20 - 112 - SQUAMOUS CELL CARCINOMA AND KERATOACANTHOMA Flashcards
What is the most common skin cancer in immunocompetent white individuals?
A. SCC
B. BCC
C. Melanoma
D. Keratoacanthoma
Answer B p 1901
What is the most common skin cancer in immunosuppressed organ transplant recepients?
A. SCC
B. BCC
C. Melanoma
D. Keratoacanthoma
Answer A p 1901
Metastases in SCC are predominantly ________ .
A. Pulmonary
B. Hepatic
C. Cutaneous
D. Nodal
Answer D p 1901
Which of the following is not at higher risk of acquiring SCC?
A. Red hair
B. Blue eyes
C. High latitude
D. High altitude
Answer C p 1902
Which of the following photosensitizing drugs increase the risk for SCC?
A. Fluoroquinolones
B. Isoniazid
C. Lithium
D. Terbinafine
Answer A p 1905
Which of the following is mismatched?
A. Oral cavity: oral florid papillomatosis
B. Genitoanal region: giant condyloma acuminatum Buschke-Lowenstein
C. Plantar skin: epithelioma cuniculatum
D. Amputation stump: stump papillomatosis
Answer D p 1908
High risk features of SCC inludes the following except _______ .
A. >2 mm
B. Clark level >II
C. Perineural invasion
D. Primary site at the lip
Answer B p 1911
The primary mode of therapy for SCC is ______ .
A. Wait for spontaneous resolution
B. Conventional standard excision
C. Mohs surgery
D. Radiation therapy
Answer C p1912
Which of the following is false regarding keratoacanthoma?
A. It is regarded as a subtype of poorly differentiated SCC
B. It usually erupts rapidly within a few weeks
C. It has the ability to spontaneously regress
D. It clinically presents as a sharply circumscribed firm nodule with a central horn-filled crater that typically arises on the head and sun-exposed areas of the extremities
Answer A p1908
The histopathologic hallmark of invasive SCC is __________ .
A. pleomorphic nuclei with a high degree of atypia
B. frequent mitoses
C. the growth of atypical keratinocytes beyond the basement membrane into the dermis
D. very few areas of keratinization
Answer C p1909
second most common skin cancer in immunocompetent white individuals
SCC
most common skin cancer in immunocompetent white individuals
BCC
most common skin cancer in immunosuppressed organ transplantation recipients worldwide
SCC
Risk factors for SCC
- ultraviolet (UV) radiation
- genetic predisposition
- physical and chemical carcinogens
- immunosuppression
- drugs
- viral infection
- chronic inflammation
- chronic injury of the skin
Precursor lesions of SCC
Actinic keratosis, bowen disease, bowenoid papulosis, erythroplasia of Queyrat
High-risk features for local recurrence and the development of metastatic disease for SCC
- > 2 mm thickness;
- Clark level higher than IV;
- perineural invasion;
- lip or ear as primary site;
- poorly or undifferentiated tumor
risk of developing metastasis from SCC is generally low, with a 5-year metastatic rate of ?
5%
Major route of SCC metastasis
Nodal metastasis
predominant etiologic risk factor for skin carcinogenesis in SCC
cumulative lifetime exposure to UVR
Sun-sensitive individuals with ______ hair, ____ eyes, and ______ complexion are at higher risk for developing SCC than individuals with darker pigmentation.
red hair, blue eyes, and fair complexion
most important environmental risk factor for SCC
UVR
- class I carcinogen, sufficient for the initiation, promotion, and progression of squamous carcinogenesis of the skin
UVB-induced mutagenesis of the skin gives rise to specific UV signature mutations (ie, characteristic _______________ dipyrimidine transitions), which constitute the majority of mutations found in SCC. 2
C-T and CC-TT dipyrimidine transitions
Syndromes associated with a predisposition for keratoacanthoma
- Muir-Torre syndrome
- Multiple self-healing squamous epithelioma (Ferguson–Smith syndrome)
Risk Factors for the Development of Squamous Cell Carcinoma
Oral SCC may arise on apparently normal mucosa but are usually preceded by
leukoplakia, erythroplakia, or leukoerythroplakia,
SCC of the lip occurs more often where?
Lower lip
Typical locations of verrucous SCC
- oral cavity: oral florid papillomatosis
- genitoanal region: giant condyloma acuminatum Buschke-Löwenstein
- plantar skin: epithelioma cuniculatum
- amputation stumps
hallmark of invasive SCC
growth of atypical keratinocytes beyond the basement membrane into the dermis
Basic Features of Histopathology Report of Cutaneous Squamous Cell Carcinoma Diagnosis
This variant of SCC bears an increased propensity for metastasis. The main histologic characteristic is extensive acantholysis of the atypical keratinocytes leading to pseudoglandular structures within the tumor area
ACANTHOLYTIC (ADENOID) SQUAMOUS CELL CARCINOMA
a well-differentiated variant of SCC that slowly grows and is locally destructive, but with only low metastatic potential
VERRUCOUS SQUAMOUS CELL CARCINOMA
Distinct variant of SCC that shows a highly infiltrative growth pattern with abundant mucinous stroma surrounding the tumor cells.
This often is associated with perineural or perivascular infiltration, and reveals a high rate of recurrence and metastases
DESMOPLASTIC SQUAMOUS CELL CARCINOMA
What are the histologic variants of SCC
- SPINDLECELL SQUAMOUS CELL CARCINOMA
- ACANTHOLYTIC (ADENOID) SQUAMOUS CELL CARCINOMA
- VERRUCOUS SQUAMOUS CELL CARCINOMA
- DESMOPLASTIC SQUAMOUS CELL CARCINOMA
- KERATOACANTHOMA
What are the margins for conventional standard excision of SCC
4 - 6 mm margins
- may be acceptable as primary treatment of local, low-risk SCCs
A prospective Phase II trial has demonstrated the efficacy of monotherapy with ___________ as a first-line treatment of unresectable SCC (a 29% response rate).
cetuximab
frequently found to be the first indicator of aggressive biologic behavior in SCC
Local recurrence at the site of the primary lesion
High risk areas for SCC
“mask areas” of face (central face, eyelids, eyebrows, periorbital, nose, lips [cutaneous and vermilion], chin, mandible, preauricular and postauricular skin/sulci, temple, ear), genitalia, hands, and feet.
Moderate risk areas for SCC
cheeks, forehead, scalp, neck, and pretibia
Low risk areas for SCC
trunk and extremities (excluding pretibia, hands, feet, nail units, and ankles)
A metaanalysis and systematic review on all published data found that tumor depth (ie, Breslow thickness exceeding _______ mm and invasion beyond subcutaneous fat) is associated with the highest relative risk of local recurrence and metastasis of SCC.
2 mm
A tumor diameter exceeding ________mm is associated with the highest relative risk for disease-specific death of SCC
20 mm
Tumors larger than________ mm are associated with a high risk of metastasis and local recurrence.
6 mm
independent risk factor for local recurrence
Desmoplastic growth
Another prospective study found that lesion size equal to or greater than _______ cm and histologic evidence of perineural invasion and deep invasion beyond subcutaneous structures were the factors most significantly associated with disease-specific mortality in cutaneous SCC
4 cm
Overall, the 3-year cumulative risk of a subsequent SCC after an index SCC is ____%, at least a 10-fold increase in incidence compared with the incidence of first tumors in a comparable general population
18%
Vitamin B suitable fir chemoprevention of NMSC
niacinamide (Vitamin B3) 500 mg twice daily
Although there were numerous side effects, this treatment was the first demonstration of effective chemoprevention of cancer in humans.
Systemic retinoids (Vitamin A)
