Fibrosarcomatous ("High-Grade") Dermatofibrosarcoma Protuberans

Abstract

The fibrosarcomatous variant of dermatofibrosarcoma protuberans (FS-DFSP) represents an uncommon form of DFSP, in which the prognostic influence of the fibrosarcomatous component is still debated. We analyzed the clinicopathologic and immunohistochemical features in a series of 41 patients. Patient age ranged from 8 to 87 years (median, 48 years), and 19 patients were female. Twenty five lesions were seen on the trunk, 6 on the upper limbs, and 4 on the lower limbs, and five neoplasms were located in the head/neck region; in one case, exact anatomic site was unknown. Twenty seven tumors involved purely dermal and subcutaneous tissues, in 10 cases, deeper structures were also involved, 1 case arose in the breast, and, in 3 cases, it was impossible to define exact depth of the lesion. Preoperative duration ranged from 1 month to 60 years (median, 3 years). Twenty six tumors were excised locally with clear margins, 7 were treated by wide excision, 3 by incomplete excision, and, in 4 patients, the lesion was shelled out. In one case, exact treatment was unknown. In addition, radiotherapy was administered in three cases and chemotherapy in one case. Histologically, the lesions showed areas of typical, low-grade DFSP adjacent to fibrosarcomatous areas. In four cases, a previously ordinary DFSP recurred as pure fibrosarcoma, in two cases, local recurrence of FS-DFSP showed features of ordinary DFSP. Fibrosarcomatous change was more common in the primary (de novo) lesions than in recurrent lesions (3.6:1). Proportion of fibrosarcoma varied between < 30% in 6 cases to > 70% of tumor tissue in 21 cases. An abrupt transition between both components was seen in 19 cases. The fibrosarcomatous component showed focal necrosis in seven cases and showed a higher mitotic rate in comparison with ordinary DFSP areas (mean, 13.4 versus 2.3 mitoses in 10 high-power fields). Additional histologic features included progression to pleomorphic sarcoma in 2 recurrent cases, melanin-pigmented cells (Bednar FS-DFSP) in 1 case, focal myxoid change in 13 cases, plaque or keloidlike hyalinization in 3 cases, and myoid bundles and nodules in 9 cases. Immunohistochemically, tumor cells in DFSP areas stained positively for CD34, whereas, in FS-DFSP areas, only 15 out 33 cases were positive for CD34. Follow-up in 34 of 41 patients (mean, 90 months; median, 36 months) revealed local recurrence in 20 patients (58%) (recurrence occurred in 5 patients on two or more occasions). Metastases (5 lung, 1 bone, and 1 soft tissue) were seen in 5 patients (14.7%), and 2 patients have died of tumor to date (5.8%). Necrosis, high mitotic rate (> 10 mitoses per 10 high-power fields), and presence of pleomorphic areas in FS-DFSP tended to be related with poor clinical outcome, but no statistically significant association was detected. Fibrosarcomatous change in DFSP represents a form of tumor progression in DFSP and is associated with a significantly more aggressive clinical course than in ordinary DFSP, indicating a possible need for treatment intensification in ...

Current treatment options in dermatofibrosarcoma protuberans

“…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.…”

“…Tumor size does not appear to have a signiWcant inXuence on incidence of recurrence or on prognosis (McPeak et al 1967;Roses et al 1986;Gloster 1996;Khatri et al 2003). DermatoWbrosarcoma protuberans is characterized by a low but deWnitive potential for distant metastases (Mentzel et al 1998;Bowne et al 2000;Chang et al 2004;Nakra et al 2004;Yokoyama et al 2004;Fiore et al 2005). In the literature, the rate of metastasis is 5%, but in the classic form of DFSP, only 0.5% can be assumed.…”

“…Metastases to lymph nodes are rare with only a few case reports in the literature (Brenner et al 1975;Mavili et al 1994;Lal et al 1999). Distant hematogenous metastases are even rarer, mostly aVecting the lungs via hematogenous spread, but they are also possible in brain, bone (pelvis, ribs) and other soft tissues (Mentzel et al 1998). Rutgers et al (1992) reviewed 913 cases of DFSP and found only 11 patients (1%) with regional lymph node metastases and 37 patients (4%) suspected to have distant metastases.…”

“…The sensitivity of CD34 staining in DFSP ranges from 84 to 100%. Immunohistochemical staining for neural markers (especially S-100 protein and CD56) are helpful in distinguishing DFSP from malignant peripheral nerve sheath tumor seen in the skin and subcutis (Mentzel et al 1998).…”

“…In approximately 3.2-15% of DFSP, the tumors contain the already mentioned high-grade Wbrosarcomatous component (FS-DFSP) that typically occupies between 20 and 80% of the tumor mass (Mentzel et al 1998;Bowne et al 2000;Goldblum et al 2000;Fiore et al 2005). 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.…”