Atypical Spitz tumors in patients younger than 18 years

Abstract

Background: Diagnosis and proper management of atypical Spitz tumors in pediatric age are still controversial.

Objective: We sought to investigate the clinicopathological and molecular features of atypical Spitz tumors in patients aged 18 years or younger.

Methods: We performed a retrospective clinicopathological and fluorescence in situ hybridization study on 50 pediatric atypical Spitz tumors.

Results: Parameters that were significantly correlated with a diagnosis of atypical Spitz tumors over Spitz nevus included asymmetry, level IV/V, lack of maturation, solid growth, nuclear pleomorphism, high nuclear-cytoplasmic ratio, atypical and deep mitoses, and more than 6 mitoses/mm(2). In the atypical Spitz tumors group, a significantly higher mitotic rate was observed in prepuberal age (P = .04). The 4-probe fluorescence in situ hybridization melanoma assay did not discriminate atypical Spitz tumors from Spitz nevi. Heterozygous 9p21 loss was found in 3 of 37 cases and homozygous 9p21 loss in 2 of 37 cases. Only 1 child experienced a fatal outcome, showing genetic abnormalities by melanoma fluorescence in situ hybridization probe and a heterozygous 9p21 deletion.

Limitations: The limited number of adverse outcomes did not allow the prognostic analysis of single morphologic features.

Conclusion: Pediatric atypical Spitz tumors are associated with minimal lethal potential. Atypical Spitz tumors require complete excision and careful follow-up while our data do not support any clinical benefit for the sentinel lymph node biopsy procedure and completion lymphadenectomy.

Keywords: Spitz nevus; atypical Spitz tumor; fluorescence in situ hybridization; pediatric age; sentinel lymph node.