Dermatology Book

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Keratoacanthoma

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  1. Pathophysiology
    1. Benign epithelial lesion
    2. No longer thought to be associated with malignancy
      1. Not a squamous cell cancer variant
      2. May be difficult to distinguish from SCC (see below)
  2. Causes
    1. Ultraviolet light exposure
    2. Human papillomavirus
    3. Coal tar derivative exposure
  3. Signs
    1. Characteristics
      1. Initial
        1. Red to skin-colored dome-shaped Papule
        2. Smooth surface
        3. Central umbilicated keratinous core
        4. May reach up to 2 cm in size
        5. Rapid growth
      2. Later (after 4-6 months)
        1. Lesion regresses
        2. Keratin core expelled
        3. Hypopigmented scar remains
    2. Distribution (sun-exposed areas)
      1. Face
      2. Extremities
  4. Differential Diagnosis
    1. Squamous Cell Carcinoma
      1. Similar grossly and histologically to keratoacanthoma
  5. Management
    1. Smaller keratoacanthoma
      1. Electrodessication and Curettage
      2. Blunt Dissection
    2. Larger keratoacanthoma
      1. Excision
      2. Moh's Surgery for difficult areas
    3. Other options
      1. Topical agents
        1. 5-Fluorouracil 5% cream
          1. Apply during rapid growth tid
          2. Use under tape occlusion
          3. Effective in 1-6 weeks
        2. Podophyllum 25% in benzoin
          1. Remove central crust and apply every 2 weeks prn
          2. Apply in clinic only due to high concentration
      2. Intralesional injections during rapid growth phase
        1. 5-Fluorouracil intralesional injection
        2. Methotrexate intralesional injection
        3. 5-Interferon alfa-2a injection
      3. Oral agents (for multiple lesions)
        1. Isotretinoin (Accutane)
      4. Radiotherapy
        1. Indicated for difficult cosmetic areas
  6. References
    1. Habif (1996) Dermatology, Mosby-Year, p. 638
    2. Luba (2003) Am Fam Physician 67(4):729

keratoacanthoma (C0022572)

Definition (MSH)A benign, non-neoplastic, usually self-limiting epithelial lesion closely resembling squamous cell carcinoma clinically and histopathologically. It occurs in solitary, multiple, and eruptive forms. The solitary and multiple forms occur on sunlight exposed areas and are identical histologically; they affect primarily white males. The eruptive form usually involves both sexes and appears as a generalized papular eruption.
Definition (CSP)benign papular lesion with a superficial crater filled with a keratin plug, usually on the face.
Definition (NCI)(KER-a-toe-AK-an-THOW-ma) A benign (noncancerous), rapidly growing skin tumor that usually occurs on sun-exposed areas of the skin and that can go away without treatment.
Definition (NCI)A dome-shaped, rapidly growing skin lesion composed of well differentiated squamous cells. It represents a proliferation of the infundibular epithelium of the hair follicle and its morphologic distinction from a well differentiated carcinoma may be difficult or impossible. Keratoacanthomas affect males more frequently than females and the majority tends to regress spontaneously. It has been suggested that keratoacanthoma represents a distinct subtype of squamous cell carcinoma of the skin. --2003
ConceptsNeoplastic Process (T191)
MSHD007636
EnglishKA - Keratoacanthoma, keratoacanthoma, Keratoacanthomas, Molluscum sebaceum
Spanishmolusco sebaceo, queratoacantoma, queratoacantoma localizado
Parent Conceptsskin disorder (C0037274), Epithelial neoplasm of skin (C0345976), Neoplastic disease of uncertain behavior (C0154129), Ambiguous concept (C1274012), Neoplasm of integumentary system (C1302872), Duplicate concept (C1274013)
SourcesCOSTAR, CSP, LCH, MSH, MTH, NCI, NDFRT, OMIM, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)



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