
==== Front
Int J Surg Case Rep
Int J Surg Case Rep
International Journal of Surgery Case Reports
2210-2612
Elsevier

S2210-2612(24)00992-1
10.1016/j.ijscr.2024.110211
110211
Case Report
Dermatofibrosarcoma protuberans of the breast: A rare breast tumor mimicking a cutaneous lesion
Ingenito Mafalda mafalda.ingenito@outlook.it
ab⁎1
Rocco Nicola ab1
Russo Daniela ab
Accarino Rossella ab
Velotti Nunzio b
Musella Mario ab
a Department of Advanced Biomedical Sciences, University of Naples “Federico II”, Naples, Italy
b Breast Unit, University Hospital Federico II, Naples, Italy
⁎ Corresponding author at: Department of Advanced Biomedical Sciences, University of Naples “Federico II”, Via Sergio Pansini 5, 80131 Naples, Italy. mafalda.ingenito@outlook.it
1 The authors equally contributed to the preparation of the manuscript.

25 8 2024
10 2024
25 8 2024
123 11021112 7 2024
21 8 2024
22 8 2024
© 2024 The Authors
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction and importance

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue tumor which generally affects people from the second to the fifth decades of life, with the same incidence in both sexes. DFSP can appear as a slow-growing, flesh-colored or erythematous plaque or nodule, often becoming protuberant if untreated.

Case presentation

We report two cases of DFSP. The first case regards a 22-year-old woman with a 1.5-centimeter, mobile nodule of hard-elastic consistency in the left breast initially suspected to be a sebaceous cyst. Ultrasound and MRI suggested benign features, but histopathological examination post-excision confirmed DFSP. The second patient come to our attention is a 54-year-old woman with a 6 mm erythematous lump in the right breast, which reached 22 mm after two years. Mammography and histological examination post-excision confirmed DFSP. Both patients underwent to wide local excision and after four years of follow-up no recurrence or complications are observed.

Clinical discussion

DFSP is a soft tissue sarcoma with low metastatic potential but requires early diagnosis and surgical excision to avoid malignant transformation. There are no standardized guidelines for its diagnosis and treatment. Imaging techniques, including ultrasound, CT, and MRI, are crucial to define tumor extension and planning surgical intervention. Surgical excision with clear margins is the primary treatment, but there are also emerging treatments as Mohs micrographic surgery or Imatinib Mesylate therapy for unresectable cases.

Conclusion

Our cases highlight the importance of an accurate diagnostic evaluation and effective surgical management to achieve favorable outcomes.

Highlights

• Dermatofibrosarcoma protuberans of the breast is a rare soft tissue sarcoma.

• It appears as a plaque or nodule of hard consistency and it could be misdiagnosed with a skin lesion.

• The translocation t(17;22)(q22;q13) is present in 90% of cases.

• The growth is slow, but if untreated it could transform in malignant tumor.

• DFSP has a high rate of recurrence after excision while metastases are rare.

Keywords

Breast surgery
Dermatofibrosarcoma protuberans
DFSP
Case report
Pathology
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pmc1 Introduction

Dermatofibrosarcoma protuberans (DFSP) is a rare type of soft tissue tumor representing approximately 1 % of all soft-tissue sarcomatous tumors. The tumor can affect people of any age but more frequently it occurs from the second to the fifth decades of life. It has the same incidence in both sexes and there is no racial predilection but the pigmented variant, called Bednar's tumor, is more common in black population [[1], [2], [3]]. Clinically, it can appear as a flesh-colored or erythematous plaque or nodule of hard consistency but sliding on the underlying planes. The growth is very slow and many of these tumors became protuberant after several months or often after years from the first appearance. Generally, the size ranges from 1 to 6 cm but if untreated it can reach and exceed 20 cm.

On pathological examination the tumor is an oval or multi-nodulated mass with a hard or hard-elastic consistency and it can contain also cystic or hemorrhagic areas, while the necrosis is rare. In advanced stages it can evolve to an irregular protuberant mass associated to pain, ulceration and exudation and it is possible the infiltration of underlying tissues; in these cases, the tumor becomes adherent to the epidermis which may thin out and show telangiectasias [[3], [4], [5]].

2 Patients, methods and results

We report two cases of dermatofibrosarcoma protuberans presenting our diagnostic workup and our therapeutic approach.

2.1 Case 1

A 22-year-old patient came to our attention for a lump in the right breast noticed during self-examination. The patient, who experienced menarche at the age of 11, had no family history of breast cancer.

Clinical examination revealed no signs of injury, with intact and normochromic skin, normal areola-nipple complex and no nipple discharge.

Palpation of the breast instead, revealed a mobile oval mass approximately 1.5 cm in size in the left lower-outer quadrant, with characteristics suggestive of a benign lesion such as mobility, hard-elastic consistency, and well-defined edges.

Ultrasound examination of the breasts showed a fibroglandular predominance with a 13 mm lesion with superfluid content in the left lower-outer quadrant, consistent with a sebaceous cyst. In association, there were reactive lymphadenopathies in both axillary regions.

Despite initial suspicion of a sebaceous cyst, further evaluation including magnetic resonance imaging (MRI) and ultrasound-guided biopsy was performed for a more accurate diagnosis. MRI revealed early enhancement followed by wash-out, indicative of a benign lesion (Fig. 1).Fig. 1 MRI: hyperintense oval-shaped formation in the left lower-outer quadrant (12 mm) with early enhancement and subsequent wash out in T2 sequences.

Fig. 1

We performed a wide excision of the lesion.

Histopathological examination revealed a hypercellular mesenchymal tumor comprising small to medium-sized spindle cells with small nucleus, indistinct nucleoli, and scant eosinophilic cytoplasm admixed with adipose tissue (Fig. 2).Fig. 2 Histopathological examination wide excision of the lesion. Hypercellular mesenchymal tumor extending throughout the biopsy with no mitotic activity and necrosis admixed with adipose tissue (A, hematoxylin and eosin staining, original magnification ×10; B, hematoxylin and eosin staining, original magnification ×20).

Fig. 2

No sign of necrosis and atypical mitoses was seen. The Ki-67 index was lower than 10 % (Fig. 3). On immunohistochemistry, the tumor cells were positive for CD34 and negative for STAT6, smooth muscle actin (SMA), desmin, S-100 protein, beta-catenin (Fig. 4) and pan-cytokeratin (not showed).Fig. 3 Ki67 (Mib-1) positive in <10 % of tumor cells (Ki67/Mib-1 immunohistochemical staining, original magnification, ×20).

Fig. 3

Fig. 4 Immunohistochemical studies. The tumor cells were positive for and negative for smooth muscle actine, desmin, S-100 protein, STAT6 and beta-catenin with membranous but not nuclear staining. (A, CD34 immunohistochemical staining, original magnification ×20; B, smooth muscle actine immunohistochemical staining, original magnification, ×10; C, desmin immunohistochemical staining, original magnification, ×10; D, S100-protein immunohistochemical staining, original magnification, ×10; E, STAT6 immunohistochemical staining, original magnification, ×20; F, beta catenin immunohistochemical staining, original magnification, ×20).

Fig. 4

The histological analysis confirmed a diagnosis of DFSP.

2.2 Case 2

Outside the age range most commonly affected, we have treated a 54-year-old patient came to our attention for an erythematous skin lump on the right breast, not associated with other breast nodularities or nipple discharge. The patient, who had been in menopause for a year, declared no case of breast or ovarian cancer in her family.

We performed a breast ultrasound with the evidence of a hypoechoic lesion on the right breast measuring approximately 6 mm, which didn't show involvement of the pectoral muscles or other anomalies aside from benign enlargement of axillary lymph nodes.

The patient is subjected to six-monthly clinical and instrumental follow-up.

Over two years, the lesion increased in size, so we integrated the diagnostic process with mammography that showed a radiopaque lesion with clear-cut margins of 22 mm in the upper-outer quadrant of right breast (Fig. 5).Fig. 5 Mammography: cranio-caudal view showing a radiopaque lesion with clear-cut margins of 22 mm in the upper-outer quadrant of right breast.

Fig. 5

Subsequently, we performed breast surgery with the excision of the lesion and the histological examination confirmed the diagnosis of dermatofibrosarcoma.

All patients were treated by wide local excision and they are subjected to six-monthly clinical and diagnostic follow-up. We didn't observe post-operative complications or disease recurrence at 4-year follow-up.

The work has been reported in line with the SCARE criteria [6].

3 Discussion

Dermatofibrosarcoma protuberans is a rare soft tissue sarcoma with low potential of remote dissemination. It's important the early diagnosis and the surgical excision to avoid the transformation in malignant form of tumor as fibrosarcoma.

Being an extremely rare condition, there are currently no guidelines for diagnosis and treatment. Only histological examination can provide a definitive diagnosis, but imaging techniques can help defining tumor extension, planning the best surgical treatment and performing differential diagnosis with other benign soft tissue lesions. On ultrasound, the tumor appears as a clear-cut lesion, sometimes lobulated, hypoechoic or with mixed hypoechoic and hyperechoic regions. On color Doppler, the vascularization is often moderate and peripheral. Also, on TC the mass can show well-defined margins and a density similar to skeletal tissue, without calcifications. An MRI is the best way to define the tumor, for its high soft tissue contrast resolution; generally, on T1-Weighted images, it appears homogeneous, isointense to skeletal tissue and hypointense to subcutaneous fat. On T2-Weighted MR sequences, DFSP appears with high signal intensity [[7], [8], [9]].

Although the etiology of the tumor is not fully known, it has been shown that the translocation t (17;22) (q22;q13) is present in 90 % of cases. This translocation brings to the fusion of collagen type 1, alpha 1 gene (COL1A1) to the platelet-derived growth factor b-chain gene (PDGFB) resulting in up regulation of PDGFB, overproduction of PDGF and constitutive activation of the platelet growth factor receptor. Hyperactivation of this pathway is responsible for the proliferation of tumor cells [4,7].

Tumor, which is positive for CD34 and negative for factor XIIIa, arises in the dermis but it can infiltrate the underlying tissues. Microscopically, it is constituted by spindle cells surrounded by collagenous tissue. When the tumor reaches the underlying tissue, the cells are organized to form neoplastic tentacles, responsible to the typical honeycomb appearance. The mitotic activity is low-moderate; the increase in mitoses with a 10/10 HPF could be indicative of a metastatic spread and fibrosarcomatous transformation, which is a more aggressive form of tumor [2,9].

DFSP has a high rate of recurrence after excision while metastases through the lymphatic and blood circulation are rare and they are localized especially in the lungs [3].

The trunk is the most affected area (50 %), followed by lower and upper extremities, head and neck while less frequently the tumor can develop in the breasts and vulva [7].

Treatment consists of surgical excision of the lesion and the most frequent technique used is wide local excision, involving removal of the tumor and part of the surrounding tissue (2–3 cm).

The most adverse prognostic factor is an incomplete surgical excision characterized by positive tumor resection margins or margins in close proximity to the surgical edge. In case of positive margins, it is possible to re-operate by widening the resection margins or performing radiotherapy. Studies are underway to evaluate the actual effectiveness of treatment with Imatinib Mesylate, when surgical intervention is not feasible.

On average, our patients, who underwent a four-year follow-up, didn't experience any recurrence of disease, despite indications suggesting a higher rate of tumor recurrence associated with this type of surgery, especially within the first three years post-surgery.

Alternatively, it's currently under study the Mohs micrographic surgery which allows the examination of the lesions' margins at the same time of surgery, offering the chance to obtain wider margins during the same procedure [10].

Unresectable, recurrent and metastatic tumors can be treated radiotherapy or Imatinib, a competitive tyrosine kinase inhibitor, which can block tumor proliferation by inhibiting the PDGF-beta receptor [8].

Ethical approval

Ethical approval is not required because the patients have been treated following the latest guidelines and they have signed informed consent for the participation in scientific study. Local ethical committee: Comitato Etico Campania 3 (segreteria@comitatoeticocampania.it).

Funding

The authors received no funding for this work.

Author contribution

Mafalda Ingenito: writing the paper, data analysis and interpretation.

Nicola Rocco: study concept and design, revision and editing.

Daniela Russo: data analysis and interpretation.

Rossella Accarino: data collection.

Nunzio Velotti: supervision.

Mario Musella: supervision.

Guarantor

Nicola Rocco.

Research registration number

1. Name of the registry: Research Registry

2. Unique identifying number or registration ID: researchregistry10439

3. Hyperlink to your specific registration (must be publicly accessible and will be checked): https://www.researchregistry.com/browse-the-registry#home/

Consent

Written informed consent was obtained from the patient for publication and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Conflict of interest statement

The authors declare no conflict of interests.
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