| Malignant Melanocytic Lesions Pathologymindmap.com |
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Melanocytic Lesions
Malignant lesions
General Features
Asymmetric
Nuclear atypia
Pagetoid spread
No Neurotization
“shoulder” of melanocytic hyperplasia
No downward maturation of Nevus cells
Breslow’s System (Melanoma Thickness)
Melanoma thickness measured from top of granular layer
Can’t use if epidermis is ulcerated
Correlates w/ prognosis and LN metastasis
1. Low risk: <0.76 mm
2. Intermediate risk: 0.76 – 1.50 mm
3. High risk: >1.5 mm
Clark’s System (Vertical Growth)
Based of level of vertical invasion
Correlates w/ 5 year survival & metastatic potential
Level I: In situ
Level II: Invades Papillary dermis
Level III: Fills Papillary dermis & interface of Reticular dermis
Level IV: Into Reticular dermis
Level V: Into Subcutaneous fat
Lentigo Maligna
AKA Hutchinson freckle
Usually on cheeks of elderly
Lentiginous pattern of atypical melanocytes
@ dermal-epidemal junction
Single cells or nests
Atrophic overlying epidermis
DDx: Melanoma Acral Lentiginous (Hyperplastic epidermis)
Melanoma (Acral Lentiginous)
Most common in Blacks & Asians
Usually on acral & anal skin
Most aggressive melanoma
Lentiginous pattern of atypical melanocytes
@ dermal-epidemal junction
Single cells or nests
Hypertrophic overlying epidermis
DDx: Lentigo Maligna (Atrophic epidermis)
Melanoma (Superficial Spreading)
Most common form in whites
Pagetoid spread of atypical melanocytes
Nest formation
Pigmented parakeratosis (Melanin up to the top)
Malignant lesions
General Features
Asymmetric
Nuclear atypia
Pagetoid spread
No Neurotization
“shoulder” of melanocytic hyperplasia
No downward maturation of Nevus cells
Breslow’s System (Melanoma Thickness)
Melanoma thickness measured from top of granular layer
Can’t use if epidermis is ulcerated
Correlates w/ prognosis and LN metastasis
1. Low risk: <0.76 mm
2. Intermediate risk: 0.76 – 1.50 mm
3. High risk: >1.5 mm
Clark’s System (Vertical Growth)
Based of level of vertical invasion
Correlates w/ 5 year survival & metastatic potential
Level I: In situ
Level II: Invades Papillary dermis
Level III: Fills Papillary dermis & interface of Reticular dermis
Level IV: Into Reticular dermis
Level V: Into Subcutaneous fat
Lentigo Maligna
AKA Hutchinson freckle
Usually on cheeks of elderly
Lentiginous pattern of atypical melanocytes
@ dermal-epidemal junction
Single cells or nests
Atrophic overlying epidermis
DDx: Melanoma Acral Lentiginous (Hyperplastic epidermis)
Melanoma (Acral Lentiginous)
Most common in Blacks & Asians
Usually on acral & anal skin
Most aggressive melanoma
Lentiginous pattern of atypical melanocytes
@ dermal-epidemal junction
Single cells or nests
Hypertrophic overlying epidermis
DDx: Lentigo Maligna (Atrophic epidermis)
Melanoma (Superficial Spreading)
Most common form in whites
Pagetoid spread of atypical melanocytes
Nest formation
Pigmented parakeratosis (Melanin up to the top)