Spitzoid Melanoma-Case Report; Potential Role of Alk Expression in the Diagnosis of Spitzoid Melanocytic Lesions

Abstract

Spitzoid neoplasms are classifi ed as Spitz naevi, atypical Spitz tumours and spitzoid melanomas. In 10-15% of these lesions, anaplastic lymphoma kinase (ALK) fusions were identifi ed, that can be demonstrated by immunohistochemical tests.We report a case of spitzoid melanoma in a 15-year-old female patient. The tumor occurred as an un-ulcerated polypoid pigmented nodule on the left thigh; the histopathologic examination revealed a spitzoid melanoma with Breslow index of 13 mm, with lympho-vascular invasion and immunohistochemical phenotype HMB45+, T311+, Melan A+, p16-, p21+, ALK-; sentinel lymph node biopsy identifi ed three of four positive lymph nodes. The patient is well 20 months after the fi rst diagnosis.Differential diagnosis in spitzoid melanoma is extremely diffi cult, no reliable biomarkers for treatment response prediction or prognosis being available to date.