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NaevusDiagnostic challengeICD-10 D22.x

Combined melanocytic naevus

Combined naevus · biphenotypic naevus · combined banal + blue / Spitz / deep penetrating naevus

A combined melanocytic naevus contains two or more morphologically distinct populations of melanocytes within a single lesion — most commonly a common acquired naevus combined with a blue, Spitz, or deep penetrating naevus component. The hybrid clinical appearance (e.g. eccentric blue or pink island within a brown naevus) is a frequent diagnostic challenge, prompting concern for melanoma and excisional biopsy. Genetically driven (BAP1-mutant tumours within a common naevus are a specific subset).

CurrentLast reviewed 16 May 2026

Pathology

  • Two or more histologically distinct melanocytic populations within the same lesion:
    • Common acquired naevus + blue naevus (commonest combination).
    • Common naevus + Spitz / atypical Spitz tumour.
    • Common naevus + deep penetrating naevus.
    • Common naevus + BAP1-inactivated melanocytic tumour (BIMT) — recognised entity; BAP1 / BRAF mutations; possible BAP1-TPDS marker.
  • Each component retains its diagnostic histological features.
  • Genetic basis: BRAF (V600E in common naevus component), GNAQ / GNA11 (blue), HRAS (Spitz), BAP1 loss (BIMT).

Clinical features

  • Single lesion with two distinct components:
    • Brown background naevus with eccentric blue-grey nodule.
    • Brown naevus with central pink papule (Spitz component).
    • Brown naevus with darker speckled / mosaic area.
  • Sites: trunk, limbs, face.
  • Adolescents and young adults commonly.
  • Slow growth; stable or slowly enlarging.
  • Often asymptomatic; cosmetic / diagnostic concern is main driver.

Dermoscopy

  • Multicomponent pattern with discrete colour zones.
  • Brown reticular network (common naevus component).
  • Homogeneous blue area (blue component).
  • Pink globules / vascular pattern (Spitz component).
  • Generally symmetric within each component.
  • If features overlap with melanoma (asymmetry, atypical network, regression) — excise.

Differentials

  • Melanoma (especially nodular melanoma within a naevus) — most important DDx.
  • Naevus-associated melanoma — pre-existing naevus + new atypical region.
  • Spitz naevus (pure).
  • Blue naevus (pure).
  • Deep penetrating naevus.
  • BAP1-inactivated melanocytic tumour.
  • Pigmented BCC.

Management

  • Excisional biopsy with 1-2 mm margins typically performed for diagnostic clarity, given diagnostic challenge.
  • Complete excision provides full histological assessment.
  • Send to specialist dermatopathologist familiar with combined / hybrid naevi.
  • If atypical features or component suspected to be BIMT:
    • BAP1 IHC; consider BAP1 germline testing if multiple BIMTs or family history (mesothelioma, uveal melanoma, RCC).
    • Multidisciplinary follow-up if BAP1-TPDS confirmed.
  • Routine surveillance per NICE NG14 / local pigmented-lesion protocol if any atypia.
  • Counsel patient about benign nature of confirmed combined naevus; recurrence in scar possible but unusual.

References

  1. Pulitzer DR et al. The combined nevus: a histologic spectrum. J Am Acad Dermatol. 1991;25:1051-1058.
  2. Pollock PM et al. High frequency of BRAF mutations in nevi. Nat Genet. 2003;33:19-20.
  3. Wiesner T et al. BAP1-inactivated melanocytic tumors. Am J Surg Pathol. 2012;36:818-830.
  4. NICE NG14. Melanoma: assessment and management. London: NICE; 2015 (last updated 27 July 2022).

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