Updated: 7/2/2019

Squamous Cell Carcinoma

Topic
Review Topic
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Questions
6
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Evidence
4
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Snapshot
  • A 74-year-old man presents to the dermatologist’s office for his annual total body skin exam. His past medical history is significant for multiple actinic keratoses, previously treated with cryotherapy. At this visit, he points to a larger lesion on his ear, complaining that it grew back after last year’s cryotherapy. A shave biopsy was done and pathology reveals malignant cells invading the dermis. He is scheduled for an excision.
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 )
    • major risk factor = significant sun exposure (damage to keratinocytes) 
      • actinic keratosis
      • actinic cheilitis
    • other risk factors
      • immunosuppression (similar to treatment for organ transplant)
      • arsenic exposure
      • old scars or burns
      • xeroderma pigmentosum
      • ionizing radiation
  • Pathogenesis
    • typically develop from precursor actinic keratoses, but may arise de novo
    • slow-growing malignancy
    • metastases are rare
  • Keratoacanthoma is a variant of low-grade squamous cell carcinoma
    • grows rapidly and regresses spontaneously
  • Bowen disease is a kind of cutaneous squamous cell carcinoma in situ that usually appears
    • well-demarcated
    • scaly patch or plaque
    • often erythematous; however,
      • can be pigmented or skin colored
Presentation
  • Symptoms
    • typically asymptomatic, but may be tender especially if ulcerated 
  • Physical exam 
    • from actinic keratosis
      • red, poorly defined base with adherent yellow or white scale
    • de novo
      • sharply defined smooth, dull, red, dome-shaped nodule
      • crusted center
    • frequently ulcerates
    • frequently on sun-exposed areas
      • face, neck, hands, ears
      • common on lower lips
      • lesions often against a background of sun-damaged skin
        • atrophy, telangiectasias, blotchy hyperpigmentation
Evaluation
  • Diagnosis by skin biopsy 
    • atypical keratinocytes and malignant cells
    • invasion into dermis
    • keratin “pearls” on histology
Differential
  • Actinic keratosis
  • Actinic cheilitis
Treatment
  • Wide local surgical excision
    • with histologic confirmation of negative margins
  • Radiation if surgery is not an option 
Prognosis, Prevention, and Complications
  • Prognosis
    • if treated, very excellent prognosis
    • lesions on lip, ear, or scalp may be more aggressive
  • Prevention
    • sun avoidance
    • sunscreen use 
  • Complications
    • potential recurrence if immunosuppressed
 

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Questions (6)
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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(M3.ON.9) A 71-year-old man presents to his primary care doctor for a lesion on his skin. The patient states he is generally healthy but has noticed this lesion enlarging over the past several months. He worked in the navy and is not currently taking any medications. His temperature is 98.1°F (36.7°C), blood pressure is 123/83 mmHg, pulse is 85/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical exam is notable for the finding in Figure A on the patient's head. Which of the following is the most likely diagnosis? Review Topic

QID: 102763
FIGURES:
1

Actinic keratosis

0%

(0/2)

2

Basal cell carcinoma

0%

(0/2)

3

Melanoma

100%

(2/2)

4

Squamous cell carcinoma

0%

(0/2)

5

Xerosis

0%

(0/2)

M2

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(M2.ON.40) A 67-year-old landscaper presents to his primary care physician for a routine visit. On exam, the physician notes a 2x2 cm rash above his upper lip, shown in Figure A. Upon further questioning, the patient states the rash has been there for weeks, but it hasn’t really bothered him. It is not painful or pruritic. He does not recall any recent bug bites. Which of the following is the most important risk factor for this type of lesion? Review Topic

QID: 104251
FIGURES:
1

Increasing age

1%

(1/80)

2

Sun exposure

86%

(69/80)

3

Immunosuppression

5%

(4/80)

4

Smoking

1%

(1/80)

5

History of eczema

5%

(4/80)

M2

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