Yale 2014 - 2 - Dermatological Malignancies Flashcards
What lesion is this and what is the pathophysiology and associated risks?
Actinic keratosis
Pathophysiology:
These erythematous scaly “age spots” are likely actinic keratosis (AK) lesions: epidermal keratinocytes that have become neoplastic under UV radiation exposure.
Risks:
Squamous Cell Carcinoma (SCC) in situ is typically more erythematous, scalier, and larger in size compared to AK. Once the dermis has been invaded the lesion becomes SCC.
Progression Risk:
Rates of transformation are estimated to be 0.03-20% annually or 6-10% at 10 years (Marks, 1988), and 25% resolve spontaneously within one year.
What kind of lesions are these?
Squamous Cell Carcinoma:
These lesions make up 20% of non-melanoma skin cancers. They have a strong association with cumulative exposure to UV light and therefore are most often found on sun-exposed areas such as the forearms and hands in persons typically >50 years old. They usually appear to be firm, smooth, hyperkeratotic papules or plaques but can have central ulcerations and even appear verrucous. While hematogenous metastasis is rare (only 5% of all SCC), SCC can be locally invasive and spread to regional lymph nodes.
Actinic Keratosis is a typically a precursor lesion.
What kind of lesions are these? Risk Factors?
basal cell carcinoma (BCC)
This is the most common type of non-melanoma skin cancer (80%). BCCs are frequently found in persons <50 years old and typically occur on the face and neck (85%). The association with UV exposure is not as strong as that of SCC, but early exposure to UV light as a child or adolescence is described as a risk factor.
What is the pathophysiology of Basal Carcinoma?
What are the types of BCC?
BCCs arise from basal keratinocytes of the epidermis, hair follicles, and eccrine sweat ducts. This patient’s lesion is a “pearly pink papule” which is a classic description of a nodular subtype of BCC. Superficial BCC can also be a scaly plaque like actinic keratosis or SCC, but usually has pearly white raised borders that are characteristic of BCC. Notably, BCCs can contain black, blue, or brown pigments so they can be easily mistaken for melanomas. The other subtypes of BCC (morpheaform, infiltrative, and micronodular) are much less common and are generally considered more aggressive.
Who are at risk for skin cancer?
People at increased risk of developing skin cancers include: immunosuppressed patients (especially status-post organ transplant), personal history of skin cancer, more than 100 nevi, history of radiotherapy for malignancy, arsenic exposure, and patients with psoriasis treated with more than 250 UVA+ psoralen treatments.
Studies have also shown a 2.5- and 1.5-fold increase in SCC and BCC, respectively, with use of tanning beds. Family history of non-melanoma skin cancer is also a recognized risk factor despite there being relatively little data. There is one review in Sweden that found first degree relatives of patients affected with SCC had 2-3x increased risk of SCC (Hussain, 2009) and there is even less data about family histories in patients with BCC.
How are Actinic Keratosis lesions managed?
They are typically managed with “watchful waiting” but some patients may request removal if they cause symptoms (itch, pain) or for cosmetic purposes. The most common and readily available method of removal is cryotherapy.
If malignant progression is suspected, a shave biopsy can be considered but surgical excision is first-line treatment for SCC.
How do you classify lesions in terms of risk regarding locations on the body?
- *Low Risk:** Trunk and extremities
- *Moderate Risk:** Cheeks, forehead, scalp, and neck;
- *High Risk: **A high risk location is on the “mask” areas of the face (central face, eyelids, nose, lips, chin, ears), genitalia, hands, and feet.
What are the low-risk of recurrence features for skin lesions?
Low-risk recurrence features include:
well-defined borders
primary lesions
<20mm in size in a low risk location
<10mm in a moderate-risk location
<6mm in a high-risk location
nodular and superficial BCC
well-differentiated SCC <2mm thickness
What are high risk features of a skin lesion?
High Risk Features:
recurrent lesion
poorly defined borders
immunosuppressed patients
sites of prior radiotherapy or chronic inflammatory process >20mm in low risk location
>10 mm in moderate risk location
>6mm in high risk location
BCC with aggressive growth pattern
moderately or poorly- differentiated SCC >2mm in depth
How do you treat skin lesions based on their risk?
There are also alternative and adjunctive non-surgical treatments for non- melanoma skin cancers. Topical imiquimod and fluorouracil are effective in certain subtypes, but the use of these agents should be monitored by a specialist. Radiotherapy and photodynamic therapy are active areas of research, and while current data seems promising, at the time of publication there is no current standard guideline on when and how to use these methods. Low Risk lesions:
Electrodessication and curettage (ED&C) or cryotherapy are appropriate treatments only for small, low-risk lesions as they cannot provide definitive histopathology.
Moderate to high risk lesions:
Any other lesions, especially if it is a patient’s first suspected skin cancer, should have at least a shave or punch biopsy to obtain histopathology.
The preferred method for skin cancer removal is Mohs micrographic surgery as it maximally preserves non-affected tissue and has better outcomes (1% vs. 5% at 5yr recurrence rate compared to excision) (Thissen, 1999). However, it is expensive and appropriately trained dermatologists are often not readily available.
Adjunctive therapies for non-melenomatous include:
Topical imiquimod and fluorouracil (specialists)
Radiotherapy and photodynamic therapy (experimental)
How should you counsel patient regarding reducing the risk for skin cancer?
Reducing risk of skin cancer relies on behavioral modifications such as:
staying indoors during the midday
wearing sun-protective clothing (hats, sunglasses, long-sleeves)
using sunscreen with both UVA/UVB protection.
Strongly advised to stop using tanning beds.
What approach would you recommend for screening for skin cancer?
For screening:
- -The American Cancer Society recommends a clinical Total Skin Exam (TSE) every three years in people 20 to 40 years old, and yearly thereafter.
- -The USPTSF and AAFP say there is insufficient evidence advising for or against the use of annual screening TSE.
- -The AAFP recommends counseling fair-skinned children and young adults about minimizing UV exposure (Grade B recommendation), but states there is insufficient evidence for this practice in adults >24 years old (Grade I recommendation).
What approach would you use for monitoring for skin cancer?
With a history of non-melanoma skin cancer, the National Comprehensive Cancer Network (NCCN) recommends that patients with only local disease have a total skin exam (TSE) every three to six months for two years, then every six to 12 months for three years, then annually for life.
For patients with regional disease, they recommend TSE one to three months for one year, two to four months for the following year, four to six months for three years, and then six to 12 months for life.
All patients may be advised on how to perform a self-skin exam (SSE) at home that ideally should include a wall and handheld mirror with special attention to the back and neck which are difficult to view.
How do you characterize a skin lesion for risk for being a melanoma?
Highly suspicious lesions for melanoma as it fits all the ABCDE mnemonic criteria:
asymmetry
border irregularity
color variegation
diameter >6mm
evolving over time.
What is in the ddx for a melanomatous appearing lesion?
typical melanocytic nevus (“mole”)
atypical melanocytic nevus
blue nevus
lentigo
spitz nevus
pigmented BCC
pigmented AK
seborrheic keratosis
pyogenic granuloma
dermatofibroma
keratoacanthoma
subungal hematoma (if under a nail).
