Updated: 3/24/2019

Squamous Cell Carcinoma (SCC) of the Skin

Topic
Review Topic
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Questions
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Evidence
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Snapshot
  • A 70-year-old man presents to the dermatologist’s office for his annual skin exam. He complains of a large pink lesion on his cheek that oozes and bleeds. It never seemed to heal properly. He is concerned, because he knows that he should have used more sunscreen throughout his life.
 
Introduction
  • Invasive primary skin malignancy arising from keratinocytes of skin or mucosa
  • Epidemiology
    • common in fair-skinned individuals
    • common in elderly patients
    • 2nd most common form of skin cancer (first is basal cell carcinoma )
    • risk factors
      • sun exposure 
      • actinic keratosis
      • immunosuppression (similar to treatment after organ transplant)
      • arsenic exposure
      • old scars or burns 
      • xeroderma pigmentosum
      • ionizing radiation
  • Pathogenesis
    • damage to keratinocytes
    • metastases are rare
  • Keratoacanthoma is a variant of low-grade squamous cell carcinoma
    • grows rapidly and regresses spontaneously
Presentation
  • Symptoms
    • typically asymptomatic
  • Physical exam
    • red, poorly defined base with adherent yellow or white scale
    • smooth, dull, red, dome-shaped nodule with ulcerated center
    • frequently on sun-exposed areas
      • face, neck, hands, ears
      • common on lower lips
      • lesions often against a background of sun-damaged skin
Evaluation
  • Diagnosis by skin biopsy 
    • atypical keratinocytes and malignant cells
    • invasion into dermis
    • keratin “pearls” on histology
Differential Diagnosis
  • Actinic keratosis
  • Actinic cheilitis
Treatment
  • Surgical
    • wide local excision with negative margins
Prognosis, Prevention, and Complications
  • Prognosis
    • if treated, very excellent prognosis
  • Prevention
    • sun avoidance
    • sunscreen use
 

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Questions (7)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M1.ON.51) A 71-year-old man presents to his primary care physician with the lesion seen in Figure A. He states that it has been present for several months. He has no significant past medical history and is a retired construction worker. What would be the expected pathology on biopsy? Review Topic

QID: 104262
FIGURES:
1

Palisading basal cells

12%

(1/8)

2

Keratin pearls

75%

(6/8)

3

S-100 postive staining cells

12%

(1/8)

4

Parakeratosis

0%

(0/8)

5

Hyperkeratosis

0%

(0/8)

M1

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(M1.ON.57) A 62-year-old man presents to your office for evaluation of a chronic ulcer on the plantar aspect of his right foot. He has a history of peripheral vascular disease and poorly-controlled diabetes mellitus. He states that he has had this ulcer for years, but that it seems to be growing. On examination of his right foot you note the heaped up edges surrounding the ulcer (Figure A). A wedge biopsy reveals irregular masses of anaplastic epidermal cells proliferating down to the dermis and the pathologist reports "keratin pearls". What is the diagnosis? Review Topic

QID: 106379
FIGURES:
1

Melanoma

2%

(2/133)

2

Squamous cell carcinoma

83%

(110/133)

3

Basal cell carcinoma

8%

(11/133)

4

Osteomyelitis

2%

(3/133)

5

Plantar fasciitis

4%

(5/133)

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(M1.ON.1) A 58-year-old lifeguard develops squamous cell carcinoma of the skin on his forehead. Which of the following most likely preceded the development of this carcinoma? Review Topic

QID: 101308
1

Hamartomatous lesion of sebaceous glands

3%

(4/140)

2

Dry, scaly, hyperkeratotic papule

68%

(95/140)

3

A single, large pink patch

5%

(7/140)

4

Dermatophyte infection

0%

(0/140)

5

UVC exposure

24%

(33/140)

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