Codes

Look For

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

• Congenital melanocytic nevus – Usually raised in comparison to CALMs and has some variation in pigmentation.
• Pigmentary mosaicism / nevoid hypermelanosis – Often occurs in the same demographic as CALMs so can be difficult to differentiate but may have more jagged borders.
• Nevus spilus – May be uniformly pigmented early on but ultimately has a speckled pigmentation pattern within the lesion.
• Becker nevus – Usually develops in adolescence, becomes slightly raised, and may contain hair.
• Post-inflammatory hyperpigmentation (PIH) – CALMs typically have more well-defined borders. PIH may be associated with a scar and typically fades with time.
• Urticaria pigmentosa / mastocytoma – Positive Darier sign where stroking the lesion elicits urticaria (or even blistering) via mast cell degranulation.
• Lentigines, ephelides – Typically smaller, more numerous, and seen in sun-exposed areas.

• Neurofibromatosis – Neurofibromatosis type 1 is the most common syndrome associated with CALMs with ≥6 CALMs (≥1.5 cm in postpubertal and ≥0.5 cm in prepubertal individuals). CALMs may also be seen in neurofibromatosis type 2.
• Multiple familial café au lait syndrome – autosomal dominant
• Legius syndrome – SPRED1 mutation
• McCune-Albright syndrome - The CALMs of McCune-Albright syndrome compared with neurofibromatosis are typically fewer in number, irregular in contour ("Coast of Maine" – jagged, versus "Coast of California" – more smooth), larger, darker, and tend to be near midline and follow Blaschko's lines. McCune-Albright syndrome signs include precocious puberty, other endocrinopathies, and polyostotic fibrous dysplasia.
• Constitutional mismatch repair deficiency syndrome – mutations in MLH1, MSH2, MSH6, PMS2
• Ring chromosome syndromes – intellectual disability, skeletal anomalies
• LEOPARD / multiple lentigines syndrome – PTPN11 mutation
• Cowden syndrome – PTEN mutation
• Bannayan-Riley-Ruvalcaba syndrome – PTEN mutation

• Ataxia-telangiectasia
• Bloom syndrome
• Fanconi anemia
• Russell-Silver syndrome
• Tuberous sclerosis
• Turner syndrome
• Noonan syndrome
• Multiple endocrine neoplasia syndromes (MEN1)
• Johanson-Blizzard syndrome
• Microcephalic osteodysplastic primordial dwarfism, type II
• Nijmegen breakage syndrome
• Rubinstein-Taybi syndrome
• Kabuki syndrome

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Management Pearls

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Therapy

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References

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