Spitz Nevus Workup
- Author: Zoltan Trizna, MD, PhD; Chief Editor: Dirk M Elston, MD more...
Dermatoscopy: A starburst pattern is observed (ie, pigmented streaks symmetrically distributed at the periphery of the lesion). A 2015 multicenter study found that Spiz nevi show a multicomponent and nonspecific pattern.
Histopathologic evaluation of a suspected Spitz nevus is indicated.
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.
Analyses of mutations of BRAF, NRAS, and HRAS were promising in distinguishing Spitz nevi from melanomas, but BRAF mutations do not separate all Spitz nevi from spitzoid melanomas and other melanocytic proliferations.[5, 6, 7]
Surgical excision (generally with local anesthesia) and histopathologic evaluation of the margins of the specimen is recommended. With regard to sentinel node biopsy, 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.
Most Spitz nevi are 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 the images below).
The spindle cells are usually observed in a fascicular arrangement, and typically have a vertical orientation. These cells have abundant cytoplasm and contain a vesicular nucleus with a conspicuous nucleolus. The epithelioid cells have prominent nucleoli. Tumors composed only of epithelioid cells, those that lack dispersion at the base, those that are grossly asymmetrical, those with deep mitoses, and those in older individuals are more likely to represent malignant melanoma.
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. Immunohistochemistry and comparative genomic hybridization have proved helpful. Spitz nevi stain diffusely with S100A6, demonstrate no deep Ki-67 positive cells and show a gradient with HMB-45 staining. Melanomas show the opposite patterns.
A rare variant is the desmoplastic Spitz nevus in which the proliferating large epithelioid and/or fusiform melanocytes are embedded in a desmoplastic stroma with thick eosinophilic collagen bundles. Spitz nevi showing architectural features of Clark nevi (dysplastic nevi) were also described in a small series and have been termed Spark nevi or spastic nevi. The spindle cells were oriented parallel to the epidermis with fused rete and lamellar fibroplasia.
A case of a pseudogranulomatous variant (with inflammatory infiltrate mimicking a granulomatous dermatitis) was described.
Berlingeri-Ramos AC, Morales-Burgos A, Sánchez JL, Nogales EM. Spitz Nevus in a Hispanic Population: A Clinicopathological Study of 130 Cases. Am J Dermatopathol. 2010 Jan 22. [Medline].
Li CC, Harrist TJ, Noonan VL, Woo SB. Intraoral Spitz nevus: case report and literature review. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013 Oct 16. [Medline].
Rossiello L, Zalaudek I, Ferrara G, Docimo G, Giorgio CM, Argenziano G. Melanoacanthoma simulating pigmented spitz nevus: an unusual dermoscopy pitfall. Dermatol Surg. 2006 May. 32(5):735-7. [Medline].
Moscarella E, Lallas A, Kyrgidis A, Ferrara G, Longo C, Scalvenzi M, et al. Clinical and dermoscopic features of atypical Spitz tumors: A multicenter, retrospective, case-control study. J Am Acad Dermatol. 2015 Nov. 73 (5):777-84. [Medline].
Fullen DR, Poynter JN, Lowe L, et al. BRAF and NRAS mutations in spitzoid melanocytic lesions. Mod Pathol. 2006 Oct. 19(10):1324-32. [Medline].
Gill M, Cohen J, Renwick N, Mones JM, Silvers DN, Celebi JT. Genetic similarities between Spitz nevus and Spitzoid melanoma in children. Cancer. 2004 Dec 1. 101(11):2636-40. [Medline].
van Dijk MC, Bernsen MR, Ruiter DJ. Analysis of mutations in B-RAF, N-RAS, and H-RAS genes in the differential diagnosis of Spitz nevus and spitzoid melanoma. Am J Surg Pathol. 2005 Sep. 29(9):1145-51. [Medline].
Da Forno PD, Fletcher A, Pringle JH, Saldanha GS. Understanding spitzoid tumours: new insights from molecular pathology. Br J Dermatol. 2008 Jan. 158(1):4-14. [Medline].
Egberts F, Kaehler KC, Brasch J, Schwarz T, Cerroni L, Hauschild A. Multiple skin metastases of malignant melanoma with unusual clinical and histopathologic features in an immunosuppressed patient. J Am Acad Dermatol. 2008 May. 58(5):880-4. [Medline].
Nojavan H, Cribier B, Mehregan DR. [Desmoplastic Spitz nevus: a histopathological review and comparison with desmoplastic melanoma]. Ann Dermatol Venereol. 2009 Oct. 136(10):689-95. [Medline].
Ko CJ, McNiff JM, Glusac EJ. Melanocytic nevi with features of Spitz nevi and Clark's/dysplastic nevi ("Spark's" nevi). J Cutan Pathol. 2009 Oct. 36(10):1063-8. [Medline].
Sabater Marco V, Escutia Muñoz B, Morera Faet A, Roig MM, Botella Estrada R. Pseudogranulomatous Spitz nevus: a variant of Spitz nevus with heavy inflammatory infiltrate mimicking a granulomatous dermatitis. J Cutan Pathol. 2012 Sep 18. [Medline].
Gelbard SN, Tripp JM, Marghoob AA, et al. Management of Spitz nevi: a survey of dermatologists in the United States. J Am Acad Dermatol. 2002 Aug. 47(2):224-30. [Medline].
Murphy ME, Boyer JD, Stashower ME, Zitelli JA. The surgical management of Spitz nevi. Dermatol Surg. 2002 Nov. 28(11):1065-9; discussion 1069. [Medline].
Caracò C, Mozzillo N, Di Monta G, Botti G, Anniciello AM, Marone U, et al. Sentinel lymph node biopsy in atypical Spitz nevi: is it useful?. Eur J Surg Oncol. 2012 Oct. 38(10):932-5. [Medline].
Sepehr A, Chao E, Trefrey B, et al. Long-term Outcome of Spitz-Type Melanocytic Tumors. Arch Dermatol. 2011 Oct. 147(10):1173-9. [Medline].
Massi D, Tomasini C, Senetta R, Paglierani M, Salvianti F, Errico ME, et al. Atypical Spitz tumors in patients younger than 18 years. J Am Acad Dermatol. 2015 Jan. 72(1):37-46. [Medline].
Rapini RP. Spitz nevus or melanoma?. Semin Cutan Med Surg. 1999 Mar. 18(1):56-63. [Medline].