Atypical Spitz nevus

    Article Contributors: 
    Sean Klepper M.D.
    Artur Zembowicz M.D....
    • The criteria for atypia in Spitz nevi are not well agreed upon.
    • Proposed criteria are divided into those applying to the intraepidermal component and those applying to the dermal component.  These are enumerated below, with the most essential criteria in bold.
    • Intraepidermal component:
      • Large size (>1 cm)
      • Asymmetry
      • Ulceration
      • Lateral extension of the intrepidermal component ("shoulder phenomenon")
      • Disordered architecture:
        • Lentiginous or single-cell pattern
        • Variation in the size, shape, orientation, spacing or cohesion of nests
        • Pagetoid spread
      • Poor circumscription
      • Cytologic atypia beyond that which is typical for a Spitz nevus:
        • Pleomorphism
        • Variation in chromatin pattern
        • Nucleomegaly
        • Variation in nucleoli
      • Host response:
        • Patchy to band-like upper dermal mononuclear infiltrates
        • Fibroplasia
    • Dermal component:
      • Disordered architecture:
        • Increased cellularity
        • Cohesive, expansive cellular nodules
        • Asymmetry
        • Extension into the lower dermis or subcutis
        • Lack of maturation or orderly infiltration of collagen
        • Ulceration
        • Necrosis
      • Cytologic atypia:
        • Pleomorphism
        • Variation in chromatin pattern
        • Nucleomegaly
        • Variation in nucleoli
      • Mitotic activity, especially in the deeper aspect of the lesion and the presence of atypical mitoses
      • Host response:
        • Prominent mononuclear infiltrates
        • Formation of tumor stroma
    • Many of these criteria are quite subjective, in particular cytologic atypia, and a diagnosis of atypia or malignancy should be taken with great care, evaluating all of the features as a whole.
    • The threshold for a diagnosis of malignancy should be lowered in an older patient, especially one over the age of 30, and if the lesion presents on a location that is unusual for a Spitz nevus, such as the back.
    • In many cases malignancy or benignity cannot be definitively diagnosed with confidence, and if this is the case it should be clearly communicated to the clinician.

    Cases associated with this book:

  • Atypical Spitz nevus
    Author: Artur Zembowicz M.D. Ph.D.

    Conference: Dr. Z's Consultations
  • Right cheek lesion, 12-year-old girl
    Author: Artur Zembowicz M.D. Ph.D.

    Conference: Dr. Z's Consultations