a 45-year - old male , who had a history of diabetes , presented to our department with the complaint of swelling of left eye ( le ) . he had noticed a gradual increase in the swelling for the last 6 - 8 months . on examination , le revealed loss of perception of light , edema of lids , and bluish black pigmentation in the periorbital region and conjunctiva [ fig . an irregular mass could be felt through the upper lid , which was fixed to deeper structures . scar of orbitotomy was seen on the left side . on retraction of the lids , approximately 13 years back , he had noticed protrusion of le and was diagnosed elsewhere as orbital malignant melanoma . it was managed with lateral orbitotomy for excision biopsy followed by external beam radiotherapy . later , cosmetic correction with scleral shell prosthesis was given elsewhere , over the phthisical le . four years back , in 2005 , he attended the oncology department of amala institute of medical sciences , for check up . computerized tomography ( ct ) scan and magnetic resonance imaging ( mri ) of left orbit showed orbital lesion and he was given cobalt-60 teletherapy . ( a ) proptosis with artificial eye ( january 2009 ) and cutaneous pigmentation ; ( b ) tumor mass pushing the eyeball upward [ arrows ( 1 ) part of cornea , and ( 2 ) tumor mass covered by conjunctiva ] ; and ( c ) posttreatment ( february 2011 ) of le with prosthesis in late 2008 , he was referred to us with recurrence of left orbit swelling which gradually increased in size . repeat ct showed recurrent malignant melanoma in left orbit with extension into the optic canal and lateral wall of orbit [ fig . 2 ] . the orbit was filled by the pigmented tumor with infiltration into the orbital tissues and periorbita . histopathology showed a mass of brownish soft tissue measuring 3.5  3  1.5 cm behind the eyeball . microscopic examination showed cellular neoplasm arranged in a fascicular pattern composed of spindle cells having prominent nuclei and eosinophilic cytoplasm [ fig . 3 ] . there was infiltration into the optic nerve , orbital muscles , and retrobulbar fibroadipose tissue . in view of the extensive spread of the tumor locally , after 1 year of follow - up , the patient did not have any recurrence or metastasis . ct scan showing mass lesion in left orbit [ arrows ( a ) retrobulbar extension of the tumor , ( b ) phthisis bulbi , and ( c ) tumor mass ] histopathology of left orbital tissue showing malignant melanoma ( stained by h and e ) . however , in 1939 , ota from the university of tokyo coined the name nevus fuscoceruleus ophthalmo - maxillaris and melanosis bulbi . since then , the condition is known as nevus of ota . it occurs commonly in asians ( 0.0140.034% prevalence ) but rarely in caucasians , with female preponderance . variable prevalence among different population groups indicates genetic influences . two peak ages of onset , in early infancy ( 50% ) and in early adolescence , suggested hormonal influence . even though nevus of ota is common in the orientals , malignant transformation is extremely rare . it is still rarer to come across a malignant melanoma which is presenting as a nonchoroidal intraorbital mass . it has been suggested that nevoid cells originate from schwann cells or other neural elements . the exact embryologic events that produce such abnormalities are unknown , but changes in the local embryonic environment could be important . changes in glycosaminoglycans , which fill the cell free space in early embryologic development , may play an important role in the neural crest migration , leading to dermal melanosis . exact pathophysiology is not yet known . however , suggested theories include failure of dermal melanocytes to disappear during fetal life , arrested migration of melanocytes in the dermis , and active melanin production by intradermal melanocytes . choroidal melanomas occur in less than 4% and glaucoma in less than 10% of cases . primary orbital melanoma has tendency to spread along nerves through the superior and inferior orbital fissures , producing melanocytosis of the contiguous bone and meninges that result in poor prognosis . in this case , there was local spread of the tumor in le , involving the bone , orbital tissues , and optic nerve resulting in visual loss . specific malignant conversion rates have not been recorded , but follow - up is particularly essential in caucasian patients , where complications are frequent . any suspicious clinical change of malignant transformation warrants biopsy . regardless of the race , greater chances are there to develop malignant melanoma within one of the affected tissues in patients with the nevus of ota . ( 2000 ) have reported a better prognosis in a case with short history and early treatment . in this case , the patient had a long drawn out course with intervals of nonsurveillance , which increased the chances for the local spread of the tumor . if circumscribed , local excision of the tumor may be done by orbitotomy with preservation of the eye . ideally , the lesion should be removed as a whole with adequate clearance . in this patient , the prognosis would have been better if the lesion was excised as a whole , in the early stage . if the excised margins are not free from neoplasm , appropriate radiotherapy or chemotherapy may have to be instituted . frequent follow - up and proper education of the patient regarding the condition also should be done . with prolonged history , existing lesion can undergo occult malignant changes , as evidenced in this case . to conclude , this was a rare case with malignant transformation in oculodermal melanosis , which warrants close follow - up and patient education .
nevus of ota ( oculodermal melanosis ) is a dermal melanocytic hamartoma with bluish hyperpigmentation along the first and second branches of the trigeminal nerve . 
 extracutaneous involvement , especially ocular , has been reported . a 45-year - old male presented with malignant melanoma of the left orbit in association with nevus of ota . 
 being locally invasive , a modified exenteration with frontal flap repair was done on left eye . 
 adjuvant chemotherapy was given after wound healing . 
 all pigmented lesions of the eye require close monitoring to help in the early diagnosis . 
 since malignant transformation has been reported in oculodermal melanosis , close follow - up and patient education will facilitate early diagnosis and prompt management . 
 this case is reported for its rarity and unusual presentation .