Skin melanocytic tumor
Spitzoid neoplasms, BAP1 inactivated neoplasms, and deep penetrating nevi
Spitz nevus


Minor changes: 21 July 2021

Copyright: 2002-2021, PathologyOutlines.com, Inc.

PubMed Search: Spitz nevus [title] review[ptyp]

See also: Atypical Spitz nevus, Desmoplastic Spitz nevus

Katharina Wiedemeyer, M.D., Ph.D.
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Cite this page: Wiedemeyer K. Spitz nevus. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticspitz.html. Accessed July 24th, 2021.
Definition / general
Essential features
  • Benign melanocytic tumors
  • Composed of large spindled and epithelioid melanocytes
  • Primarily affect children and young adults
  • Treatment options: observation or complete excision
Terminology
  • First described by Sophie Spitz in 1948 (Am J Pathol 1948;24:591)
  • Synonyms for Spitz nevus:
    • Benign juvenile melanoma
    • Spindle cell nevus
    • Spindle and epithelioid cell nevus
ICD coding
  • ICD-O: 8770/0 - epithelioid and spindle cell nevus
Epidemiology
  • Exact data about prevalence and incidence are lacking
  • Approximately 1 - 2% of all excised nevi are Spitz nevi
  • Predilection for children and young adults but may occur at any age
  • Females are affected more commonly than males
  • Congenital Spitz nevi are very rare
  • References: Cancer 1977;40:217, Am J Surg Pathol 2002;26:654
Sites
  • Anatomical distribution of Spitz nevi is wide
  • Lower extremities, the face (especially in children) and the trunk (preferably in adults) are most commonly affected
  • Reference: Adv Anat Pathol 2010;17:73
Pathophysiology
  • Spitz nevus usually arises de novo but also in association with an existing melanocytic nevus
  • Congenital variants have been described
Etiology
  • Etiology of Spitz nevi is unknown
  • Spitzoid melanocytic neoplasms have significant morphologic and molecular differences from conventional melanocytic lesions
Clinical features
  • Prototypic or conventional Spitz nevi are solitary, well circumscribed, symmetrical, pink or pigmented, dome shaped papules several millimeters in size, typically < 6 mm
  • May appear verrucous and may ulcerate
  • Can resemble hemangioma or pyogenic granuloma
  • Rarely occur in multiples, either disseminated or in clusters (agminated Spitz nevi)
  • Show a risk of recurrence after incomplete excision
  • Behavior is entirely benign
  • Reference: Am J Dermatopathol 2009;31:107
Diagnosis
  • The diagnosis of conventional Spitz nevi is straightforward clinically and histopathologically
  • Conventional Spitz nevi need to be distinguished from atypical Spitz nevi and spitzoid melanoma
Laboratory
  • Not applicable; no laboratory values exist to diagnose or monitor Spitz nevi
Prognostic factors
  • Conventional Spitz nevi are benign, the prognosis is good
  • Recurrences should be treated with re-excision
Case reports
Treatment
  • Complete excision with evaluation of margins
Clinical images

AFIP images

Small, symmetrical pinkish tan lesion



Images hosted on other servers:

On ear of child

Gross description
  • Well circumscribed, dome shaped pink or pigmented papule, size is several millimeters (usually < 1 cm)
Microscopic (histologic) description
  • Conventional Spitz nevi are well circumscribed, symmetrical and show an overall wedge shaped silhouette
  • Consist of large junctional and dermal melanocytic nests formed by spindled or epitheliod cells
  • Melanocytes are large, spindled or epitheliod, contain abundant pale or ground glass cytoplasm and finely dispersed pigment (if present)
  • Mild nuclear pleomorphism may occur, mitoses are rare or absent
  • Melanocytic nests may show maturation with depth and break up into single melanocytes at the dermal base of the lesion
  • Junctional nests often show separation artifacts (clefting) to the surrounding epidermis and are oriented perpendicularly to the epidermis
  • Mild pagetoid scatter of single melanocytes may be a feature but is usually confined to the lower half of the epidermis and found only in the center of the lesion
  • Transepidermal elimination of melanocytic nests may occur
  • A typical finding of classic Spitz nevi are PAS+, eosinophilic, hyaline globules, so called Kamino bodies, located at the dermoepidermal junction
  • Perivascular lymphocytic infiltrates are variably present
  • Histopathological variants of Spitz nevi:
    • Pigmented spindle cell nevus (Reed nevus)
    • Angiomatous Spitz nevus
    • Desmoplastic Spitz nevus
    • Plexiform Spitz nevus
    • Polypoid Spitz nevus
    • Agminated Spitz nevus
    • Pseudogranulomatous Spitz nevus
    • Myxoid Spitz nevus
    • Combined Spitz nevus
  • Reference: J Am Acad Dermatol 2014;71:1077
Microscopic (histologic) images

Contributed by Katharina Wiedemeyer, M.D., Ph.D.

Symmetrical, sharply demarcated tumor

Nested spindled and epitheliod melanocytes

Epidermal hyperplasia and large junctional nests

Kamino bodies and clefting of junctional nests


Epithelioid cell morphology

No cell atypia within dermis

Spindle cell morphology

Cytology description
Positive stains
Negative stains
Electron microscopy description
  • No elecron miscroscopic studies of Spitz nevi exist
Molecular / cytogenetics description
Sample pathology report
  • Skin, left arm (clinical nevus), excision:
    • Spitz nevus, conventional (see comment)
    • Comment: The gross specimen is a 0.5 cm, pink-brown, dome shaped papule of the right arm. Microscopically, the tumor is symmetrical and well demarcated with a wedge shaped growth pattern. There is epidermal hyperplasia with hypergranulosis and hyperkeratosis. The tumor consists of large melanocytic nests composed entirely of spindle and epithelioid cells containing abundant cytoplasm with varying amounts of melanin granules. Single Kamino bodies are found at the dermal-epidermal junction, with occasional upward scatter of single melanocytes confined to the center of the lesion. No atypia is noted. Dermal melanocytes show maturation with depth and are dispersed singly within the collagen bundles at the base of the tumor. No dermal mitoses are found. Immunohistochemical staining demonstrates strong positivity for S100 protein; HMB45 staining is partially positive within junctional and upper dermal nests. The margins are clear.
Differential diagnosis
  • Atypical Spitz tumor:
    • Age usually > 10 years or postpubertal
    • Atypical Spitz tumors are usually larger (> 5 - 10 mm) than Spitz nevi and show some worrisome histological features, such as asymmetry, pagetoid scatter in the periphery of the tumor, moderate nuclear pleomorphism and hyperchromatic nuclei
    • Mitotic rate can be increased but no mitoses are found in the deep dermis
    • There is no reliable immunohistochemical marker to distinguish atypical Spitz nevus from conventional Spitz nevus
  • Malignant Spitz tumor / Spitz melanoma:
    • Age usually postpubertal
    • Histopathological criteria of malignancy are size > 10 mm, an asymmetric outline with poor circumscription, infiltrative growth, consumption of the epidermis, ulceration, nuclear pleomorphism, increased mitotic activity within dermis including atypical mitoses, lack of maturation of cells with depth and lymphovascular invasion
  • References: Surg Pathol Clin 2017;10:281, Pathology 2016;48:113
Board review style question #1
    Spitz nevi

  1. Are benign melanocytic neoplasms affecting children and young adults
  2. Behave biologically similar to melanoma
  3. Frequently show BRAF mutations
  4. Require wide excision and sentinel lymph node biopsy
  5. Usually affect sun exposed skin of elderly adults
Board review style answer #1
A. Are benign melanocytic neoplasms affecting children and young adults

Comment Here

Reference: Spitz nevus
Board review style question #2

    Histopathologically, Spitz nevi

  1. Are always unpigmented
  2. Can show Kamino bodies at the epidermodermal junction
  3. Exhibit marked cytological atypia
  4. Often show atrophy of the epidermis
  5. Show mitoses in the dermis
Board review style answer #2
B. Can show Kamino bodies at the epidermodermal junction

Comment Here

Reference: Spitz nevus
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