Platelet-Derived Growth Factor-D Fusion-Positive Dermatofibrosarcoma Protuberans: Case Report of an Atypical Breast Mass and Literature Review.

Dermatofibrosarcoma protuberans (DFSP) is a rare, CD34+ mesenchymal neoplasm that classically involves the dermis. A COL1A1::PDGFB t(17;22) translocation is present in 91.4% to 96% of cases, resulting in aberrant proliferation due to tyrosine kinase hyperactivity. Here, we present a postmenopausal woman with a CD34-positive spindle cell neoplasm of the breast without cutaneous involvement, lacking muscle marker expression, STAT6 expression, and 13q14 deletion by fluorescence in situ hybridization (FISH). Although the classic PDGFB translocation was not detected by FISH, the overall features were highly suspicious for DFSP. Subsequent RNA-based next-generation sequencing revealed an EMILIN2::PDGFD fusion. A literature review showed that PDGFD fusions can be detected in up to 55% PDGFB FISH negative cases, with EMILIN2::PDGFD fusion highly associated with fibrosarcomatous transformation. This holds important diagnostic and prognostic information as fibrosarcomatous-DFSP is associated with higher recurrence and metastatic potential. The tumor was completely resected with clear margins, showed no fibrosarcomatous areas, and no evidence of recurrence is documented 2 years since resection. This review and case report adds to the literature regarding PDGFD-translocation positive DFSP as a differential diagnosis of CD34-positive spindle cell tumors of the breast, while emphasizing the prognostic importance of EMILIN2::PDGFD fusions.

Perspectives of Patients With Dermatofibrosarcoma Protuberans on Diagnostic Delays, Surgical Outcomes, and Nonprotuberance.

Importance: Dermatofibrosarcoma protuberans (DFSP) may have a deceptively benign clinical appearance, including a nonprotuberant presentation. Patients with DFSP often perceive misdiagnoses and delays in receiving a diagnosis. Use of existing, patient-designed Facebook patient support groups (FBSGs) to recruit large numbers of patients with rare diseases may be an effective novel research method. Objectives: To collaborate with patients with rare disease through social media and answer questions important to both patients and the medical field, including sources of diagnostic delay, risk of recurrence, and flat presentation of DFSP. Design, Setting, and Participants: A multiple-choice survey created by a team of medical practitioners and patients with DFSP was administered to 214 patients with DFSP or family members from international DFSP FBSGs and a nonprofit foundation patient database via Lime Survey from October 30 to November 20, 2015. The survey asked questions designed to determine risk of recurrence and metastasis, surgical outcomes, sources of diagnostic delay, symptoms of recurrence, number of recurrences, scar size, and number of clinicians seen before biopsy. Statistical analysis was performed from January 1, 2016, to April 1, 2019. Main Outcomes and Measures: The study goal was to collect at least 200 survey responses. Results: Of 214 survey respondents (169 females and 45 males; mean [SD] age, 40.7 [12.1] years; range, <1 to 72 years), 199 were patients with DFSP and 15 were family members. Delays occurred between the patient noticing the DFSP lesion and receiving a diagnosis of DFSP (median, 4 years; range, <1 to 42 years). Most patients (112 [52.3%]) believed that they received a misdiagnosis at some point: by dermatologists (35 of 107 [32.7%]), primary care clinicians (80 of 107 [74.8%]), or another type of physician (27 of 107 [25.2%]). The most frequent prebiopsy clinical suspicion included cyst (101 [47.2%]), lipoma (30 [14.0%]), and scar (17 [7.9%]). Many patients first noticed their DFSP as a flat plaque (87 of 194 [44.8%]). Of these lesions, 73.6% (64 of 87) became protuberant eventually. Surgical treatments included Mohs micrographic surgery (56 of 194 [28.9%]), wide local excision (122 of 194 [62.9%]), and conservative excision (16 of 194 [8.2%]). The reported rate of recurrence was 5.4% (3 of 56) for Mohs micrographic surgery, 7.4% (9 of 122) for wide local excision, and 37.5% (6 of 16) for conservative excision. The higher rate of recurrence for conservative excision was significant (P = .001); there was no significant difference in the rate of recurrence between Mohs micrographic surgery and wide local excision (P = .76). Conclusions and Relevance: This study reports what appears to be disease-relevant statistics from the largest survey of patients with DFSP to date. Because of the dissonance between the name of the neoplasm and its clinical presentation, the alternative term dermatofibrosarcoma, often protuberant is proposed. This study suggests that FBSGs are useful tools in medical research, providing rapid access to large numbers of patients with rare diseases and enabling synergistic collaborations between patients and medical researchers.

Impact of Pathologist Involvement in Sarcoma and Rare Tumor Patient Support Groups on Facebook: A Survey of 542 Patients and Family Members.

CONTEXT: - Patients with rare tumors have difficulty finding reliable information about their disease. Facebook patient support groups allow patients to educate one another. OBJECTIVE: - To investigate how these patients perceive the value of pathologists, both in Facebook groups and real-world patient care. DESIGN: - Survey links were posted in 12 Facebook patient groups: 6 with an active pathologist member (angiosarcoma, epithelioid hemangioendothelioma, epithelioid sarcoma, dermatofibrosarcoma protuberans [×2], and desmoid fibromatosis), and 6 without "active" pathologist involvement (aggressive angiomyxoma, chondrosarcoma, Ewing sarcoma, leiomyosarcoma, liposarcoma, and osteosarcoma). RESULTS: - A total of 542 people responded (403 were patients): 264 from groups with a pathologist, and 278 from groups without active pathologist involvement. Of groups with an active pathologist, respondents agreed the pathologist's posts helped them better understand their disease (107 of 119; 90%) and relieved some of their disease-related anxiety (92 of 119; 77%). And for these groups 98% (117 of 119) of respondents agreed that having a pathologist in their group was a good thing; 83% (192 of 232) wanted more pathologists involved. More respondents from groups with an active pathologist (219 of 236; 93%) than without one (215 of 252; 85%) agreed: "pathologists are an important part of the patient care team for patients with cancer and other rare tumors" ( P = .008). CONCLUSIONS: - This study is the first to evaluate the impact of pathologist interaction with Facebook patient support groups and to assess perceptions about the specialty of pathology from a large group of patients with rare tumors. Pathologist involvement in Facebook patient groups appears to positively influence patient perception of the importance of pathologists. We hope these data will encourage more pathologists to participate in Facebook patient support groups.