Outcome after surgical treatment of dermatofibrosarcoma protuberans: Is clinical follow‐up always indicated?

Current patterns of care and outcomes for dermatofibrosarcoma protuberans: An international multi-institutional collaborative

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a cutaneous sarcoma with an infiltrative growth pattern that makes it challenging to clear margins. High quality data regarding DFSP natural history, management, and outcomes are limited.

METHODS

Data were retrospectively collected for adult DFSP patients who underwent resection at 10 institutions in eight countries. Demographics, tumor characteristics, treatment strategies, and outcomes were analyzed.

RESULTS

Analysis included 347 patients consisting of young (median, 42 years), White (76.2%), males (54.2%) with truncal lesions (57.3%). The majority (76.8%) were symptomatic at presentation. Preoperative imaging was used in 55.9% of cases. Diagnosis was established with excisional biopsy in 50.9% versus incisional biopsy in 25.0% of cases. Despite planned margins of >1.0 cm in 67.4% of cases, only 69.0% of patients achieved R0 resection. Twenty-two percent of patients underwent at least one re-excision. R0 resection was achieved at a second procedure in 80.2% and a third procedure in 86.2%. Ultimately, R0 resection was feasible in 89.5% of all patients. Fibrosarcomatous transformation (FST) was observed in 12.6%. In total, 6.6% (N = 23) recurred (17 local, six distant). Of the six distant recurrences, 50.0% had FST. With a median follow-up of 47.0 months, disease-specific survival rate was 98.8%. In multivariable analysis, R0 margins at index resection were associated with wider circumferential margins and non-FST histology.

CONCLUSIONS

In this international, multicenter collaborative, DFSP practice patterns were heterogeneous but achieved favorable recurrence rates and survival. Multiple excisions to clear margins remain commonplace and can inform future efforts to optimize margin selection.

UK guidelines for the management of soft tissue sarcomas

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location, means that developing evidence-based guidelines is complicated by the limitations of the data available. This makes it more important that STS are managed by expert multidisciplinary teams, to ensure consistent and optimal treatment, recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous versions published in 2010 and 2016 [1, 2]. The original guidelines were drawn up by a panel of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This iteration of the guidance, as well as updating the general multidisciplinary management of soft tissue sarcoma, includes specific sections relating to the management of sarcomas at defined anatomical sites: gynaecological sarcomas, retroperitoneal sarcomas, breast sarcomas, and skin sarcomas. These are generally managed collaboratively by site specific multidisciplinary teams linked to the regional sarcoma specialist team, as stipulated in the recently published sarcoma service specification [3]. In the UK, any patient with a suspected soft tissue sarcoma should be referred to a specialist regional soft tissues sarcoma service, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging and a tissue biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon, combined with pre- or post-operative radiotherapy for tumours at higher risk for local recurrence. Systemic anti-cancer therapy (SACT) may be utilised in cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late effects of treatment.

A case report of abdominal metastatic dermatofibrosarcoma protuberans misdiagnosed as gastrointestinal stromal tumor

Dermatofibrosarcoma protuberans (DFSP) is a low-grade malignant soft-tissue tumor that originates from the skin. It has a slow onset in the early stages, non-specific clinical symptoms, low specificity, and can easily be overlooked, missed, or misdiagnosed by clinicians and pathologists. In addition, DFSP is prone to recurrence after local surgical treatment; however, distant metastasis, especially abdominal metastasis, is rare, which is also a challenge for the accurate diagnosis of DFSP when it progresses distantly. Now a case of abdominal metastasis of DFSP is reported. The patient has been treated with imatinib for ten years, and the lesion has shrunk, but because the patient has been receiving imatinib treatment, his abdominal lesion was once misdiagnosed as gastrointestinal stromal tumor. Therefore, we report on this case to enhance the understanding of the diagnosis and treatment of DFSP, and to provide reference for the pathological diagnosis and precise treatment of such patients.

Subtotal Thigh Flap for Large Abdominal Wall Defect Reconstruction in Patient With Recurrent Dermatofibrosarcoma Protuberans: A Case Report and Literature Review

BACKGROUND

Harvesting an adequate-sized flap is challenging for reconstructing large defects on the abdominal wall. A subtotal thigh flap would be one of the choices as it provides a well-vascularized large flap with muscle components. Moreover, dermatofibrosarcoma protuberans (DFSP) is a low-grade dermal neoplasm with a high recurrence rate. There is still no consensus on the extent of resection to prevent a recurrence.

OBJECTIVES

We present a case of a patient who underwent the reconstruction of a large abdominal wall defect with a subtotal thigh flap after the resection of recurrent DFSP.

MATERIALS AND METHODS

A 59-year-old man killed from a recurrent huge mass in the lower abdomen with an invasion of the small intestine. His baseline characteristics and records of operations, medications, and outcomes were reviewed.

RESULT

After tumor excision, a 28 × 30-cm subtotal thigh flap was harvested from his left thigh to reconstruct the abdominal defect. A microvascular anastomosis with left deep inferior epigastric vessels was made eventually. The flap was in good condition, and the donor site was covered with a split-thickness skin graft.

CONCLUSIONS

Subtotal thigh flap may be considered for large abdominal wall defect reconstruction as it allows good perfusion of relatively large skin paddles compared with other free flaps. Also, patients with DFSP need definite margin-free resection and close follow-up to prevent a recurrence.

Machine learning-based radiomics analysis for predicting local recurrence of primary dermatofibrosarcoma protuberans after surgical treatment

BACKGROUND AND PURPOSE

Dermatofibrosarcoma protuberans (DFSP) is characterized by locally invasive growth patterns and high local recurrence rates. Accurately identifying patients with high local recurrence risk may benefit patients during follow-up and has potential value for making treatment decisions. This study aimed to investigate whether machine learning-based radiomics models could accurately predict the local recurrence of primary DFSP after surgical treatment.

MATERIALS AND METHODS

This retrospective study included a total of 146 patients with DFSP who underwent MRI scans between 2010 and 2016 from two different institutions: institution 1 (n = 104) for the training set and institution 2 (n = 42) for the external test set. Three radiomics random survival forest (RSF) models were developed using MRI images. Additionally, the performance of the Ki67 index was compared with the three RSF models in the external validation set.

RESULTS

The average concordance index (C-index) scores of the RSF models based on fat-saturation T2W (FS-T2W) images, fat-saturation T1W with gadolinium contrast (FS-T1W + C) images, and both FS-T2W and FS-T1W + C images from 10-fold cross-validation in the training set were 0.855 (95% CI: 0.629, 1.00), 0.873 (95% CI: 0.711, 1.00), and 0.875 (95% CI: 0.688, 1.00), respectively. In the external validation set, the C-indexes of the three trained RSF models were higher than that of the Ki67 index (0.838, 0.754, and 0.866 vs. 0.601, respectively).

CONCLUSION

Random survival forest models developed using radiomics features derived from MRI images were proven helpful for accurate prediction of local recurrence of primary DFSP after surgical treatment and showed better predicting performance than the Ki67 index.

Outcome After Surgical Treatment of Dermatofibrosarcoma Protuberans (DFSP): Does it Require Extensive Follow-up and What is an Adequate Resection Margin?

INTRODUCTION

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous tumour of indeterminate malignant potential. The mainstay treatment for DFSP is surgical resection. Given the reported high local recurrence rate, the ideal resection margin for DFSP is unclear. The purpose of this study was to ascertain the local recurrence and metastatic rate of DFSP and DFSP with fibrosarcomatous degeneration (FS-DFSP), with specific attention to margin status in an attempt to address the issue of margin adequacy.

METHODS

Patients treated for DFSP at a single sarcoma centre were identified from a prospective database. DFSP and FS-DFSP patients with and without prior surgery were included. Patients were followed after surgery to monitor complications, local recurrence and metastasis.

RESULTS

The study included 200 patients: 166 patients with DFSP and 34 patients with FS-DFSP. In the DFSP group, nine patients (5.4%) had positive margins, one case (0.6%) developed local recurrence (LR) and no patients developed distant metastases. In the FS-DFSP group, seven patients (20.6%) had positive margins, six patients (17.6%) developed local recurrence (LR) and eight patients (23.5%) developed distant metastases, of which three (37.5%) were in the lungs, one (12.5%) in bone and four (50%) in other soft tissue sites.

DISCUSSION AND CONCLUSION

Local recurrence and metastases are extremely rare in patients with DFSP. Achieving a negative as opposed to a wide surgical margin may be sufficient to avoid local recurrence of most DFSP. We suggest that no ongoing surveillance for local or systemic relapse is required for DFSP patients after negative margin resection. For FS-DFSP, we recommend the same surveillance schedule, based on tumour grade, as other soft tissue sarcoma.

Surgical Outcomes of Primary Dermatofibrosarcoma Protuberans: A Retrospective, Multicenter Study

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive tumor with a low rate of metastatic disease. Previous series have shown a superiority of Mohs micrographic surgery (MMS) compared with wide local excision (WLE). Likewise, there is paucity of data examining the long-term follow-up of patients.

OBJECTIVE

The purpose of the current study was to examine the outcome of surgical treatment of primary DFSP of the trunk and extremities.

METHODS

We reviewed 236 patients (115 females, 121 males, mean age 41 ± 15 years) undergoing MMS (n = 81, 34%) or WLE (n = 155, 66%) to treat a primary DFSP. Mean tumor size and follow-up was 4 ± 2 cm and 7 years, respectively. Final margins were negative in 230 (97%) patients.

RESULTS

There was no difference (p > 0.05) in patient age, sex, tumor size, negative margin excision, or history of a previous inadvertent excision between patients who underwent WLE and those undergoing MMS. There were two cases of local recurrence and two cases of metastasis, with no difference in the 5-year local recurrence-free survival (98% vs. 99%, p = 0.69) or metastatic-free survival (98% vs. 100%, p= 0.27) between WLE and MMS.

CONCLUSION

There was no difference in oncologic outcome comparing MMS with WLE for DFSP outside the head and neck. The goal of treatment for DFSP is to achieve a negative margin, regardless of surgical treatment modalities. A 'less is more' approach to follow-up can likely be taken for patients with completely resected DFSP in easy-to-examine anatomical areas. In these patients, no formal follow-up should be required.

Comparison of 68Ga-FAPI and 18F-FDG PET/CT in Dermatofibrosarcoma Protuberans

ABSTRACT

Dermatofibrosarcoma protuberans is a rare soft tissue sarcoma with a high recurrence rate. Herein, we present 68Ga-FAPI and 18F-FDG PET/CT findings of dermatofibrosarcoma protuberans in a 45-year-old man. Dermatofibrosarcoma protuberans only shows limited FDG uptakes on 18F-FDG PET/CT, but demonstrated intense tracer uptakes on 68Ga-FAPI PET/CT. In this case, 68Ga-FAPI was superior to 18F-FDG PET/CT in detecting dermatofibrosarcoma protuberans.

Determination of Margins for Tumor Clearance in Dermatofibrosarcoma Protuberans: A Single-Center Study of 222 Cases Treated With Modified Mohs Surgery

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is an invasive skin tumor traditionally associated with very high recurrence rates when treated with conventional surgery (CS).

OBJECTIVE

To calculate the minimum margin that would have been required to achieve complete tumor clearance with hypothetical CS. To analyze DFSP characteristics and Mohs micrographic surgery (MMS) effectiveness in treatment of this tumor.

MATERIALS AND METHODS

Minimum margin was calculated by measuring the largest distance from the visible edge of the tumor to the edge of the surgical defect. Tumor variables (age, sex, size, time since onset, and location) were correlated with surgical variables (number of stages and minimum margin).

RESULTS

We studied 222 cases of DFSP treated with MMS. A mean of 1.47 MMS stages and a mean minimum margin of 1.23 cm were required to achieve tumor clearance. Tumors on the head and neck required significantly more stages and a significantly wider margin. Tumor size was positively correlated with time to diagnosis, age, and number of MMS stages.

CONCLUSION

Tumors located on the head and neck have greater subclinical extension. Tumor size was also a predictor of surgical difficulty, but time to diagnosis was not.

Risk factors for the development of local recurrence in extremity soft-tissue sarcoma

INTRODUCTION

Local recurrence (LR) is one of the main pitfalls in surgery for extremities soft tissue sarcoma (eSTS). Achieving clear histopathological margins is the most important factor to reduce the risk of LR, but the ability to do so depends on not only surgical technique but also the interplay between tumor biology, anatomical location and surgical approach. The balance between postoperative morbidity and oncological benefits in reducing the risk of LR needs to be considered.

AREAS COVERED

This review will cover which etiological factors for the development of eSTS lead to an increased risk of LR and discuss histological subtypes that have a high risk of LR and which surgical and neoadjuvant therapeutic strategies can minimize the risk of LR.

EXPERT OPINION

The traditional view that surgical radicality always results in low rates of LR, while marginality alone always leads to high rates of relapse, is outdated. In the modern era of surgical oncology, limb salvage and high-level function after resectional surgery are the key surgical goals. The best results are achieved by combining effective neoadjuvant treatments with planned bespoke oncological operations that consider the biological and anatomical factors of each individual sarcoma.

Clinical Outcome of Dermatofibrosarcoma Protuberance. Report From the Bone and Soft Tissue Tumor (BSTT) Registry in Japan

BACKGROUND

Owing to its rarity, dermatofibrosarcoma protuberance (DFSP) is often inappropriately excised. After unplanned excision (UE), additional excision is commonly performed. We aimed to elucidate the effect of additional excision after UE.

PATIENTS AND METHODS

We examined 306 patients with primary DFSP. We analyzed surgical outcomes in 291 patients who received planned excision (PE) or additional excision after UE.

RESULTS

Of 306 patients, 194 received PE and the remaining 112 received UE. Of 112 patients, 97 received additional excision after UE. Additional surgery due to complications was more frequent in patients with UE than in those with PE. The 5-year local recurrence-free rate in patients without additional excision after UE was significantly worse than that in those with additional excision after UE.

CONCLUSION

If UE is performed, we recommend additional excision for preventing local recurrence; however, the surgical wound should be carefully observed.

Dermatofibrosarcoma Protuberans: A Clinicopathologic and Therapeutic Analysis of 254 Cases at a Single Institution

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare low-grade tumor that typically does not metastasize but often recurs. Fibrosarcomatous DFSP (FS-DFSP) is associated with a substantially higher rate of metastasis and a poorer prognosis.

OBJECTIVE

This study sought to investigate the epidemiological, histopathological, and clinical characteristics of DFSP, especially with a particular focus on FS-DFSP.

MATERIALS AND METHODS

Clinical data from 254 patients treated between January 1999 and July 2018 were retrospectively reviewed. Endpoints of the study were the incidence of significant disease-related clinical events.

RESULTS

Follow-up data from 211 patients were available for analysis, with a median follow-up time of 38 months (range: 1-196 months). The 5-year recurrence-free survival rate of patients underwent wide-local excision (WLE) was 97.1%. Patients underwent WLE exhibited a significantly decreased recurrence rate relative to patients treated through local excision (2.9% vs 37.7%; p < .001). Fibrosarcomatous DFSP had significantly higher rates of distant metastasis (66.7% [n = 4] vs 2.0% [n = 4]; p < .001) and long-term mortality (50.0% [n = 3] vs 1.5% [n = 3]; p < .001), compared with classical DFSP (C-DFSP).

CONCLUSION

Wide-local excision is an effective means of reducing DFSP recurrence. Rates of metastasis are higher for FS-DFSP than for C-DFSP, with the former having significantly poorer outcomes.

Clinicopathological features of fibrosarcomatous dermatofibrosarcoma protuberans and the construction of a back-propagation neural network recognition model

BACKGROUND

Fibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP) is a form of tumor progression of dermatofibrosarcoma protuberans (DFSP) with an increased risk of metastasis and recurrence. Few studies have compared the clinicopathological features of FS-DFSP and conventional DFSP (C-DFSP).

OBJECTIVES

To better understand the epidemiological and clinicopathological characteristics of FS-DFSP.

METHODS

We conducted a cohort study of 221 patients diagnosed with DFSP and built a recognition model with a back-propagation (BP) neural network for FS-DFSP.

RESULTS

Twenty-six patients with FS-DFSP and 195 patients with C-DFSP were included. There were no differences between FS-DFSP and C-DFSP regarding age at presentation, age at diagnosis, sex, size at diagnosis, size at presentation, and tumor growth. The negative ratio of CD34 in FS-DFSP (11.5%) was significantly lower than that in C-DFSP (5.1%) (P = 0.005). The average Ki-67 index of FS-DFSP (18.1%) cases was significantly higher than that of C-DFSP (8.1%) cases (P < 0.001). The classification accuracy of the BP neural network model training samples was 100%. The correct rates of classification and misdiagnosis were 84.1% and 15.9%.

CONCLUSIONS

The clinical manifestations of FS-DFSP and C-DFSP are similar but have large differences in immunohistochemistry. The classification accuracy and feasibility of the BP neural network model are high in FS-DFSP.

Dermatofibrosarcoma protuberance in a black African cohort-a clinicopathologic study

Background

Dermatofibrosarcoma protuberance (DFSP) is the commonest, yet rare, dermal sarcoma globally. There are few reports in the literature of this neoplasm in Nigerians and indeed in sub-Saharan Africa. This study documents our institutional practice observation and compares it with those from other regions of the world.

Methods and materials

This study was a retrospective review of all cases of histologically diagnosed DFSP at the University College Hospital, Ibadan, Nigeria, spanning a period of 27 years (January 1989–December 2016). Data on patient age, gender, tumour location, size, tumour recurrence and metastasis status were obtained from clinical and surgical pathology archival files and records.

Results

Sixty-nine cases of DFSP were recorded over the period reviewed with a male–female ratio of 1.6:1. The mean age of the study population was 39.6 years. The youngest patient was 5-year old, while the oldest was 86 years and the modal age group was the 4th decade. The trunk was the commonest anatomic tumour location. Recurrences were seen in seven cases with recurrence interval ranging from 6 to 240 months. The correlation between tumour size and age was non-significant (r = −0.183; p = 0.182). There was fibrosarcoma-like transformation in three cases (4.3%) studied.

Conclusion

Dermatofibrosarcoma protuberance is rare in our population and occurs more commonly in males and on the trunk. Recurrence can occur beyond the recommended follow-up period of 10 years.

Adequate surgical margins for dermatofibrosarcoma protuberans - A multi-centre analysis

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive tumour. Adequate margins have a positive impact on recurrence rates. The aim of this study is to assess how adequate margins are achieved and secondly which additional treatment modalities might be necessary to achieve adequate margins.

MATERIAL & METHODS

Patients with DFSP treated between 1991 and 2016 at three tertiary centres were included. Patient- and tumour characteristics were obtained from a prospectively held database and patient files.

RESULTS

A total of 279 patients with a median age of 39 (Interquartile range [IQ], 31-50) years and a median follow-up of 50 (IQ, 18-96) months were included. When DFSP was preoperatively confirmed by biopsy and resected with an oncological operation in a tertiary centre, in 86% was had clear pathological margins after one excision. Wider resection margins were significantly correlated with more reconstructions (p = 0.002). A substantial discrepancy between the primary surgical macroscopic and the pathological margins was found with a median difference of 22 (range, 10-46) mm (Fig. 1). There was no significant influence of the width of the pathological clear margins (if > 1 mm) and the recurrence rate (p = 0.710).

CONCLUSION

The wider the resection margins, the more likely it is to obtain clear pathological margins, but the more likely patients will need any form of reconstruction after resection. The aim of the primary excision should be wide surgical resection, where the width of the margin should be balanced against the need for reconstructions and surgical morbidity.

Dermatofibrosarcoma Protuberans: Update on the Diagnosis and Treatment

Dermatofibrosarcoma protuberans (DFSP) is a slow growing, low- to intermediate-grade dermal soft-tissue tumor. It has a high local recurrence rate but low metastatic potential. It is characterized by a uniform spindle cell arrangement, classically with a storiform pattern and CD34 immunoreactivity. The histomorphology and immunophenotype overlap with a broad range of other neoplasms. The standard treatment is complete surgical excision. The surgical procedures include wide local excision (WLE) with tumor free margins, Mohs micrographic surgery (MMS) and amputation. Unresectable DFSPs are treated with radiation therapy and/or targeted therapy. DFSP has characteristic t(17; 22) (q22; q13), resulting in a COL1A1- PDGFB fusion transcripts in more than 90% of DFSPs. Molecular detection of the gene rearrangement or fusion transcripts is helpful for the diagnosis of patients with atypical morphology and for screening candidates for targeted therapy with tyrosine kinase inhibitors. The aims of the present review are to update the clinical presentation, tumorigenesis and histopathology of DFSP and its variants for diagnosis and differential diagnosis from other benign and malignant tumors, to compare the advantages and drawbacks of WLE and MMS, to propose the baseline for selecting surgical procedure based on tumor’s location, size, stage and relationship with surrounding soft tissue and bone structures, and to provide a biologic rationale for the systemic therapy. We further propose a modified clinical staging system of DFSP and a surveillance program for the patients after surgical excision.