Nevus of Ota: Clinical Aspects and Management

Henry H.L. Chan, MB, FRCPG, FRCPE, Taro Kono, MD

Disclosures
In This Article

Differential Diagnosis of Nevus of Ota

Although a diagnosis can usually be made without further investigation, other congenital melanocytic nevi can present in similar locations. A café-au-lait patch can present on the face, but its uniform brownish, flat appearance usually poses no difficulty in diagnosis (Figure 3). Histologically, there is an increase in pigmentation in the basal layer. Nevus spilus is a flat brown patch within which are dots of dark brown or blackish-brown areas of hyperpigmentation (Figure 4). Histology reveals the presence of junctional or dermal nevoid cells together with basal hyperpigmentation, as seen in a café-au-lait patch. In doubtful cases, a wood light can be used to differentiate the epidermal pigmentation of nevus spilus from the dermal melanoses as seen in nevus of Ota. Other dermal melanoses can usually be easily distinguished from nevus of Ota. Mongolian spot and nevus of Ito are located in different sites. There are four types of blue nevus: 1) common; 2) cellular; 3) macular; and 4) atypical. The common blue nevus presents as dome-shaped and blue-black papules, often in the dorsal aspects of the hands and feet. Histologically, dendritic pigmented melanocytes are seen in clumps over the mid to reticular dermis. The cellular blue nevus is a firm blue nodule that is located over the buttock and sacrococcygeal region. Biopsies reveal dendritic melanocytes and large pale, spindle-shaped cells with little pigment. The less common plaque-type blue nevus can manifest clinically either as numerous blue macules and papules within a circumscribed area, or as a blue patch without palpable components. The latter variant can be mistaken as nevus of Ota, but the lack of mucosal involvement is useful in differentiating the two conditions.[17] Histologic examination of the plaque-type blue nevus usually reveals findings similar to those that are observed in a common or cellular blue nevus with or without lentigo-like epidermal changes. The dermal melanocytes in the plaque-type blue nevus are deeper and more densely located than in the nevus of Ota. A typical nevus applies to the presence of blue nevus with other nevoid growth, including pigmented nevocellular nevus, nevus spilus, and connective tissue nevus.

Café-au-lait patch

Nevus spilus

In terms of acquired conditions, acquired bilateral nevus of Ota-like macules, or Hori's macule, can be mistaken for nevus of Ota.[18] Acquired bilateral nevus of Ota-like macules, which is a pigmentary disorder that was first described by Hori et al.,[18] is clinically characterized by speckled or confluent brownish-blue or slate-gray pigmentation over the face (Figure 5), and histologically characterized by diffuse upper dermal melanocytosis. The sites that are involved include the malar regions, the temples, the root of the nose, the alae nasi, the eyelids, and the forehead. One or more sites may be involved. Unlike nevus of Ota, the pigmentation occurs in a symmetrical bilateral fashion, has a late onset in adulthood, and does not involve the mucosa.

Acquired bilateral nevus of Ota-like macules

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