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EWSR1‐SMAD3 rearranged fibroblastic tumor: Case series and review
Author(s) -
Habeeb Omar,
Korty Katelen E.,
Azzato Elizabeth M.,
Astbury Caroline,
Farkas Daniel H.,
Ko Jennifer S.,
Billings Steven D.
Publication year - 2021
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.13870
Subject(s) - series (stratigraphy) , pathology , medicine , biology , paleontology
We report the largest series to date (N = 6) of EWSR1 ‐ SMAD3 rearranged fibroblastic tumor. Initially described in 2018, the tumor features a marked female predominance (F:M, 5:1, mean age 44‐years, median age 45.5 years; range 27‐57), with most cases (5/6, 83%) arising in acral locations (4 on foot/toe, 1 on hand). One case presented on the lower extremity. The lesions presented as nodules and were composed of short, variably cellular, intersecting fascicles of uniform spindled cells in a collagenous to myxoid stroma. In four cases, the tumor abutted the epidermis without a grenz zone. In one case, there was an abrupt transition to a central, acellular hyalinized area. Two other cases had admixed smaller collagenous areas, reminiscent of collagen rosettes. One had a concentric arrangement of tumor cells around blood vessels. Mitotic activity was low (<1/10 HPFs). All were positive for ERG by immunohistochemistry and negative for CD34 (6/6). An EWSR1‐SMAD3 fusion was identified in three cases tested by next‐generation sequencing (3/3). Rearrangement of EWSR1 by fluorescence in situ hybridization was showed in 1/1 case. Our series reaffirms prior findings and expands the known histopathologic spectrum of this emerging entity.