Cellular fibrous histiocytoma of the skin: Evidence of a clonal process with different karyotype from dermatofibrosarcoma

Cytogenetic evidence of clonality in cutaneous benign fibrous histiocytomas: a report of the CHAMP Study Group

“…Clinical evidence in support of the former includes the tendency for occasionally persistent or recurrent growth, which is much more frequent in the cellular and aneurysmal variants. 2–13 Rare examples of cellular BFH associated with metastases have been reported, 14 and one of us has seen similar cases (Fletcher, unublished data). Conversely, others have argued that the frequent tendency of many of these lesions to hyalinize and regress spontaneously, their common topographical association with insect bites and their cytomorphological features would all support a reactive (inflammatory) pathogenesis.…”

“…The typical cytomorphology and presence of epidermal hyperplasia, however, with collagen trapping at the periphery, as well as the presence of cytogenetic abnormalities other than those associated with DFSP, were in keeping with cellular BFH. 10 Lu 342 was also initially reported as DFSP, 12 but upon histopathological re‐examination this lesion was found to display features of cellular BFH; unfortunately, no material was available for molecular studies. Lu 317, with combined cellular and aneurysmal features in which there were prominent branching vessels, had a misleading appearance which lead to its misdiagnosis as haemangiopericytoma.…”

“…At the time of writing, none of the patients showed evidence of recurrent tumour. Three of these cases have been published prior to the CHAMP study 10–12 two of them with different diagnoses (Lu 317 as haemangiopericytoma, and Lu 342 as dermatofibrosarcoma protuberans).…”

A case of dermatofibrosarcoma protuberans of the vulva with a COL1A1/PDGFB fusion identical to a case of giant cell fibroblastoma

“…Due to the tendency of DFSP to infiltrate the surrounding tissue via microscopic projections, a very wide excision was required, with surgical margins of 3 cm being recommended [24]. To avoid unnecessary wide surgical margins, misdiagnosis with more innocuous lesions that may mimic DFSP should be excluded, such as the cellular variant of benign fibrous histiocytoma [5,30]. To this aim, the possibility of confirming the diagnosis using other ancillary analyses, such as cytogenetic and molecular studies, seems particularly useful.…”

Is cutaneous benign fibrous histiocytoma (dermatofibroma) a reactive inflammatory process or a neoplasm?

“…Cytogenetic abnormalities were first reported in a single case of cellular BFH in 1997. 9 This was followed by a larger study of 13 ordinary BFHs published this year. 4 In this study, evidence of clonality was demonstrated in eight cases.…”