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Atypical Spitz nevus

Editor: unassigned
Article Contributors:
Sean Klepper M.D.
Artur Zembowicz M.D. Ph.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.
‹ Spitz nevusupDesmoplastic Spitz nevus ›

Cases associated with this book:

  • Right cheek lesion, 12-year-old girl
    Author: Artur Zembowicz M.D. Ph.D.
    Spitz nevus with moderate atypia 1Spitz nevus with moderate atypia 2Spitz nevus with moderate atypia 3Spitz nevus with moderate atypia 4

    Conference: Dr. Z's Consultations
  • Atypical Spitz nevus
    Author: Artur Zembowicz M.D. Ph.D.
    Atypical Spitz nevus 1Atypical Spitz nevus 2Atypical Spitz nevus 3Atypical Spitz nevus 4Atypical Spitz nevus 5Atypical Spitz nevus 6

    Conference: Dr. Z's Consultations