BRAF Mutated and Morphologically Spitzoid Tumors, a Subgroup of Melanocytic Neoplasms Difficult to Distinguish from True Spitz Neoplasms

Pedram Gerami*, Alice Chen, Natasha Sharma, Pragi Patel, Michael Hagstrom, Pranav Kancherla, Tara Geraminejad, Shantel Olivares, Asok Biswas, Marcus Bosenberg, Klaus J. Busam, Arnaud De La Fouchardière, Lyn M. Duncan, David E. Elder, Jennifer Ko, Gilles Landman, Alexander J. Lazar, Lori Lowe, Daniela Massi, Daniela Mihic-ProbstDouglas C. Parker, Richard A. Scolyer, Christopher R. Shea, Artur Zembowicz, Sook Jung Yun, Willeke A.M. Blokx, Raymond L. Barnhill

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Drivers of Spitz neoplasms include activating point mutations in HRAS and Spitz-Associated genomic fusions. It has become evident that some BRAF-mutated melanocytic neoplasms can morphologically mimic Spitz tumors (STs). These have been termed BRAF mutated and morphologically spitzoid (BAMS). In this study, 17 experts from the International Melanoma Pathology Study Group assessed 54 cases which included 40 BAMS and 14 true STs. The participants reviewed the cases blinded to the genomic data and selected among several diagnostic options, including BAMS, ST, melanoma, and other. A total of 38% of all diagnostic selections in the BAMS cases were for BAMS, whereas 32% were for ST. In 22 of the BAMS cases, the favored diagnosis was BAMS, whereas in 17 of the BAMS cases, the favored diagnosis was ST. Among the 20 cases in the total group of 54 with the highest number of votes for ST, half were BAMS. Of BAMS, 75% had a number of votes for ST that was within the SD of votes for ST seen among true ST cases. There was poor interobserver agreement for the precise diagnosis of the BAMS (kappa = 0.16) but good agreement that these cases were not melanoma (kappa = 0.7). BAMS nevi/tumors can closely mimic Spitz neoplasms. Expert melanoma pathologists in this study favored a diagnosis of ST in nearly half of the BAMS cases. There are BAMS cases that even experts cannot morphologically distinguish from true Spitz neoplasms.

Original languageEnglish (US)
Pages (from-to)538-545
Number of pages8
JournalAmerican Journal of Surgical Pathology
Volume48
Issue number5
DOIs
StatePublished - May 1 2024

Keywords

  • BRAF
  • Spitz melanoma
  • Spitz nevi
  • atypical Spitz tumors
  • dysplastic nevi
  • melanoma

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine

Fingerprint

Dive into the research topics of 'BRAF Mutated and Morphologically Spitzoid Tumors, a Subgroup of Melanocytic Neoplasms Difficult to Distinguish from True Spitz Neoplasms'. Together they form a unique fingerprint.

Cite this