Preceding expansion in the treatment of dermatofibrosarcoma protuberans involving the frontal bone

1 Sociedade Brasileira de Cirurgia Plástica, São Paulo, SP, Brazil. 2 Hospital Felício Rocho, Belo Horizonte, MG, Brazil. 3 Instituto de Cirurgia Plástica Avançada, Belo Horizonte, MG, Brazil. 4 Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. 5 Faculdade de Medicina da Universidade de Itaúna, MG, Brazil. 6 Hospital e Maternidade Therezinha de Jesus, Juiz de Fora, MG, Brazil. 7 Faculdade de Ciências Médicas de Minas Gerais, Belo Horizonte, MG, Brazil. Conflicts of interest: none. Case Report


INTRODUCTION
Dermatofibrosarcoma protuberans (DFSP) is a rare infiltrative skin tumor with intermediate malignancy.It has a low potential for metastasis but a high rate of recurrence after surgical treatment [1][2][3][4][5] .The treatment of choice is surgical wide resection with lateral margins of at least 3 cm and a deep margin including an anatomical structure without tumor infiltration, such as the deep fascia, muscle, periosteum, or outer table of cranial bone 2,[6][7][8] .

OBJECTIVE
This retrospective study reviewed data of patients with dermatofibrosarcoma protuberans of the forehead involving invasion of frontal bone, treated by preceding expansion of frontal flaps between September 1992 and May 2005.

METHODS
Data of 3 patients who underwent surgery at Hospital Felício Rocho (Belo Horizonte, MG) between September 1992 and April 2005 were reviewed.The patients underwent preceding expansion of tissues of the forehead using two conventional expanders.Lateral margins of normal-appearing tissue 3-cm apart were tattooed with China ink.In a preceding operation, expanders were inserted through skin incisions at a distance from that marks, by undermining the surgical plane just above the periosteum, while preserving the area of wide resection previously delimited.After the lateral tissues were expanded, the patients underwent surgical resection.The deep margin included the outer plate of the frontal bone.The expansion period averaged 45 days.
There were no conflicts of interest or sources of funding.The principles of the Declaration of Helsinki were followed.All patients received an Informed Consent Form.The study was conducted at Hospital Felício Rocho, Belo Horizonte, MG, in the year 2017

RESULTS
Three cases of DFSP of the forehead with involvement of the outer plate of the frontal bone were identified.There was no recurrence during an average follow-up of 194 months.

Case 1
A male, aged 38 years, with tumor appearance 14 years prior.Tumor resection plus radiotherapy performed elsewhere were followed by recurrence.
After admission, biopsy confirmed DFSP.Insertion of expanders was performed in September 1992.Enlarged resection was performed in October 1992, using 3-cm lateral margins, with removal of the outer table of the frontal bone.Expanded flaps easily closed the defect.In March 2008, the patient underwent left nephrectomy for renal carcinoma.In August 2010, he died with multiple metastases of the renal tumor, but no recurrence of DFSP.After the excision, the patient remained free of tumor for 214 months (Figure 1).A male, aged 41 years, with tumor appearance 10 years prior.Two previous surgical resections followed by recurrences were performed elsewhere.After admission, biopsy confirmed DFSP.The patient underwent insertion of skin expanders in April 1998.Enlarged resection was performed in July 1998 using 3-cm lateral margins, with removal of the outer table of the frontal bone.Expanded flaps easily closed the defect.The last follow-up examination was in May 2017 showed no signs of DFSP.The patient was free of tumor for the prior 226 months (Figure 2).A male, aged 28 years, reported appearance of the tumor 2 years prior.A previous resection performed elsewhere was followed by a recurrence.Insertion of expanders was performed in April 2005.Wide resection was performed in May 2005, using 3-cm lateral margins, with removal of the outer table of the frontal bone.The last follow-up examination in May 2017 showed no signs of DFSP.The patient was free of tumor for the prior 144 months.

DISCUSSION
Silva Filho et al. 1 originally described the use of tissue expanders for a case of DFSP of the frontal region.That particular case was case 1 in the present series.Alves et al. 2 described 2 more cases of preceding expansion for forehead DFSP.Khachemoune et al. 6 reported a single case of DFSP involving the frontal region in which the outer tables of the calvarium were removed and the patient underwent multistaged repair using skin expanders.
No other papers were found reporting use of tissue expansion in the treatment of DFSP of the frontal region.
Although considered a malignant tumor, DFSP grows slowly and rarely metastasizes.In a series of 30 patients treated with radical surgery, Alves et al. 2 found no cases with metastatic disease.This characteristic allows the use of tissue expanders near the tumor without increased risk of disseminating the DFSP.

CONCLUSION
Preceding expansion of forehead tissue in treatment of DFSP invading frontal bone, using 3-cm lateral margins with removal of the outer table, allowed easy closure of the defect in 3 different patients.Average follow-up of 194 months with no recurrence of the lesion showed the effectiveness of the method.

COLLABORATIONS
JCRRA Analysis and/or interpretation of data; statistical analyses; final approval of the manuscript; conception and design of the study; completion of surgeries and/or experiments; writing the manuscript or critical review of its contents.

AFSF
Final approval of the manuscript; completion of surgeries and/or experiments.

RPLF
Analysis and/or interpretation of data; final approval of the manuscript.

NAP
Analysis and/or interpretation of data; final approval of the manuscript.

Figure 1 .
Figure 1.Case 1. A: Dermatofibrosarcoma protuberans in the right frontal region; B: Lateral view; C: Complete flap expansion, frontal view; D: Complete flap expansion, lateral view; E: Location of the incision used to position the expander in the frontal region; F: Preoperative marking of the tumor resection area; G: Extensive resection of dermatofibrosarcoma protuberans; H: Postoperative result, frontal view; I: Postoperative result, lateral view.

Figure 2 .
Figure 2. Case 2. A: Dermatofibrosarcoma protuberans in the left frontal region; B: Preoperative marking for placement of the expander, frontal view; C: Preoperative marking, lateral view; D: Expander in left temporal region; E: Expander in right frontal region; F: Complete flap expansion; G: Extensive resection of dermatofibrosarcoma protuberans, with removal of the outer table of the frontal bone; H: Postoperative result, frontal view; I: Postoperative result, lateral view.