Dermatofibrosarcoma protuberans

Novel role of fluorescent in situ hybridization technique (FISH) in recommended surgical margins of dermatofibrosarcoma protuberans: A preliminary study

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare skin tumor. There is no standard recommendation for its surgical management. The currently used histological analysis are HES (hematoxylin eosin saffron) staining and immunohistochemistry for CD34 expression in particular cases. Fluorescent in situ hybridization (FISH) technique is only used to qualify the DFSP as translocated or non-translocated and is not used as a diagnostic method. The aim of our study was to determine by FISH (as a diagnostic method) whether cancerous cells that could not be identified through HES staining±immunohistochemistry were present at the two-centimeter margins that were found to be tumor-free.

METHODS

Samples from patients who underwent surgery between 2010 and 2018 were collected. Intralesional and peripheral (at 2cm margins) paraffin slides were included. An average of 7.4 slides per specimen was analyzed. Firstly, the preselected slides were reread by a senior pathologist to confirm the absence of microscopic findings of DFSP at 2cm margins. Secondly a FISH analysis was used as a quantitative diagnostic approach, in order to find the t(17;22) translocation.

RESULTS

Among the seven specimens that included 2cm margins, two samples presented one or more translocations, which were not visible in standard morphology assessments at two centimeters tumor-free margins.

CONCLUSIONS

FISH analysis can have a new role in defining tumor-free margins. This would reduce the incidence of disease recurrence after resection and improve the post-operative complementary care.

Giant dermatofibrosarcoma protuberans head and neck: a diagnostic dilemma

Dermatofibrosarcoma protuberans (DFSP) is rare, generally slow growing tumor, originating from dermal stem cell or undifferentiated mesenchymal cell. DFSP primarily occurs on the trunk and proximal extremities, with reported only 10-15% occurring in the head and neck region. There can be varied presentations of DFSP in atypical sites mimicking a benign appearance and history due to which diagnostic dilemmas can occur. The underlying malignancy needs to be unveiled by histopathology and immunohistochemistry which reveals bland spindle cells in sub epithelium arranged in whorled storiform pattern which was CD34+, suggestive of dermatofibrosarcoma protuberans. Surgical excision is the treatment of choice, wherever possible. We herein report two intriguing cases of DFSP in uncommon sites.

Pediatric dermatofibrosarcoma protuberans: A clinicopathologic and genetic analysis of 66 cases in the largest institution in Southwest China

Background

Dermatofibrosarcoma protuberans (DFSP) is an uncommon cutaneous tumor in children. Most published articles are sporadic or small series and lack systematically molecular analyses. The aim of our study is to better understand the clinicopathologic and genetic features of these rare lesions.

Methods

All patients diagnosed with DFSP aged ≤ 18 years were retrospectively reviewed from January 2006 to May 2022.

Results

A total of 66 cases (32 male and 34 female patients) were identified, with ages ranging from 0.3 to 18 years (median, 13 years). Tumor locations predominantly occurred on the trunk (38/66, 57.6%), followed by the extremities (20/66, 30.3%) and head/neck (8/66, 12.1%). Histological findings revealed classic (41/66, 62.1%), myxoid (4/66, 6.1%), pigmented (6/66, 9.1%), plaque-like (3/66, 4.5%), giant cell fibroblastoma (GCF; 6/66, 9.1%), and fibrosarcomatous (6/66, 9.1%) variants of DFSP. Immunochemistry revealed minority tumors (9/66, 13.6%) showing patchy or negative staining for CD34. Fluorescence in situ hybridization (FISH) indicated that 49 of 53 tested cases including all detected biopsy specimens (11/11) contained COL1A1-PDGFB fusion, in which the average copy number gain of COL1A1-PDGFB was 0.68. There were four cases negative for COL1A1-PDGFB rearrangement, one of which was found to harbor a novel COL3A1-PDGFB fusion by next-generation sequencing (NGS). Treatment for 63 patients comprised 40 marginal excisions and 23 wide local excisions (WLEs), including 1 with imatinib therapy. Follow-up information was available on 49 patients with a duration of 12-161 months (median, 60 months). Fourteen patients developed tumor recurrence, all with initial marginal excisions. The others survived with no evidence of disease.

Conclusions

This study of pediatric DFSP indicates certain discrepancies in clinicopathologic characteristics between children and adults. The majority of pediatric DFSPs contain COL1A1-PDGFB fusion, the same as their adult counterparts. The COL3A1-PDGFB chimerism might be associated with the special morphology of GCF, which needs further investigation. FISH is valuable in biopsy tissues and cases with atypical CD34 immunostaining, while supplementary NGS could be helpful to identify the cytogenetically cryptic DFSP. Overall, an urgent accurate diagnosis is needed to formulate an optimal therapeutic strategy in the pediatric population.

Dermatofibrosarcoma Protuberans: What Is This?

Dermatofibrosarcoma protuberans (DFSP) is a rare, locally aggressive dermal-based sarcoma. Metastatic potential is extremely low, primarily in the setting of fibrosarcomatous transformation. DFSP is characterized by a t(17;22) (q22;q13) translocation that results in active PDGFB signaling. Surgical resection with negative margins (typically including the underlying fascia) is the potentially curative treatment. Delayed wound closure should be considered for cases requiring extensive resection or tissue rearrangement. Tyrosine kinase inhibitors, such as imatinib, have shown response rates of 50% to 60% in patients with locally advanced or metastatic disease. Radiation can be useful for residual or recurrent diseases.

A unique case of Dermatofibrosarcoma Protuberans arising from an inguinal hernial repair scar in a Middle Eastern male - A Case Report

INTRODUCTION AND IMPORTANCE

Dermatofibrosarcoma Protuberans (DFSP) is a rare and fatal variant of Spindle Cell Sarcoma. It has an annual incidence rate of 0.8 to 4.5 cases per one million individuals. It's locally aggressive and has vague and masquerading clinical presentations. Misdiagnosis is devastating as it can lead to time wasting, expenditure of unnecessary resources, and possibly raise morbidity and mortality for patients. It is warranted to raise preoperative clinical awareness to achieve prompt surgical therapeutic interventions to reach an up-to-par prognosis.

CASE PRESENTATION

We demonstrate the case of a 50-year-old previously healthy Middle Eastern male patient, who was referred to our General Surgery clinic with the chief complaint of an expansive bulge in his left iliac fossa. Preoperative imaging could not exclude a neoplastic cause behind the presentation. Based on the clinical picture, a surgical intervention was decided.

CLINICAL DISCUSSION

Our patient's treatment was consummated by means of classical surgical resection of the lesion with adequate negative margins and referring him to an oncologist specialized in DFSP to undergo the necessary adjuvant treatment. Definitive diagnosis was firmly entrenched postoperatively after finalization of the histopathological and immunohistochemical analyses of the resected protuberance.

CONCLUSION

DFSP is an eminently rare entity, especially DFSPs which originate from a surgical scar -as was our patient's- and fluctuates in its clinical presentation, thus, it is our responsibility to depict, study this malignant tumor, and document its incidence, so that we can make ironclad clinical decrees to plummet the morbidity and mortality of this relentless neoplasia.

Dermatofibrosarcoma protuberans of the anterior abdominal wall: case report and literature review

Dermatofibrosarcoma protuberans (DFSP) is a rare and slowly growing cutaneous tumor with high risk of local invasion and recurrence. Here, we report a case of a DFSP of the anterior abdominal wall diagnosed in a 45-year-old woman. The clinical examination showed an indurated well-limited oval mass localized in the supra-umbilical level and measuring 5 cm by 3 cm. The histological finding of skin biopsy was consistent with the diagnosis of DFSP. A wide local excision was performed while respecting minimum safety margins of 3 cm. The primary closure was possible after advancing the subcutaneous adjacent tissue. The histological examination of the surgical specimen confirmed the DFSP diagnosis and determined safe microscopic margins. After 4 years of regular follow-up, no locoregional or distant recurrence was observed. We discuss through this case the diagnosis difficulties and the particularities of the abdominal wall localization.

Dermatofibrosarcoma protuberans of the scalp

Dermatofibrosarcoma protuberans is a rare entity. Due to its high propensity for local recurrence, knowledge of the appropriate management, both surgical and medical, is important for optimal patient outcomes.

Assessing the Safety and Utility of Wound VAC Temporization of the Sarcoma or Benign Aggressive Tumor Bed Until Final Margins Are Achieved

BACKGROUND

Local recurrence of microinvasive sarcoma or benign aggressive pathologies can be limb- and life-threatening. Although frozen pathology is reliable, tumor microinvasion can be subtle or missed, having an impact on surgical margins and postoperative radiation planning. The authors' service has begun to temporize the tumor bed after primary tumor excision with a wound vacuum-assisted closure (VAC) pending formal margin analysis, with coverage performed in the setting of final negative margins.

METHODS

This retrospective analysis included all patients managed at a tertiary referral cancer center with VAC temporization after soft tissue sarcoma or benign aggressive tumor excision from 1 January 2000 to 1 January 2019 and at least 2 years of oncologic follow-up evaluation. The primary outcome was local recurrence. The secondary outcomes were distant recurrence, unplanned return to the operating room for wound/infectious indications, thromboembolic events, and tumor-related deaths.

RESULTS

For 62 patients, VAC temporization was performed. The mean age of the patients was 62.2 ± 22.3 years (median 66.5 years; 95% confidence interval [CI] 61.7-72.5 years), and the mean age-adjusted Charlson Comorbidity Index was 5.3 ± 1.9. The most common tumor histology was myxofibrosarcoma (51.6%, 32/62). The mean volume was 124.8 ± 324.1 cm³, and 35.5% (22/62) of the cases were subfascial. Local recurrences occurred for 8.1% (5/62) of the patients. Three of these five patients had planned positive margins, and 17.7% (11/62) of the patients had an unplanned return to the operating room. No demographic or tumor factors were associated with unplanned surgery.

CONCLUSIONS

The findings showed that VAC-temporized management of microinvasive sarcoma and benign aggressive pathologies yields favorable local recurrence and unplanned operating room rates suggestive of oncologic and technical safety. These findings will need validation in a future randomized controlled trial.

Advanced dermatofibrosarcoma protuberans: an updated analysis of cases from an Indian sarcoma clinic

AIM

Dermatofibrosarcoma protuberans (DFSP) accounts for less than 2% of all soft-tissue sarcomas.

PATIENTS & METHODS

We retrospectively reviewed our database for patients with locally advanced or metastatic DFSP who had presented to our clinic between January 2016 and January 2020.

RESULTS

We identified a total of 14 patients, of whom ten had sarcomatous transformation. Eleven cases had metastatic disease and three were locally advanced. The initial partial response rate to first-line imatinib was 76.9% and the overall median progression-free survival on imatinib was 15 months.

CONCLUSION

We had a high proportion of patients with sarcomatous transformation, in contrast to their relative rarity in the West. While most patients had initial good responses to imatinib, second-line therapies were not as effective.

Role of a new acellular dermal matrix in a multistep combined treatment of dermatofibrosarcoma protuberans of the lumbar region: a case report

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare skin fibroblastic tumor, with a high rate of recurrence. The treatment of DFSP is generally surgical, and wide local excision is the mainstay of surgical treatment. Therefore, complete assessment of all surgical margins is fundamental before definitive reconstruction. The reconstruction is a challenge for plastic surgeons, especially in particular anatomical areas (for aesthetic or functional problems) or in patients who are not candidates for more complex surgical treatments. We describe an alternative approach for reconstructive treatment of the lumbar area after wide excision of DFSP (without fresh-frozen sections) in a young obese woman with a history of smoking, using a new type of acellular dermal matrix (ADM) in a combined management protocol. The benefits of ADM are numerous: immediate wound closure and prevention of infections and excessive drying; minimal donor site morbidity; and good functional and aesthetic outcomes. Moreover, it is a temporary cover while the anatomical specimen is histologically analyzed, without donor site morbidity or prevention of any future surgery (if the margins are not tumor-free) or radiotherapy.

CASE PRESENTATION

In October 2019, a 34-year old obese Caucasian Woman with a history of smoking came to our institute for a multinodular growing polypoid mass in her lumbar region. An incisional biopsy diagnosed DFSP. The patient underwent proper staging. A wide local excision with 3 cm clinically healthy tissue margins down to the muscle fascia was performed and the defect was repaired using a combined approach with a new artificial bilaminar dermal template (Pelnac®, Gunze Ltd., Osaka, Japan) and a negative-pressure wound therapy system (V.A.C.®, KCI, San Antonio, USA). After the final histological examination revealed tumor-free margins, a split-thickness graft was harvested from the right gluteus and fixed to the new derma with negative-pressure wound therapy. Postoperative radiotherapy was not necessary. After 15 days, the wound had healed without complications, with satisfactory aesthetic outcome and with no limitation of back motion or pain. After 6 months of follow-up, the patient was free from disease.

CONCLUSIONS

This is the first reported case of Pelnac® use in DFSP reconstruction of the lumbar region. We believe that the multistep approach described herein may be a good alternative approach in selected patients with wide resections in particular anatomical areas, especially when frozen sections (with Mohs micrographic surgery) are not available.

[Case report: Epigastric dermatofibroma reconstruction by reverse abdominoplasty with umbilic transposition]

Dermatofibrosarcoma is the most common cutaneous sarcoma. Its surgical management is a technical challenge due to the high amount of substance loss. We explain a new technique of abdominal wall reconstruction by a reverse abdominoplasty with umbilical transposition. This new surgical technique allowed, in one time, the excision and the abdominal wall reconstruction. Functional and esthetic results are really satisfactory.

Terahertz radiation and the skin: a review

SIGNIFICANCE

Terahertz (THz) radiation has demonstrated a great potential in biomedical applications over the past three decades, mainly due to its non-invasive and label-free nature. Among all biological specimens, skin tissue is an optimal sample for the application of THz-based methods because it allows for overcoming some intrinsic limitations of the technique, such as a small penetration depth (0.1 to 0.3 mm for the skin, on average).

AIM

We summarize the modern research results achieved when THz technology was applied to the skin, considering applications in both imaging/detection and treatment/modulation of the skin constituents.

APPROACH

We perform a review of literature and analyze the recent research achievements in THz applications for skin diagnosis and investigation.

RESULTS

The reviewed results demonstrate the possibilities of THz spectroscopy and imaging, both pulsed and continuous, for diagnosis of skin melanoma and non-melanoma cancer, dysplasia, scars, and diabetic condition, mainly based on the analysis of THz optical properties. The possibility of modulating cell activity and treatment of various diseases by THz-wave exposure is shown as well.

CONCLUSIONS

The rapid development of THz technologies and the obtained research results for skin tissue highlight the potential of THz waves as a research and therapeutic instrument. The perspectives on the use of THz radiation are related to both non-invasive diagnostics and stimulation and control of different processes in a living skin tissue for regeneration and cancer treatment.

Dermatofibrosarcoma protuberans in children and adolescents: The European Paediatric Soft Tissue Sarcoma Study Group prospective trial (EpSSG NRSTS 2005)

BACKGROUND

As dermatofibrosarcoma protuberans (DFSP) are rare with no prospective series within paediatric sarcoma trials, the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG) examined the clinical data and outcomes of DFSP enrolled in a multinational study of non-rhabdomyosarcoma soft tissue sarcomas (NRSTS).

PATIENTS AND METHODS

Forty-six patients with confirmed DFSP were enrolled into the EpSSG NRSTS 2005 study. All had surgical resection and none had any further therapy at diagnosis.

RESULTS

The median age at diagnosis was 6.9 years (range 0.4-17.5). All patients had localised disease, and the majority had small <5 cm tumours (93%), and 76% had Intergroup Rhabdomyosarcoma Study (IRS) I tumours. All patients had up front surgery, 32 requiring two operations. There were 11 patients with IRS II tumours, of which only two went on to have a local recurrence. After a median follow up of 49.0 months (range 4.2-130.9), all patients were alive at the time of this report, with 5-year event-free survival of 92.6% (CI 78.8-97.6) with a 100% overall survival.

CONCLUSION

This report demonstrates the ability to run prospective paediatric studies in NRSTS in multiple European countries, with reasonable numbers of DFSP patients, with few events and no deaths, and hence excellent outcomes.

Multidisciplinary surgical treatment approach for dermatofibrosarcoma protuberans: an update

Dermatofibrosarcoma protuberans (DFSP) is a cutaneous sarcoma that has remained a challenge for oncologic and reconstructive surgeons due to a high rate of local recurrence. The objective of this study is to investigate the oncologic and reconstructive benefits of employing a multidisciplinary two-step approach to the treatment of DFSP. A retrospective review was conducted using a prospectively collected database of all patients who underwent resection and reconstruction of large DFSPs by a multidisciplinary team, including a Mohs micrographic surgeon, surgical oncologist, dermatopathologist, and plastic and reconstructive surgeon, at one academic institution from 1998-2018. Each patient underwent Mohs micrographic surgery for peripheral margin clearance (Step 1) followed by wide local excision (WLE) of the deep margin by surgical oncology and immediate reconstruction by plastic surgery (Step 2). 57 patients met inclusion criteria. Average defect size after WLE (Step 2): 87.3 cm² (range 8.5-1073.5 cm²). Mean follow-up time was 37 months (range 0-138 months). There were no cases of recurrence. A two-step multidisciplinary surgical treatment approach for DFSP minimizes risk of recurrence, decreases patient discomfort, and allows immediate reconstruction after deep margin clearance.

Dermatofibrosarcoma protuberans: surgical management of a challenging mesenchymal tumor

INTRODUCTION

Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade malignant mesenchymal tumor of the soft tissue, characterized by slow infiltrative growth and common local recurrence, with rare distant metastases.

PATIENTS AND METHODS

We present a retrospective study of nineteen patients who were diagnosed with DFSP and operated at our institution in > 10-year period. We examined the clinicopathological parameters with special emphasis on the margin status regarding the clinical outcome and the follow-up.

RESULTS

A total of eight cases underwent re-excision at our institution following primary excision or incisional biopsy performed at a different institution. Seven cases received excision after incisional biopsy at our institution. Four patients developed recurrent disease following primary excision with histological R0 margins at other institutions and received re-excision at our institution. All excisions at our institution resulted in R0 margins with no recurrence recorded at last follow-up (6 to 175; mean 84 months). The mean margin for those who received resection at our institution was 1.67 cm. Negative margins upon primary excision were achieved using a mean margin width of 2.04 cm. Most common tumor localization was the trunk (10 cases).

CONCLUSION

Awareness of this rare entity is important for a prompt diagnosis and a proper management of the disease. The greatest clinical challenge in the management of DFSP is achieving local control. Complete excision of the tumor with surgical margin widths of at least 2 cm is recommended.

Advances in the Understanding of Skin Cancer: Ultraviolet Radiation, Mutations, and Antisense Oligonucleotides as Anticancer Drugs

Skin cancer has always been and remains the leader among all tumors in terms of occurrence. One of the main factors responsible for skin cancer, natural and artificial UV radiation, causes the mutations that transform healthy cells into cancer cells. These mutations inactivate apoptosis, an event required to avoid the malignant transformation of healthy cells. Among these deadliest of cancers, melanoma and its 'younger sister', Merkel cell carcinoma, are the most lethal. The heavy toll of skin cancers stems from their rapid progression and the fact that they metastasize easily. Added to this is the difficulty in determining reliable margins when excising tumors and the lack of effective chemotherapy. Possibly the biggest problem posed by skin cancer is reliably detecting the extent to which cancer cells have spread throughout the body. The initial tumor is visible and can be removed, whereas metastases are invisible to the naked eye and much harder to eliminate. In our opinion, antisense oligonucleotides, which can be used in the form of targeted ointments, provide real hope as a treatment that will eliminate cancer cells near the tumor focus both before and after surgery.

On the diagnosis and treatment of cutaneous and soft tissue tumours misdiagnosed as scars: Lessons from four cases

Some types of skin and soft tissue tumours may be misdiagnosed as scars because of the scar-like manifestation or the history of injury. It is generally believed that injuries will activate wound healing, ultimately ending in fibrosis. Because of the tumour-promoting properties of both the microenvironment of the wound and the wound-healing process that may go awry, there is a likelihood that injuries may trigger tumour growth. From 2012 to 2016, we treated four patients who underwent unsuccessful treatments because of the misdiagnosis of scars or keloids. Upon the pathological diagnoses of skin and soft tissue tumours in the four cases, extended resection of the tumours was performed. Recurrence was not observed up to the last follow up. Since then, soft tissue tumours have much greater visibility and are considered during diagnosis if a wound is presented with the atypical appearance of scar after injuries. Under these circumstances, biopsy should be conducted.

Recurrence case of rare scalp dermatofibrosarcoma protuberans: Two case reports of a wide radical excision, craniectomy bone involvement followed by cranioplasty and reconstruction

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare low-grade sarcoma of the fibroblast originating from the dermal layer of the skin, characterized by a locally aggressive growth and high rate of local recurrence.

CASE DESCRIPTION

Two patients underwent a wide radical excision of recurrent scalp DFSP which was reconstructed with translational skin flap and split-thickness skin graft. We described above cases several years ago with a local excision of the tumor; recently, they developed local recurrence of DFSP with calvarial involvement. We then performed a wide radical excision, with craniectomy of the cranial defect followed by cranioplasty using titanium mesh, continuing with reconstruction.

CONCLUSION

A successful treatment and management depends on achieving local control and preventing cosmetic and functional deficit; all efforts should be made for complete excision. Postoperative follow-up recommended for highly suspicious cases and annual checkups should be performed up to 5 years after definitive therapy.

Operative management of dermatofibrosarcoma protuberans of the breast

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous tumor with a tendency towards local recurrence. A 26-year-old woman presented with a 3 × 2 cm raised, purple-hued lesion on her left breast. Excisional biopsy identified the lesion as a DFSP. She underwent two additional operations to achieve widely clear margins. Operative excision is the primary treatment of dermatofibrosarcoma protuberans of the breast.

Dermatofibrosarcoma protuberans in pediatric patients: a report of 17 cases

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue tumor. In children, there are acquired and congenital presentations. Due to clinical similarities with other conditions, diagnosis may be delayed.

OBJECTIVE

To review the clinical characteristics and treatment of DFSP in pediatric patients.

METHODS

A retrospective chart review was performed from January 2002 to September 2012. Inclusion criteria were patients under 18 years of age with a histopathologic diagnosis of DFSP. Data on demographics, clinical characteristics, treatments, and outcomes were collected.

RESULTS

Information was gathered from 17 patients; 9 (53%) were female. Congenital lesions were reported in 7 patients. The mean delay of diagnosis was 5.7 years; the most common anatomic location was the trunk in 8 of 17 (47%) cases. Treatment options included wide local surgery, Mohs surgery, and imatinib mesylate.

CONCLUSION

A detailed medical history and identification of the natural course of common conditions seen in pediatric patients are important to identify less common lesions and to suspect DFSP.

Dermatofibrosarcoma Protu-Berans with Lung Metastasis Requiring Pneumonectomy

We report the case of a young man diagnosed with dermatofibrosarcoma protuberans lung metastases seven years after primary tumor resection. Notably, no previous local recurrences had been observed. A multimodal approach was used for the management of this patient: surgery, radiotherapy and targeted therapy with Imatinib. The patient is alive with stable disease after thirty months of the metastases diagnoses. Dermatofibrosarcoma protu-berans metastasizes very rarely, and when it does, it is usually either after local recurrence or whenever fibrosarcomatous transformation is found in the histopathological analysis, which confers an increased risk of local recurrence and metastases. This is the second report of a metastatic dermatofibrosarcoma protuberans occurring in a patient with no previous local recurrence or histological fibrosar-comatous features, emphasizing the rarity of the disease presentation and the importance of targeted therapy in improving patient quality of life and survival.

Surgical Treatment of Enormous Recurrent Dermatofibrosarcoma Protuberans

A patient with enormous recurrent dermatofibrosarcoma protuberans underwent modified three-dimensional histology surgery. Frozen-section examination was used to identify the margins. The patient had a normal postoperative course.

Wide Local Excision for Dermatofibrosarcoma Protuberans: A Single-Center Series of 90 Patients

Background. Dermatofibrosarcoma protuberans (DFSP), a rare low-grade sarcoma of fibroblast origin, tends to extend in a finger-like fashion beyond macroscopic tumor margins. Therefore, incomplete removal and subsequent recurrence are common. This study aimed to determine the efficacy of wide local excision (WLE) for controlling local recurrence of DFSP. Methods. The medical records of 90 DFSP patients who received WLE at our hospital between June 1992 and January 2015 were retrospectively reviewed. WLE was conducted including a 3 cm (range, 1 to 5 cm) safety margin according to tumor size, location, and recurrence status. Clinical and tumor characteristics and surgical methods were evaluated for risk factor analysis and local recurrence-free survival. Results. DFSP occurred most often in patients in their 30s (30%) and on the trunk (51.1%). Five patients (5.5%) experienced local recurrence during the 43.4-month follow-up period. Recurrence was found at a mean of 10.8 months after WLE. Although no factors were significantly associated with recurrence, recurrences were more frequent in head and neck. Recurrence-free survival was 87% in 6 years and 77% in 7 years. Conclusions. WLE with adequate lateral and deep margins can effectively control local recurrence rate and is a simple and effective method to treat DFSP.

Unusual presentation of dermatofibrosarcoma protuberans in a male patient's breast: a case report and review of the literature

We herein present a case report and literature review of dermatofibrosarcoma protuberans in the breast of a male patient. A 27-year-old man presented with a painless lump in his right breast with areas of bluish skin discoloration. The diagnostic work-up comprised clinical examination, ultrasonography, core biopsy, mammography, and magnetic resonance imaging. After surgical excision, the preoperative diagnosis of dermatofibrosarcoma protuberans was proven by pathological examination and immunohistochemistry. The patient was still free of recurrence 1 year after surgical excision. This extremely rare case is, to the best of our knowledge, the fifth such case reported in the literature.

Genetic aberrations in imatinib-resistant dermatofibrosarcoma protuberans revealed by whole genome sequencing

Dermatofibrosarcoma protuberans (DFSP) is a very rare soft tissue sarcoma. DFSP often reveals a specific chromosome translocation, t(17;22)(q22;q13), which results in the fusion of collagen 1 alpha 1 (COL1A1) gene and platelet-derived growth factor-B (PDGFB) gene. The COL1A1-PDGFB fusion protein activates the PDGFB receptor and resultant constitutive activation of PDGFR receptor is essential in the pathogenesis of DFSP. Thus, blocking PDGFR receptor activation with imatinib has shown promising activity in the treatment of advanced and metastatic DFSP. Despite the success with targeted agents in cancers, acquired drug resistance eventually occurs. Here, we tried to identify potential drug resistance mechanisms against imatinib in a 46-year old female with DFSP who initially responded well to imatinib but suffered rapid disease progression. We performed whole-genome sequencing of both pre-treatment and post-treatment tumor tissue to identify the mutational events associated with imatinib resistance. No significant copy number alterations, insertion, and deletions were identified during imatinib treatment. Of note, we identified newly emerged 8 non-synonymous somatic mutations of the genes (ACAP2, CARD10, KIAA0556, PAAQR7, PPP1R39, SAFB2, STARD9, and ZFYVE9) in the imatinib-resistant tumor tissue. This study revealed diverse possible candidate mechanisms by which imatinib resistance to PDGFRB inhibition may arise in DFSP, and highlights the usefulness of whole-genome sequencing in identifying drug resistance mechanisms and in pursuing genome-directed, personalized anti-cancer therapy.

Dermatofibrosarcoma protuberans: long-term outcomes of 53 patients treated with conservative surgery and radiation therapy

PURPOSE

To evaluate outcomes of conservative surgery and radiation therapy (RT) treatment in patients with dermatofibrosarcoma protuberans.

METHODS AND MATERIALS

We retrospectively reviewed the medical records of 53 consecutive dermatofibrosarcoma protuberans patients treated with surgery and preoperative or postoperative radiation therapy between 1972 and 2010. Median tumor size was 4 cm (range, 1-25 cm). Seven patients (13%) were treated with preoperative RT (50-50.4 Gy) and 46 patients (87%) with postoperative RT (60-66 Gy). Of the 46 patients receiving postoperative radiation, 3 (7%) had gross disease, 14 (30%) positive margins, 26 (57%) negative margins, and 3 (7%) uncertain margin status. Radiation dose ranged from 50 to 66 Gy (median dose, 60 Gy).

RESULTS

At a median follow-up time of 6.5 years (range, 0.5 months-23.5 years), 2 patients (4%) had disease recurrence, and 3 patients (6%) had died. Actuarial overall survival was 98% at both 5 and 10 years. Local control was 98% and 93% at 5 and 10 years, respectively. Disease-free survival was 98% and 93% at 5 and 10 years, respectively. The presence of fibrosarcomatous change was not associated with increased risk of local or distant relapse (P=.43). One of the patients with a local recurrence had gross residual disease at the time of RT and despite RT to 65 Gy developed both an in-field recurrence and a nodal and distant recurrence 3 months after RT. The other patient with local recurrence was found to have in-field recurrence 10 years after initial treatment. Thirteen percent of patients had an RT complication at 5 and 10 years, and 9% had a moderate or severe complication at 5 and 10 years.

CONCLUSIONS

Dermatofibrosarcoma protuberans is a radioresponsive disease with excellent local control after conservative surgery and radiation therapy. Adjuvant RT should be considered for patients with large or recurrent tumors or when attempts at wide surgical margins would result in significant morbidity.