Nevus of Ota: Presentation of a Case with Oral Pigmentation and Codicil to Tanino’s Classification

Nevus of Ota is a rare pigmented disorder affecting the skin along the distribution of trigeminal nerve. Oral involvement of this pigmented lesion is very rare. Classification of Nevus of Ota given by Tanino represents the skin manifestations well but does not include the extra cutaneous manifestations. Hence an addition to this classification is being proposed through this case report which describes the 17th case of palatal involvement in a male patient in a female dominant Nevus of Ota. Introduction Congenital or acquired melanocytoses are benign pigmented lesions of the skin or mucosa. Nevus of Ota also known as nevus fuscocaeruleus ophthalmomaxillaris is a congenital dermal melanocytosis first described by Ota in 1939 as a melanocytic hamartoma. It clinically presents as bluish hyperpigmentation along the branches of the trigeminal nerve. Case Report A 22-year old male patient visited for a routine dental check up. His medical, surgical, drug and personal histories were non contributory. Examination of the facial skin revealed a brownish grey pigmentation of the left eyebrow region of 1-1.2 cm size and associated slate-grey pigmentation of the left conjunctiva (Figure 1). Examination of the ipsilateral and contralateral side of face revealed no additional pigmentation. On oral examination, the hard palate on the left side showed irregular greyish macule on Correspondence Dr Srikanth H Srivathsa, MDS Reader Department of Oral Medicine and Radiology, Annoor Dental College and Hospital, Perumattom, Muvattupuzha 686673 Ernakulum Dist, Kerala Email: [email protected] the left side with a few surrounding scattered similar coloured macules (Figure 2). The rest of the oral mucosa appeared normal. Upon eliciting the history of the pigmentation, patient was unaware of the oral lesions but the eye pigmentation was present since birth. Evaluation by an ophthalmologist and otolaryngologist did not reveal any pigmentation in the nasal or aural mucosa and no eye complications were present. Based on the history and clinical appearance a diagnosis of Nevus of Ota was arrived at. An attempt to classify was futile as an effective classification is unavailable and hence a codicil is being proposed to the existing Tanino’s classification. Discussion Although Hulke in 1861 first described oculodermal melanosis, in 1939 Ota M coined the explanatory name for this condition as nevus fuscocaeruleus ophthalmomaxillaris. Subsequently the condition is known as nevus of Ota. The exact etiology of this disorder is yet to be determined. But it is suggested that amelonocytic nevoid cells present at birth become pigmented in the teenage life or later due to many triggering factors such as ultraviolet light exposure, female hormones, infection or trauma. Another suggestion is that it may be due to non migration of melanocytes from the neural crest to the epidermis during the embryonic stage. Other theories postulated is an active production by intradermal melanocytes. Although most patients have a negative family history, rarely familial cases have been described, representing heredity as a possible aetiology. The original classification by Tanino in 1939 has remained the most useful clinical classification, although mucosal pigmentations or extra cutaneous manifestations are not included. Tanino’s classification is summarized in table 1. Malaysian Journal of Dermatology 23 MJD 2013 Dec Vol 31 Type