MFH classification: differentiating undifferentiated pleomorphic sarcoma in the 21st Century

Abstract

The essence and origin of malignant fibrous histiocytoma (MFH) have been debated for now close to five decades. Originally characterized as a morphologically unique soft tissue sarcoma subtype in 1963 of unclear etiology with a following decade and a half of research only to conclude that "the issue of histogenesis [of MFH] is largely unresolvable"; it is "now regarded as synonymous with [high grade] undifferentiated pleomorphic sarcoma [HGUPS] and essentially represents a diagnosis of exclusion". Yet despite this apparent lack of progress, the first decade of the 21 st century has seen some significant progress in terms of defining the origins of MFH. Perhaps more importantly these origins might also pave the way for novel therapies. This manuscript will highlight MFH's troubled history, discuss recent advances, comment as to what the coming years may promise, and what further needs to be done to make sure that progress continues. KeywordsMalignant fibrous histiocytoma (MFH); undifferentiated pleomorphic sarcomas; mesenchymal stem cells; differentiation therapy; classification Classification of SarcomasThere are approximately 12,000 new adult sarcoma cases each year [1], encompassing seventy different histologic types of mesenchymal tumors that arise from bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. An in depth understanding of the molecular biology for most of these tumor types is unfortunately lacking [2] thus greatly hindering our abilities to develop rational therapeutic options.Cytogenetics has long been used to divide sarcomas into two broad groups [3]: (1) sarcomas with specific genetic alterations and usually simple karyotypes, including reciprocal translocations that result in fusion genes; and (2) sarcomas with nonspecific genetic

Computed tomography and magnetic resonance imaging findings of malignant fibrous histiocytoma of the head and neck

“…Inflammatory MFH was also renamed undifferentiated pleomorphic sarcoma with prominent inflammation, and this diagnosis is confirmed only if all the markers of mesenchymal lineage are negative. Storiform-pleomorphic MFH remains a category of fibrohistiocytic tumors (19,20) and is the most common subtype in the head and neck region. MFHs lack typical CT̸MRI imaging characteristics due to the variable degrees of histological differentiation.…”

Recurrent Angiomatoid Fibrous Histiocytoma of thigh in a middle aged female: A case report

“…Initially, A MFH was described as a variant of malignant fibrous histiocytoma; Because of its benign microscopic appearance , relatively rarity of metastasis [7] and overall excellent clinical course, in World Health Organization (WHO) 2002 classification, it was removed from the malignant fibrous histiocytoma subtype of sarcoma and was placed under the category of tumors of uncertain differentiation as angiomatoid fibrous histiocytoma [6]. AFH is mostly seen in the first 2 decades of life, although the age distribution is wide, ranging from infant [8] to eight decade [2].…”

Sex chromosome alterations in undifferentiated pleomorphic sarcoma

“…1 STSs in general are rare tumors occounting for less than 1% of all cancers. 2,3 UPS is the most common STS seen in patients over the age of 40. Chromosomal abnormalities (CAs) are one of the hallmarks of neoplastic cells in general, and the persistent presence of chromosome instability has been demonstrated in many human cancers.…”