Spitzoid melanoma in children: Clinicopathological study and application of immunohistochemistry as an adjunct diagnostic tool

Introduction The term spitzoid melanoma (SM) is reserved for a rare group of tumors with striking resemblance to Spitz nevus, often developing in children diagnosed in retrospect after the development of metastases. Objectives To determine the biological significance of SM and to analyze the effectiveness of adjuvant diagnostic techniques. Materials and methods A retrospective, observational study of 38 cases of SM in patients younger than 18 years. Histological type, Clark level and Breslow thickness, radial and vertical growth phase, mitotic count/mm², ulceration, regression, vascular and perineural invasion, satellitosis, cytology and associated nevi were reviewed. An immunohistochemical analysis with HMB45 and Ki67 was performed in 10 cases. These features were correlated to patient's stage and outcome. Results Analysis of histological and immunohistochemical features should allow accurate diagnosis in most cases. Given the low mortality rate, no conclusions about the prognostic significance of histological parameters of the primary tumor could be established. Conclusion We report the largest series of SM from a unique center. Although these patients may have a better prognosis than adults, some patients with SM develop metastasis and die, particularly after age 11 years. Therefore, we recommend using the same treatments as in adults.