PRAME Expression as Helpful Immunohistochemical Marker in Rhabdoid Melanoma

Valerie Glutsch; Marion Wobser; Bastian Schilling; Anja Gesierich; Matthias Goebeler; Hermann Kneitz

doi:10.3390/dermatopathology9020019

PRAME Expression as Helpful Immunohistochemical Marker in Rhabdoid Melanoma

Dermatopathology (Basel). 2022 May 2;9(2):148-157. doi: 10.3390/dermatopathology9020019.

Authors

Valerie Glutsch¹, Marion Wobser¹, Bastian Schilling¹, Anja Gesierich¹, Matthias Goebeler¹, Hermann Kneitz¹

Affiliation

¹ Department of Dermatology, Venereology and Allergology, University Hospital Würzburg, 97080 Würzburg, Germany.

Abstract

Background: Rhabdoid melanoma is a rare variant of malignant melanoma with characteristic cytomorphologic features. Due to the potential loss of conventional melanocytic markers, histopathologic diagnosis is often challenging. We hypothesize that immunostaining for PReferentially expressed Antigen in MElanoma (PRAME) might have the potential to uncover the melanocytic origin of these dedifferentiated tumors.

Methods: Four cases of rhabdoid primary melanomas were assessed by immunohistochemistry for expression of PRAME and conventional melanocytic markers. Immunohistochemical expression patterns were analyzed in the rhabdoid primaries and, if available, associated metastases.

Results: All four cases of rhabdoid primary melanomas showed a strong nuclear positivity for PRAME, while the expression of conventional melanocytic markers S100, MART-1, SOX-10 and HMB-45 was variable between the analyzed cases.

Conclusions: In summary, we report four cases of rhabdoid primary melanoma with high to intermediate expression of PRAME despite the partial and variable loss of other melanocytic markers. Hence, PRAME might facilitate the recognition of this highly aggressive entity to avoid misdiagnosis due to histopathologic pitfalls.

Keywords: PRAME; immunohistochemistry; melanocytic markers; rhabdoid differentiation; rhabdoid melanoma.

Grants and funding

This research was funded by the Open Access Publication Fund of the University of Würzburg. V.G. is supported by the Else Kröner Forschungskolleg TWINSIGHT and by the Interdisziplinäres Zentrum für klinische Forschung (IZKF), University Hospital Würzburg.