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Biphasic dermatofibrosarcoma protuberans with a labyrinthine plexiform high‐grade fibrosarcomatous transformation
Author(s) -
Monteagudo Carlos,
Llombart Beatriz,
Burgués Octavio,
Rubio Luis,
Calabuig Silvia,
Sanmartín Onofre,
LópezGuerrero José Antonio
Publication year - 2015
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.12456
Subject(s) - dermatofibrosarcoma protuberans , pathology , cd34 , immunostaining , pdgfb , biology , sarcoma , dermatofibrosarcoma , immunohistochemistry , fluorescence in situ hybridization , medicine , microbiology and biotechnology , gene , chromosome , biochemistry , platelet derived growth factor receptor , stem cell , receptor , growth factor
Several variants of dermatofibrosarcoma protuberans, a low‐grade superficial sarcoma, are well recognized. The most prognostically important is the fibrosarcomatous variant. We report a case of biphasic dermatofibrosarcoma protuberans in which the high‐grade component exhibited a previously undescribed plexiform pattern. A clinicopathological study complemented with immunohistochemical, ultrastructural, reverse transcription polymerase chain reaction and fluorescence in situ hybridization analyses of this unique case. Histopathologically, a conventional low‐grade dermatofibrosarcoma protuberans was admixed with intratumoral high‐grade areas showing a striking labyrinthine plexiform pattern characterized by a higher cellularity of larger and slightly atypical tumor cells. CD34 expression was present in both components, while Ki‐67 immunostaining was significantly higher in the plexiform high‐grade areas. Focal epithelial membrane antigen and claudin‐1 immunostaining was present at the interphase between high‐ and low‐grade areas. COL1A1‐PDGFB fusion transcripts, with breakpoints at exon 25 of COL1A1 and exon 2 of PDGFB , were present in both components, being more numerous, as the extra copies of both genes, in the high‐grade areas. A previously undescribed histopathologic pattern of high‐grade sarcomatous transformation of dermatofibrosarcoma protuberans is reported: a biphasic tumor with a labyrinthine plexiform high‐grade component.