Original StudyMAP2K1-Mutated Melanocytic Neoplasms With a SPARK-Like MorphologyDonati, Michele MD*,†; Nosek, Daniel MD‡; Waldenbäck, Pia MD‡; Martinek, Petr PhD§; Jonsson, Björn-Anders PhD¶; Galgonkova, Petra MD‖; Hawawrehova, Marcela MD**; Berouskova, Petra MD††; Kastnerova, Liubov MD, PhD†,§; Persichetti, Paolo MD, PhD‡‡; Crescenzi, Anna MD*; Michal, Michal MD†,§; Kazakov, Dmitry V. MD, PhD†,§ Author Information *Department of Pathology, University Hospital Campus Bio-Medico, Rome, Italy; †Sikl's Department of Pathology, Medical Faculty in Pilsen, Charles University in Prague, Pilsen, Czech Republic; ‡Department of Pathology, Umeå University, Umeå, Sweden; §Bioptical Laboratory, Pilsen, Czech Republic; ¶Department of Clinical Genetics, Umeå University, Umeå, Sweden; ‖Department of Pathology, Regional Hospital, Ceske Budojovice, Czech Republic; **Department of Pathology, NEMOS Hospital, Sokolov, Czech Republic; ††Department of Pathology, Regional Hospital, Kladno, Czech Republic; and ‡‡Department of Plastic, Reconstructive and Aesthetic Surgery, Campus Bio-Medico di Roma University, Rome, Italy. Correspondence: Dmitry V. Kazakov, MD, PhD, Sikl's Department of Pathology, Charles University Medical Faculty Hospital, Alej Svobody 80, 304 60 Pilsen, Czech Republic (e-mail: [email protected]). The authors declare no conflicts of interest. The American Journal of Dermatopathology 43(6):p 412-417, June 2021. | DOI: 10.1097/DAD.0000000000001840 Buy Metrics Abstract Specific alterations involving MAPK genes (MAP3K8 fusions, MAP3K3 fusions) have been recently detected in a subgroup of spitzoid neoplasms that seem to constitute a distinctive clinicopathologic group, occur mostly in younger patients (median age 18 years) and present with atypical histologic features associated with frequent homozygous deletion of CDKN2A, qualifying a high proportion of them as Spitz melanoma (malignant Spitz tumor). Apart from lesions with spitzoid morphology harboring MAP3K8 or MAP3K3 fusion, a single case with MAP2K1 deletion has been identified. The authors report herein 4 melanocytic lesions with a MAP2K1 mutation, all showing similar microscopic appearances, including spitzoid cytology and dysplastic architectural features, resembling so-called SPARK nevus, suggesting that these lesions may represent another distinctive group. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.