Dermatofibrosarcoma protuberans with fibrosarcomatous transformation: our experience, molecular evaluation of selected cases, and short literature review

Establishment and characterization of NCC-DFSP4-C1: a novel cell line from a patient with dermatofibrosarcoma protuberans having the fibrosarcomatous transformation

Dermatofibrosarcoma protuberans (DFSP) is a superficial low-grade sarcoma, genetically characterized by a fusion gene in collagen type I α (COL1A1) gene and platelet-derived growth factor subunit β (PDGFB). DFSP is locally aggressive and does not typically metastasize. However, DFSP with fibrosarcomatous transformation, which occurs in 7-16% of DFSP cases, demonstrates a poor prognosis than classic DFSP with a higher local recurrence rate and metastatic potential. Although imatinib, a PDGF receptor inhibitor, is a potent therapeutic agent for classic DFSP, it is less effective for DFSP with fibrosarcomatous transformation. The development of definitive chemotherapies for DFSP with fibrosarcomatous transformation is required. Patient-derived tumor cell lines are indispensable tools for preclinical research to discover novel therapeutic agents. However, only seven cell lines were derived from DFSP, out of which only two were established from DFSP with fibrosarcomatous transformation. Hence, in the present study, we established a novel DFSP cell line, NCC-DFSP4-C1, from a surgically resected DFSP tumor specimen with fibrosarcomatous transformation. NCC-DFSP4-C1 harbored an identical COL1A1-PDGFB fusion gene as its donor tumor. NCC-DFSP4-C1 cells retained the morphology of their donor tumor and demonstrated constant proliferation, spheroid formation, and invasion capability in vitro. By screening a drug library, we found that bortezomib and romidepsin demonstrated the strongest suppressive effects on the proliferation of NCC-DFSP4-C1 cells. In conclusion, we report a novel cell line of DFSP with fibrosarcomatous transformation, and demonstrate its utility in the development of novel therapeutic agents for DFSP.

Fibrosarcomatous dermatofibrosarcoma protuberans: a rapidly growing 30 cm mass on the posterior scalp

Dermatofibrosarcoma protuberans (DFSP) is a rare, slow-growing sarcoma of the skin and subcutaneous tissue, accounting for around 5 cases per million per year. Fibrosarcomatous transformation of DFSP occurs in 10%-15% of DFSP cases, with a higher risk of local recurrence, metastasis, and death. We present a case of a male in his 30s with a complaint of rapidly progressive mass in the occipital region of the head. Within 1 year, the mass enlarged by >30 cm. Physical examination revealed a skin-colored 40×30 cm mass with an overlying skin necrosis at the posterior scalp. Brain, neck, and chest computed tomography (CT) scans were performed. The mass was surgically excised by wide excision with a 2 cm margin. Pathological report confirmed fibrosarcomatous DFSP Grade 3 with decreased CD34 expression. Delayed reconstruction of free flap and split-thickness skin graft were subsequently performed. No recurrence was detected 3 months postoperatively.

Wilms' Tumor 1 (WT1): A Novel Immunomarker of Dermatofibrosarcoma Protuberans-An Immunohistochemical Study on a Series of 114 Cases of Bland-Looking Mesenchymal Spindle Cell Lesions of the Dermis/Subcutaneous Tissues

Simple Summary

Dermatofibrosarcoma protuberans (DFSP) is a superficial fibroblastic spindle cell sarcoma with a high rate of local recurrence (20% to 50%) but with a low metastatic potential. DFSP is characterized by COL1A1-PDGFB gene fusion and diffuse immunohistochemical expression of CD34. This immunomarker is especially useful in distinguishing DFSP from its morphological mimickers, especially when pathologists are faced with small biopsies. Apart from CD34, there are no additional diagnostic immunomarkers for DFSP, and thus, there is the need to identify more sensitive and specific markers for this sarcoma. Recently, Wilms’ tumor 1 (WT1) has been shown to be diffusely expressed in the cytoplasm of several benign and malignant mesenchymal spindle cell lesions. Based on this background, the aim of this study is to evaluate the immunohistochemical expression of WT1 protein in a series of bland-looking spindle cell lesions of the dermis/subcutis, emphasizing its potential diagnostic role in identifying DFSP among its morphological mimickers.

Abstract

Purpose: to investigate the immunohistochemical expression and distribution of Wilms’ tumor 1 (WT1) (transcription factor produced by the tumor suppressor gene of the same name) in a series of 114 cases of bland-looking mesenchymal spindle cell lesions of the dermis/subcutaneous tissues to establish whether this immunomarker is differentially expressed in dermatofibrosarcoma protuberans (DFSP) versus its potential morphological mimickers. Methods: This retrospective multi-centric immunohistochemical study included 57 DFSP cases, 15 dermatofibromas, 5 deep fibrous histiocytomas, 8 neurofibromas, 5 spindle cell lipomas, 8 dermal scars, 6 nodular fasciitis, 5 cutaneous leiomyomas and 5 solitary fibrous tumors. Among the 57 DFSP cases, 11 were recurrent lesions; 2 non-recurrent cases exhibited an additional “fibrosarcomatous” overgrowth and 1 recurrent and 2 primary tumors contained a minority of “giant cell fibroblastoma” components. Results: Most DFSP (95% of cases) exhibited cytoplasmic staining for WT1; 11/11 residual/recurrent tumors showed diffuse and strong WT1 cytoplasmic immunoreactivity; apart from neurofibromas, WT1 expression was lacking in all the other cases studied. Conclusions: The cytoplasmic expression of WT1 may be exploitable as a complementary diagnostic immunomarker to CD34 in confirming the diagnosis of DFSP and to better evaluate the residual/recurrent tumor component.

Dermatofibrosarcoma protuberans, fibrosarcomatous variant: A rare tumor in children

Fibrosarcomatous transformation of dermatofibrosarcoma protuberans is associated with a significantly worse prognosis in adults, but is a very rare feature in the pediatric population. Here, we report a case that occurred in a child. The diagnosis of fibrosarcomatous transformation of dermatofibrosarcoma protuberans was confirmed by a histopathological assessment and fluorescence in situ hybridization. A comparison with eleven other patients reported in the literature revealed that the local recurrence and mortality rates in children are similar to those observed in adults.

Dermatofibrosarcoma protuberans with fibrosarcomatous transformation arising at the site of breast implant

Fibrosarcomatous transformation of dermatofibrosarcoma protuberans (DFSP) is a rare variant with higher risk of recurrence and metastasis, and no known associations with breast implants. We report a rare case of fibrosarcomatous dermatofibrosarcoma protuberans arising at the site of breast implant in a 33-year-old patient followed by brief discussion on fibrosarcomatous DFSP.