Unusual Soft Tissue Research Articles

Unusual soft tissue metastases in a patient with chondrosarcoma: a case report.

Chondrosarcoma (CS) is the second most frequent primary malignant bone tumour, characterized by production of non-osteoid cartilage matrix. Up to more than 30% of patients with CS present distant metastases, and the lungs represent the preferred site. Hence, CS soft tissue metastases and superficial cutaneous lesions are extremely rare. We report the case of a female who developed unusual multiple soft tissue CS metastases. This patient underwent left hindquarter amputation for recurrent grade 3 chondrosarcoma of the femoral neck with extension to the pelvis approximately 4years after internal fixation with an intramedullary nail for pathological fracture of left proximal femur and subsequent total proximal femoral endoprosthetic replacement for grade 1-2 chondrosarcoma. In the following years, she underwent metastasectomy for several grade 2 pulmonary metastatic chondrosarcomas. More than 14years after the amputation, she presented with multiple unusual superficial cutaneous lesions, and a whole-body magnetic resonance imaging demonstrated multiple soft tissue foci of metastatic disease. The histology of multiple soft tissue lesions excised confirmed metastatic chondrosarcoma. Then, she underwent marginal excision of further multifocal soft tissue metastatic high-grade chondrosarcoma. Unlike the poor survival from the onset of these metastases in the other cases reported in the literature, our patient is still alive 2years after the first multiple soft tissue excision of metastatic chondrosarcoma, and approximately 20years after the diagnosis of chondrosarcoma. Soft tissue CS metastases are a rare entity with few cases described in literature. This study aims to make the reader aware of this lesser-known CS manifestation.

Unusual Soft Tissue Uptake of Tc-99m MDP in Radiation-induced Sarcoma: Diagnostic Conundrum

Unusual Soft Tissue Uptake of Tc-99m MDP in Radiation-induced Sarcoma: Diagnostic Conundrum

EWSR1::WT1 Fusions in Neoplasms Other Than Conventional Desmoplastic Small Round Cell Tumor: Three Tumors Occurring Outside the Female Genital Tract

Desmoplastic small round cell tumor (DSRCT) is a high-grade, primitive round cell sarcoma classically associated with prominent desmoplastic stroma, coexpression of keratin and desmin, and a characteristic EWSR1::WT1 gene fusion. DSRCT typically arises in the abdominopelvic cavity of young males with diffuse peritoneal spread and poor overall survival. Although originally considered to be pathognomonic for DSRCT, EWSR1::WT1 gene fusions have recently been detected in rare tumors lacking the characteristic morphologic and immunohistochemical features of DSRCT. Here, we report 3 additional cases of neoplasms other than conventional DSCRCT with EWSR1::WT1 gene fusions that occurred outside the female genital tract. Two occurred in the abdominopelvic cavities of a 27-year-old man and a 12-year-old girl, whereas the third arose in the axillary soft tissue of an 85-year-old man. All cases lacked prominent desmoplastic stroma and were instead solid and cystic with peripheral fibrous pseudocapsules and occasional intervening fibrous septa. Necrosis was either absent (1/3) or rare (2/3), and mitotic activity was low (<1 to 3 per 10 hpf). In immunohistochemical studies, there was expression of smooth muscle actin (3/3) and desmin (3/3), rare to focal reactivity for EMA (2/3), and variable expression of CK AE1/AE3 (1/3). Myogenin and MyoD1 were negative, and C-terminus-specific WT1 was positive in both cases tested (2/2). All 3 tumors followed a more indolent clinical course with 2 cases demonstrating no evidence of disease at 20 and 44 months after resection. The patient from case 3 died of other causes at 14 months with no evidence of recurrence. DNA methylation profiling showed that the 3 cases clustered with DSRCT; however, they demonstrated fewer copy number variations with 2 cases having a flat profile (0% copy number variation). Differential methylation analysis with hierarchical clustering further showed variation between the 3 cases and conventional DSRCT. Although further study is needed, our results, in addition to previous reports, suggest that EWSR1::WT1 gene fusions occur in rare and seemingly distinctive tumors other than conventional DSRCT with indolent behavior. Proper classification of these unusual soft tissue tumors with EWSR1::WT1 gene fusions requires direct correlation with tumor morphology and clinical behavior, which is essential to avoid overtreatment with aggressive chemotherapy.

Complementary value of molecular analysis to expert review in refining classification of uncommon soft tissue tumors.

The classification of many soft tissue tumors remains subjective due their rarity, significant overlap in microscopic features and often a non-specific immunohistochemical (IHC) profile. The application of molecular genetic tools, which leverage the underlying molecular pathogenesis of these neoplasms, have considerably improved the diagnostic abilities of pathologists and refined classification based on objective molecular markers. In this study, we describe the results of an international collaboration conducted over a 3-year period, assessing the added diagnostic value of applying molecular genetics to sarcoma expert pathologic review in a selected series of 84 uncommon, mostly unclassifiable mesenchymal tumors, 74 of which originated in soft tissues and 10 in bone. The case mix (71% historical, 29% contemporary) included mostly unusual and challenging soft tissue tumors, which remained unclassified even with the benefit of expert review and routine ancillary methods, including broad IHC panels and a limited number of commercially available fluorescence in situ hybridization (FISH) probes. All cases were further tested by FISH using a wide range of custom bacterial artificial chromosome probes covering most of known fusions in sarcomas, whereas targeted RNA sequencing was performed in 13 cases negative by FISH, for potential discovery of novel fusion genes. Tumor-defining molecular alterations were found in 48/84 tumors (57%). In 27 (32%) cases the tumor diagnosis was refined or revised by the additional molecular work-up, including five cases (6%), in which the updated diagnosis had clinical implications. Sarcoma classification is rapidly evolving due to an increased molecular characterization of these neoplasms, so unsurprisingly 17% of the tumors in this series harbored abnormalities only very recently described as defining novel molecularly defined soft tissue tumor subsets.

An unusual soft tissue mass masquerading as sarcoma: a case report of soft tissue cysticercosis

Cysticercosis is a parasitic infection caused by Taenia solium, and occurs worldwide but is endemic to countries in Central and South America, Africa and various parts of Asia. Outside of endemic areas, common presentations included central nervous system infections and rarely muscle infections. We present a case report of a 32-year-old man presenting with a soft tissue lesion of his left trapezius muscle. The lesion was imaged with MRI and was suspected to be a sarcoma. The biopsy was performed, revealing the unusual finding of a parasitic organism, in keeping with Taenia solium.

Successful early diagnosis and surgical treatment of congenital caval foramen hernia in an 8-month-old mixed breed cat

An 8-month-old neutered female domestic mixed breed cat was presented to Dr. L. Kriaučeliūnas Small Animal Clinic due to coughing that persisted for 2 weeks. Lateral and dorsoventral chest radiographs revealed an unusual dome-shaped soft tissue opacity mass that had contact with the cranial part of the diaphragm. Together with heart and abdominal ultrasound findings, we decided that one of the differential diagnoses was a diaphragmatic hernia. During the diagnostic celiotomy, a vertical 4 cm in length diaphragmatic deficit was visualized. Left medial and lateral liver lobes were herniated, yet healthy-looking. Adhesions between the liver lobes and the pericardium sac were visualized and dissected. The pericardium was sutured with simple interrupted suture pattern. A herniorrhaphy was performed suturing the diaphragm with the continuous suture pattern. Successful surgical treatment resulted in fully resolved clinical symptoms.

Unusual complications at the recipient site following periodontal plastic surgery procedures: a systematic review.

To identify and describe unusual soft tissue complications of periodontal plastic surgery procedures at the recipient site after periodontal grafts. Two independent reviewers performed a comprehensive search in MEDLINE, Cochrane, periodontics journals, reference lists, and grey literature for articles dated up to July 2021. Publications related to surgical interventions only around the teeth with an unusual complication at the recipient site were selected. No restrictions were made in the number of cases, follow-up period, or language. The Cochrane Collaboration's tool for assessing risk of bias, the Newcastle-Ottawa Scale (NOS), and two validated case report/series checklists were used to critically appraise the studies. A total of 1434 articles were examined, of which 28 met the inclusion criteria: one RCT, two cohort studies, and twenty-five case reports/series. The periodontal plastic surgery procedures described in these articles were conducted to treat lack of attached gingiva and gingival recessions. The following unusual complications were found: bone exostosis, epithelial inclusion, root resorption, abscess, overgrowth, "liver clot" formation, and oroantral communication. Bone exostosis and epithelial inclusions were the most prevalent unusual complications following treatment with subepithelial connective tissue graft, free gingival graft, and acellular dermal matrix allograft. Due to the nature of the reports, the clinical recommendations for diagnosis and treatment cannot be homogenized. Clinical studies reporting complications are required to develop management protocols (PROSPERO CRD42021230875). Clinicians need to know the main complications that can occur in mucogingival surgeries as well as their clinical management to provide a successful and predictable treatment.

Magnesium implants in orthopaedic surgery create a diagnostic conundrum: A radiology case series and literature review.

During a routine post-operative orthopaedic radiograph reading session, repeated unusual radiographic soft tissue and bone appearances became evident. It was discovered that these patients had received biodegradable magnesium implants which have recently been introduced into orthopaedic clinical practice. To the untrained eye, the combination of peri-metallic bone resorption with associated soft tissue gas, could easily be mistaken for post-operative infection. The aim of this study is to properly characterise the radiographic post-operative appearances of biodegradable magnesium orthopaedic hardware. We retrospectively evaluated radiographs of all patients who underwent magnesium screw implantation for fractures over a 6 month period. Four patients, mean age of 9.75 (range: 6-15) years who underwent magnesium screw fixation following fracture were included in the study. Follow up duration was 100 days (range: 75-122) with a mean of 2.5 postoperative radiographs being performed per patient during this period. All cases demonstrated post-operative peri-metallic radiolucency which developed around the magnesium screws on x-ray, which subsequently resorbed over time. Peri-metallic soft tissue gas was observed in all patients. In two cases, magnesium implants fractured. As the use of biodegradable metal implants becomes more common, it is important for radiologists to be aware of their imaging characteristics. Prior to reporting a case, it would be prudent to know if biodegradable screws have been utilised and whether there exists a clinical concern for post-operative infection in patients with these particular implants, in which case it would be critical not to dismiss peri-prosthetic radiolucencies and soft tissue gas as merely a sequela of the natural metal degradation process.

Identifying the uncommon solitary fibrous tumour in a rare location - A case report.

Introduction and importanceThe authors describe a case work up of an unusual natal cleft soft tissue tumour which eventually was concluded as solitary fibrous tumour. Solitary fibrous tumour is an uncommon fibroblastic tumour which commonly presents in pleural region and very rarely in extrapleural location such as natal cleft. Accurate identification of this tumour, considering the indeterminate nature of the tumour irrespective of the location, avoided misdiagnosis and played a vital role in follow up management of the patient.Case presentation43 year old female patient presented with a painless lump in the natal cleft region for a short duration of 7 months with no other significant medical or surgical or family or psychosocial history. She was not on any regular medications.Clinical discussionDue to unusual location of the tumour broad range of differential diagnosis including benign and malignant entities were discussed based on histological findings and immunophenotyping. Mammary type myofibroblastoma, glomus tumour, clear cell renal cell carcinoma and clear cell sarcoma of soft tissue were few to note. STAT6 immunohistochemical stain played a crucial role in unravelling this case. Due to gradual increase in size of the lump complete surgical excision was performed with no local recurrence of the tumour.ConclusionIt is important to recognise this rare mesenchymal tumour with intermediate malignant potential occurring at uncommon natal cleft region for which complete surgical enucleation is curative.

Clinical presentation and imaging characteristics of clear cell sarcoma-like tumour of the gastrointestinal tract with liver metastasis: a case description.

The clear cell sarcoma-like tumor of the gastrointestinal tract (CCSLTGT) is an unusual malignant soft tissue tumor in the gastrointestinal tract. Although initially identified as a type of clear cell sarcoma (CCS) (1), further studies revealed it to be a new entity that resembles but is different from CCS (2). Only 96 cases have been reported worldwide (3), mostly occurring in the small intestine. Only 13 cases have been reported in the stomach (2-7). However, few studies have been conducted to evaluate the imaging characteristics of CCSLTGT. We report an extremely rare case of CCSLTGT of the stomach with liver metastasis in a middle-aged woman.

Crosstalk between Macrophages and Myxoid Liposarcoma Cells Increases Spreading and Invasiveness of Tumor Cells.

Simple SummaryMyxoid liposarcoma (MLPS) is the second most common subtype of liposarcoma, occurs predominantly in the extremities, and tends either to recur locally and metastasize to unusual soft tissue locations. To date, the mechanisms of invasion and metastasis of MLPS remain unclear, and yet, there is a high need to identify new prognostic biomarkers to enable the development of novel targeted therapeutic strategies. This study firstly aimed to assess the role of immune cellular components that infiltrate MLPS tissues. Our data show that high grade, heavily vascularized MLPS tissues exhibit T lymphocyte-poor and M2-like macrophage-rich phenotypes, while low grade MLPS tissues are mainly infiltrated by T lymphocytes. In line with these findings, evidence is shown that a crosstalk occurring between MLPS cells and macrophages exists as MLPS cells drive an M2-like phenotype in monocytes which in turn, increase the invasive capability of MLPS cells.Myxoid liposarcoma (MLPS) is the second most common subtype of liposarcoma and has tendency to metastasize to soft tissues. To date, the mechanisms of invasion and metastasis of MLPS remain unclear, and new therapeutic strategies that improve patients’ outcomes are expected. In this study, we analyzed by immunohistochemistry the immune cellular components and microvessel density in tumor tissues from patients affected by MLPS. In order to evaluate the effects of primary human MLPS cells on macrophage polarization and, in turn, the ability of macrophages to influence invasiveness of MLPS cells, non-contact and 3D organotypic co-cultures were set up. High grade MLPS tissues were found heavily vascularized, exhibited a CD3, CD4, and CD8 positive T lymphocyte-poor phenotype and were massively infiltrated by CD163 positive M2-like macrophages. Conversely, low grade MLPS tissues were infiltrated by a discrete amount of CD3, CD4, and CD8 positive T lymphocytes and a scarce amount of CD163 positive macrophages. Kaplan–Meier analysis revealed a shorter Progression Free Survival in MLPS patients whose tumor tissues were highly vascularized and heavily infiltrated by CD163 positive macrophages, indicating a clear-cut link between M2-like macrophage abundance and poor prognosis in patients. Moreover, we documented that, in co-culture, soluble factors produced by primary human MLPS cells induce macrophage polarization toward an M2-like phenotype which, in turn, increases MLPS cell capability to spread into extracellular matrix and to cross endothelial monolayers. The identification of M2-like polarization factors secreted by MLPS cells may allow to develop novel targeted therapies counteracting MLPS progression.

Target-like chondrocytes with thick perichondrocytic rings in cartilage-forming tumours. Preliminary report.

Here we present our experience with the occurrence of neoplastic chondrocytes with target-like appearance surrounded with unusual hypertrophic thick eosinophilic perichondrocytic rings (baskets), sometimes containing two or several layers. Pericellular rings (baskets) were positive in APAS and Masson's staining method and showed immunoreactivity with antibody against type IV collagen. Such single cells or small groups of such cells were observed rarely in 3 osteochondromas, 2 skeletal chondromas, 2 extraskeletal chondromas and 2 skeletal and 1 laryngeal chondrosarcomas. Moreover, 1 unusual soft tissue chondrosarcoma was composed entirely of target-like chondrocytes with hypertrophic extremely thick perichondrocytic rings. Such cartilage-forming tumour with target-like cells, which, to the best of our knowledge, is the first such chondrosarcoma reported in the literature. Ultrastructural evidence is presented that perichondrocytic rings have complicated structure.They contained microfibrillar component with abundant admixture of irregular aggregates of dense amorphous non-fibrillar material localised in lacunar spaces. In outer part of the rings predominated microfibrillar structures corresponding to type VI collagen that produced a rather dense capsule-like demarcation line against surrounding intercellular spaces. The described unusual changes are probably the result of hyperproduction and remodelation of perichondrocytic matrix by abnormal neoplastic chondrocytes in response to unknown factors. Local vascular and molecular signals, may be supposed as probable causes of this phenomenon.

An Unusual Soft Tissue Tumor of Uncertain Differentiation: a Case Report.

An Unusual Soft Tissue Tumor of Uncertain Differentiation: a Case Report.

Soft tissue huge solitary neurofibroma in the sacral region without neurofibromatosis: a pediatric case report

Neurofibromas are thick and irregular benign neural sheath tumors touching the peripheral nerve and it may occur at any point along a nerve. Neurofibromas occur frequently as a neurofibromatosis manifestation and less commonly solitary, in unusual sites without neurofibromatosis. The imaging especially MRI is relatively helpful to determine radiological features necessary for the diagnosis, but the definitive diagnosis is established basing on the histopathological examination of the specimen. The primary therapeutic approach for neurofibromas is a complete surgical removal to prevent tumor recurrence. This article highlights a rare case of unusual soft tissue huge solitary neurofibroma in the sacral region without neurofibromatosis in a 12-old-girl.

Giant Cell Tumor of Soft Tissue: A Rare Entity.

Giant cell tumor (GCT) of the soft tissue (GCT-ST) is a rare, unusual primary soft tissue tumor that is completely distinct from, and should not be confused with, any giant cell-rich tumor of bone or soft tissue. Currently, GCT-ST is included in the group of so-called fibrohistiocytic tumors of intermediate (borderline) malignancy. The most common symptom is a painless, slow-growing mass in a superficial location. Computed tomography and magnetic resonance imaging show a solid, nonhomogeneous, frequently hemorrhagic mass. Differential diagnosis is broad and should include benign and malignant entities. The treatment and excision margins of GCT-ST are controversial. Incomplete surgical excision is usually followed by local recurrence. Biological behavior is unpredictable. Giant cell tumor of the soft tissue has shown a lower mean local recurrence rate compared to GCT of bone but has a higher metastatic and death rate. Therefore, close clinical follow-up is recommended. [Orthopedics. 2019; 42(4):e364-e369.].

Varied Presentation Of Unusual Soft Tissue Lesions- A Case Series

Varied Presentation Of Unusual Soft Tissue Lesions- A Case Series

On the diverse and widely ignored Paleocene avifauna of Menat (Puy-de-Dôme, France): new taxonomic records and unusual soft tissue preservation

AbstractThe Paleocene locality of Menat (Puy-de-Dôme, France) has yielded several avian fossils, which remained poorly studied, even though some were found almost a century ago. Here, we review some of the material in public collections and show that those birds from Menat, which are at least tentatively identifiable, resemble taxa from early Eocene fossil localities. A largely complete skeleton of a medium-sized bird with strong feet shows affinities to the early Eocene Halcyornithidae and Messelasturidae, which are considered to be representatives of the clade including Psittaciformes and Passeriformes. Another skeleton of a small species resembles the Songziidae from the lower Eocene of China, which are representatives of Ralloidea, the clade including Rallidae and Heliornithidae. A new and previously unreported specimen exhibits exceptional soft tissue preservation, in that the bones appear to be largely dissolved but the podotheca of the feet and even the soft parts around the shank are visible; the plumage remains of this specimen furthermore show an unusual bluish hue.

Abstract B04: Oncogenic relevance of IGF-IR and PI3K/AKT/GSK3-beta signaling in myxoid liposarcoma

Abstract Introduction: Myxoid liposarcoma (MLS) accounts for 30-35% of all LS cases and is the second most common type of liposarcoma. One third of MLS lesions will become metastatic with tumors spreading to unusual bone and soft tissue locations. Ninety percent of MLS are characterized by a specific reciprocal translocation t (12; 16) (q13; p11), leading to the pathogenic gene fusion of FUS and DDIT3. The resulting chimeric FUS-DDIT3 fusion protein is suggested to play a crucial role in MLS pathogenesis, although the specific biological function and the mechanism of action remain to be defined. Aiming at the preclinical identification of novel therapeutic options in vitro and in vivo, we investigate the functional relevance of IGF-IR and PI3K/AKT/GSK3-beta signaling in primary MLS and tumor-derived cell lines. Methods: Immunohistochemical analyses of IGF-IR and PI3K/AKT/GSK3-beta signaling effectors and modulators were performed in a comprehensive cohort of primary MLS specimens. FUS-DDIT3-dependent activation of the PI3K/AKT/GSK3-beta signaling cascade was analyzed by siRNA knockdown experiments and protein immunoblotting in vitro. Cell proliferation and FACS assays were performed in two different MLS cell lines. An in vivo tumor model was successfully established performing the chicken chorioallantoic membrane (CAM) assay. Results: In a significant subset of MLS specimens, immunohistochemical staining revealed elevated phosphorylation levels of the respective signaling components, indicating that activated IGF-IR and PI3K/AKT/GSK3-beta signaling is a frequent feature in MLS. IGF-IR inhibition significantly suppressed the PI3K/AKT/GSK3-beta downstream cascade, associated with reduced phosphorylation levels of several signaling components, impairment of MLS cell viability and induction of apoptosis in vitro and in vivo. Furthermore, siRNA-mediated knockdown of FUS-DDIT3 lead to dephosphorylation of PI3K/AKT/GSK3-beta signaling components, implying that the FUS-DDIT3 fusion protein is involved in the IGF-IR regulated signaling cascade. Conclusion: Our study emphasizes the pivotal role of IGF-IR and PI3K/AKT/GSK3-beta signaling in MLS pathogenesis and indicates its functional dependence on the characteristic FUS-DDIT3 fusion protein. Furthermore, our in vitro and in vivo results demonstrate that targeting the IGF-IR and PI3K/AKT/GSK3-beta signaling pathway might provide a specific, molecular founded therapeutic strategy in the treatment of MLS. Citation Format: Marcel Trautmann, Christian Bertling, Jasmin Menzel, Magdalene Cyra, Konrad Steinestel, Inga Grünewald, Pierre Åman, Eva Wardelmann, Sebastian Huss, Wolfgang Hartmann. Oncogenic relevance of IGF-IR and PI3K/AKT/GSK3-beta signaling in myxoid liposarcoma [abstract]. In: Proceedings of the AACR International Conference: New Frontiers in Cancer Research; 2017 Jan 18-22; Cape Town, South Africa. Philadelphia (PA): AACR; Cancer Res 2017;77(22 Suppl):Abstract nr B04.

Lateral lymph node metastasis in a patient with T1 upper rectal cancer treated by lateral lymph node dissection: a case report and brief literature review

BackgroundLateral lymph node (LLN) metastasis may occur in patients with advanced rectal cancers of which the lower margins are located at or below the peritoneal reflection. However, LLN metastasis from a T1 rectal cancer is rare. Here, we report a case of LLN metastasis from a T1 upper rectal cancer that was successfully treated by sequential LLN dissection.Case presentationA 56-year-old man was referred to our hospital for the treatment of a T1 upper rectal cancer. We performed a laparoscopic low anterior resection. Histological examination showed a moderately differentiated adenocarcinoma with submucosal layer invasion; the invasion depth was classified as head invasion, without vessel or lymph duct invasion. Tumor budding was classified as grade 1. A total of six lymph nodes were harvested, and no lymph node metastases were detected. The postoperative course was uneventful. At 6 months after surgery, however, the serum carcinoembryonic antigen levels were elevated, and abdominal computed tomography (CT) revealed swollen lymph nodes in the right internal and common iliac artery area. Positron emission tomography with CT revealed hot spots in the same lesions. A retrospective re-evaluation of the preoperative CT images revealed no apparent swollen lymph nodes; however, an unusual soft tissue area was detected around the right internal iliac artery. A right LLN dissection was performed. Fifteen lymph nodes were resected, and histologically, metastases of adenocarcinoma were identified in 3 nodes. The postoperative course was again uneventful. The patient was given 12 cycles of adjuvant chemotherapy with FOLFOX (fluorouracil, leucovorin, and oxaliplatin). The patient remains healthy and with no signs of recurrence at 30 months after the second surgery.ConclusionsLLN metastasis occurs very rarely in patients with T1 upper rectal cancer and no risk factors for lymph node metastasis; however, a careful perioperative examination of the LLN should be performed. In cases involving LLN metastasis, a LLN dissection may be a therapeutic option if performed with curative intent.

Prediction of local and metastatic recurrence in solitary fibrous tumor: construction of a risk calculator in a multicenter cohort from the French Sarcoma Group (FSG) database

Solitary fibrous tumors (SFT) are rare unusual ubiquitous soft tissue tumors that are presumed to be of fibroblastic differentiation. At present, the challenge is to establish accurate prognostic factors. A total of 214 consecutive patients with SFT diagnosed in 24 participating cancer centers were entered into the European database (www.conticabase.org) to perform univariate and multivariate analysis for overall survival (OS), local recurrence incidence (LRI) and metastatic recurrence incidence (MRI) by taking competing risks into account. A prognostic model was constructed for LRI and MRI. Internal and external validations of the prognostic models were carried out. An individual risk calculator was carried out to quantify the risk of both local and metastatic recurrence. We restricted our analysis to 162 patients with local disease. Twenty patients (12.3%) were deceased at the time of analysis and the median OS was not reached. The LRI rates at 10 and 20 years were 19.2% and 38.6%, respectively. The MRI rates at 10 and 20 years were 31.4% and 49.8%, respectively. Multivariate analysis retained age and mitotic count tended to significance for predicting OS. The factors influencing LRI were viscera localization, radiotherapy and age. Mitotic count, tumor localization other than limb and age had independent values for MRI. Three prognostic groups for OS were defined based on the number of unfavorable prognostic factors and calculations were carried out to predict the risk of local and metastatic recurrence for individual patients. LRI and MRI rates increased between 10 and 20 years so relapses were delayed, suggesting that long-term monitoring is useful. This study also shows that different prognostic SFT sub-groups could benefit from different therapeutic strategies and that use of a survival calculator could become standard practice in SFTs to individualize treatment based on the clinical situation.