II. Epidemiology
- Most common benign epithelial tumor
- Occurs in patients over age 30 years old
- Number of lesions increase with age
- Men and women affected equally
- Autosomal Dominant inheritance
III. Pathophysiology
- Common benign, hereditary tumor
- Hyperkeratotic epidermal lesion
IV. Signs
- Characteristics
- Early (Flat lesions)
- Small (<3mm)
- Slightly elevated
- Variable hyperpigmented coloration
- Late (Raised pigmented lesions)
- Large Plaque (1 to 6 cm)
- May feel greasy, velvety or warty
- Keratotic (warty) appearance
- Appears "stuck-on" like clay
- Rough surface
- Yellow, tan, brown or black pigmentation
- Sharp well-circumscribed border
- Early (Flat lesions)
- Distribution (typically multiple are present)
- Trunk (most common location)
- Face
- Scalp
- Upper extremities
- Associated lesions
- Horn cysts
- Milia-like cysts
V. Variants
- Stucco Keratoses
- Numerous small white, dry scaly lesions on extremity
-
Dermatosis Papulosa
- Small, dark Papules on face seen in darker skin
- Leser-Trelat Sign (paraneoplastic sign)
- Sudden onset and increase in number of keratoses
- Requires thorough evaluation for malignancy
- Seborrheic Keratoses often resolve with malignancy treatment and reappear with cancer recurrence
- Associated with underlying adenocarcinoma
VI. Differential Diagnosis
- Early Seborrheic Keratosis (Flat)
- Solar Lentigo
- Spreading pigmented Actinic Keratosis
- Malignant Melanoma
- Late Seborrheic Keratosis (Raised pigmented)
- Pigmented Basal Cell Carcinoma
- Malignant Melanoma
VII. Management
- Indications for excision
- Cosmesis
- Local irritation due to recurrent Trauma
- Malignancy suspected (Excisional Biopsy needed)
- Techniques
- Curettage with light Electrocautery
- Inject Local Anesthesia first
- Lesion easily rubs off
- Lightly cauterize base to prevent recurrence
- Cryotherapy with Liquid Nitrogen
- May not be effective in very thick lesions
- Excision
- Shave Excision
- Excisional Biopsy (if possible Melanoma)
- Topical Corticosteroids
- Indicated for irritated Seborrheic Keratoses
- Curettage with light Electrocautery
VIII. References
- Fitzpatrick (1999) Color Atlas Dermatology
- Higgins (2015) Am Fam Physician 92(7): 601-7 [PubMed]