Transformed dermatofibrosarcoma protuberans: a clinicopathological study of eight cases

Abstract

Background: Fibrosarcomatous (FS) or malignant fibrous histiocytomatous (MFH) transformation of dermatofibrosarcoma protuberans (DFSP) is a rare, but well known, entity. DFSPs with sarcomatous areas have questionable biological behaviour. Several studies suggest that they have a higher risk for local recurrence and distant metastases than ordinary DFSPs. One recent study described no difference in the behaviour of conventional and transformed DFSP. Aims: To investigate the biological behaviour of a series of transformed DFSPs. Methods: Eight transformed DFSPs were analysed clinicopathologically. Follow up ranged from four to 36 years. Results: The tumours involved the trunk (six cases) and lower extremity (two cases) and measured 3.5-8 cm (median, 4). Sarcomatous change presented de novo in all cases. The type of sarcomatous change was FS (five cases) and MFH (three cases). The estimated proportion of sarcomatous area in the tumour was 25-70% (median, 43.37%). Mitotic counts ranged from nine to 16 mitotic figures/10 high power fields in the FS and MFH areas (median, 12), and from one to three in the DFSP areas. Six patients were treated by wide local excision with histopathologically negative margins and two were treated by simple surgical excision with positive margins. Three patients developed recurrences and one developed metastasis during follow up. Of those treated by wide local excision, one developed recurrence. All tumours expressed CD34 in the DFSP component, but only three in the sarcomatous area. Conclusions: Although DFSP containing sarcoma may be a more aggressive tumour, its behaviour can be influenced by surgical treatment.

Current treatment options in dermatofibrosarcoma protuberans

“…The cells in these areas usually show higher cellularity, increased mitotic rate, a focal loss of CD34 in 50% of cases (Mentzel et al 1998;Szollosi and Nemes 2005;Abbott et al 2006), and a marked nuclear pleomorphism to normal DFSP tissue. Sarcomatous change of DFSP is a form of tumor progression and is associated with a worse prognosis than ordinary DFSP (Mentzel et al 1998;Szollosi and Nemes 2005).…”

“…They are the "classic" form of DFSP. Rarely, DFSP can transform into Wbrosarcomatous DFSP (FS-DFSP), a more aggressive tumor, characterized clinically by a higher metastatic potential (Wrotnowski et al 1988;Ding et al 1989;Connelly and Evans 1992;Mentzel et al 1998;Bowne et al 2000;Fiore et al 2005;Szollosi and Nemes 2005). It may require a more intensive treatment approach.…”

Detection of COL1A1-PDGFB fusion transcripts and PDGFB/PDGFRB mRNA expression in dermatofibrosarcoma protuberans

“…Histologically, dermatofibrosarcoma protuberans with fibrosarcomatous areas shows higher proliferative activity (higher mitotic rate or MIB-1 labeling index) than ordinary dermatofibrosarcoma protuberans. 23,29,30 Since no correlation was observed between the mRNA expression level of PDGFB/PDGFRB and the histologic subtype, the fibrosarcomatous transformation of dermatofibrosarcoma protuberans is thought to be caused by mechanisms such as the TP53 gene mutation 29,31 or microsatellite instability 31 rather than the generation of the fusion gene and the activation of its downstream PDGFRB signaling pathway.…”

Two Cases of Dermatofibrosarcoma Protuberans

“…A review of the literature published in 1996 found a mean recurrence rate of 18% (range, 0-60%) after treatment with wide local excision in 15 studies by DuBay D et al (2004). Szollosi Z et al (2005) mentioned that distant metastasis (1 % -4%) and tumour related deaths are extremely rare. Re-excision of tumour positive areas until tumour-free margins are obtained or 'histographical surgery' ensures a high cure rate of up to 97% while preserving normal tissue as mentioned by Park T.H et al (2011).…”