|Year : 2020 | Volume
| Issue : 5 | Page : 198-201
Borderline malignancy solitary fibrous tumor of abdominal wall
Division of General Surgery, Department of Surgery, Tri-Service General Hospital, Taipei, Taiwan
|Date of Submission||07-Mar-2020|
|Date of Decision||11-May-2020|
|Date of Acceptance||02-Jun-2020|
|Date of Web Publication||19-Oct-2020|
No. 325, Sec. 2, Chenggong Road, Neihu District, Taipei 11490
Source of Support: None, Conflict of Interest: None
Solitary fibrous tumor (SFT) is a rare mesenchymal tumor originating in the pleura or at virtually any site in the soft tissue. Although they are commonly thought of as intrathoracic tumors, 50% to 70% of SFTs arise outside the thorax. Approximately 78% to 88% of SFT are benign and 12% to 22% are malignant. The most common sign/symptom of intraabdominal SFT is a palpable abdominal mass with pain and weight loss. Compression symptoms, including dysuria, urinary retention, hydronephrosis, constipation, incontinence, or vomiting have also been reported. However, an intraabdominal SFT located abdominal wall was asymptomatic in this case presentation.
Keywords: Borderline malignancy, intraabdominal, solitary fibrous tumor
|How to cite this article:|
Lung-Jui W. Borderline malignancy solitary fibrous tumor of abdominal wall. Formos J Surg 2020;53:198-201
| Introduction|| |
Solitary fibrous tumor (SFT) is a rare mesenchymal tumor originating in the pleura or at virtually any site in the soft tissue. Although they are commonly thought of as intrathoracic tumors, 50% to 70% of SFTs arise outside the thorax. Approximately 78% to 88% of SFT are benign and 12% to 22% are malignant.,,,
The most common sign/symptom of intraabdominal SFT is palpable abdominal mass with pain and weight loss. Compression symptoms including dysuria, urinary retention, hydronephrosis, constipation, incontinence, or vomiting have also been reported.
However, an intraabdominal SFT located abdominal wall was asymptomatic in this case presentation.
| Case Presentation|| |
This patient is a 24-year-old woman without a history of systemic disease or operation before. She had an intraabdominal mass accidentally found by sonography while regular health examination on August 22, 2016. Abdomen sonography revealed a heterogeneously echogenic mass of about 6.1 cm × 3.0 cm in the pelvic region [Figure 1]. However, she was not followed up for the tumor since then.
|Figure 1: August 22, 2016, abdomen sonography: A heterogeneously echogenic mass about 6.1 cm × 3.0 cm in the pelvic region|
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She came to our gynecology outpatient department for help due to irregular menstruation. Gynecologic ultrasound was arranged for her on August 13, 2018, and this intraabdominal mass was found accidentally again. Sonography revealed a well-defined heterogeneous hypoechoic mass of about 8.60 cm × 4.95 cm × 7.65 cm with blood flow [Figure 2]. Thus, she was admitted to our hospital for further evaluation.
|Figure 2: August 13, 2018, gynecologic ultrasound: A well-defined heterogeneous hypoechoic mass about 8.60 cm × 4.95 cm × 7.65 cm with blood flow|
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Abdomen computerized tomography with/without contrast was performed on August 14, 2018. The image showed a large, mildly lobulated soft-tissue mass measured 7.6 cm × 5.5 cm × 8.4 cm in the pelvic region. There are multiloculated cystic portions within the tumor, associated with large and tortuous draining veins (into the left internal iliac vein). The mass demonstrates avid enhancement in the portal venous phase [Figure 3]. The differential diagnosis includes gastrointestinal stromal tumor, desmoid tumor, neuroendocrine tumor (carcinoid, extra-adrenal pheochromocytoma, etc.), and solitary fibrous tumor (SFT).
|Figure 3: August 14, 2018, abdomen computerized tomography with/without contrast: A large, mildly lobulated soft-tissue mass measured 7.6 cm × 5.5 × 8.4 cm in the pelvic region. The multiloculated cystic portion within the tumor, associated with large, and tortuous draining veins (into the left internal iliac vein). The mass demonstrates avid enhancement in the portal venous phase|
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Diagnostic laparoscope with resection of the intraabdominal tumor was done on August 15, 2018. A well-encapsulated mass (about 8 cm) located in the preperitoneal space of the lower midabdominal wall with some engorged vessels at the surface of the tumor was noted [Figure 4] and [Figure 5]. We incised the peritoneum and dissected the tumor from the abdominal wall with an energy device. The tumor in a specimen bag was removed through the umbilical wound piece by piece. The specimen submitted consisted of multiple pieces of soft-tissue weighting 183 g and measuring up to 6.5 cm × 5 cm × 1 cm in size. The tumor specimen was tan in color and soft inconsistency. The patient stood the operation well. Then, she was discharged on August 18, 2018, with good healing of the surgical wound.
|Figure 4: August 15, 2018, diagnostic laparoscope with resection of intraabdominal tumor: A well-encapsulated mass (about 8cm) located in preperitoneal space of the lower midabdominal wall with some engorged vessels at the surface of the tumor|
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|Figure 5: August 15, 2018, diagnostic laparoscope with resection of intraabdominal tumor: A well-encapsulated mass (about 8 cm) located in preperitoneal space of the lower midabdominal wall with some engorged vessels at the surface of the tumor|
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The pathology diagnosis is SFT (WHO ICD-O-3 8815/1, borderline malignancy). Microscopically, the sections show solid tumor composed of short spindle cells with 2 mitosis/50 high power field and certain histologic type of vascular nature, but lack of necrosis [Figure 6]. Immunohistochemical stains: HMB45 (negative), CD34 (positive), D2-40 (negative), Ki-67 (proliferative index, 5%), STAT-6 (weakly positive), and Erg (mostly negative).
|Figure 6: Microscopically, the pathological sections show solid tumor composed of short spindle cells with 2 mitosis/50 HPF and certain histologic type of vascular nature, but lack of necrosis|
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After the surgery, the patient was followed by our outpatient department. Abdomen sonography was arranged on February 11, 2019, and there was no abnormal finding. Then, abdomen computerized tomography with/without contrast was performed on August 2, 2019, and showed no tumor recurrence. The recent image was ultrasound on January 14, 2020, only showed mild dilatation of the right renal pelvis. We will keep following this case and arrange an image for her per 6 months.
| Discussion|| |
Most of SFTs behave in an indolent fashion and do not recur locally or distantly. However, 10% to 25% of SFTs recur by 10 years. Recurrence in SFT may be due to incomplete resection, tumor seeding within the pleura, peritoneum or meninges, or distant hematogenous spread. The most common sites of distant metastasis in SFT at all sites are the lung, liver, bone, and brain. Prolonged survival after an SFT recurrence is possible, particularly for those who are amenable to resection. Patients with multiple synchronous metastases that are not amenable to surgical intervention have a poor prognosis. Late relapse, even for tumors initially classified as “benign” is common.,,,,,
Until now, the underlying reason for the more aggressive behavior of SFT is unknown. The prognostic value of molecular biomarkers is still under study and none is ready for clinical use. The utility of the tumor/node/metastasis (TNM) staging system to predict prognosis for SFT is unclear. The eighth edition (2017) AJCC/UICC TNM staging system recommends that malignant SFT be staged according to the guidelines of other soft-tissue sarcomas (retroperitoneum, trunk, and extremities), but there are no data stratifying outcomes according to TNM stage or prognostic stage groupings. Moreover, there was no guidance provided on how to classify SFT as “malignant.” The definition of malignancy in SFT remains a matter of some debate.,,
This underscores the need for continued long-term follow-up, particularly for high-risk individuals. For this patient with borderline malignancy SFT, we may follow post-treatment surveillance guidelines of soft-tissue sarcoma from the National Comprehensive Cancer Network. It suggests that intermediate-and high-risk tumors should image the primary tumor site every 3 to 4 months for the first 2 years, then every 6 months through year 5. We may not typically repeat local imaging after 5 years, as local recurrence at that point would be unusual.
SFT, in this case, is typical, a slow-growing mass (growing about 2.5 cm in 2 years). However, most extrathoracic SFTs were intraperitoneal. SFT located at the abdominal wall was rare. Especially SFT, in this case, was located at the anterior abdominal wall but growth to intraabdominal. The image of this case also cannot show “located at the anterior abdominal wall but growth to intraabdominal.” Thus, when we performed the operation with a laparoscope, it was very difficult because of the location at the preperitoneal space of the lower midabdominal wall.
Declaration of patient consent
The author certifies that he has obtained all appropriate patient consent forms. In the form the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]