Squamous cell carcinoma (SCC) in skin of color
Cutaneous squamous cell carcinoma (sSCC) is often described as the most common skin malignancy in those with the darkest skin types but is less common than BCC in ethnic groups with intermediate pigmentation, including Hispanics and Asians.[1] However, based on the most recent data in the US, BCC was more prevalent than cSCC in all ethnicities, including Black patients (BCC:SCC ratios, 1.60 for Asian patients, 1.45 for Black patients, 2.00 for Hispanic patients, and 1.69 for White patients of all ages). [2]
Known risk factors for SCC in skin of color patients include chronic scarring processes, inflammatory conditions, HPV, immunosuppression, sites of radiation therapy, and exposure to chemical carcinogens.[1] In comparison to patients with light skin, ultraviolet radiation exposure is not as an important a risk factor for SCC with the darkest skin.[3]
SCC in situ (Bowen’s disease - BD) is frequently seen in patients with intermediate pigmentation and may be more likely to manifest as pigmented Bowen’s disease. The epidemiology of this has not yet been established, but nonpigmented Bowen’s disease is very uncommon in the darkest skin types in our experience.
Invasive cSCC often appears as a fungating mass with ulcerations and excess keratin. These masses can be nodular, plaque-like, papillomatous or exophytic. SCC of the keratoacanthoma type has the typical appearance of a central keratin core with a rolled pearly raised border and is histologically well-differentiated. Less differentiated and more advanced cSCC has less visible keratin and appears as a vascular mass with abnormal vessels.
- Scale (rough texture) is present in almost all lesions
- Glomerular (coiled) vessels
- Focally distributed towards the periphery
- Diffusely present throughout lesion
- Aligned linearly within lesion
- White circles
- Brown circles
- Rosettes (seen with polarized light)
- Brown dots aligned in a linear fashion
- Radially arranged brown lines
- Strawberry pattern seen in actinic keratosis (AK)
- Hairpin (looped) vessels with a white halo can be seen in keratoacanthomas (KA). In KA these looped-vessels tend to be aligned at the periphery.
- Polymorphous vascular pattern composed of dotted, short linear and long linear irregular (serpentine) vessels.
See chapter on SCC for further information.
SCC superficially invasive
Superficially invasive SCC in a 76-year-old Hispanic woman. At the time of biopsy, the differential diagnosis was pigmented Bowen’s disease vs pigmented AK.
Dermoscopy showing rosettes, visible follicular openings and pigmented background.
SCC invasive
SCC on Hispanic woman’s leg
White circles
SCC 70yo HM renal transplant
Looped vessels
SCC of the Keratoacanthoma type
SCC KA type arm 51yo HM type V
Central keratin core, ulceration
SCC of KA type rt cheek 71yo HF
Central keratin core
SCC of KA type on abdomen of 75yo HM with dark type V skin
The dermoscopy is not revealing and a biopsy is clearly indicated.
SCC poorly differentiated
SCC scalp 68yo HF
Polymorphous vessels with no scale – poorly differentiated SCC
Pigmented SCC
Next 4 images courtesy of Dr. Bengü Nisa Akay
Pigmented SCC in a 70-year-old man with type 4 skin
Radially arranged brown lines
Pigmented SCC in a 73-year-old woman with type 4 skin
Radially arranged brown lines and brown dots aligned in a linear fashion
Nail SCC
Squamous cell carcinoma in situ on the nail unit of an African American woman.
Note the nail pigmentation and splinter hemorrhages.
Note the hyperkeratotic plaque and longitudinal melanonychia.
Pigmented in SCC in situ with HPV changes in a 35yo Hispanic woman
Note the pigmented lines on the periphery in the top right corner. This mimics the streaks that are seen in melanoma.
Further information on SCC of the nail:
SCC ([1])
Links to additional chapters on Skin of Color
References
- ↑ 1.0 1.1 Hogue & Harvey: Basal Cell Carcinoma, Squamous Cell Carcinoma, and Cutaneous Melanoma in Skin of Color Patients. Dermatol Clin 2019;37:519-526. PMID: 31466591. DOI.
- ↑ Lukowiak et al.: Association of Age, Sex, Race, and Geographic Region With Variation of the Ratio of Basal Cell to Cutaneous Squamous Cell Carcinomas in the United States. JAMA Dermatol 2020;. PMID: 32845319. DOI.
- ↑ Gloster & Neal: Skin cancer in skin of color. J Am Acad Dermatol 2006;55:741-60; quiz 761-4. PMID: 17052479. DOI.
