Squamous Cell and Basal Cell Carcinomas

Boris Hristov and Roland Engel

Background

Name the most common pathologic subtypes of squamous cell carcinoma (SCC).

Bowen Dz (SCC in situ), keratoacanthoma, −adenosquamous, verrucous carcinoma (low grade in anogenital, oral, or plantar foot), spindle cell carcinoma

Name the most common pathologic subtypes of basal cell carcinoma (BCC).

Noduloulcerative, superficial, sclerosing morpheaform, infiltrative, pigmented, fibroepithelial tumor of Pinkus, and basosquamous

What area of the body is at highest risk for SCC and BCC?

The H&N region is at greatest risk for SCC and BCC.

What is the most common genetic mutation in both SCC and BCC?

In SCC and BCC, p53 mutations are the most −common.

What features of SCC confer a high risk of mets?

Large, deep lesions with PNI and those that appear on dorsum of hands, lips, ears, penis, or sites of chronic infection, ulceration, or RT have a high risk of mets.

What type of UV rays are most responsible for causing skin cancer?

UVB (medium wave) rays are most responsible for skin cancer.

What is more common: basal or squamous cell skin cancer?

Basal cell (80%) is more common than squamous cell (20%).

What is the sex predilection for skin cancers?

Males are more commonly affected than females (4:1).

What are the major risk factors for skin cancers?

Major risk factors include sun exposure, chronic irritation, genetic disorders, and immunosuppression.

What genetic/inherited disorders are associated with skin cancer?

Phenylketonuria, Gorlin syndrome (PTCH), −xeroderma pigmentosa, and albinism have a genetic/inherited association with skin cancer.

What is the incidence of PNI and mets with BCC?

PNI: 1%
Mets: <0.1% (nodes > distant sites)

What is the incidence of PNI and mets with SCC?

PNI: 2%–15%
Mets: nodes: 1%–30% (1% grade 1, 10% grade 3, 30% from burns); distant: 2% (lung > liver > bones)

What are the major determinants of LN spread for SCC?

Poor differentiation, size/depth (>3 cm/>4 mm), PNI/LVI, location (lips, scars/burns, ear), and recurrent lesions

What LN regions are most commonly involved in SCC?

The upper cervical and deep parotid regions (with the H&N as the most frequent site) are most commonly involved in SCC.

Sun exposure at what stage of life correlates with BCC vs. SCC?

BCC: early in life/childhood
SCC: decade preceding Dx

What is Bowen Dz?

Bowen Dz is SCC in situ.

What is erythroplasia de Querat?

Erythroplasia de Querat is Bowen Dz of the penis.

What is a Marjolin ulcer?

Marjolin ulcer is SCC arising in a burn scar.

Which is more common when the ear is the primary site: BCC or SCC?

External ear: BCC more common
Internal/canal: SCC more common

Workup/Staging

On what is the latest AJCC T staging based for SCC/BCC?

T1: ≤2 cm (<2 high-risk features)
T2: >2 cm (≥2 high-risk features)
T3: invasion of maxilla, orbit, or temporal bone
T4: skeletal invasion, PNI of skull base

Per the latest AJCC classification, to what other site is N staging for skin cancer similar?

Skin cancer N staging is similar to that of the H&N:

N1: single, ipsi ≤3 cm
N2a: single, ipsi 3–6 cm
N2b: multiple, ipsi ≤ 6 cm
N2c: bilat or contralat LNs ≤6 cm
N3: LNs >6 cm

What defines stage groupings I, II, III, and IV?

Stage I: T1N0
Stage II: T2N0
Stage III: T3N0 or T1-3N1
Stage IV: N2-3, or T4, or M1

What defines a stage II(I) pt?

Stage II(I) represents a pt with stage II Dz that is also immunosuppressed (I). This is not part of formal staging but is allowed for studies/tumor registries.

What are considered high-risk features per the latest AJCC staging guidelines?

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