Melanocytic Nevi: Pattern Analysis

01Reticular pattern is the most common nevus pattern in adults on the trunk and extremities. A regular pigment network of brown lines on a tan background corresponds histopathologically to pigmented, elongated rete ridges. The lines are evenly spaced and the holes are uniform. Hypopigmentation may sit centrally or be patchy; large reticular nevi may show a multifocal pattern with juxtaposed hypopigmented and hyperpigmented zones.

02Globular pattern characterizes acquired and small congenital nevi in children. Brown globules are visible throughout the lesion and are accentuated at the periphery. Histopathologically, globules correspond to round nests at the dermoepidermal junction or in the upper dermis. As globular nevi mature in adults they become elevated with a papillomatous surface and shift to the cobblestone pattern (larger, angulated globules) or the fried-egg pattern (central cobblestones with a peripheral reticular rim).

03Homogeneous pattern presents as structureless brown, blue, or tan pigmentation without network or globules. Homogeneous blue corresponds to common blue nevus, with dermal dendritic melanocytes among thick collagen bundles separated from the epidermis by a Grenz zone. Hypochromic blue nevi exist and appear white-blue on dermoscopy; pigment loss is more frequent on the limbs.

04Reticular-globular (combined) pattern shows reticular at the periphery with central globules or homogeneous brown, often a fried-egg morphology. The peripheral reticular rim is interpreted as an acquired component overlying a stereotypical congenital nevus. Multiple small follicular hypopigmentations are common in larger congenital nevi.

05Starburst pattern defines pigmented Spitz/Reed nevi: peripheral pigmented streaks or large globules arranged radially in a symmetric crown. Histopathologically these correspond to confluent junctional nests of heavily pigmented spindle or epithelioid melanocytes. Starburst is most common on face, limbs, and buttocks in children and young adults. Adult-onset starburst lesions or asymmetric starburst lesions warrant excision because melanoma can rarely mimic this pattern.

06Acral patterns follow the dermatoglyphics. Parallel furrow pattern is the most common benign acral pattern: pigment lines run along the sulci. Lattice-like pattern shows pigment along furrows with crossing lines, common on weight-bearing arches. Fibrillar pattern shows fine pigmented filaments perpendicular to ridges and furrows, typical of pressure-loaded sites such as heel and forefoot. Parallel furrow, lattice-like, and fibrillar are all variants of the benign parallel-line family.

07Multicomponent pattern combines three or more dermoscopic structures (network, globules, structureless areas, blue-white veil) without symmetric distribution. While typical of melanoma, multicomponent appearance can occasionally arise in atypical nevi or combined nevi (two distinct populations juxtaposed). Multicomponent symmetric lesions in young patients are more often benign; adult-onset multicomponent asymmetric lesions are presumed malignant until proved otherwise.

08Age and site rules guide interpretation. Children and adolescents predominantly show globular patterns; adults show reticular; the elderly show fewer flat nevi and more elevated papillomatous (cobblestone) lesions. On the face, the flattened dermoepidermal junction creates a pseudonetwork interrupted by follicular openings rather than a true network. Recognizing the patient's predominant pattern (the signature nevus) enables the ugly-duckling identification that drives screening efficiency.

09Atypical-but-stable nevi (also called Clark nevi) often show multifocal or eccentric hyperpigmentation, a slightly irregular network, or peripheral globules during a growth phase in younger patients. Symmetric peripheral globules on a small nevus in a patient under 20 represent active growth and are not by themselves a melanoma sign. Adult-onset peripheral globules, by contrast, warrant excision or short-interval monitoring. Sequential digital dermoscopy lets the clinician observe stability, which is the most reliable sign of benignity in the dysplastic-nevus phenotype.

10Management of dysplastic nevi rests on overall morphology and patient phenotype. Patients with multiple atypical nevi benefit from total-body photography and digital dermoscopic monitoring at 3 to 12 month intervals; excise lesions that change asymmetrically. Solitary atypical lesions that stand out from the patient's pattern (ugly duckling) warrant excision rather than monitoring. Reticular nevi tend to involute by the seventh to ninth decades, so a new pigmented lesion in an elderly patient deserves heightened scrutiny.