Basal Cell Carcinoma

See Also

Epidemiology

Most common cutaneous malignancy
1. Most common Skin Cancer in white, asian and hispanic patients
2. Second most common Skin Cancer in Black Patients
Incidence (2017, US): 3.3 Million per year
Incidence increase after age 40 years old (although increasing Incidence in younger patients)
1. Occurs in under age 50 years in 20% of cases

Risk Factors

See Nonmelanoma Skin Cancer Risk Factors

Pathophysiology

Derived from Basal Cell Layer of Keratinocytes (Epidermis, Hair Follicles, eccrine Sweat Glands)
1. Deepest cell layer of Epidermis
2. Cells are Basophilic with large nuclei
BCC requires stroma to support growth
1. Makes metastasis improbable (<1%)

Signs

Distribution
1. Chronic sun exposed areas (head and neck) account for 85% of lesions
  1. Nose accounts for 25% of cases
2. Minimally sun exposed areas account for as many as 33% of Basal Cell Carcinoma cases
Characteristics: Nodular
1. "Pearly" or translucent dome-shaped Papule
2. Overlying Telangiectases (develop with growth)
3. Waxy or translucent surface
4. Central Ulceration
5. Raised, rolled border
6. Friable, non-healing lesions that bleed frequently
Atypical presentations
1. Pigmented Basal Cell Carcinoma (uncommon in whites)
  1. Represents 6% of BCC in white skin, but 50% of BCC in Skin of Color (e.g. black, asian, hispanic)
  2. Contains Melanin with a resulting blue, brown or black coloration
  3. Differentiate from Melanoma
2. Skin of Color (e.g. black, asian, hispanic)
  1. Typical translucent lesions with Telangiectases and central ulceration difficult to diagnose on darker skin
  2. Brown to glossy black, pearly appearance in asian patients

Signs
Risk Related to Lesion Distribution

Low risk locations
1. Trunk and extremities EXCEPT for areas specifically identified as moderate or high risk
Moderate risk locations
1. Scalp
2. Forehead
3. Cheeks (not central face)
4. Neck
5. Pretibia
High risk locations
1. Eyelids or Eyebrows
2. Temple
3. Periorbital skin
4. Nose
5. Central face
6. Lips
7. Chin
8. Mandible
9. Ear (including preauricular and postauricular skin)
10. Genitalia
11. Hands
12. Feet

Diagnosis
Skin Biopsy

Precautions
1. Small, partial biopsies may miss aggressive sclerosing or micronodular subtype findings in >25% of cases
  1. Welsch (2012) J Am Acad Dermatol 67(1): 47-53 [PubMed]
2. Complete excision of suspected primary BCC lesions is recommended
  1. Recurrent BCC is difficult to treat and therefore definitive initial management is optimal
  2. Lesion excision with 4 mm margin allows for discrepancy between skin margins and deeper margins
  3. Immediately re-excision or Mohs Micrographic Surgery is recommended for positive margins
Raised lesion: Shave Biopsy if not pigmented
1. Any suspicion of Melanoma needs full-thickness sample
Flat lesions: Punch Biopsy or full excision

Types (mixed types in 40% of cases)

Nodular lesions
1. Nodular Basal Cell Carcinoma (21%)
  1. Up to 60-80% of Basal Cell Carcinoma lesions are at least in part nodular on pathology
2. Variants with higher invasive potential
  1. Micronodular Basal Cell Carcinoma (15%)
  2. Infiltrative Basal Cell Carcinoma (7%)
Other forms
1. Superficial Basal Cell Carcinoma (17%)
  1. Localized to trunk and extremities
  2. Scaly Plaque (similar to Eczema or Psoriasis)
  3. Raised pearly white borders (similar to nodular type)
  4. Least invasive BCC subtype
2. Morpheaform Basal Cell Carcinoma (1%)
  1. Firm, yellow, ill-defined lesion (similar to Scleroderma)
  2. Carcinoma borders often extend beyond what is visible on exam
  3. Higher invasive potential

Grading

Low Risk
1. Low Risk Location (see signs above) and <20 mm in greatest lesion diameter
2. Moderate Risk Location (see signs above) and <10 mm in greatest lesion diameter
3. Well defined border
4. Primary lesion (not a recurrent lesion)
5. No Immunosuppression
6. Lesion site NOT exposed to prior Radiation Therapy
7. Pathology with superficial or nodular type
8. Pathology without perineural involvement
High Risk
1. Low Risk Location (see signs above) and >=20 mm in greatest lesion diameter
2. Moderate Risk Location (see signs above) and >=10 mm in greatest lesion diameter
3. High Risk Location of any diameter
4. Poorly defined border
5. Recurrent lesion
6. Immunosuppression
7. Lesion site exposed to prior Radiation Therapy
8. Pathology WITH perineural involvement
9. Pathology with Aggressive BCC Type
  1. Morpheaform
  2. Basosquamous (metatypical)
  3. Sclerosing
  4. Mixed infiltrative
  5. Micronodular

Management

Electrodesiccation and curettage (ED&C)
1. Indications
  1. Low-risk, primary (non-recurrent), non-fibrosing lesions
  2. Intermediate size lesions
  3. Maintains dermal integrity with minimal scar
  4. More difficult if prior Punch Biopsy
2. Technique
  1. Scrape with curette
  2. Electrodessication to base with radiofrequency
  3. Repeat "scrape and burn" 3 times
  4. Send first curettage sample to pathology
  5. Keep area moist afterward (e.g. Bacitracin)
3. Recurrence rate
  1. Low-risk site: 8.6%
  2. High-risk site: 17.5%
Full thickness excisional surgery
1. Indications
  1. Deeper, diffuse or more advanced lesions
  2. Basosquamous carcinoma
Cryotherapy
1. Indications
  1. Low risk lesions with Superficial BCC or Nodular BCC type with depth <3 mm
  2. Requires biopsy first to check depth
2. Recurrence rate: 3.5 to 16.5% depending on size and location
Topical therapy
1. Indications
  1. Must be a non-aggressive, superficial BCC only
  2. Small tumors in low risk locations and patient unwilling to undergo other more effective therapies
2. Therapies
  1. Topical 5-Fluorouracil (Efudex)
  2. Topical Imiquimod 5% (Aldara) daily for 7 weeks
  3. PDT with 5-aminolevulinic acid
3. Efficacy
  1. Cure rates 60-80% at one year
4. References
  1. Geisse (2004) J Am Acad Dermatol 50:722-33 [PubMed]
  2. Love (2009) Arch Dermatol 145(12): 1431-8 [PubMed]
Mohs' Micrographic Surgery
1. Efficacy
  1. Maximum cure rates (99% at 5 years, 4.4% recurrence at 10 years)
  2. Maximum normal tissue preservation
2. Indications
  1. Recurrent Basal Cell Carcinoma
  2. Primary basal cell lesions with invasive subtypes (Micronodular, Infiltrative, Morpheaform)
  3. Positive biopsy margins (see below)
  4. Large tumors (>2 cm on trunk or extremities)
  5. Tumors in the H-Region of the face (Nose, Eyelids, chin, jaw, ear)
Large, advanced growths (not amenable to surgical excision)
1. Radiation Therapy
2. Chemotherapy

Management
Positive biopsy margins (incomplete excision)

Seen with Shave Biopsy or Punch Biopsy
1. Re-excision often yields negative sample
2. Yet high rate of recurrence
Most recommend Mohs Micrographic Surgery
Observing low-risk sites may be acceptable
1. Less than 1 cm diameter lesions
2. Not located on nose or ears
3. Marginal involement of 4% or less

Course

Slow growing tumors
Rarely metastasize
Locally Invasive!
Histologic characteristics for local extensive spread
1. Sclerosing pattern (tumor strands in fibrous stroma)
2. Perineural or perivascular invasion
3. Focal areas of squamous differentiation
Clinical characteristics for local extensive spread
1. Basal Cell Carcinoma on nose
2. Morpheaform Basal Cell Carcinoma on cheek
3. Basal Cell Carcinoma involving neck
4. Recurrent Basal Cell Carcinoma in men
5. Basal Cell Carcinoma involving Eyelid, temple, or ear
6. Basal Cell Carcinoma lesions >10 mm in diameter
7. Batra (2002) Dermatol Surg 28:107-12 [PubMed]

Resources

Basal Cell Carcinoma Nevus Syndrome Support Network
1. http://www.bccns.org

Prevention

See Nonmelanoma Skin Cancer
See Sun Exposure (lists general preventive measures)
See Sunscreen
1. Just as important in non-white, Skin of Color patients who do not typically Sunburn

References

Habif (2004) Dermatology p. 724-35
Firnhaber (2020) Am Fam Physician 102(6): 339-46 [PubMed]
Firnhaber (2012) Am Fam Physician 86(2): 161-8 [PubMed]
Kim (2018) J Am Acad Dermatol 78(3): 540-59 [PubMed]
Stulberg (2004) Am Fam Physician 70:1481-8 [PubMed]