanese, is extremely rare in non-orientals. Any area of the oral cavity can be affected but the palatal mucosa prevails. The oral lesion is depicted as irregularly shaped, macular and bluish area.  Review of literature yielded evidence of only 14 cases of Nevus of Ota involving the oral mucosa, of which majority of them were noted on the hard palate. ,
Based on the extent of the involvement, Tanino's classified Nevus of Ota as follows: ,,
Type I: IA - Mild orbital type: Upper and lower eyelids, periorbital, and temple region, IB - Mild zygomatic type: Infrapalpebral fold, nasolabial fold, and the zygomatic region, IC - Mild forehead type: Forehead alone, ID - Ala nasi alone.
Type II: Moderate type: Over the upper and lower eyelids, periocular, zygomatic, cheek, and temple regions.
Type III: The lesion involves the scalp, forehead, eyebrow, and nose.
Type IV: Bilateral type.
Oral lesions, which are rare yet significant are not represented in the above classification, which prompted the authors to propose a modification to the above classification and include oral mucosa manifestation as subclass IE. Diseases associated with Ota's nevus in rare cases are open-angle glaucoma, uveitis, cataract, and melanoma. ,
Elongated dendritic melanocytes scattered widely in the papillary to mid reticular dermis are observed histologically, which stain weakly with 3,4-dihydroxyphenylalanine, connotes that they retain the ability to generate melanin. ,, Intriguing observation is that the melanosomes in cells cultured from Ota's nevus are in part abnormal, almost emulating those found in dysplastic nevi and melanoma. 
Although diagnosis of Nevus of Ota can be made solely based on its striking clinical characteristics, other entities that need to be particularly considered are Nevus of Ito, Mongolian spots, blue nevus, and Acquired Bilateral Nevus of Ota like Macules (ABNOM), owing to their clinical resemblance. ,,
Nevus of Ito has features similar to that of Ota's nevus, except that it occurs along the distribution of the posterior supraclavicular and lateral cutaneous branchial nerves, involving the shoulder, neck, supraclavicular area, and upper arm. , The Mongolian spot is congenital and involves the lumbosacral area and frequently regresses at about the age of 5 to 7 years. , The diagnosis of above entities is essentially clinical owing to their similar histopathological features, thus eliminating the need for diagnostic biopsy. , The blue nevus is usually papular and found on skin, with rare palatal mucosal involvement, in which the dermal melanocytes in the plaque-type variant being deeper and dense than in the Nevus of Ota. , ABNOM is clinically distinguished by speckled or coalescent brownish-blue or slate-gray pigmentation over the face with no oral mucosa and eye involvement and histologically by diffuse upper dermal melanocytosis. ,
Laser is the therapy of choice, though dermabrasion, dermabrasion with autologous cultured epithelium grafting, and combination of sequential dry ice, and epidermal peeling has been attempted. , Spontaneous regression has not been reported. ,
| Conclusion|| |
Nevus of Ota with oral involvement is seldom noted. To give the rare oral manifestation of this entity its due recognition, the authors propose a modification to Tanino's classification. Recognition and constant vigilance serve as the cornerstones in management of this not so common entity.
| References|| |
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Mahima V Guledgud
Department of Oral Medicine and Radiology, JSS Dental College and Hospital, JSS University, Mysore
[Figure 1], [Figure 2], [Figure 3], [Figure 4]