|Year : 2019 | Volume
| Issue : 10 | Page : 1412-1416
Surgical outcomes and clinical courses of solitary fibrous tumors of pleura
F Yanik, YA Karamustafaoglu, Y Yoruk
Department of Thoracic Surgery, Trakya University Faculty of Medicine, Edirne, Turkey
|Date of Acceptance||06-Mar-2019|
|Date of Web Publication||14-Oct-2019|
Dr. F Yanik
Trakya Universitesi Tip Fakultesi, Gogus Cerrahi Ad, Kat: 4, 22000, Edirne
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: This study's aim is to define the clinicopathological and surgical outcomes, clinical courses, and results of long-term follow-up of cases that underwent surgical treatment for solitary fibrous tumors of the pleura (SFTp). Subjects and Methods: Clinical and long-term follow-up records of 16 consecutive patients who had surgery for SFTp between 2006 and 2016 were reviewed in the retrospective chart review. There were nine males (56%) and seven (44%) females with an average age of 60.5 ± 17.1 (range 30—87 years). Etiological factors, diagnostic procedures, clinical and surgical outcomes, 5-year overall survival (OS), and disease-free survival (DFS) in these patients were researched. Results: There was no remarkable common etiological factor. Nine of the cases were asymptomatic. Other symptoms were chest pain, dyspnea, cough and hypertrophic osteoarthropathy, respectively. Thoracotomy for the removal of pleural mass was carried out in 15 (94%) cases. Additional resection procedures included the chest wall resection in two cases and lobectomy in two. Video-assisted thoracoscopic surgery (VATS) resection was performed in one (6%) case. Complete surgical excision was performed in 74% of cases. Nineteen percent of cases were malignant SFTp (mSFTp). One of the mSFTp cases died in the 19th month after the diagnosis. The mean follow-up time was 50.6 ± 34.2 months (2--114 months). Mean survival of mSFTp patients was 40.6 ± 19.08 months (19--55 months) and that for benign SFTp (bSFTp) was 52.9 ± 37.05 months (2--114 months). Five-year OS--DFS were 93.5% and 74%, respectively. Conclusion: SFTp is an uncommon benign neoplasm but it can have malignant features. Even in the case of recurrence, the main treatment is total surgical excision. Oncologic treatments can be tried in unresectable and metastatic cases. VATS can be used in surgical total excision for small diameter and appropriate tumors. Understanding the nature of these tumors, immunohistochemical, and genetic studies may be a guide in future.
Keywords: Pleura, solitary fibrous tumor, surgery, tumor
|How to cite this article:|
Yanik F, Karamustafaoglu Y A, Yoruk Y. Surgical outcomes and clinical courses of solitary fibrous tumors of pleura. Niger J Clin Pract 2019;22:1412-6
| Introduction|| |
Solitary fibrous tumors of the pleura (SFTp) are rarely seen tumors which are mostly located in the pleural space. They originate from fibroblastic mesenchymal cells in submesothelial pleural layer and constitute 5% of the pleural tumors. Although the vast majority of SFTp are benign because of the slow-growing and low-metastastic potential, malignant types do occur. Cases are usually asymptomatic in early stages and tumor mostly detected incidentally while performing chest imaging. No etiologic agent has been identified for SFTp., Despite rarity of these tumors, preoperative diagnosis is challenging. One of the major principles of surgical therapy of the primary tumor is to obtain adequate negative margins. Selection of surgical approach between video-assisted thoracoscopic surgery (VATS) or thoracotomy is still controversial. The role of oncologic therapies is limited in this rare neoplasms. The aim of this study was to define clinicopathological and surgical outcomes of cases who underwent surgical treatment for SFTp.
| Patients and Method|| |
Between December 2006 and December 2016, 16 consecutive cases' files, imaging methods, surgical results, survivals, and follow-ups were reviewed retrospectively. Seven of them (44%) were female and nine of them (56%) male. Cases were excluded if there was no definitive diagnosis and with no reached medical record. Demographics, characteristics, and surgical outcomes of the cases are given in [Table 1]. Nine of the cases were asymptomatic. The other symptoms were chest pain, dyspnea, cough and hypertrophic osteoarthropathy, respectively. Complete surgical excisions were performed in 74% of cases; 19% of these cases were malignant SFTp (mSFTp) due to such features as greater cellularity with an infiltrative growth pattern, cellular atypia, and high mitotic activity (>4 mitoses per 10 high power fields). Clinical and radiological follow-up were used during the follow-up period at our outpatient clinic; chest X-ray at 1, 3, and 6th months postoperatively and chest computed tomography (CT) was performed annually. The mean age was 60.5 ± 17.1 years (range 30--87 years). The preoperative diagnosis could be provided with transthoracic true-cut biopsy in five of the cases. The others were diagnosed by intraoperative frozen section examination.
|Table 1: Demographics, operation types, and tumor characteristics of the cases|
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A statistical analysis was performed using the Statistical Package for the Social Sciences program (SPSS, 20.0). Data were expressed as mean ± SD. Frequencies and percentages were used for the categorical measures.
| Results|| |
Thoracotomy for the removal of pleural mass was carried out in 15 (94%) cases. Additional resection procedures included the chest wall resection in two cases and lobectomy in two. VATS was performed in one (6%) case. In four (26%) cases, surgical margin positivity was detected. Fourteen cases were evaluated as benign SPTp (bSFTp). Two cases of mSFTp both local recurrence and distant metastasis was occured at 4 and 12 months, respectively, after surgery. One case of mSFTp only local recurrence was detected at 8 months after surgery. Chemoradiotherapy (CRT) was applied for this two metastatic cases, and only radiotherapy (RT) was applied for the case with local recurrence. Also local recurrence occurred in one patient with bSFTp after 18 months of surgery and was applied RT following surgery [Table 2]. Operative mortality did not occur. One of the mSFTp cases died in the 19th month after the diagnosis. The mean survival of mSFTp patients was 40.6 ± 19.08 months (19--55 months) and that for bSFTp was 52.9 ± 37.05 months (2--114 months). Five-year overall survival (OS) and disease-free survival (DFS) were 93.5% and 74%, respectively. OS and DFS were 100% and 93.5% for bSFTp and 77% and 33% for mSFTp, respectively. Two (12,5%) complications occurred that required bronchoscopy for atelectasis and wound infection. The mean tumor diameter was 8.9 ± 5.3 cm (2.5--22 cm). Chest X-ray and chest tomography were performed in all the cases. Additionally, positron emission tomography (PET) in 10 cases, chest magnetic resonance ımaging (MRI) in one case were used [Figure 1]. The result of PET scan was interpreted as a benign mass in four cases and multiple bone and mediastinal lymph node metastasis in two mSFTp cases (SUVmax: 8.4-- 6.7, respectively). The SUVmax was 3.2 ± 1.6 (2--4.6) for pleural mass in 10 of the cases. The mean length of hospital stay time was 7.25 ± 1.6 days (3--9 days), while 14 of them originated from the visceral pleura and two from the parietal pleura.
|Table 2: Pathological findings, imaging methods, complication, lenght of hospital stay, follow-up period and adjuvant therapy modalities of cases|
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|Figure 1: (a) Thorax CT image, (b) Postoperatif macroscopic mass view of a 22cm three lobulated mSFTp case|
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In the macroscopic examination of the tumors, it was seen that they were capsular, well-defined, fine-stemmed, round or oval-shaped. In the histopathological examination, hypo- and hypercellular areas separated by fibrous stroma having hemangiopericytoma-like branching blood vessels, low mitotic index, low Ki-67 indexes were detected. mSFTp's were characterized by greater cellularity with an infiltrative growth pattern, cellular atypia, presence of necrosis, pleomorphism, high mitotic index (>4 mitoses per 10 high-power fields) and high Ki-67 index [Table 2]. Follow-up with yearly coCT was carried out at the outpatient clinic visit with a mean follow up time of 50.6 ± 34.2 months (2--114 months).
| Discussion|| |
SFTp is an uncommon neoplasm that can be detected at approximately 2.8 of every 100,000 hospitalized patients. It peaks at 40--60 years old, although it is seen in all ages. SFTp is usually detected during routine chest radiography. The majority of the cases are asymptomatic, but in some cases such as dyspnea, cough, chest pain, weight loss, fever, fatigue, hemoptysis may occur due to the tumor's growth-related pressure effect and the developing pleural effusion. Paraneoplastic symptoms such as hypertrophic pulmonary osteoarthropathy, joint pain, and finger paraesthesia and refractory hypoglycemia (due to the production of a growth hormone-like substance, liver-derived growth factor and insulin-like growth factor, respectively) may occur also., Most of our cases were asymptomatic. In accordance with the literature, the median age was 60.5 years.
Preoperative CT-guided transthoracic true-cut biopsy is of little diagnostic value. Generally, it is not an adequate small biopsy material for definitive diagnosis. A repeated true-cut biopsy is not required when a definitive preoperative pathologic result is not obtained. Surgical resection for diagnosis and treatment is acceptable. In the five cases, the diagnosis was made by true-cut biopsy and the others were diagnosed by intraoperative frozen section examination.
Although the majority of SFTp is benign in character, 10--20% of it can have aggressive features like distant metastases or local recurrence. mSFTp is usually larger than 10 cm in diameter and is sessile. Long-term and close follow-up is necessary since local recurrence can be seen even after many years.
Complete mass resection is the first choice treatment of both SFTp and mSFTp. VATS is very useful for lesions at the lung periphery, small and pedunculated lesions. We used VATS only in one case who has 2.5 cm pedunculated mass at the visceral pleura. Open thoracotomy is still the gold standard treatment in sessile, large-sized, invasive, and malignant lesions.
Demicco et al. reported that 5 and 10-year DFS and OS rates are 89--73%, and 74--55%, respectively. According to Demicco, large tumors ≥15 cm, patients ≥55 years, mitotic figures ≥4/10 high-power field are high-risk factors for metastasis and death; and requires close follow-up. Moreover, they explained that increasing Ki-67 index is associated with recurrent tumors when compared with primary tumor's index. So it can be said that SFTp occurrence risk increases in every recurrence period. In our study 5-year OS and DFS were 93.5% and 74% respectively. OS and DFS were 100% and 93,5% for bSFTp and 77% and 33% for mSFTp, respectively. In our study, recurrence developed in one case with tumor size ≥15 cm and three cases with age ≥55 years old. Mitotic index ≥4/10 high-power fields and increased Ki-67 index were found only in three cases with mSFTp [Table 1] and [Table 2].
On radiological images, SFTp appears as a well-defined, homogeneous encapsulated mass which is noninvasive to surrounding structures. In most cases, chest radiography and CT are sufficient for showing and identifying lesions. Doppler ultrasound, MRI, and PET-CT may be helpful in differential diagnosis and metastasis especially for mSFTp. Cardillo et al. showed high negative predictive value for PET scan in mSFTp cases: (50% of positive predictive value versus 87.5% of negative predictive value). In our study, all cases underwent chest X-ray and chest CT. Additionally, FDG-PET (in 10 cases), and MRI (in one case) were used. PET helped to identify multiple bones and mediastinal lymph node in two mSFTp cases with increased FDG uptake SUVmax (Maximal Standardized Uptake Value) value as 8.4 and 6.7.
Despite adequate local control, recurrence rates for mSFTp are around 30%., Recurrence rate has been detected more common in patients with malignant histologic features compared with benign histological type. The prognosis is usually good for bSFTp. However, because of the different histopathological character of this neoplasm, long-term follow-up is necessary. OS and DFS are low in malignant ones. DeVito et al. reported that overall median survival was 186.6 months; 1-year survival rate was 91%, 85% at 3 years, and 76% at 5 years for bSFTp and, median survival was 94.4 months, 1-year survival rate was 84%, 67% at 3 years, and 55% at 5 years for mSFT cases. This rate difference has been shown to be statistically significant in the study.
The role of adjuvant therapy in SFT is controversial. If a complete surgical resection is performed, there is no need for RT or CT. RT or CT may be tried if pathologic examination reveals positive surgical margins or incomplete surgery. Although re-resection excision is recommended in the presence of recurrence, adjuvant therapies can be useful when patient refuses operation or is not fit for surgery.,
SFTp has a characteristic histologic appearance as hypo- and hypercellular areas separated by fibrous stroma having hemangiopericytoma-like branching blood vessels. In immunohistochemical studies, the tumor for SFTp tends to be positive for CD34 and bcl-2 and are always negative for cytokeratin. But mSFTp cannot always express CD34 and bcl-2. The tumor reveals a wide spectrum of morphologic variation and biologic behavior. The biologic behavior of SFTp is still unclear. Strong expression of p53 and CD34 negativity shows as a malignant process of the tumor. The proportion of cells staining positively for p53 gene was higher in mSFTp than in SFTp. Unlike the negative reaction detected with CD34 immunostaining at mSFTp. Chmielecki et al. demonstrated NAB2-STAT6 gene fusions associated with recurrence in both bSFTp and mSFTp. Hiraoka et al. reported Bcl-2 expression was a sensitive marker for SFTp. In their study, all tumors demonstrated positive reactivity for Bcl-2 and they found a significant correlation between Bcl-2 immunoexpression and a reduced tumor size. Further studies need additional biomarkers, diagnostic histopathological agents, and potential pharmacological targets for the malignant subtypes of SFTp.
Limitation of the study
We discovered some limitations in the course of our study. First, and the most important is the retrospective study design, similar to most of the studies in the literature. Secondly, our findings are from a single institution and from a small number of case sample due to the rarity of the tumor. Despite these limitations, the current study provides valuable information about the surgical and other oncologic treatment procedures of SFTp.
| Conclusion|| |
Solitary fibrous tumor of the pleura is an uncommon benign neoplasm but malignant features can occur. Even in the case of recurrence, the main treatment is total surgical excision. Oncologic treatments can be tried in inoperable and metastatic cases. VATS resection can be performed in small and peripheric tumors. Understanding the nature of these tumors, some immunohistochemical and genetic studies may be a guide in the future. Further study should be performed to identify this uncommon tumor's behaviors and factors affecting its therapeutic response.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]