Complete Response to Pembrolizumab in Stage IV Alveolar Soft Part Sarcoma After Failure of Four Lines of Treatment: A Case Report and Literature Review.

Alveolar soft part sarcoma (ASPS) is a rare malignant tumor that manifests as a slow-growing soft tissue mass and frequently presents with distant metastasis. The prognosis is variable, and complete remission of metastatic disease has rarely been reported. Our patient was diagnosed with metastatic ASPS at the age of 17, with a primary forearm lesion and metastasis to the lungs. She underwent surgical resection of her forearm mass, followed by adjuvant chemotherapy and radiation to target the lung metastasis. Over the next decade, she had a complicated course of treatment. Her disease continued to slowly progress despite treatment with sunitinib, pazopanib, and a combination of docetaxel and gemcitabine. We eventually treated her with immune checkpoint inhibitors (ICIs). Pembrolizumab, initially in combination with bevacizumab and later as monotherapy, resulted in significant tumor shrinkage, especially in the pulmonary lesions, within the first three months. Subsequent imaging reported complete remission within 15 months and no disease recurrence at her three-year follow-up. Our case highlights one of the very few reported cases of complete remission achieved in metastatic ASPS after treatment with ICIs. ICIs could offer hope for disease remission in advanced ASPS, a rare malignancy that has proven difficult to treat successfully in the past. More studies need to be conducted to further evaluate the efficacy and any associated predictors of successful treatment.

Efficacy and safety of nivolumab monotherapy in patients with unresectable clear cell sarcoma and alveolar soft part sarcoma (OSCAR Trial/NCCH1510).

BACKGROUND: Clear cell sarcoma (CCS) and alveolar soft part sarcoma (ASPS) are rare, and standard systemic therapy is not established except for sunitinib in ASPS. It is known that CCS and ASPS have a common biological feature of melanoma and Xp11.2/TFE3 translocation renal cell carcinoma, and immune-checkpoint inhibitors (ICIs) are effective in these tumors. The authors conducted a phase 2 trial to evaluate the efficacy and safety of nivolumab for CCS and ASPS. METHODS: The number of patients expected to be enrolled was 15-25 and was determined based on the Bayesian design. The primary end point was the confirmed objective response rate (ORR) according to the central review and the secondary end points included ORR, progression-free survival (PFS), overall survival (OS), and safety. RESULTS: A total of 26 patients (CCS, 12; ASPS, 14) were enrolled. Efficacy and safety were analyzed on 25 and 26 patients, respectively. The minimum number of responses required for a positive conclusion regarding the efficacy was four. However, only one patient (4.0%) with ASPS had a partial response. Complete response, stable disease, progression disease, and not evaluable were 0%, 60%, 32%, and 4.0%, respectively. Adverse events of grade 3 or 4 occurred in 57.7% (15 of 26). The median PFS was 4.9 months (95% confidence interval [CI], 3.7-8.6 months) and the median OS was 15.8 months (95% CI, 8.2-not reached). CONCLUSIONS: The primary end point of the ORR was not met for CCS and ASPS on the central review. Further studies are needed to evaluate ICIs in patients with ASPS.

Alveolar Soft Tissue Sarcoma: Correlation of MRI Features With Histological Grading and Patient Prognosis.

BACKGROUND: Alveolar Soft Part Sarcoma (ASPS) is a rare, aggressive cancer whose diagnosis and treatment depend on histological grading. However, tumor variability can lead to underestimation, affecting treatment, and patient survival. OBJECTIVE: To evaluate MRI features associated with Grade III ASPS and to determine the relationship between MRI features and patient prognosis. STUDY TYPE: Retrospective analysis. SUBJECTS: Sixty-seven patients with ASPS were included with 37 males and 30 females (M/F = 1.23) follow-up and survival analysis on 50 patients. FIELD STRENGTH/SEQUENCE: A 3.0 T, T1WI-FSE, T2WI-FSE, DWI-EPI, DCE-MRI (gradient echo). ASSESSMENT: MRI features (margin, peritumoral oedema, peritumoral enhancement, necrosis, vascular flow void signal, heterogeneous signal intensity [SI] at T1WI and T2WI, ADCmean, time-intensity curve [TIC] type, distant metastasis, and bone invasion) and histological grading were independently evaluated by three radiologists and two pathologists, with Grade III considered high-grade. STATISTICAL TESTS: The chi-square or Fisher's exact test was used to assess the correlation between MRI features and histological grading. Multivariable binary logistic regression identified independent factors associated with high-grade tumors. The Kaplan-Meier method and Cox proportional hazards model were used to calculate hazard ratios for MRI features. RESULTS: Tumor necrosis, heterogeneous SI at T2WI ≥50%, and ADCmean were associated with high-grade ASPS. Tumor necrosis was an independent factors associated with local relapse-free survival (odds ratio [OR], 3.88). TIC type was associated with 5-year survival rate (OR, 2.80) and local relapse-free survival (OR, 2.69). Heterogeneous SI at T2WI ≥50% was associated with 5-year survival (OR, 4.00), local relapse-free survival (OR, 5.58), and local relapse-free survival (OR, 4.84). DATA CONCLUSION: MRI features including tumor necrosis, heterogeneity of SI at T2WI, ADCmean, and TIC type aid in assessing ASPS grading and prognosis. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 5.

Cheek alveolar soft part sarcoma recurrence at the primary site during follow-up: a case report and review of the literature.

BACKGROUND: Alveolar soft part sarcoma (ASPS) occurs most often in the deep muscles or fascia of the extremities in adults, with only 3.4% of these tumours originating from the head, face and neck. To date, only 17 cases of buccal ASPS have been reported, including the case presented here. Only one case of ASPS recurrence at the primary site, similar to our case, has been reported thus far. Immune checkpoint inhibitors (ICPis)-associated diabetes, with an estimated incidence of 0.43%, is usually seen in older cancer patients and has not been reported in younger people or in patients with ASPS. CASE PRESENTATION: A 24-year-old male patient presented with a slowly progressing right cheek mass with a clinical history of approximately 28 months. Sonographic imaging revealed a hypoechoic mass, which was considered a benign tumour. However, a pathological diagnosis of ASPS was made after excision of the mass. Five days later, functional right cervical lymph node dissection was performed. No other adjuvant therapy was administered after surgery. In a periodic follow-up of the patient six months later, blood-rich tumour growth was noted at the primary site, and Positron emission tomography-computedtomography (PET-CT) ruled out distant metastasis in other areas. The patient was referred to the Ninth People's Hospital of Shanghai Jiaotong University. Due to the large extent of the mass, the patient received a combination of a Programmed Cell Death Ligand 1(PD-L1) inhibitor and a targeted drug. Unfortunately, the patient developed three episodes of severe diabetic ketoacidosis after the administration of the drugs. A confirmed diagnosis of ICPis-associated diabetes was confirmed. After the second operation, the postoperative pathological diagnosis was ASPS, and the margins were all negative. Therefore, we made a final clinical diagnosis of ASPS recurrence at the primary site. Currently in the follow-up, the patient is alive, has no distant metastases, and undergoes multiple imaging examinations every 3 months for the monitoring of their condition. CONCLUSIONS: In analysing the characteristics of all previously reported cases of buccal ASPS, it was found that the clinical history ranged from 1 to 24 months, with a mean of approximately 3 to 9 months. Tumour recurrence at the primary site has been reported in only one patient with buccal ASPS, and the short-term recurrence in our patient may be related to the extraordinarily long 28-month history. ICPis-associated diabetes may be noted in young patients with rare tumours, and regular insulin level monitoring after use is necessary.

Alveolar soft part sarcomas in young patients: The French national NETSARC+ network experience.

BACKGROUND AND AIMS: Alveolar soft part sarcoma (ASPS) is an ultra-rare chemo-resistant sarcoma in children, occurring preferentially in young adults. We aimed to describe and compare its clinical presentation and behaviour in children and young adults to determine whether the same therapeutic strategy should be addressed for both populations. METHODS: National retrospective multicentre study of children (0-18 years) vs. young adults (19-30 years) included in the "ConticaBase" sarcoma database, treated for ASPS between 2010 and 2019 with pathology reviewed via the NETSARC + network. RESULTS: Overall, 45 patients were identified, 19 children (42%) and 26 young adults (58%). All ASPS diagnoses were confirmed with TFE3 rearrangement by immunohistochemistry or FISH. All clinical characteristics were balanced between both populations with frequent metastases at diagnosis (8/19 vs. 10/26). The therapeutic strategy was based on surgery (17/19 vs. 21/26), radiotherapy (8/19 vs. 12/26) ± systemic treatment (8/19 vs. 9/26). In patients with initially localized disease, metastatic relapse occurred only in adults (8/16), whereas metastatic progression was present in both metastatic groups (5/8 vs. 8/10). After a median follow-up of 5.2 years (range, 0.2-12.2), 5-year EFS was 74% [95%CI, 56-96] vs. 47% [30-74] (p = 0.071) respectively, and 5-year OS was 95% [85-100] vs. 85% [70-100] (p = 0.84). For localized tumours, 5-year MFS was 100% [100-100] vs. 60% [39-91] (p = 0.005). The 5-year OS of all patients with metastasis at diagnosis was 80.2% (62.2%-100%). CONCLUSIONS: ASPS appears to have the overall same clinical characteristics, but a more aggressive behaviour in young adults than in children. However, despite frequent metastases at diagnosis, long-term survival is high in both groups. Overall, the same therapeutic strategies may be considered for both populations.

Qualitative and quantitative MRI analysis of alveolar soft part sarcoma: correlation with histological grade and Ki-67 expression.

OBJECTIVE: To investigate the correlation between MRI findings and histological features for preoperative prediction of histological grading and Ki-67 expression level in alveolar soft part sarcoma (ASPS). METHODS: A retrospective analysis was conducted on 63 ASPS patients (Jan 2017-May 2023). All patients underwent 3.0-T MRI examinations, including conventional sequences, dynamic contrast-enhanced scans with time-intensity curve analysis, and diffusion-weighted imaging with apparent diffusion coefficient (ADC) measurements. Patients were divided into low-grade (histological Grade I) and high-grade (histological Grade II/III) groups based on pathology. Immunohistochemistry was used to assess Ki-67 expression levels in ASPS. Statistical analysis included chi-square tests, Wilcoxon rank-sum test, binary logistic regression analysis, Spearman correlation analysis, and receiver operating characteristic curve analysis of various observational data. RESULTS: There were 29 low-grade and 34 high-grade patients (26 males and 37 females) and a wide age range (5-68 years). Distant metastasis, tumor enhancement characteristics, and ADC values were independent predictors of high-grade ASPS. High-grade ASPS had lower ADC values (p = 0.002), with an area under the curve (AUC), sensitivity, and specificity of 0.723, 79.4%, and 58.6%, respectively, for high-grade prediction. There was a negative correlation between ADC values and Ki-67 expression (r = -0.526; p < 0.001). When the cut-off value of ADC was 0.997 × 10-3 mm²/s, the AUC, sensitivity, and specificity for predicting high Ki-67 expression were 0.805, 65.6%, and 83.9%, respectively. CONCLUSION: Qualitative and quantitative MRI parameters are valuable for predicting histological grading and Ki-67 expression levels in ASPS. CRITICAL RELEVANCE STATEMENT: This study will help provide a more nuanced understanding of ASPS and guide personalized treatment strategies. KEY POINTS: There is limited research on assessing ASPS prognosis through MRI. Metastasis, enhancement, and ADC correlated with histological grade; ADC related to Ki-67 expression. MRI provides clinicians with valuable information on ASPS grading and proliferation activity.

Prognostic factors of alveolar soft part sarcoma in children and adolescents: A population-based study.

PURPOSE: Alveolar Soft Part Sarcoma (ASPS) is an exceedingly rare and aggressive cancer in children. Our objective was to conduct a population-based cohort study to forecast overall survival (OS) in pediatric ASPS patients. METHODS: We utilized the Surveillance, Epidemiology, and End Results (SEER) database to identify all pediatric ASPS patients diagnosed between 1975 and 2019. Kaplan-Meier estimations were employed to construct survival curves based on various criteria. Survival curves were compared using the log-rank test. Cox proportional-hazards regression was utilized to determine variables associated with OS. Additionally, we constructed a nomogram to predict overall survival in pediatric ASPS patients. RESULTS: A total of 103 pediatric ASPS patients were identified. Predominantly, the tumors affected females (62.2 %), and most of them located in the extremities (53.4 %). The majority of patients underwent surgery (83.5 %). Survival rates declined with increasing tumor size, and patients with localized tumors exhibited significantly better prognoses than those with distant tumors. Surgery conferred superior survival outcomes compared to no surgery. Cox proportional hazard regression analysis identified SEER stage and surgery as important independent predictors of survival. CONCLUSIONS: Our study highlights SEER stage and surgery as key predictors of OS in pediatric ASPS, offering crucial epidemiological insights for clinical management.

An unusual case of primary splenic soft part alveolar sarcoma: case report and review of the literature with emphasis on the spectrum of TFE3-associated neoplasms.

BACKGROUND: Alveolar soft part sarcoma is a rare tumour of soft tissues, mostly localized in muscles or deep soft tissues of the extremities. In rare occasions, this tumour develops in deep tissues of the abdomen or pelvis. CASE PRESENTATION: In this case report, we described the case of a 46 year old man who developed a primary splenic alveolar soft part sarcoma. The tumour displayed typical morphological alveolar aspect, as well as immunohistochemical profile notably TFE3 nuclear staining. Detection of ASPSCR1 Exon 7::TFE3 Exon 6 fusion transcript in molecular biology and TFE3 rearrangement in FISH confirmed the diagnosis. CONCLUSION: We described the first case of primary splenic alveolar soft part sarcoma, which questions once again the cell of origin of this rare tumour.

Mimicking angiogenic microenvironment of alveolar soft-part sarcoma in a microfluidic coculture vasculature chip.

Alveolar soft-part sarcoma (ASPS) is a slow-growing soft tissue sarcoma with high mortality rates that affects adolescents and young adults. ASPS resists conventional chemotherapy; thus, decades of research have elucidated pathogenic mechanisms driving the disease, particularly its angiogenic capacities. Integrated blood vessels that are rich in pericytes (PCs) and metastatic potential are distinctive of ASPS. To mimic ASPS angiogenic microenvironment, a microfluidic coculture vasculature chip has been developed as a three-dimensional (3D) spheroid composed of mouse ASPS, a layer of PCs, and endothelial cells (ECs). This ASPS-on-a-chip provided functional and morphological similarity as the in vivo mouse model to elucidate the cellular crosstalk within the tumor vasculature before metastasis. We successfully reproduce ASPS spheroid and leaky vessels representing the unique tumor vasculature to assess effective drug delivery into the core of a solid tumor. Furthermore, this ASPS angiogenesis model enabled us to investigate the role of proteins in the intracellular trafficking of bioactive signals from ASPS to PCs and ECs during angiogenesis, including Rab27a and Sytl2. The results can help to develop drugs targeting the crosstalk between ASPS and the adjacent cells in the tumoral microenvironment.

Establishment and characterization of NCC-ASPS2-C1: a novel patient-derived cell line of alveolar soft part sarcoma.

Alveolar soft part sarcoma (ASPS) is a rare mesenchymal tumor characterized by rearrangement of the ASPSCR1 and TFE3 genes and a histologically distinctive pseudoalveolar pattern. ASPS progresses slowly, but is prone to late metastasis. As ASPS is refractory to conventional chemotherapy, the only curative treatment is complete surgical resection. The prognosis of advanced and metastatic cases is poor, highlighting the need for preclinical research to develop appropriate treatment options. However, ASPS is extremely rare, accounting for < 1% of all soft tissue sarcomas, and only one patient-derived ASPS cell line is available from public cell banks worldwide for research. This study reports the establishment of a novel ASPS cell line derived from the primary tumor tissue of an ASPS patient, named NCC-ASPS2-C1. This cell line retains the ASPSCR1-TFE3 fusion gene, which is characteristic of ASPS. The characterization of this cell line revealed stable growth, spheroid formation, and invasive properties. By screening a drug library using NCC-ASPS2-C1, we identified several drugs that inhibited the proliferation of ASPS cells. In conclusion, the establishment of NCC-ASPS2-C1 provides a valuable resource for advancing ASPS research and developing novel treatments for this challenging disease.

Evaluation of TRIM63 RNA in situ hybridization (RNA-ISH) as a potential biomarker for alveolar soft-part sarcoma (ASPS).

Alveolar soft-part sarcoma (ASPS) is a rare soft tissue tumor with a broad morphologic differential diagnosis. While histology and immunohistochemistry can be suggestive, diagnosis often requires exclusion of other entities followed by confirmatory molecular analysis for its characteristic ASPSCR1-TFE3 fusion. Current stain-based biomarkers (such as immunohistochemistry for cathepsin K and TFE3) show relatively high sensitivity but may lack specificity, often showing staining in multiple other entities under diagnostic consideration. Given the discovery of RNA in situ hybridization (RNA-ISH) for TRIM63 as a sensitive and specific marker of MiTF-family aberration renal cell carcinomas, we sought to evaluate its utility in the workup of ASPS. TRIM63 RNA-ISH demonstrated high levels (H-score greater than 200) of expression in 19/20 (95%) cases of ASPS (average H-score 330) and was weak or negative in cases of paraganglioma, clear cell sarcoma, rhabdomyosarcoma, malignant epithelioid hemangioendothelioma, as well as hepatocellular and adrenal cortical carcinomas. Staining was also identified in tumors with known subsets characterized by TFE3 alterations such as perivascular epithelioid cell neoplasm (PEComa, average H-score 228), while tumors known to exhibit overexpression of TFE3 protein without cytogenetic alterations, such as melanoma and granular cell tumor, generally showed less TRIM63 ISH staining (average H-scores 147 and 96, respectively). Quantitative assessment of TRIM63 staining by RNA-ISH is potentially a helpful biomarker for tumors with molecular TFE3 alterations such as ASPS.

Alveolar soft part sarcoma: a clinicopathological and immunohistochemical analysis of 26 cases emphasizing risk factors and prognosis.

OBJECTIVE: This study aimed to investigate the clinicopathological features and prognostic indicators of alveolar soft part sarcoma (ASPS). METHODS: The characteristics of 26 ASPS patients diagnosed at our hospital between January 2011 and January 2019 were retrospectively analysed. RESULTS: The data for 12 male and 14 female patients, with a median age of 27.5 years, were assessed. The clinical symptoms mainly included painless enlarged masses in deep soft tissues. ASPS had a characteristic pathological morphology. Twenty-four patients were positive for TFE3, and TFE3 gene rearrangement was detected in 12 patients. Among the 26 patients who completed follow-up, 14 had metastasis, 1 had local recurrence, and 7 died. Kaplan-Meier survival analysis revealed that prognosis was significantly correlated with sex, tumour size and metastasis (P < 0.05). Multivariate Cox regression analysis revealed that sex and metastasis were independent prognostic risk factors for patients with ASPS (P < 0.05). CONCLUSION: ASPS is a rare soft tissue sarcoma of unknown origin that occurs in young people, has a slow but metastatic course, and is associated with a poor 5-year survival rate among patients with metastasis. ASPS has character TFE3 protein and gene expression, and the diagnosis is relatively specific. The diagnosis requires comprehensive analysis of clinical history, histological morphology, and immunohistochemistry.

Alveolar Soft Part Sarcoma in the Female Genital Tract: Case Series with Literature Review and SEER Database Analysis.

Introduction: Alveolar soft part sarcoma (ASPS) is a rare and distinct subtype of soft tissue sarcoma. This study aims to describe the unique presentation of ASPS in the female genital tract. Methods: Prognostic factors for cancer-specific overall survival (CSS) were evaluated using multivariate analyses. Results: In our case series, we identified a novel TFE3-PRCC gene fusion in a 24-year-old unmarried patient with cervical ASPS who underwent fertility-sparing surgery and remained recurrence-free for 41 months. The other two patients underwent radical hysterectomy and bilateral salpingo-oophorectomy. At the time of writing, the two patients had been disease-free for 49 and 71 months, fluorescence in situ hybridization showed break-apart signals for the ASPL-TFE3 gene. Among the 55 cases with available information from the PubMed/Medline database, most presented with localized disease, and at the last follow-up, all patients were alive and 45 patients showed no evidence of disease. The 5-year CSS rate in the female genital tract cohort from SEER database was 86.2%. Multivariate analysis revealed that older age was associated with a 1.042-fold increased risk of cancer-specific mortality (HR=1.042, 95% CI 1.022-1.063, P < 0.001), involvement of soft tissue including the heart was associated with a 4.786-fold higher risk (HR=4.7868, 95% CI 1.681-13.623, P= 0.003), and regional infiltration and distant metastasis were associated with approximately 8.6-fold and 18-fold higher risk of cancer-specific mortality compared to local disease, respectively (HR=8.652, 95% CI 2.529-29.63, P = 0.001; HR=18.366, 95% CI 6.153-54.817, P< 0.001). Patients who underwent radical excision did not show reduced cancer-specific mortality compared to those who underwent local excision (HR=0.492, 95% CI 0.224-1.081, P = 0.078). Discussion: Previously unrecognized genetic diversity exists in ASPS. Patients with ASPS in the female genital tract have the lowest likelihood of presenting with a distant disease and are associated with a more favorable survival outcome.

PEComa with ASPSCR1::TFE3 fusion: expanding the molecular genetic spectrum of TFE3-rearranged PEComa with an emphasis on overlap with alveolar soft part sarcoma.

AIMS: Mesenchymal neoplasms involving TFE3 gene fusions are diverse, mainly include alveolar soft part sarcoma (ASPS) that is characterised by ASPSCR1::TFE3 fusion, and a small subset of perivascular epithelioid cell tumours (PEComas) referred to as TFE3-rearranged PEComa, that most frequently harbours SFPQ::TFE3 fusion. Historically, ASPS and TFE3-rearranged PEComa are considered two distinctive entities despite their known morphological overlap. However, recent studies have suggested a potential histogenetic relationship between them, and several neoplasms that showed morphological features more closely fit PEComa rather than ASPS but harboured ASPSCR1::TFE3 fusion have been documented. In this study, we report three cases of PEComa with ASPSCR1::TFE3 fusion. METHODS AND RESULTS: Clinicopathological features were assessed and partner agnostic targeted next-generation sequencing on clinically validated platforms were performed. The patients are two females and one male with age at presentation ranging from 21 to 51 years. All three tumours were located in the viscera (rectum, kidney and cervix). On a relatively limited follow-up period (range = 9-15 months), all patients are alive without evidence of recurrent or metastatic disease. The neoplasms were composed of tight nested architecture of epithelioid clear cells separated by a delicate vascular network, two of which were associated with sheets of plump spindle cells, and none showed significant discohesive tumour morphology. Immunohistochemically, in addition to TFE3 protein, all three neoplasms demonstrated co-expression of melan-A and smooth muscle actin. RNA-sequencing identified ASPSCR1::TFE3 fusion in all three cases that were confirmed by subsequent fluorescence in-situ hybridisation analyses. CONCLUSIONS: Our study expands the molecular genetic spectrum of TFE3-rearranged PEComa and further indicates its close relationship to ASPS.

Primary Uterine Alveolar Soft Part Sarcoma in a Postmenopausal Woman: Histopathologic and Immunohistochemical Characteristics of a Rare Case.

BACKGROUND: Primary uterine alveolar soft part sarcoma (ASPS) is a rare, indolent mesenchymal malignancy with less than 40 patients documented in the literature. CASE: We report an example of ASPS in a 61-year-old postmenopausal woman. Macroscopically, the uterus showed multiple nodular masses. Microscopic examination revealed tumor arranged in nests and alveolar pattern. The tumor cells were moderately to markedly pleomorphic, epithelioid to polygonal, with eccentrically placed nuclei, vesicular chromatin, prominent macro-nucleoli, and moderate to abundant eosinophilic cytoplasm. PAS-positive and diastase-resistant intracytoplasmic crystals were also seen in some tumor cells. On immunohistochemistry, the tumor cells showed diffuse positivity for vimentin and nuclear positivity for TFE3, a surrogate marker for ASPS. These were negative for SMA, desmin, CD10, h-caldesmon, cyclin D1, EMA, Melan A, and CD34. SMARCB1 expression was retained. Based on the histopathology and IHC, a final diagnosis of uterine ASPS was rendered. CONCLUSIONS: Knowledge of the characteristic histopathologic and immunohistochemical features can help accurately diagnose such rare tumors. Knowledge of the characteristic histopathologic and immunohistochemical features can help accurately diagnose such rare sarcoma in an uncommon site with an unusual age.

Alveolar Soft Tissue Sarcoma in the Right Thigh: A Case Study at King Abdulaziz Medical City, Jeddah, Saudi Arabia.

The term soft tissue sarcoma (STS) refers to a rare group of multiple subtypes of cancer that arise in connective tissues, such as fat, muscles, and blood vessels. The disease is known to metastasize rapidly. Herein, we report a case of a 24-year-old female who complained of a painless mass in her right thigh that was gradually growing in size. The patient had lost 11 kg of weight unintentionally. On examination, there was a large mass at the right upper lateral thigh, which was warm and nontender on palpation with relatively well-defined margins clinically. The magnetic resonance imaging (MRI) scan suggested the presence of sarcoma. When biopsied, the histopathological assessment showed neoplastic infiltrates consistent with alveolar soft-part sarcoma (ASPS). There was no evidence of metastasis on computerized tomography (CT). Treatment with preoperative radiation followed by surgery was offered after discussion at the Tumor Board meeting, but the patient opted for surgery alone. This was mainly due to her concerns about the adverse effects of radiotherapy on her fertility. The patient did not develop any postoperative complications. This case highlights the importance of identifying and managing such cases promptly to improve clinical outcomes and aims to contribute to improving understanding of this rare disease.

Efficacy of immune checkpoint inhibitors in alveolar soft-part sarcoma: results from a retrospective worldwide registry.

BACKGROUND: Conventional cytotoxic drugs are not effective in alveolar soft-part sarcoma (ASPS). Immune checkpoint (programmed cell death protein 1/programmed death-ligand 1) inhibitors (ICIs) are promising drugs in ASPS. A worldwide registry explored the efficacy of ICI in ASPS. MATERIALS AND METHODS: Data from adult patients diagnosed with ASPS and treated with ICI for advanced disease in expert sarcoma centers from Europe, Australia and North America were retrospectively collected, including demographics and data related to treatments and outcome. RESULTS: Seventy-six ASPS patients, with a median age at diagnosis of 25 years (range 3-61 years), were registered. All patients received ICI for metastatic disease. Immunotherapy regimens consisted of monotherapy in 38 patients (50%) and combination in 38 (50%) (23 with a tyrosine kinase inhibitor). Among the 68 assessable patients, there were 3 complete responses and 34 partial responses, translating into an overall response rate of 54.4%. After a median follow-up of 36 months [95% confidence interval (CI) 32-40 months] since the start of immunotherapy, 45 (59%) patients have progressed on ICI, with a median progression-free survival (PFS) of 16.3 months (95% CI 8-25 months). Receiving ICI in first line (P = 0.042) and achieving an objective response (P = 0.043) correlated with a better PFS. Median estimated overall survival (OS) from ICI initiation has not been reached. The 12-month and 24-month OS rates were 94% and 81%, respectively. CONCLUSIONS: This registry constitutes the largest available series of ASPS treated with ICI. Our results suggest that the ICI treatment provides long-lasting disease control and prolonged OS in patients with advanced ASPS, an ultra-rare entity with limited active therapeutic options.

The dynamic contrast enhanced-magnetic resonance imaging and diffusion-weighted imaging features of alveolar soft part sarcoma.

Background: Alveolar soft part sarcoma (ASPS) is a rare type of soft tissue sarcoma that predominantly affects adolescents and young adults. Early diagnosis of ASPS is crucial for optimal therapeutic planning and improving prognosis, but its diagnostic features are not well delineated. This study aimed to retrospectively analyze the imaging features of ASPS with an emphasis on the dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) findings to identify imaging findings that might suggest the diagnosis to radiologists. Methods: The imaging features of 34 patients with pathologically proven limb ASPS were retrospectively analyzed. A total of 23 underwent DCE-MRI, and 12 underwent DWI. Results: Among the 34 cases of ASPS, 31 tumors were in the lower extremities, and 3 were in the upper extremities. The maximum tumor diameters ranged from 3.0 to 19.4 cm (mean, 8.7±3.96 cm). A total of 28 cases had well-defined borders. The masses demonstrated heterogeneous high signal intensity on T2-weighted imaging (T2WI) and the fat-suppressed (FS) T2WI sequence and slight hyperintensity on T1-weighted imaging (T1WI). A total of 25 lesions had thin hypointense bands on T1WI and T2WI. Intra- and peri-tumoral tubular areas of flow void were exhibited on both T1WI and T2WI in all cases. A total of 12 cases showed a high signal on DWI, and the mean apparent diffusion coefficient (ADC) value was (0.86±0.07)×10-3 mm2/s [range, (0.6-1.4)×10-3 mm2/s]. Persistent remarkable enhancement of the lesion was displayed on contrast-enhanced scans. The time-intensity curves (TICs) of 23 masses showed early arterial enhancement and slow washout of contrast. Conclusions: ASPS most commonly presents in the lower extremities of adolescents or young adults. Hyperintense T1WI, T2WI, and DWI signals, low ADC, flow voids, early arterial enhancement are frequent MRI features.

Alveolar soft part sarcoma in a child - a case report.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a very rare mesenchymal malignancy of uncertain origin. It mostly affects young people, with about a quarter of cases being diagnosed in children. CASE: An 11-year-old girl had a painless subcutaneous "lump" in the left elbow area. Imaging exams revealed a solid soft-tissue intramuscular mass of suspicious appearance. A surgical excision of lesion was performed. The biopsy consisted of a lobular tumor measuring 35 × 20 × 12 mm. Histology revealed an epithelioid-cell population arranged in organoid pseudoalveolar pattern. It immunohistochemically expressed TFE3 and harbored the ASPSCR1:: TFE3 gene fusion. A diagnosis of ASPS was established. Subsequently, a wide re-excision of the scar was performed without microscopic residual tumor. The patient is currently without evidence of local recurrence or metastasis. CONCLUSION: ASPS is considered an aggressive and prognostically unfavorable chemoresistant neoplasm. Children have a better prognosis compared to adults. Early detection of tumor in a localized stage with complete surgical removal remains a mainstay therapeutic option. Due to its tendency to late metastases, a long-term thorough follow-up of the patient is necessary.

Alveolar soft part sarcoma of the uterine corpus: A 13-year follow-up case report and review of the literature.

OBJECTIVE: Female genital alveolar soft part sarcoma (ASPS) is rare and has a favourable prognosis compared to ASPS from other sites. We reported our experience to manage a case with uterine corpus ASPS (UC ASPS) and conducted a literature review on prognosis of ASPS from different sites of female genital tract. CASE REPORT: This report represented a 33-year-old woman who had UC ASPS. She received tumor excision with uterine preservation and had the longest follow-up time (155 months) without recurrence in the literature. CONCLUSION: UC ASPS has better prognosis than ASPS from the uterine cervix, the low uterine segment, vulvovaginal area and perineum. We recommended conservative treatment for young women with UC ASPS.