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Dermatology > BENIGN NEOPLASMS
Spitz Nevus
Article Last Updated: Feb 7, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Zoltan Trizna, MD, PhD, Private Practice
Zoltan Trizna is a member of the following medical societies: American Academy of Dermatology, American Medical Association, and Texas Medical Association
Coauthor(s):
Ronald P Rapini, MD, Professor and Chair, Professor of Pathology, Department of Dermatology, University of Texas Medical School, MD Anderson Cancer Center
Editors: Maureen B Poh-Fitzpatrick, MD, Professor Emerita of Dermatology and Special Lecturer, Columbia University; Professor of Medicine (Dermatology), University of Tennessee; Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA; Rosalie Elenitsas, MD, Associate Professor of Dermatology, University of Pennsylvania School of Medicine; Director, Penn Cutaneous Pathology Services, Department of Dermatology, University of Pennsylvania Health System; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Author and Editor Disclosure
Synonyms and related keywords:
spindle and epithelioid cell nevus, juvenile melanoma, benign juvenile melanoma, nevus of large spindle and/or epithelioid cells, Spitz nevi, prepubertal melanoma
Background
Physicians have known for almost a century that some childhood lesions histologically diagnosed as melanomas did not show malignant behavior. The terms juvenile melanoma and prepubertal melanoma were used to describe such lesions.
After Spitz's original report of a series of patients, several attempts were made to establish objective criteria that would clearly delineate Spitz nevi and melanomas. The controversial classification of some cases as metastasizing Spitz nevi further confounded the issue; however, such cases illustrate the difficulty of accurately distinguishing Spitz nevi from melanoma based on histological criteria alone. Even today, no set of criteria can be used to predict the clinical outcome with absolute assurance.
Pathophysiology
A Spitz nevus can arise de novo or in association with an existing melanocytic nevus.
Frequency
International
Exact data on incidence or prevalence are not available. Spitz nevi are estimated to represent less than 1% of all childhood melanocytic nevi.
Mortality/Morbidity
These lesions are clinically benign.
Race
Spitz nevi have been described almost exclusively in fair-skinned individuals.
Sex
Both sexes are equally affected. Some authors describe a slight female predominance.
Age
About 50% of cases occur in children younger than 10 years; 70% of all cases are diagnosed during the first 2 decades of life.
History
- After its appearance, the lesion tends to grow rapidly and may reach a size of 1 cm within 6 months.
- Spitz nevi tend to become static after the rapid initial growth phase; however, color changes may be observed, and bleeding and pruritus are rarely noticed (see Media File 1).
Physical
- Single, dome-shaped, red or pigmented papules or nodules are typical.
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- Most lesions occur on the face or legs.
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- The color may vary from nonpigmented through pink to orange-red.
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- Some lesions are pigmented, especially those found on lower extremities.
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- Note that the rare recurrences may mimic metastatic malignant melanoma.
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Causes
The cause of Spitz nevi is not known.
Basal Cell Carcinoma
Juvenile Xanthogranuloma (Nevoxanthoendothelioma)
Nevi, Melanocytic
Pyogenic Granuloma (Lobular Capillary Hemangioma)
Warts, Nongenital
Other Problems to be Considered
Melanoma
Epidermal nevus
Granulomas
Histiocytoma
Reed nevus
Vascular tumors
Imaging Studies
- Dermatoscopy: A starburst pattern is observed (ie, pigmented streaks symmetrically distributed at the periphery of the lesion).
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Other Tests
- Histopathologic evaluation of a suspected Spitz nevus is indicated.
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- The value of including individual proliferation index and histopathological parameters (eg, Ki-67, Pi-21, fatty acid synthetase) into models of predictive probabilities is uncertain, but a panel of markers including Ki-67, HMB-45, and S100A6 can be helpful in establishing a histologic diagnosis. Ki-67 staining is usually absent in dermal nuclei of benign Spitz nevi. HMB-45 staining demonstrates a gradient, and S100A6 diffusely stains the lesion.
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- Analysis of mutations of B-raf, N-ras, and H-ras were promising in distinguishing Spitz nevi from melanomas. Contrary to previous reports, B-raf mutations did not separate all Spitz nevi from spitzoid melanomas and other melanocytic proliferations.
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Procedures
- Surgical excision (generally with local anesthesia) and histopathologic evaluation of the margins of the specimen is recommended.
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- Sentinel node biopsy: In a series of 12 cases with atypical Spitz nevi showed nodal micrometastases in one third of the patients, suggesting a yet not understood metastatic potential.
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Histologic Findings
The classic Spitz nevus is predominantly compound, although junctional and intradermal lesions are also observed. The sine qua non of the diagnosis is the presence of large and/or spindle-shaped melanocytes, usually in nests. The nests are composed of an admixture of spindle cells and/or epithelioid cells, although frequently, the spindle-shaped cells predominate (see Media Files 2-5). The spindle cells are usually observed in a fascicular arrangement. These cells have abundant cytoplasm and contain a vesicular nucleus with a conspicuous nucleolus. The epithelioid cells are bizarrely shaped, show poor cohesion, often have several nuclei, and frequently have multiple large nucleoli. Striking symmetry, sharp lateral demarcation, absent (or rare) mitoses, absence of atypical mitoses, presence of eosinophilic and periodic acid-Schiff (PAS)–positive globules (Kamino bodies) and nondisruptive (single-file like) infiltration of collagen are important features indicating the diagnosis of Spitz nevi. Single-file melanocytes may also be observed in the reticular dermis located at the base of the lesion (dispersion). Another important feature is the maturation of cellular elements toward the dermis. Pagetoid spread of the melanocytes is usually confined to the center of the lesion; when present, it can cause confusion with melanoma. The epidermis is hyperkeratotic and acanthotic. A cleavage artifact of fixation is commonly noticed above the nests and around superficial dermal elements. The histologic distinction between Spitz nevi and melanomas is equivocal in up to 8% of cases.
Surgical Care
Excision of lesions suspected of being Spitz nevi with histopathologic evaluation of the margins of the specimen is indicated.
Consultations
Consult a plastic surgeon or head and neck surgeon if the excision requires extensive repair.
Activity
Activity is restricted only to the extent that the surgical procedure justifies.
Further Outpatient Care
- Regular follow-up, preferably by a dermatologist, is indicated.
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Deterrence/Prevention
- Sun protection is recommended.
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Complications
- The only complications are those that may occur after any surgical excision and repair.
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Prognosis
- The prognosis is good. Recurrences should be treated with re-excision.
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Patient Education
- Educate patients about sun protection and self-examination of the skin.
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- For excellent patient education materials, visit eMedicine's Cancer and Tumors Center. Also see eMedicine's patient education article Skin Cancer.
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Medical/Legal Pitfalls
- Misdiagnosis of Spitz nevi as melanomas and misdiagnosis of melanomas as Spitz nevi
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- In one study, 6.5% of cases diagnosed clinically as melanomas were Spitz nevi.
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- Histopathologic differentiation from melanomas is equivocal in up to 8% of cases.
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- Criteria that in concert strengthen the probability of the diagnosis of Spitz nevus in any given case include a young patient, a well-demarcated and symmetrical lesion, maturation and dispersion of melanocytes at its base, and the presence of epithelial hyperplasia, but no criterion is absolutely reliable.
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Special Concerns
- Clinical data are invaluable for the dermatopathologist in reaching the diagnosis of Spitz nevus with reasonable certainty.
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- In adults, assuring that a lesion that clinically looks like a Spitz nevus is not a melanoma is more difficult.
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- In a few cases, only the clinical course over time provides the answer.
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- A special concern for the surgeon is whether clear margins must be obtained for the excision to be considered adequate.
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- This has been extensively discussed in the literature.
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- Striving for clear margins is prudent from the medicolegal point of view.
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- Considerable confusion exists in the literature whether a Spitz nevus is a melanoma.
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- Dal Pozzo V, Benelli C, Restano L, Gianotti R, Cesana BM. Clinical review of 247 case records of Spitz nevus (epithelioid cell and/or spindle cell nevus). Dermatology. 1997;194(1):20-5. [Medline].
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Spitz Nevus excerpt Article Last Updated: Feb 7, 2007
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