Melanoma Flashcards
What is the incidence of melanoma in the United States?
∼87,000 cases/yr of melanoma in the United States (and rising).
What are some risk factors for developing melanoma?
UV RT, fair complexion, light hair/eyes, numerous benign nevi or larger atypical nevi (>5 mm, variable pigmentation, asymmetric, indistinct borders),
personal Hx of melanoma (900 times), family Hx of melanoma, and polyvinyl chloride exposure
In terms of UV exposure, what is the most important risk factor associated with development of melanoma?
Intermittent intense exposure to UVA and UVB, such as Hx of blistering burns in childhood, is the most important risk factor for developing melanoma.
What are the sex differences in terms of body distribution of melanoma lesions?
Males: lesions predominantly on trunk (e.g., upper back)
Females: lesions predominantly on extremities
What % of melanomas derive from melanocytic nevi?
∼15% of melanomas derive from melanocytic nevi.
What are the 2 common types of noncutaneous melanoma?
Uveal melanoma and mucosal melanoma
What is the most common site of mucosal melanoma?
H&N, then anorectal and vulvovaginal regions
What % of melanoma pts have LN involvement at Dx, and how does this differ by T stage?
15% of pts have LN involvement at Dx, 5% of T1 pts and 25% of ≥T2 pts.
What % of melanoma pts present with DM at Dx?
5% of pts present with DM at Dx.
What proportion of DM pts present with DM from an unknown melanoma primary?
One-third of DM pts or 1%–2% of all pts present with mets from an unknown primary.
What are the 5 subtypes of melanoma?
Superficial spreading, nodular, lentigo maligna, acral lentiginous, and desmoplastic variant
Which of the 5 melanoma subtypes is the most common?
Superficial spreading (70%) is the most common subtype → nodular (25%).
What are typical features of desmoplastic melanoma?
Features of the desmoplastic subtype include older pts (60–70 yo), more infiltrative, higher rate of PNI, amelanotic, higher LF rates, and lower nodal mets/DM rates
Which melanoma subtype has the best prognosis?
Lentigo maligna melanoma has the best prognosis
What subtype commonly presents in dark-skinned populations, and what body locations do it commonly affect?
Acral lentiginous, which commonly affects the palms/soles and subungual areas, is the most common melanoma subtype in dark-skinned populations.
Which subtype of melanoma is most common and has the worst prognosis?
Superficial spreading is the most common subtype. This subtype also has the worst prognosis.
What are 3 commonly used immunohistochemical stains for melanoma?
S100, HNB-45, and Melan-A stains are commonly used for melanoma
A pt presents with a pigmented lesion. What in the Hx can help to determine if this is a suspicious lesion?
Changes in Asymmetry, Borders, Color, Diameter (>6 mm), and Enlargement (Mnemonic: ABCDE)
Per the latest NCCN guidelines, for what melanoma pts should imaging be performed?
Per the NCCN, imaging should be performed for specific signs/Sx or stage ≥III (not recommended for Stages IA–II).
What are some common DM sites for melanoma?
The skin, SQ tissues, distant LNs, lung, liver, viscera, and brain are common melanoma DM sites.
What is the preferred method of tissue Dx for a suspected melanoma?
For suspected melanoma, full-thickness or excisional Bx (elliptical/punch) with a 1–3-mm margin is preferred for tissue Dx.
Why should wider margins on excisional Dx be avoided?
Avoid wide margins to permit accurate subsequent lymphatic mapping.
For what locations is full-thickness incisional or punch Bx adequate?
Full-thickness incisional and punch Bx are adequate for the palms/soles, digits, face, and ears or for very large lesions.
When is a shave Bx sufficient?
Shave Bx is sufficient when the index of suspicion for melanoma is low.
What is the latest AJCC (8th edition) T staging for melanoma?
T1: ≤1 mm thickness T1a: ≤0.8 mm without ulceration T1b: ≤0.8 mm with ulceration or 0.8–1 mm with or without ulceration T2: >1–2 mm thickness T2a: no ulceration T2b: ulceration T3: >2–4 mm thickness T3a: no ulceration T3b: ulceration T4: >4 mm thickness T4a: no ulceration T4b: ulceration
What is considered N1, N2, and N3 in melanoma staging?
N1: 1 + node
N2: 2–3 + nodes
N3: ≥4, or matted, or in-transit mets with mets to regional node(s)
For melanoma nodal groups, into what further categories are N1–N3 stages broken into and on what basis (for AJCC 8th edition)?
N1a: 1 occult (SLN Bx) node and no in-transit/satellite, and/or microsatellite mets
N1b: 1 clinical node and no in-transit/satellite, and/or microsatellite mets
N1c: no +LNs with in-transit/satellite, and/or microsatellite mets
N2a: 2–3 occult (SLN Bx) nodes and no in-transit/satellite, and/or microsatellite mets
N2b: 2–3 + nodes, ≥1 clinically detected, and no in-transit/satellite, and/or microsatellite mets
N2c: 1 occult or clinical node with in-transit/satellite, and/or microsatellite mets
N3a: ≥4 occult (SLN Bx) nodes and no in-transit/satellite, and/or microsatellite mets
N3b: ≥4, one of which clinical node or any number of matted nodes and no in-transit/satellite, and/or microsatellite mets
N3c: 2 or more occult/clinical nodes and/or any matted nodes with intransit/satellite, and/or microsatellite mets
For AJCC 8th edition, what replaces the micromets vs. macromets distinction for nodal staging?
Clinically occult (typically found on SLNB) = “a,” vs. clinically detected (by exam or imaging) = “b”
How do M1a, M1b, M1c, and M1d differ in a pt with metastatic melanoma?
M1a: skin, ST, distant LNs
M1b: lung only with or without M1a sites
M1c: non-CNS viscera or other sites with/without M1a or M1b sites
M1d: CNS mets with or without M1a, M1b, M1c sites
What does the parenthetical 0 or 1 denote in the most current M-staging (e.g., M1a(0) vs. M1a(1))?
(0) : normal LDH
(1) : elevated LDH
Describe the overall clinical stage groupings per the latest AJCC classification.
Stage 0: TisN0 Stage IA: T1aN0 Stage IB: T2aN0 or T1bN0 Stage IIA: T3aN0 or T2bN0 Stage IIB: T4aN0 or T3bN0 Stage IIC: T4bN0 Stage III: any N+ Stage IV: any M1
Describe the overall pathologic stage groupings per the latest AJCC classification.
Stage 0: TisN0 Stage IA: T1a or T1bN0 Stage IB: T2aN0 Stage IIA: T3aN0 or T2bN0 Stage IIB: T4aN0 or T3bN0 Stage IIC: T4bN0 Stage III: any N+ (see AJCC manual for specific breakdown of IIIA–D) Stage IV: any M1
What are the Clark levels? Under what circumstance does the Clark level need to be known on the pathology report for a pt with melanoma?
Level I: epidermis only Level II: invasion of papillary dermis Level III: filling papillary dermis, compressing reticular dermis Level IV: invading reticular dermis Level V: SQ tissue
The Clark level should be provided on the pathology report for lesions ≤1 mm; not used in latest AJCC staging system.
What are the similarities and differences b/t clinical and pathologic staging for melanomatous lesions?
Both require microstaging of the primary after resection:
Clinical staging: clinical exam + radiology allowed (after complete resection)
Pathologic staging: pathology assessment of LN after dissection