Benign Melanocytics Neoplasms

Onset in childhood (UVR-induced) and tends to fade with age and in the absence of sun exposure (e.g. winter months)

Small, well-circumscribed, usually multiple, tan to brown macules on sun-exposed areas in fair-skinned individuals

Onset usually in childhood; not related to sun exposure

Small, sharply circumscribed, brown to black macule that can occur at any site, including mucosae; typically a few lesions

Multiple or generalized lentigines may be an isolated phenomenon or a marker of an underlying disorder ( Table 92.3 )

Oral melanotic macules ( Fig. 92.1 )

Onset in adulthood

Typically, an isolated to a few, brown to brown-black macule(s) on the vermilion portion of the lower lip (labial melanotic macules); occasionally on the gingiva, buccal mucosa, tongue, or palate ( Fig. 92.1 )

Multiple lesions (lentiginosis) may be a marker of Peutz–Jeghers or Laugier–Hunziker syndromes

Anogenital lentiginosis (anogenital melanotic macules) ( Fig. 92.2 )

Onset typically in adulthood; females > males

One or more brown to black macules, sometimes with irregular or jagged borders, mottled pigmentation, and occasionally of large size (>1 cm)

In females favors the labia minora > labia majora, vaginal introitus, perineum; in males favors the glans penis and penile shaft

Multiple lesions are a feature of lichen sclerosis, Laugier–Hunziker syndrome, and Bannayan–Riley–Ruvalcaba syndrome (see Table 52.1 )

Conjunctival melanosis (conjunctival melanotic macules)

Conjunctival brown to black pigmented macules, streaks, or patches

While congenital form is typically benign, primary acquired ocular melanosis is considered a precursor lesion of conjunctival melanoma

Onset in adulthood (UVR-induced); persists throughout life and may darken with sun exposure, but does not fade

Typically, multiple tan to dark brown macules, often with irregular borders, ranging from a few millimeters to >1 cm in diameter

Distribution limited to sun-exposed sites, favoring those areas of greatest cumulative exposure (e.g. face, dorsal hands and forearms, upper trunk)

Clinical variants: ink spot lentigo, PUVA lentigo, tanning bed lentigo, sunburn lentigo

If present or widespread in young children, consider: xeroderma pigmentosum, type 2 oculocutaneous albinism (lesions are unusually large and jagged)

Onset at birth or in early childhood; not UVR-induced, but may first become noticeable following sun exposure

Uniformly colored, tan to brown macule or patch, varying in size from a few millimeters to >15 cm; grows proportionately with the child

Usually isolated but occasionally multiple; single CALM seen in ∼25–35% of children; <1% of children have ≥3 CALMs

Multiple CALMs may be associated with a variety of disorders (see Table 50.3 )

May be present at birth, but the majority appear around puberty; male:female ratio ∼5:1; stimulated by androgens

Classically, unilateral, tan to brown patch or thin plaque on the shoulder and/or upper trunk, but can occur elsewhere; margins typically irregular and break up into “islands” at the periphery; hypertrichosis in ∼50%

Associated smooth muscle hamartoma often present and is clinically apparent by the presence of perifollicular papules that are accentuated with rubbing

Infrequently associated with ipsilateral developmental anomalies (e.g. supernumerary nipples, breast hypoplasia, hypoplasia of the pectoralis major muscle, bony abnormalities)

Typically apparent at birth or within the first few weeks of life

Regresses in >95% of patients by age 18 years; more likely to persist in extensive or extra-sacral variants; most common in Asians and Blacks

Presents as a single or multiple, uniform, blue-gray patch(es) with indefinite borders; favors the lumbosacral area and buttocks > back; varies in size from a few centimeters to >20 cm

CALM and melanocytic nevi that reside within these areas often have a “halo” that lacks dermal melanocytes ( Fig. 92.6 )

DDx: ecchymosis, child abuse, patch blue nevus, venous malformation

Extensive lesions may be associated with a port-wine stain (phakomatosis pigmentovascularis; see Ch. 85 ), developmental abnormalities (e.g. cleft lip), or inborn errors of metabolism (e.g. Hurler syndrome)

Bimodal age of onset, with the majority (50–60%) present at birth or in infancy (before 1 year of age), and the remainder (40–50%) appearing at or around puberty; lifelong persistence

More common in Asians and Blacks; females > males

Involves those areas innervated by the first and second divisions of the trigeminal nerve, including the skin, conjunctiva, sclera, tympanic membrane, and/or oral and nasal mucosa; 10% of cases are bilateral

Lesions are characterized by speckled or mottled, grayish-brown to blue-black patches; may extend in size over time but usually stable by adulthood

Occasionally associated with neurocutaneous melanosis, glaucoma, ipsilateral sensorineural hearing loss, ocular melanoma (yearly ophthalmologic exams recommended)

Favored populations and clinical appearance are similar to nevus of Ota (see above)

Involves areas of skin innervated by the posterior supraclavicular and lateral brachiocutaneous nerves, namely the supraclavicular, scapular, or deltoid regions; typically unilateral

Most often seen in middle-aged Asian females

Multiple grayish-brown macules arising in a symmetric, bilateral distribution on the malar cheeks and forehead and sometimes the eyelids, temple, and nose; does not involve mucosa

Important to distinguish from melasma, as laser therapy improves nevus of Ota-like macules