Clumped perinuclear BAP1 expression is a frequent finding in sporadic epithelioid Spitz tumors
Article first published online: 15 MAR 2013
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Journal of Cutaneous Pathology
Volume 40, Issue 6, pages 538–542, June 2013
How to Cite
Clumped perinuclear BAP1 expression is a frequent finding in sporadic epithelioid Spitz tumors., , .
- Issue published online: 6 MAY 2013
- Article first published online: 15 MAR 2013
- Accepted manuscript online: 1 MAR 2013 12:56PM EST
- Manuscript Accepted: 22 FEB 2013
- Manuscript Revised: 28 JAN 2013
- Manuscript Received: 3 JUL 2012
- immunohistochemical method;
- melanocytic lesions;
- nevus with architectural disorder
BRCA1-associated protein 1 (BAP1) represents a recently identified tumor suppressor protein. Loss of BAP1 has been observed in cutaneous epithelioid Spitz tumors. These cutaneous melanocytic tumors show a distinct histopathologic phenotype characterized by an intradermal sheet-like proliferation of epithelioid melanocytes.
We retrospectively reviewed the clinical outcomes, histopathologic findings and immunophenotype in spitzoid melanocytic neoplasms with the morphologic features seen in BAP1 mutated Spitz tumors. Cases were obtained from our files. BAP1 immunohistochemistry was evaluated dichotomously for the presence of nuclear staining.
Fifteen of 19 cases showed loss of nuclear BAP1 expression. Of the 15 cases displaying nuclear loss of BAP1, clumped perinuclear staining was observed in 8 cases while 7 cases showed complete loss. Follow up ranging from 0–45 months (mean 17 months) was uneventful.
Our data are consistent with an indolent overall clinical course for epithelioid Spitz tumors with loss of BAP1. Furthermore, a large subset of epithelioid Spitz tumors display loss of nuclear expression but show a reproducible clumped perinuclear staining pattern.