Abstract
Dear Editor
We read with great interest the article by Zouirech et al titled “Surgical management of pediatric dermatofibrosarcoma protuberans: about 2 challenging case reports” published in Global Pediatric Health. 1 To further enhance the value of this paper in the diagnosis and treatment of pediatric dermatofibrosarcoma protuberans (DFSP), I would like to discuss its clinical features, preoperative diagnosis, margins, and fibrosarcomatous DFSP (F-DFSP) by comparing pediatric and adult cases to the greatest extent possible. Additionally, we will highlight recent advances in this field.
Dermatofibrosarcoma protuberans is a locally invasive fibroblastic neoplasm with low-to-intermediate malignancy. 2 It has an incidence of fewer than 1 case per 100 000 people and is most commonly observed in middle-aged individuals (20-50 years), with a slight male predominance. 2 In previously reported pediatrics cases, the mean tumor size was approximately 3 cm, and a female predominance was noted.3,4 The most frequent tumor site was the trunk, followed by the extremities.3,4 Clinically, pediatric DFSP typically presents as plaques that are flat or slightly raised. Other presentations include nodules, masses, and pigmented lesions. Due to its slow growth, DFSP is frequently misdiagnosed as various benign tumors, such as hemangiomas and dermatofibromas.5,6
The first step in achieving an accurate diagnosis for DFSP, as well as other soft tissue tumors, is magnetic resonance imaging (MRI). While computed tomography can provide valuable information about the depth of invasion and involvement of surrounding structures, MRI is generally preferred due to its superior soft tissue contrast and lack of radiation exposure. 5 The MRI characteristics of DFSP include well-defined homogeneous isointensity on T1-weighted images and intermediate or mild hyperintensity on T2-weighted images, with intermediate to strong contrast enhancement. Unfortunately, these findings are nonspecific. 7 Furthermore, diagnosing soft-tissue tumors using MRI alone requires caution. For example, in synovial sarcoma, the misdiagnosis rate when using MRI alone is approximately 50%. 8 Therefore, needle or open biopsy for pathological diagnosis is essential, and the preoperative diagnosis should be based on the pathological diagnosis and MRI findings, which is a crucial and standard step. Interestingly, in cases of soft tissue sarcoma in children, performing the diagnostic process, including imaging and biopsy at expert centers, along with molecular biological analysis, can lead to better prognosis. 9 Overall, preoperative diagnosis is crucial, and we recommend performing both MRI and biopsy. We interpret that the surgeries in these 2 cases, were unfortunately unplanned. Particularly, cases with small sized tumors like those in case 1, often occur in unplanned surgery. 10 Unplanned surgery also tends to result in R1 resections. However, in DFSP, even if the initial surgery results in an R1 resection, a reoperation achieving an R0 resection is associated with a lower recurrence rate, suggesting that ensuring negative margins is a novel factor in reducing recurrence. 11 In preoperative management, preoperative MRI is beneficial because it allows for easier and more rational planning of margins during additional surgery. The next concern is appropriate margin length. In this study, a uniform margin of 4 cm was used for the reoperation. We agree that longer margins increase the likelihood of achieving R0 resection and reduce the risk of recurrence; however, they result in the inability of direct closure, the need for reconstructive plastic surgery, and an increase in wound complications. Winer et al 12 reported, although in the case of margins measuring 0.6 to 1.0 cm, only 43% of cases were estimated as R0 resection, in the cases of margin measuring 1.1 to 2 cm, 83.3% cases were estimated as R0, suggesting considered with balance of wound complication and achievement of R0, 2 cm margin may be a more realistic. Because these 2 cases are considered to be conventional DFSP, and considering the low recurrence rate, a 2 cm margin may be sufficient. As another treatment option, particularly in pediatric cases, Mohs micrographic surgery has been considered to help avoid reconstructive procedures such as skin grafts and flaps. 5
Finally, we would like to discuss F-DFSP, which is clinically problematic because of its higher rate of recurrence and metastasis compared with conventional DFSP. 11 The proportion of F-DFSP in adult DFSP was reported as approximately 10% to 16%, whereas in children, it was approximately 7.5% to 9.1%, showing a slightly lower tendency.3,11 In contrast, subtypes including pigmented, giant cell fibroblastoma, and plaque-like were relatively common in children. Although the pathological findings of DFSP have been omitted, immunohistochemically, the cells tested positive for CD34 and EMA (note that the target of AML in the text was not clear). 2 In contrast, in F-DFSP, there was a decrease or absence of CD34 positive intensity, and an increase in the expression of p53 and PRAME.13,14 In addition, the Ki67 labeling index in F-DFSP areas was significantly higher than that in DFSP areas. 15 Regarding adequate margin length, a 2 cm margin was generally considered sufficient for local control, even in F-DFSP; however, the necessity of a 4 cm margin was reported, which remains inconclusive.15,16 In pediatric cases, no recurrences of F-DFSP have been reported after R0 surgery, whereas all cases after R1 surgery have shown recurrence. 3 The 5-year overall survival rate for conventional DFSP was 100%, and patient deaths occurred only in F-DFSP cases; however, the mortality rate remains unclear due to the limited number of cases. 11 In the follow-up periods of F-DFSP, the incidence of high-grade metastasis by the modified FNCLCC system, tended to be higher than that of low-grade grade metastasis, indicating that a 10-year follow-up period is recommended, similar to other soft tissue sarcomas. 17 In pediatric cases, the appropriate follow-up duration for both DFSP and F-DFSP remains uncertain, because Zhang et al 3 reported recurrence occurring 10 years after initial treatment, highlighting the need for further studies.
In conclusion, the importance of accurate diagnosis and treatment strategies for DFSP remains unchanged between pediatric and adult cases. For diagnosis, the combination of MRI and biopsy is essential for optimal surgical planning. R0 resection remains the primary treatment, while margin length should be carefully considered to balance recurrence prevention with minimizing the need for reconstructive surgery. Additionally, physicians should remain vigilant about this rare disease, DFSP, to ensure timely and appropriate management.
