Cutaneous fibrohistiocytic tumours – an update

Abstract

The term 'fibrohistiocytic' tumour is a descriptive designation without histogenetic connotation for a group of heterogeneous lesions that share morphological features of histiocytes and fibroblasts on light microscopy. However, over the years it has become apparent that many so-called 'fibrohistiocytic' tumours are largely composed of relatively undifferentiated mesenchymal cells, but can also show areas of myofibroblastic differentiation. This review focuses on the clinical and histological features as well as differential diagnosis of so-called fibrohistiocytic tumours. Special emphasis is given to more recently described histological variants of fibrous histiocytoma, e.g. cellular, epithelioid, aneurysmal and atypical fibrous histiocytoma, to angiomatous and plexiform fibrous histocytoma (plexiform fibrohistiocytic tumour), lesions that are not true variants of fibrous histiocytomas but have erroneously been designated such, and to atypical fibroxanthoma. The literature on metastasizing fibrous histiocytoma is also reviewed.

Gene fusion detection in formalin-fixed paraffin-embedded benign fibrous histiocytomas using fluorescence in situ hybridization and RNA sequencing

“…Morphological variants include cellular, aneurysmal, epithelioid, and atypical types, and clinical manifestations range from benign tumors of the skin, deep soft tissues or skeleton to, rarely, metastasizing tumors. [1][2][3] We recently showed that both cutaneous and deep FH may carry specific gene fusions, in which a membereither PRKCB and PRKCD-of the gene family encoding protein kinase C (PRKC) is juxtaposed with a gene encoding a membrane-associated protein. 4 The pathogenetic mechanism was assumed to involve the uncoupling of the carboxy-terminal kinase domain of the PRKC protein from its regulatory domain, and its ectopic localization through fusion with the amino-terminal part of a membrane-associated protein.…”

Pattern Analysis Of Purely Dermal Cutaneous Mesenchymal Tumours Presenting As Superficial Palpable Growth

“…Atypical fibrous histiocytoma has been discussed by Bostjan Luzer and Eduardo Colonje in their review article published in 2010. [18] Thomas Mentzel et al [19] reported in their study published In present study 70% tumours measured 1-3cm in greatest dimensions and on cut surface showed whitish homogenous appearance. All revealed classical microscopy of neurofibroma [20] , schwannoma [2] and, MPNST [21] .…”

Hemosiderotic dermatofibroma: Unique clinical presentation and dermoscopic findings of a rare dermatofibroma variant

“…[8] Several DF variants exist and are distinguished by their histopathological characteristics. [8] However, variant characterization is not always clear-cut, as the histologic features of several variants can be present within the same lesion.…”