Heterocromia de íris: uma revisão das condições que podem afetar a pigmentação iridiana / Heterochromia: a review of conditions that may affect iris pigmentation

RESUMO A íris é responsável pela cor dos olhos. Ela ainda realiza o controle da quantidade de luz que penetra no olho pela pupila. Variações nos genes de cada indivíduo, além da quantidade e da qualidade de melanina na íris, determinam a cor dos olhos. A heterocromia é caracterizada por diferenças na coloração da íris de um mesmo indivíduo, sendo, na maioria das vezes, benigna. Existem basicamente três tipos de heterocromia de íris: central, setorial e completa. A heterocromia de íris pode ter como causa alterações genéticas e congênitas, relacionadas ou não a síndromes específicas, como a de Sturge-Weber, a de Waardenburg, a de Parry-Romberg e a de Horner congênita. Há também causas adquiridas, como doenças ou lesões, trauma ocular e corpos estranhos intraoculares, uso de certas medicações tópicas, siderose ocular, irites ou uveítes como a síndrome uveítica de Fuchs, dentre outras. Diante de um paciente com heterocromia de íris, deve-se entender o contexto e o curso clínico desse sinal, pois pode se tratar de uma alteração de pigmentação benigna ou existir uma doença base em curso, que requer terapêutica específica. Este artigo de revisão de literatura visa abordar as principais etiologias relacionadas à heterocromia de íris, além de discorrer sobre a anatomia e a fisiologia da coloração iridiana e sobre a fisiopatologia de suas possíveis alterações.

ABSTRACT The iris is responsible for eye color and controls the amount of light that enters the eye through the pupil. Variation in each individual's genes, besides the quantity and quality of melanin in the iris, determine eye color. Heterochromia is characterized by different colors of irises in the same individual, and it is benign in most cases. There are basically three types of heterochromia: central, partial and complete. Heterochromia can be caused by genetic and congenital alterations, which may or may not be related to specific conditions, such as Sturge-Weber syndrome, Waardenburg syndrome, Parry-Romberg syndrome and congenital Horner syndrome. It may be associated to acquired causes like diseases or injuries, such as eye trauma and intraocular foreign bodies, use of some topical medications, ocular siderosis, iritis or uveitis, such as Fuchs´ uveitis, among others. When assessing a patient with heterochromia, one must understand the context and clinical course of this signal, since it may be a benign pigmentation disorder or there may be an underlying disease, which requires specific therapy. This literature review article was set out to address the main etiologies related to heterochromia, in addition to describing the anatomy and physiology of the iris color and the pathophysiology of possible alterations.

Primary acquired melanosis (PAM) without atypia/WHO low-grade conjunctival melanocytic intraepithelial lesion over areas of oculodermal melanocytosis.

An elderly white man with a history of left oculodermal melanocytosis presented with new onset brown pigmentation of the left bulbar and inferior tarsal conjunctiva. The bulbar conjunctival pigmentation was at the level of the conjunctival epithelium and was overlying areas of typical slate-grey scleral pigmentation characteristic of oculodermal melanocytosis. Both areas of new pigmentation were biopsied. The bulbar conjunctiva revealed primary acquired melanosis (PAM) without atypia with increased melanin production and the tarsal conjunctival biopsy showed PAM without atypia sine pigmentio overlying areas of substantia propria spindle-shaped heavily pigmented melanocytes of oculodermal melanocytosis. The case report examines the relationship between the epithelial and substantia propria melanocytes and correlates the findings with what is known about this association from the dermatopathology literature.

Case report: nevus of Ota and nevus of Ito associated with meningeal melanocytosis. / Caso clínico: nevo de Ota y nevo de Ito asociados a melanocitosis meníngea.

BACKGROUND: Nevus of Ota and nevus of Ito are hyperpigmentary dermal melanocytoses which develop as a consequence of disturbances or failures during migration of melanocytes from the neural crest towards the epidermis; they have a relatively unknown aetiopathogenesis and may be congenital or acquired. CASE REPORT: This case involves a male patient with a simultaneous diagnosis of nevus of Ota and nevus of Ito at birth. He attended the Neurosurgery department at Carlos Andrade Marín hospital (Quito) with sudden severe headache associated with left brachio-crural hemiparesis. PROGRESS: Investigations revealed two extra-axial space-occupying lesions, one parasagittal at the right frontal and parietal lobes and the other located at the right temporal lobe pole. A surgical resection was planned for the parasagittal lesion and the histopathological diagnosis was meningeal melanocytosis. The temporal pole lesion was referred for treatment with Gamma Knife®. CONCLUSION: Primary melanocytic neoplasms are extremely rare. There is evidence of their association with dermal melanocytosis and, in particular, with nevus of Ota. This highly unusual case describes the coexistence of two very rare dermal melanocytoses (nevus of Ota and nevus of Ito) and a primary melanocytic neoplasms in the same patient.

Nevus of Ota, a classic presentation / Nevus de Ota de presentación clásica

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The color of skin: gray diseases of the skin, nails, and mucosa.

Gray diseases are a group of skin disorders characterized mainly by gray discoloration with or without involving the mucous membranes and nails. These diseases may be hereditary or acquired. Some of the better-known hereditary entities are dermal melanocytosis, incontinentia pigmenti, hypomelanosis of Ito, hemochromatosis, ochronosis, and silvery hair syndrome. Acquired diseases with gray coloring include late-stage organ failure, lichen planus pigmentosus, erythema dyschromicum perstans, and drug reactions. The discoloration is due to either increased epidermal and or dermal melanin or dermal deposition of a chromogen or a combination of both. Investigations are directed to determining the underlying medical condition and a skin biopsy is usually unnecessary. Likewise, treatment is directed mainly toward the underlying medical disease. Although bleaching (lightening) agents may diminish the discoloration, better results may be obtained from using a Q-switched laser and intense pulsed light, either alone or in combination with topical agents.

Nevus of Ota associated with a primary uveal melanoma and intracranial melanoma metastasis.

Nevus of Ota is a blue, hyperpigmented, benign dermatosis of the skin and mucosae that most often occurs unilaterally in the distribution of the ophthalmic (V1) and maxillary (V2) branches of the trigeminal nerve. Although uncommon, association with malignant melanoma is a complication that must be considered in the evaluation of patients with nevus of Ota. Mutations in the GNAQ and BAP1 genes in patients with nevus of Ota place them at higher risk for malignant melanoma and metastasis. We report the case of a 29-year-old woman with a long-standing history of nevus of Ota who presented acutely with an intracranial melanoma as an extension of a primary uveal melanoma.

Melanocitosis dérmica agminada en el territorio del nevus de Ota / Agminated Dermal Melanocytosis in the Territory of Ota's Nevus

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[Vitiligo occurring on dermal melanocytosis (nevus of Ota) in a dark-skinned patient]. / Vitiligo dévéloppé sur une mélanocytose dermique (nævus de Ota) chez une patiente à peau foncée.

BACKGROUND: Nevus of Ota is a rare disease most frequently found in Asians. It presents clinically as a bluish gray hyperpigmentation of one side of the face. Transformation into melanoma and glaucoma are the main risks. The appearance of vitiligo lesions with poliosis within a nevus of Ota is exceptional. PATIENTS AND METHODS: A 22-year-old female patient with a nevus of Ota consulted for depigmentation of the eyelashes. Physical examination revealed hyperpigmentation in the right orbitofrontal part of her face, achromic macules and eyelash poliosis. A diagnosis was made of vitiligo developing on a nevus of Ota. Ophthalmologic examination showed hyperpigmentation of the sclera. Regular dermatologic and ophthalmologic follow-up was instituted. DISCUSSION: Vitiligo is a condition characterized by the development of depigmented lesions secondary to chronic degradation of the melanocytes of the epidermis and the follicles. Its occurrence on congenital nevus and melanoma has already been reported. However, its appearance in dermal melanocytosis is very rare. Since the first observation of this association in 1979, only 4 other cases have been reported. The pathogenic mechanisms of this association are still poorly understood. Histopathological examination generally shows a loss of epidermal melanocytes, especially in the basal layer, while dermal melanocytes remain unaffected. In this context, vitiligo developed on dermal melanosis appears to result from the difference between the properties of normal (epidermal) melanocytes and ectopic (dermal) melanocytes. CONCLUSION: Association of vitiligo with nevus of Ota is rare. Herein, we report a new case in a dark-skinned subject.

Ocular Features in a Case of Nevus of Ota.

Oculodermal melanocytosis, also known as Nevus of Ota, is a hamartomatous melanocytic nevus of dermal melanocytes. It presents as a bluish grey patch on the face, which may be congenital or acquired involving the area of distribution of the ophthalmic and maxillary branches of the trigeminal nerve. The nevus can be unilateral or bilateral, and, in addition to skin, it may involve ocular and oral mucosal surfaces. It is a rare disorder and the ocular complications, such as glaucoma and melanoma, may be vision or life-threatening. Here, we report a 26-year male who presented with decreased vision in his left eye. On detailed examination, he turned out to be a case of nevus of Ota.

Phakomatosis Pigmentovascularis Associated With Sturge-Weber Syndrome, Ota Nevus, and Congenital Glaucoma.

Phakomatosis pigmentovascularis (PPV) is a rare congenital malformation syndrome that is characterized by a combination of capillary abnormalities and dermal melanocytosis.We describe 3 cases of PPV combined with bilateral Sturge-Weber syndrome (SWS), Ota nevus, and congenital glaucoma.Case 1 was a 2-year-old boy. Facial port-wine stains distributed along the 3 branches of his trigeminal nerves, which suggested the existence of SWS. Gray-blue patches were spread over the frontal and temporal areas of bilateral face, waist, buttocks, and thigh. Bilateral triangular alopecia was found on the temporal scalp. The diagnosis of Ota nevus was made by the bilateral scleral malanocystosis. Increased intraocular pressure, enlarged cornea, and pathologic optic disc cupping supported the diagnoses of infantile bilateral glaucoma. Case 2 was a 4-year-old boy. Port-wine stains were found on the face along the 3 branches of the trigeminal nerve and distributed along the trunk, arms, and legs. Mongolian spots spread over his frontal and temporal areas of the bilateral face, waist, buttocks, thigh, abdomen, and back. Infantile glaucoma was found in both eyes. Ota nevus were found in the both eyes. Optic coherent tomography (OCT) scans revealed increased thickness of choroid. Case 3 was a 5-year-old boy. Besides Ota nevus and infantile glaucoma in both eyes, color Doppler ultrasonography showed choroidal hemagioma. OCT scan showed increased choroidal thickness. The bilateral triangular alopecia on the child's temporal scalp was similar to that of Case 1. Cases 1 and 2 presented with port-wine stain patches that were consistent with the characteristic manifestation of PPV type IIb. However, the CMTC of Case 3 met the diagnostic criteria for PPV type Vb.Case 1 was treated with trabeculotomies in both eyes. For Cases 2 and 3, surgical interventions were not considered due to the high risks of antiglaucomatous operation complications. We prescribed them antiglaucoma indications.The simultaneously coexistence of PPV with SWS, Ota nevus, and congenital glaucoma is rare. In the clinic, additional detailed examinations and tests of PPV patients to exclude other ocular abnormalities or extraocular involvements are necessary.

Pruritic acquired nevus of Ota.

Nevus of Ota is a unilateral, asymptomatic cutaneous and mucosal hyperpigmentation of the face that is congenital or may appear during childhood. We present a case of symptomatic acquired nevus of Ota in an adult, associated with intense pruritus, not described in the literature so far. A 32-year-old woman presented with brownish mottled macules which appeared on her face progressively over 8 days, following the distribution of the first and second divisions of the left trigeminal nerve and partially covering the iris and sclera of the left eye. She reported an intense pruritus in this area. We performed a biopsy on the left forehead, which confirmed the diagnosis of nevus of Ota. Specific stains and immunohistochemistry revealed increased numbers of mast cells. Ophthalmological tests showed acute acquired melanocytosis of the left iris and sclera. The origin of the nevus is still unclear. Several hypotheses suggest a reactivation of melanocytes during their migration from the neural crest. The pruritus reported in our patient may be explained by the increased quantity of mast cells observed in the lesion and/or neuronal stimulation of the ophthalmic and maxillary divisions of the fifth cranial nerve.

Intracranial meningeal melanocytoma associated with nevus of Ota.

We report a rare intracranial meningeal melanocytoma associated with the nevus of Ota. The patient was 36-year-old man with a 2-week history of headache and difficulty in opening his right eye. Physical examination showed a black nevus scattered on the right-hand side of the face, right eyelid ptosis and papilledema. CT scans and MRI showed a tumor in the region of the right cavernous sinus. The tumor was subtotally resected. Histological examination confirmed the diagnosis of melanocytoma.