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Introduction

  1. Top of page
  2. Introduction
  3. Case report
  4. Discussion
  5. Conclusions
  6. Acknowledgments
  7. References

Dermatofibrosarcoma protuberans (DFSP) is a rare, low to intermediate grade soft tissue sarcoma originating from the dermal layer of the skin. It is a locally aggressive but rarely metastatic skin tumor, which tends to recur after excision.1 Although historically it has been attributed as fibroblastic in origin, recent immunohistochemical evidence suggests that it may arise from dendritic cells in the skin. In 1924, Darier and Ferrad1 first described the entity of DFSP as a “progressive and recurring dermatofibroma,” underscoring its predilection for local recurrence. DFSP is a locally aggressive tumor and despite sharing some histologic features with fibrohistiocytic tumors, it tends to grow in a more infiltrative manner.

This tumor has been reported to involve many body surfaces, mainly the trunk, followed by the extremities, and less commonly in the head and neck.2 Although DFSP constitutes less than 0.1% of all malignant neoplasms, it represents the most frequent skin sarcoma (nearly 1% of all soft tissue sarcomas), more than 1% of all head and neck malignant tumors, and 7% of all head and neck sarcomas.3,4 This article describes a case of dermatofibrosarcoma of the scalp in a young male patient. It also seeks to highlight difficulties in managing this condition in resource limited settings, while including a review of relevant literature.

Case report

  1. Top of page
  2. Introduction
  3. Case report
  4. Discussion
  5. Conclusions
  6. Acknowledgments
  7. References

A 26-year-old Nigerian man presented to the outpatient department of the Nigerian Christian Hospital with a massive tumor on the right side of his scalp, extending down his cheek. The patient was seen by a visiting outreach surgical program. The tumor demonstrated indolent growth for more than two years and was friable, easily bleeding on contact. There was an associated purulent, foul-smelling discharge. Earlier consultations in nearby teaching hospitals were inadequate as the surgeons either lacked required skills and/or the patient lacked required funds to secure treatment.

Initial evaluation revealed a fleshy, friable, ulcerative lesion that was nodular and firm. The tumor had surface areas of necrosis. The tumor extended from his right temple down his entire right cheek and involved the lateral aspect of his eyebrow and anterior portion of his ear (Fig. 1a). There was no cervical lymphadenopathy. Complete blood count showed a hematocrit of 30% with relative lymphocytosis. The economic constraints of the patient prohibited the use of staging investigations such as computed tomography.

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Figure 1.  Preoperative photo of the large fungating mass arising in the pre-auricular area of the face/scalp of a young Nigerian male (left). The tumor was friable with focal ulceration but non-painful. Immediately after completion of surgery, the excision bed is shown (right)

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The patient underwent radical surgical excision of the lesion with a margin of ∼2 cm where possible (Fig. 1b). In areas of the eye and ear, margins were less due to the depth of infiltration and limited soft tissue. The patient’s nutritional status was poor and the wound base appeared unhealthy so the wound was left open initially (Fig. 2a). After intensive nutritional support (six eggs a day) for 10 days, the wound was granulating (Fig. 2b). A split thickness skin graft was performed, which healed well (Fig. 2c).

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Figure 2.  Progressive images of the surgical would that was left open to heal before plastic surgical closure. Initially, good granulation tissue (a) began to develop as the patient was supplemented with a high protein diet. When the bed was well granulated and vascularized (b), a myocutaneous flap was used to close the wound. The healed surgical bed afterward (c) was clean, intact, and functional

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Pathology review of the specimen showed a DFSP–fibrosarcomatous variant (DFSP-FS). The tumor showed areas of classic DFSP, which demonstrated the typical behavior of invading subcutaneous fat at the deep margins (Figs. 3 and 4). Immunohistochemical staining showed positivity of CD34 and negativity of S-100 protein (Fig. 5a,b). The fibrosarcomatous areas showed increased numbers of mitoses (Fig. 5c). The DFSP-FS has a high rate of local recurrence with a 10% chance of metastasis. Three months after the operation, the patient developed a 0.5 cm recurrence, which was excised and was consistent with DFSP but did not contain fibrosarcomatous elements (Fig. 5d). He is scheduled for radiation therapy, which will require a 20-hour journey from the patient’s home.

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Figure 3.  Typical storiform areas of dermatofibrosarcoma protuberans present throughout the lesion. (Hematoxylin and eosin, ×200)

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Figure 4.  The base of the tumor demonstrating infiltration into soft tissue, including the entrapment of adipose tissue (left middle). Focal areas of fibrosarcomatous change are seen. (Hematoxylin and eosin, ×100)

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Figure 5.  Immunohistochemistry demonstrated positive staining for CD34 (a, ×200) and was negative for S-100 protein (b, ×200). Areas of fibrosarcomatous change demonstrated higher mitotic counts (c, ×600). Three months after initial surgery, the patient presented with a small nodule in area of the previous excision that was a small focus of recurrent dermatofibrosarcoma protuberans without evidence of fibrosarcomatous change (d, ×200)

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Discussion

  1. Top of page
  2. Introduction
  3. Case report
  4. Discussion
  5. Conclusions
  6. Acknowledgments
  7. References

Epidemiology

The estimated incidence of DFSP is 4.5 cases per million persons per year in the United States, nearly three in France, and four in Sweden.5 There are no published incidence reports in Nigeria or Africa. DFSP affects either sex but occurs slightly more often in men, with a male-to-female ratio of 3 : 2.6,7 There is some suggestion, however, that women may be at increased risk of the development of DFSP-FS.8 The incidence among African-Americans compared with Caucasians is almost double (6.5 vs. 3.9 per million).9 Although it appears predominantly in adults (30–50 years), it has also been reported in children.6,8,10–12 No evidence of hereditary or familial predisposition exists. The five-year relative survival rates for all reported population-based studies can reach up to 100%.5

Clinical presentation

Dermatofibrosarcoma protuberans usually presents as an asymptomatic plaque or nodule, purple or pink, with a history of slow but persistent growth.13 It may start as a small asymptomatic papule, which is likely ignored, and then gradually enlarges into a lumpy nodule or it may evolve into an atrophic and/or sclerotic plaque.14 Over time, it develops into an ulcerative protuberant tumor.

Commonly, DFSP develops superficially and is mobile upon palpation, as it is initially adhered to the overlying skin but not with its underlying tissues. Infiltration of adipose tissue as well as fixation to deeper structures such as fascia and muscle may present in the latter stage of the tumor. Scalp fixation caused by periosteal attachment may occur in early stages due to the thickness of skin and soft tissue in this area. Telangiectasias may be apparent on the surface or at the periphery. Delay in diagnosis and clinical misdiagnosis of the initial lesion is not uncommon and may be due to absence of symptoms or confusion with other benign dermal fibrohistocytic lesions. Pain and tenderness are rare. In addition, cachexia, which usually characterizes advanced malignancies, is also uncommon. The differential diagnosis in the initial stages should include lipomas, epidermal cysts, keloid, dermatofibroma, and nodular fasciitis. In late stages, when it becomes protuberant, it should be differentiated from pyogenic granuloma, Kaposi sarcoma, and other soft tissue sarcomas.5

Histopathological features

Dermatofibrosarcoma protuberans is a slow-growing tumor. It typically arises in the dermis. Although DFSP arises in the dermis, lesions may abut the epidermis, rendering the epidermis attenuated or ulcerated. These tumors infiltrate the dermis and subcutaneous tissue, and some may involve skeletal muscles. Histologically, the tumor is highly cellular and composed of monomorphic, fusiform cells with elongated nuclei showing little or no pleomorphism or hyperchromasia. The cells have little cytoplasm, which usually appears amphophilic to eosinophilic. They are arranged in irregular interwoven fascicles forming a storiform pattern. Mitotic activity is moderate, rarely exceeding five mitoses per 10 high-powered fields. Lack of multinucleated giant cells and presence of entrapped isolated fat cells are other diagnostic features. Uncommon variants of DFSP include myxoid DFSP, in which myxoid features predominate, and Bednar tumor, which is a pigmented DFSP characterized by the presence of melanin-containing dendritic cells dispersed throughout the tumor.15,16

Immunohistochemical staining demonstrates strong positivity for CD34 (sensitivity 84–100%) and negativity for S-100 protein. The diagnosis is easily confirmed by demonstrating strong immunoreactivity for CD34. Areas of fibrosarcomatous change, however, are characterized by a herringbone growth pattern, rather than the typical storiform pattern, and possess foci of increased cellularity, cell size, and mitotic activity.11 Myxoid change also appears to be more prominent in tumors with fibrosarcomatous areas.16 Immunohistochemically, fibrosarcomatous areas show markedly diminished or absent CD34 immunoreactivity.12

Staging

Currently, there is no universally accepted staging for DFSP. However, the American Musculoskeletal Tumor Society Staging system is widely used. This takes into account tumor grade and compartmentalization: stage IA tumors are low-grade intracompartmental (without extension beyond the subcutaneous compartment) lesions that can be managed adequately solely with wide excision; stage IB tumors are again low-grade lesions that exhibit extracompartmental extension, which involves underlying fascia, muscle, or bone erosion.17 Meanwhile, Ugurel18 proposed a staging system according to German Guidelines for DFSP. In this system, stage I represents the primary tumor stage; stage II describes a DFSP with regional lymph node metastases; and stage III characterizes distance metastases.

Treatment and prognosis

The treatment for DFSP is wide local excision with histologically negative margins.12,14,19 There is a high local recurrence rate after inadequate excision, and several published series have stressed the importance of wide excision, defined as ≥3 cm of clinically uninvolved skin down to and including the fascia. More recently, Mohs micrographic surgery is being advocated as the treatment of choice,10 with relatively little chance of recurrence compared to wide local excision. Mohs micrographic surgery allows precise histological mapping of all margins, both deep and lateral. This technique requires continuing sequential horizontal sectioning during resection and immediate frozen microscopic examination, until a free margin is obtained; however, this is difficult to obtain in resource-limited settings as in Nigeria. Owing to the large size of this tumor, the structures involved, and cosmetic considerations in this case, a margin of resection of only 2 cm could be achieved. As primary closure is not always feasible, reconstructive surgery using a local skin flap, skin grafting, mesh, or myocutaneous flap may be required. Neck dissection is not necessary unless suspicious regional lymphadenopathy is present. Only in DFSP-FS cases is sentinel lymph node biopsy recommended.5

Although DFSP is non-sensitive to chemotherapy, Ng et al.20 reported a case of pediatric DFSP with chemosensitivity. The patient was given a treatment trial with weekly vinblastine and oral methotrexate. A good partial response was achieved after six weeks, and complete remission had been achieved at the five-month follow-up.20 Interestingly, Rutkowski et al.21 have reported response of up to 50% using imanitib. Radiotherapy is a treatment option for unresectable lesions or in case of margin involvement but has limited value as primary therapy of patients who can be cured by surgery.21 Although adjuvant radiation seems to provide a benefit for some of the treated patients, the present data remain highly inconclusive regarding the true effectiveness of adjuvant radiation in preventing recurrence and metastasis of DFSP-FS.22

Local recurrence is most commonly a factor of the margin of resection and tumor subtype.5,10,12,13,19,22 There have been reports of recurrence with tumor margins <2.5 cm for DFSP on the head and neck as well as DFSP-FS.5 Presence of fibrosarcomatous transformation in a head and neck lesion in this patient almost guarantees local recurrence, which was seen in follow-up. There are reports of metastatic disease to the bones, lungs, and even pancreas.5,12 These metastases, although rare, are more common with DFSP-FS.19

Conclusions

  1. Top of page
  2. Introduction
  3. Case report
  4. Discussion
  5. Conclusions
  6. Acknowledgments
  7. References

DFSP is a rare skin malignancy. This entity is more likely to recur when there is a small margin of excision, head/neck disease, or fibrosarcomatous transformation. Wide local excision is the gold standard of primary treatment while radiotherapy is recommended for recurrent disease.

Acknowledgments

  1. Top of page
  2. Introduction
  3. Case report
  4. Discussion
  5. Conclusions
  6. Acknowledgments
  7. References

The authors would like to thank Dr. Jason Hornick of the Soft Tissue Pathology Unit of the Brigham and Women’s Hospital for his assistance with the clinical case and Dr. Christopher Fletcher for his continued support of this collaboration.

References

  1. Top of page
  2. Introduction
  3. Case report
  4. Discussion
  5. Conclusions
  6. Acknowledgments
  7. References