Spitz tumors represent a heterogeneous group of melanocytic neoplasms with a spectrum of biological behavior ranging from benign (Spitz nevus) to malignant (spitzoid melanoma). Prediction of the behavior of these lesions based on their histological presentation is not always possible. Recently, mutually exclusive activating kinase fusions, involving ALK, NTRK1, NTRK3, RET, MET, ROS1, and BRAF, have been found in a subset of spitzoid lesions. Some of these genetic alterations were associated with specific morphological features. Here, we report the histological presentation of 6 Spitz tumors with ROS1 fusion. The age of the patients ranged from 6 to 34 years, with strong female prevalence (5:1). All neoplasms were compound melanocytic proliferations with a predominant dermal growth but a conspicuous junctional component displaying atypical microscopic features qualifying them as atypical Spitz tumor. FIP1L1 and CAPRIN1 were identified as 2 novel 5'-fusion partners of ROS1 along with the known PWWP2A-ROS1 fusion. FISH for copy number changes of 9p21, 6p25, and 11q13 was negative in all but 1 neoplasm harboring isolated gain of 8q24. TERT-promoter hotspot mutation analysis was negative in all tumors. All patients are disease-free after a mean follow-up period of 30 months. It is concluded that ROS1-fused spitzoid neoplasms seem to have no distinctive histopathological features although consistent findings were spindled melanocytes arranged in confluent whorling nests, prominent transepidermal elimination of melanocytic nests, and myxoid/mucinous changes.

• MeSH
• chromozomální proteiny, nehistonové genetika   MeSH
• dítě MeSH
• dospělí MeSH
• epiteloidní a vřetenobuněčný névus genetika   patologie   MeSH
• faktory štěpení a polyadenylace mRNA genetika   MeSH
• hybridizace in situ fluorescenční MeSH
• lidé MeSH
• melanom genetika   patologie   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutační analýza DNA MeSH
• nádory kůže genetika   patologie   MeSH
• onkogenní fúze MeSH
• proteiny buněčného cyklu genetika   MeSH
• protoonkogenní proteiny genetika   MeSH
• telomerasa genetika   MeSH
• tyrosinkinasy genetika   MeSH
• variabilita počtu kopií segmentů DNA MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH