Prognostic impact of fibrosarcomatous transformation in dermatofibrosarcoma protuberans: A cohort study

Nodular fasciitis complicating a staged surgical excision of dermatofibrosarcoma protuberans

“…Classic DFSP is composed of a dense proliferation of uniform spindle cells in a cartwheel or storiform pattern with invasion of the subcutaneous tissue in a characteristic "honeycomb" pattern. Minimal cytologic atypia is present with minimal to no mitoses and diffuse staining for CD34 is evident [1][2][3][4][5]. Our patient's initial biopsy, debulking specimen, and first stage en face margins were typical of DFSP pathology.…”

“…DFSP is a unique low-grade soft tissue sarcoma, characterized by a significant risk of local recurrence but minimal risk of metastasis or death [1,2]. The typical clinical presentation is a firm nodule or plaque on the trunk or proximal extremities without adherence to underlying bone.…”

“…Local recurrence with the myxoid DFSP variant is thought to be slightly lower than DFSP with classic histology [4,6]. Foci of fibrosarcomatous change involving at least 5% of the specimen are found in 10-20% of DFSP tumors [1][2][3]. In contrast to DFSP, fibrosarcomatous change is characterized by a dense proliferation of fusiform cells in a fascicular or herringbone pattern with significant cellular atypia, numerous mitosis, large nuclei, and negative staining for CD34 [1,2].…”

“…Foci of fibrosarcomatous change involving at least 5% of the specimen are found in 10-20% of DFSP tumors [1][2][3]. In contrast to DFSP, fibrosarcomatous change is characterized by a dense proliferation of fusiform cells in a fascicular or herringbone pattern with significant cellular atypia, numerous mitosis, large nuclei, and negative staining for CD34 [1,2]. A systematic review of 1422 patients with DFSP and 225 DFSP-FS found an increased risk of local recurrence (29%), metastasis (14%), and death (14%) with any proportion of fibrosarcomatous change.…”

Dermatofibrosarcoma protuberans with fibrosarcomatous transformation

“…FS-DFSP is a rare variant of DFSP, involving greater aggression, higher rates of local recurrences and a greater metastatic potential, affecting the lungs in particular. 1 Given their clinical similarities, differentiating these two entities relies on histopathology, although a sudden rapid growth should lead the clinician to suspect transformed DFSP. Wide excision with margins ≥2 cm represent the gold standard in the treatment of FS-DFSP, since this prevents recurrences and metastases.…”