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Pigmented lesions of the skin that you

must diagnose with confidence

Deba P Sarma, MD

Omaha

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Common sense classification of pigmented lesions

Benign: Lentigo simplexSolar lentigoNevus (Junctional, Dermal, Compound, Blue,

Spitz, Dysplastic)

Potentially malignant:Atypical melanocytic hyperplasia

Malignant:Melanoma in-situInvasive melanoma

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Melanoma

In-situ InvasiveLentigo maligna Lentigo maligna melanoma

Superficial spreading Superficial spreading(Pagetoid melanoma)

Acral-lentiginous Acral-lentiginous melanoma

None NodularNone Desmoplastic

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Lentigo simplex

Elongated rete ridgesBasal melanosisNo junctional nestNo solar elastosis

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Solar lentigo

Elongated rete ridgesBasal melanosisNo junctional nestDermal solar elastosis

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Nevus: Junctional

Flat epidermal lesionJunctional nests with clefts

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Nevus: Dermal

Raised lesionDermal nests

No junctional nests

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Nevus: Compound

Raised or flat (older person) lesionJunctional clefted nests and dermal nests

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Nevus: Epithelioid (Spitz nevus)

70% occurs in pts < 20 yrsRaised, junctional or compound nevusEpithelioid clefted nests oriented vertically

Cytologic and nuclear

pleomorphism

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Nevus: Dysplastic

All agesCompound nevusJunctional clefted nests with transverse growth pattern(bridging)

Cytologic and nuclear pleomorphism

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Nevus: Blue

Flat lesionNo junctional nestDermal pigmented spindled melanocytes

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Lentiginous nevus

Flat lesion.Common nevus + lentigo simplex

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Atypical melanocytic hyperplasia

Flat, lentiginous lesion in older peopleJunctional melanocytic hyperplasia with small nestsMild to moderate pleomorphism

Not like any common nevusNot enough for in-situ melanoma

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Melanoma

Lentigo maligna & lentigo maligna melanoma

Superficial spreading ( Pagetoid): In-situ & invasive

Acral-lentiginous: In-situ & invasive

Nodular: Invasive

Desmoplastic: Invasive

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Melanoma in-situ: Lentigo maligna type

Epidermal atrophy, solar elastosis

Confluent and nested proliferation of pleomorphic melanocytes

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Melanoma in-situ: Lentigo maligna type

Neoplastic melanocytes spread from the junction upwardsand along the adnexa.No dermal invasion.

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Malignant melanoma: Lentigo maligna type(Lentigo maligna melanoma)

Tumor has invaded into the dermis

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Superficial spreading in-situ & invasive melanoma

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Acral-lentiginous in-situ & invasive melanoma

Location: foot,toes, hand,fingersRace: Dark-skinned peopleMicroscopic appearance: same as lentigo maligna melanoma

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Nodular and Desmoplastic melanoma

No in-situ phaseInvasive at diagnosis

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Nodular melanoma

Raised, ulcerated, no radial spread, deep dermal invasion

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Desmoplastic melanoma

Sun-exposed skinOlder peopleIndurated plaque

Spindle cell proliferation in dermisSolar elastosisLymphocyte-plasma cell aggregates

NEED HIGH DEGREE OF SUSPICIONGET S-100 STAIN

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REMEMBER

1. Most (95%) of the pigmented lesions are benign, 4% malignant, 1% borderline.

2. Most (70%) of the melanomas are superficial spreading type.

3. Most of the melanomas occur in the sun-protected skin.

4. Most of the melanomas occur on the trunk (specially back) of man andlower extremities (specially thigh) of woman.

5. Melanoma is very rare in person below 20 years of age. Exclude Spitz nevusfirst.

6. If you are not sure of melanoma, do not call MELANOMA. Raise the possibilityin comment, ask for complete resection for further evaluation.

7. Ask for another expert opinion.

8. Do not make wishy-washy and confusing comment in melanoma diagnosis.