Etiology, pathogenesis, and management of angiosarcoma associated with implants and foreign body: Clinical cases and research updates.

Angiosarcomas are rare and highly malignant soft tissue sarcomas originating from endothelial cells lining the lymphatic or vascular system. While they predominantly emerge from (sub)cutaneous regions, occurrences have been reported throughout the body. The etiology of angiosarcoma remains elusive in most clinical cases. Nevertheless, several prognosis risk factors play a pivotal role, including chronic lymphedema, therapeutic irradiation, environmental carcinogens, familial syndromes, and the presence of foreign materials like metallic objects and biomedical implants. Despite evidence implicating retained foreign material in angiosarcoma development, understanding its prognosis and pathogenesis remains limited. The pathogenesis of angiosarcoma appears to involve a complex interplay of chronic inflammation, tissue remodeling, and genetic factors that create a conducive microenvironment for malignant transformation. Management of these sarcomas remains challenging due to their infiltrative nature owing to the high chance of metastasis and local recurrence. The primary treatment modalities currently include surgery, radiotherapy, and chemotherapy, but recent advances in targeted immunotherapy and gene therapy hold promise for more effective approaches. This comprehensive review delves into the potential etiological and pathogenic roles of foreign materials, such as metallic objects, biomedical implants, and biomaterials, in the development of angiosarcoma. Further research into the underlying molecular mechanisms could provide valuable insights for tailored management and developing novel targeted therapeutic strategies.

Radiation-induced angiosarcoma of the breast: retrospective analysis at a regional treatment centre.

BACKGROUND: Radiation-induced angiosarcoma (RIA) is an uncommon but morbid complication after radiotherapy for breast cancer. METHODS: Retrospective analysis of breast RIA patients at Cambridge University Hospital (CUH), a regional treatment centre in the East of England. RESULTS: 22 patients were identified between 2010 and 2022. Median age of diagnosis was 65 years (range 41-78). Median time from breast radiotherapy to RIA diagnosis was 6.5 years (range 2.4-16.0)-this interval has decreased over the last 24 years (r2 = 0.6601). 9% had metastasis at presentation. All patients underwent surgery (55% at CUH, 45% at local hospitals). 27% received peri-operative pegylated liposomal doxorubicin in the first-line setting. 62% relapsed following their primary curative-intent treatments after a median of 28 months. Metastases occurred in 36%, the commonest sites being lung (100%) and lymph node (50%). 2-year and 5-year overall survival (OS) rates for all patients were 73% and 60%, respectively. No correlation between progression-free survival (PFS) and OS was found with tumour size, margin, peri-operative chemotherapy, and whether surgery was performed at CUH. Patients with multifocal disease on their breasts had shorter PFS following surgery compared to single-lesion disease (median 10 vs 65 months; HR = 4.359 [95% CI 1.342-14.16]; P = 0.0143). Patients aged > 72 years had a median OS of 45 months vs 102 months for those ≤ 72 years (HR = 7.129 [95% CI 1.646-30.88]; P = 0.0086). CONCLUSION: RIA has high rates of recurrence and mortality and appears to be occurring sooner after breast radiotherapy. Further studies on its pathogenesis and effective treatment are warranted.

Clinical benefit of switching from paclitaxel to docetaxel or vice versa in cutaneous angiosarcoma patients resistant to first taxane chemotherapy.

Cutaneous angiosarcoma (CAS) is a rare soft-tissue sarcoma of vascular endothelial origin. Paclitaxel (PTX) and docetaxel (DTX) are used as systemic chemotherapy; however, chemoresistance often occurs in CAS. Switching one taxane to the other (i.e., PTX to DTX, or vice versa) is an option when the first taxane is no longer effective in malignant cancers such as ovarian or breast cancer. However, the efficacy of the same strategy in CAS has not been reported. Herein, we report the clinical response of switching one taxane-based chemotherapy to the other in CAS patients with resistance to the first taxane. Twelve CAS patients were included for analyses. In all patients, the median overall survival from the start of the first taxane treatment was 29.0 months (range, 6.47-58.5). During the first taxane, the median PFS for all patients was 5.96 months (1.81-47.1). Similarly, the median (range) PFS for all patients during the second taxane was 5.87 months (1.60-18.2). Furthermore, the median OS was 22.7 months (PTX to DTX) and 39.5 months (DTX to PTX) (p = 0.307). The median PFS during the first taxane was 5.14 (PTX to DTX) and 12.5 months (DTX to PTX), respectively (p = 0.380). The median PFS during the second taxane was 3.5 (PTX to DTX) and 7.1 months (DTX to PTX), respectively (p = 0.906). The objective response rate, defined as the sum of complete response (CR) and partial response (PR) rates, was 16.7%. The disease control rate, defined as the sum of CR, PR, and stable disease rates, was 50%. The frequency of adverse events during the second taxane was the same between the two groups (p > 0.999). Our report suggests that CAS patients could benefit from the second taxane treatment if the tumor is resistant to the first taxane.

Radiation-induced angiosarcoma of the breast: individual participant meta-analysis of Japanese population.

BACKGROUND: Radiation-induced angiosarcoma (RIAS) of the breast is a very rare and poor prognostic disease. According to previous studies, the efficacy of chemotherapy for RIAS is still controversial. However, no study has assessed the prognosis of RIAS and the prognostic impact of preoperative or postoperative chemotherapy in Japanese patients. Our study aimed to assess them in Japanese people using publication data with our three patients. METHODS: Thirty-nine patients diagnosed with RIAS, including 36 patients from 34 published case series, and three patients from our hospital were used for analysis. Disease-free survival (DFS), distant disease-free survival (DDFS), and overall survival (OS) were assessed. RESULTS: Among the 39 patients, 36 patients (92.3%) underwent surgery. The median DFS and OS periods were 14 months (range 1-75 months) and 23 months (range 4-84 months), respectively. Chemotherapy with taxane-based regimen was administered in 13 cases (33.2%) pre- or post-operatively. DFS was significantly improved with chemotherapy in addition to surgery (p = 0.037). However, addition of chemotherapy to surgery did not improve DDFS (p = 0.09) and OS (p = 0.878). In multivariate analysis, age ≥ 70 years was an independent but poor prognostic factor of DFS. Additionally, a lack of chemotherapy showed a trend to be associated with worse DFS. There was no independent variable contributing to DDFS and OS. CONCLUSIONS: Chemotherapy may have reduced the recurrence rate of RIAS in Japanese patients but did not improve OS. Further data are needed to confirm the efficacy and proper regimen of chemotherapy.

Is there a role for adjuvant therapy in radiation-induced angiosarcoma of the breast? A case report and review of the literature.

BACKGROUND: Angiosarcoma (AS) of the breast is very rare, accounting for 1% of all soft tissue breast tumors. AS may present as primary tumors of the breast or as secondary lesions usually associated with previous radiotherapy. Commonly, secondary AS affects older women (median age 67-71 years) with a clinical history of breast cancer. The preferred site of onset of RIAS is the edge of radiation fields, where radiation doses and tumor necrosis may be heterogeneous, resulting in a DNA damage and instability. Radical surgery is the treatment of choice, but no clear consensus exists on surgical management of breast AS. CASE REPORT: We describe an atypical case of relapsed RIAS after radical mastectomy, treated with new surgery and, considering the higher risk of recurrence, subsequent adjuvant chemotherapy with weekly paclitaxel. CONCLUSIONS: The frequency of radiation-induced angiosarcomas (RIAS) after breast-conserving surgery and radiotherapy has been increased to 0.14-0.5% among long survivors. Nevertheless, even if RIAS continues to be prognostically an extremely unfavorable cancer due to a high rate of recurrence, distant spread, and median overall survival (OS) of about 60 months, the benefits of loco-regional breast radiotherapy are clearly higher than the risk in developing angiosarcoma.

Treatment of radiation-associated angiosarcoma.

PURPOSE OF REVIEW: Radiation-associated angiosarcoma is a cutaneous aggressive tumor that is very rare and it represents a specific entity poorly studied in literature. It requires new therapeutic opportunity. RECENT FINDINGS: The complete surgical resection with negative margins is the mainstay treatment of localized treatment, even though it is difficult to reach in case of diffuse cutaneous infiltration. Adjuvant re-irradiation may improve local control with no benefit demonstrated on survival. Many systemic treatments can be efficient not only in metastatic setting but also in neoadjuvant setting in case of diffuse presentation. These treatments have never been compared to each other; the most efficient regimen remains to be determined, and a high heterogeneity of treatment is observed, even between sarcoma reference centers. SUMMARY: Immune therapy represents the most promising treatment under development. At the time of building clinical trial to assess the efficacy of immune therapy, the lack of randomized studies prevents the identification of a strong and consensual reference arm treatment. Given the rarity of the disease, only international collaborative clinical trials may have a chance to include enough patients to draw any conclusion and so will have to counteract the heterogeneity of management.

Trimodality Therapy Improves Disease Control in Radiation-Associated Angiosarcoma of the Breast.

PURPOSE: To evaluate the impact of trimodality treatment versus monotherapy or dual therapy for radiation-associated angiosarcoma of the breast (RAASB) after prior breast cancer treatment. EXPERIMENTAL DESIGN: With Institutional Review Board approval, we identified patients diagnosed with RAASB and abstracted data on disease presentation, treatment, and oncologic outcomes. Trimodality therapy included (i) taxane induction, (ii) concurrent taxane/radiation, and then (iii) surgical resection with wide margins. RESULTS: A total of 38 patients (median age 69 years) met inclusion criteria. Sixteen received trimodality therapy and 22 monotherapy/dual therapy. Skin involvement and disease extent were similar in both groups. All trimodality patients required reconstructive procedures for wound closure/coverage, compared with 48% of monotherapy/dual therapy patients (P < 0.001). Twelve of 16 (75%) patients receiving trimodality therapy had a pathologic complete response (pCR). With median follow-up of 5.6 years, none had local recurrence, 1 patient (6%) had distant recurrence, and no patients died. Among 22 patients in the monotherapy/dual therapy group, 10 (45%) had local recurrence, 8 (36%) had distant recurrence, and 7 (32%) died of disease. Trimodality therapy demonstrated significantly better 5-year recurrence-free survival [RFS; 93.8% vs. 42.9%; P = 0.004; HR, 7.6 (95% confidence interval, CI: 1.3-44.2)]. Combining all patients with RAASB regardless of treatment, local recurrence was associated with subsequent distant recurrence (HR, 9.0; P = 0.002); distant recurrence developed in 3 of 28 (11%) patients without local recurrence compared with 6 of 10 (60%) with local recurrence. The trimodality group had more surgical complications that required reoperation or prolonged healing. CONCLUSIONS: Trimodality therapy for RAASB was more toxic but is promising, with a high rate of pCR, durable local control, and improved RFS.

Secondary breast angiosarcoma following accelerated partial breast irradiation with intracavitary multicatheter applicator brachytherapy.

PURPOSE: Secondary angiosarcoma of the breast is a rare complication of breast radiotherapy and is associated with a poor prognosis. There are many reported cases of secondary angiosarcoma following whole breast irradiation (WBI), however development of secondary angiosarcoma following brachytherapy-based accelerated partial breast irradiation (APBI) is not as well characterized. METHODS AND MATERIALS: We reviewed and reported a case of a patient who developed secondary angiosarcoma of the breast following intracavitary multicatheter applicator brachytherapy APBI. RESULTS: A 69-year-old female was originally diagnosed with T1N0M0 invasive ductal carcinoma of the left breast and treated with lumpectomy followed by adjuvant intracavitary multicatheter applicator brachytherapy APBI. Seven years following her treatment, she developed secondary angiosarcoma. However, the diagnosis of secondary angiosarcoma was delayed due to nonspecific imaging findings and a negative biopsy. CONCLUSIONS: Our case highlights the need for secondary angiosarcoma to be considered in the differential diagnosis when patients present with symptoms such as breast ecchymosis and skin thickening following WBI or APBI. Prompt diagnosis and referral to a high-volume sarcoma treatment center for multidisciplinary evaluation is vital.

Intractable Bleeding After Revision Hip Arthroplasty Because of Angiosarcoma: A Report of 2 Cases.

CASE: Two cases of revision total hip arthroplasty (THA) for pseudotumor and infection with persistent postoperative bleeding because of angiosarcoma are presented. After surgery, both patients' health deteriorated because of hypovolemic shock despite transfusion, pressors, embolization, and prothrombotics. Diagnosis was obscure and delayed despite extensive imaging. Standard and computed tomography angiogram were nondiagnostic and did not localize the tumors or bleeding. Repeat surgeries and biopsies requiring special staining ultimately revealed epithelioid angiosarcoma. CONCLUSION: A diagnosis of angiosarcoma was etiologic for persistent postoperative bleeding after revision THA and should be considered in such cases.

The capillary lobule variant of radiation-associated angiosarcoma in the setting of breast cancer: A diagnostic pitfall.

AIM: Post-radiation angiosarcoma is an iatrogenic event seen in the setting of breast cancer treatment. Histopathologically, there are morphologic variants of angiosarcoma that mimic benign entities, including the capillary lobule variant of post-radiation angiosarcoma. We present the largest case series to date of this histopathologic variant of post-radiation angiosarcoma. METHODS AND RESULTS: Cases of the capillary lobule variant of post-radiation angiosarcoma from institutional/consultation archives from 2008 to June 2022 were reviewed. For inclusion, tumors had to occur in irradiated skin and exhibit a multi-lobular proliferation of tightly packed capillary-like vessels, as previously described in this variant. Prior ancillary studies were also reviewed. Eight cases met the criteria. All occurred in women treated with radiation for breast cancer (median age 75 years). All cases had similar findings, including a multi-lobular proliferation of tightly packed vessels, infiltrative cords, and atypical single endothelial cells. A conventional angiosarcoma pattern was also seen in five cases. All cases tested were positive for vascular markers (CD31, CD34, and/or ERG) and MYC. MYC amplification was shown by FISH in all cases tested. Smooth muscle actin (SMA) was positive in pericytes in the capillary lobules in all five cases tested and areas of conventional angiosarcoma in two of three cases. CONCLUSIONS: The capillary lobule variant of angiosarcoma is a rare and therefore potentially under-recognized variant of post-radiation angiosarcoma. The lobular architecture and SMA positivity may mimic benign vascular proliferations. Careful attention to histopathologic features and ancillary tests may facilitate accurate diagnosis.

Angiosarcoma after endovascular aneurysm repair: case report and literature review.

INTRODUCTION: Epithelioid angiosarcoma is a rare soft tissue sarcoma with a poor prognosis. We report two cases of patients who presented with a history of lower back pain, inflammatory signs and weight loss 5 and 6 years after endovascular aortic repair (EVAR) of an elective infrarenal abdominal aortic aneurysm (AAA). Imaging suggested graft infection but tissue samples revealed an epithelioid angiosarcoma. The objective is to report the clinical presentation, investigative modalities and immunohistochemical findings of an angiosarcoma after EVAR. PATIENTS AND METHODS: Two cases are described of an angiosarcoma of the aorta after EVAR. A literature search using PubMed, Embase and Web of Science was performed in English about angiosarcoma after EVAR published between 2007 and 2021. Relevant reports were selected and analysed. RESULTS: Fifteen case reports were identified, including the current two cases. Time to tumour detection after EVAR ranged from 6 to 120 months with a mean interval of 68 months. Most patients underwent endovascular repair of an AAA (13/15). Males (13 male/2 female patients) were predominant with a median age of 72 years (IQR 68-78 years). Over half of the patients had metastases at the time of diagnosis (9/15), most frequently in bones and liver. CONCLUSION: Diagnosis of angiosarcoma after EVAR remains challenging due to indistinctive clinical and radiological findings mimicking graft infection or endoleak. Angiosarcoma should be included in the differential diagnosis in patients previously treated with EVAR presenting with unintended weight loss, abdominal back pain and contrast enhancement of the aortic wall.AbbreviationsAAAabdominal aortic aneurysmCTAcomputed tomography angiographyCRPc-reactive proteinEVARendovascular aortic repairESRerythrocyte sedimentation rateFDGfluoro-deoxyglucoseMRImagnetic resonance imagingMeSHmedical subject headings.

Single-agent gemcitabine in patients with advanced, pre-treated angiosarcoma: A multicenter, retrospective study.

Gemcitabine has shown clinical activity against angiosarcoma in small series, alone, or combined with taxanes. We aimed to evaluate its activity as a single-agent in a larger series of patients with advanced angiosarcoma. We retrospectively reviewed the electronic medical records of consecutive adult patients with advanced angiosarcoma treated with single-agent gemcitabine at our institutions from January 2010 to January 2021. Response was evaluated according to RECIST 1.1, and toxicity was graded according to NCI-CTC v5.0. 42 patients were identified. 38 patients (90%) had received prior anthracyclines and weekly paclitaxel, and 9 (21%) had received pazopanib. The best tumor response was partial response (PR) in 16 patients (38%), or stable disease (10 patients, 24%). All 8 patients with cardiac angiosarcoma experienced a PR. Median PFS was 5.4 months (95%CI: 3.1-6.5), and median OS was 9.9 months (95%CI: 6.6-13.4). Single-agent gemcitabine has clinically meaningful activity in advanced, heavily pre-treated angiosarcoma.

Treatment-related thoracic soft tissue sarcomas in US breast cancer survivors: a retrospective cohort study.

BACKGROUND: Soft tissue sarcoma is a rare but serious side-effect of radiotherapy to treat breast cancer, and rates are increasing in the USA. We evaluated potential co-factors in two complimentary cohorts of US breast cancer survivors. METHODS: In this retrospective cohort study, we sourced data from the Kaiser Permanente (KP) cohort and the Surveillance, Epidemiology, and End Results (SEER) 13 registries cohort, both in the USA. The KP cohort included 15 940 women diagnosed with breast cancer from Jan 1, 1990, to Dec 31, 2016, in KP Colorado, KP Northwest (which serves Oregon and Southwest Washington state), or KP Washington, with detailed treatment data and comorbidities (including hypertension and diabetes at or before breast cancer diagnosis) from electronic medical records. The SEER cohort included 457 300 women diagnosed with breast cancer from Jan 1, 1992, to Dec 31, 2016, within the 13 SEER registries across the USA, with initial treatment data (yes vs no or unknown). Eligibility criteria in both cohorts were female breast cancer survivors (stage I-III) aged 20-84 years at diagnosis who had breast cancer surgery, and had survived at least 1 year after breast cancer diagnosis. The outcome of interest was any second thoracic soft tissue sarcoma (angiosarcomas and other subtypes) that developed at least 1 year after breast cancer diagnosis. Risk factors for thoracic soft tissue sarcoma were assessed using multivariable Poisson regression models. FINDINGS: In the KP cohort, median follow-up was 9·3 years (IQR 5·7-13·9) and 19 (0·1%) of 15 940 eligible, evaluable women developed a thoracic soft tissue sarcoma (11 angiosarcomas, eight other subtypes). Most (94·7%; 18 of 19) thoracic soft tissue sarcomas occurred in women treated with radiotherapy; thus, radiotherapy was associated with a significantly increased risk of developing a thoracic soft tissue sarcoma (relative risk [RR] 8·1 [95% CI 1·1-60·4]; p=0·0052), but there was no association with prescribed dose, fractionation, or boost. The RR of angiosarcoma after anthracyclines was 3·6 (95% CI 1·0-13·3; p=0·058). Alkylating agents were associated with an increased risk of developing other sarcomas (RR 7·7 [95% CI 1·2-150·8]; p=0·026). History of hypertension (RR 4·8 [95% CI 1·3-17·6]; p=0·017) and diabetes (5·3 [1·4-20·8]; p=0·036) were each associated with around a five-times increased risk of angiosarcoma. In the SEER cohort, 430 (0·1%) of 457 300 patients had subsequent thoracic soft tissue sarcomas (268 angiosarcomas and 162 other subtypes) after a median follow-up of 8·3 years (IQR 4·3-13·9). Most (77·9%; 335 of 430) cases occurred after radiotherapy; thus, radiotherapy was associated with a significantly increased risk of developing a thoracic soft tissue sarcoma (RR 3·0 [95% CI 2·4-3·8]; p<0·0001) and, for angiosarcomas, the RR for breast-conserving surgery plus radiotherapy versus mastectomy plus radiotherapy was 1·9 (1·1-3·3; p=0·012). By 10 years after radiotherapy, the cumulative incidence of thoracic soft tissue sarcoma was 0·21% (95% CI 0·12-0·34) in the KP cohort and 0·15% (95% CI 0·13-0·17) in SEER. INTERPRETATION: Radiotherapy was the strongest risk factor for thoracic soft tissue sarcoma in both cohorts. This finding, along with the novel findings for diabetes and hypertension as potential risk factors for angiosarcomas, warrant further investigation as potential targets for prevention strategies and increased surveillance. FUNDING: US National Cancer Institute and National Institutes of Health.

Radiation Induced Atypical Vascular Lesion in the Breast.

BACKGROUND AND PURPOSE: Atypical vascular lesion (AVL) became a separate WHO diagnosis in November 2019. Due to a possible risk of developing angiosarcoma, extensive surgery with excision of AVL has been recommended but the benefit from this is questionable. We investigated whether the change in WHO classification has led to an increase in the number of patients diagnosed with AVL, thereby leading to an increase in extensive surgery. METHOD: The Danish National Pathology Databank was used to identify patients diagnosed with AVL between June 1, 2010 to June 31, 2020. The rate of AVL diagnosed before and after change in WHO classification was compared. RESULTS: In total, 13 cases of AVL were identified, 3 cases diagnosed before changes in WHO classification corresponding to 0.025 cases per month, compared to 8 cases, 1.143 cases per month, after the change in WHO classification. This corresponded to a 45-fold increase (95%CI: 10.88-265,31) (P < .0001) in AVL diagnosis. The mean patient age at diagnosis was 67 years. Patients received treatment varying from yearly follow up to extensive surgery. Non developed angiosarcoma in the follow-up period of 22 months. CONCLUSION: The changes in WHO classification of AVL has led to a considerable increase in the number of patients diagnosed with the lesion. No standardized treatment exists for this rare condition, but extensive surgery is often recommended to this frail population despite the lack of evidence for prognostic benefit from the procedure. Prospective follow-up studies are needed to determine the optimal treatment strategy.

Breast angiosarcoma after primary breast cancer surgery: A systematic review.

BACKGROUND: A potentially fatal disease of breast angiosarcoma (AS) can occur after breast cancer treatments, and previous studies have revealed that lymphedema is a risk factor of AS development. However, little is known, and there is no systematic review focusing on the relationship between lymphedema and breast AS. This systematic review aimed to evaluate all publications on breast AS after primary breast cancer surgery to identify prognostic factors and evaluate treatment modalities. METHODS: Databases were searched for articles with published individual patient data on prognostic factors, treatment, and follow-up of patients with breast AS after primary breast cancer surgery. Statistical analysis was performed to test the prognostic values of age, gender, location, tumor-node-metastasis classification of primary breast cancer (tumor and node), stage of primary breast cancer, treatment for primary breast cancer, breast cancer recurrence, post-operative lymphedema, latent period from primary breast cancer to AS, treatment for AS, AS recurrence, and time until death or last follow-up. RESULTS: Twenty articles were included, representing data on 41 patients. In these articles, 15 patients were referred to post-operative lymphedema. Eleven patients of them had post-operative lymphedema. As for this research, post-operative lymphedema was not a significant prognostic factor. AS recurrence was significant as a prognostic factor (P-value < 0.001) in univariate analysis for follow-up status; patients who had AS recurrence had a shorter time until death. CONCLUSION: In this systematic review, AS recurrence was of prognostic value for breast AS patients after primary breast cancer surgery. There are only a few articles that refer post-operative breast lymphedema.

Angiosarcoma after Popliteal Aneurysm Exclusion Surgery. A Systematic Review.

BACKGROUND: Expansion after popliteal artery aneurysm exclusion with bypass is a common phenomenon. Popliteal angiosarcoma is seldom reported in literature and in most cases after popliteal artery aneurysm surgery. This paper aims to present the case of a popliteal angiosarcoma, initially diagnosed as late aneurysmal growth after exclusion surgery, to conduct a systematic review of popliteal angiosarcoma and assess any association between angiosarcoma and previous popliteal aneurysm surgery. METHODS: We performed a secondary popliteal aneurysmorraphy through posterior approach for symptomatic aneurysm expansion in a 79-year-old woman, 9 years after medial femoropopliteal venous bypass and aneurysm exclusion. The postoperative course was complicated by recurrent hematomas and wound spillages requiring multiple revisions. Pathological analysis identified an angiosarcoma. Staging revealed bone invasion and pulmonary metastasis. Despite transfemoral amputation and adjuvant chemotherapy the patient died 8 months later. We performed a systematic review through MEDLINE on 'primary' and 'secondary' (with previous vascular surgery) angiosarcoma in popliteal artery aneurysm. Research was done using the terms '(hem) angiosarcoma', 'aneurysm', 'popliteal aneurysm or artery', 'femoral aneurysm or artery'. Other soft tissue sarcoma or nonpopliteal locations were excluded. RESULTS: Including this case, only 13 angiosarcomas in popliteal aneurysms are currently described. Two were reported without previous surgery considered as primary angiosarcoma and 11 after popliteal artery aneurysm surgery (secondary angiosarcoma). Patient age ranges from 8 months to 83 years with a male predominance (10/3). Nine of the 11 patients with secondary angiosarcoma were initially diagnosed as popliteal aneurysm expansion after previous bypass surgery, the 2 other secondary cases presented respectively with pain and inflammatory syndrome without expansion. All prior surgical exclusion was carried out by a medial approach. Interval with the index operation ranges from 3 months to 15 years. Death was reported in 8 of the 13 cases within the first year of diagnosis. CONCLUSIONS: Although seldom reported, popliteal angiosarcomas are mainly described after popliteal artery aneurysm exclusion surgery, raising suspicion on a potential association, yet causality cannot be demonstrated. Angiosarcoma should be included in the differential diagnosis of popliteal aneurysm growth or unexpected outcome after exclusion bypass surgery. Systematic imaging and pathological studies should be undertaken to allow early diagnosis and treatment. Routine use of a posterior approach, with aneurysm resection, when feasible as initial popliteal artery aneurysm treatment, might reduce the risk of late sarcomatous transformation.