Primary Sarcoma Research Articles

Intracranial Ewing sarcoma with obstructive hydrocephalus in pediatric patient: a rare case report

Link of Video Abstract: https://youtu.be/b4jB7Jos8tw Background: Ewing’s sarcoma is the second most common primary bone tumor presenting in childhood and adolescence. Ewing's sarcoma of the skull bones is an unusual occurrence (6 to 9% of all Ewing’s. sarcoma cases). Here, we present a rare case of Ewing's sarcoma involving the central nervous system (CNS) in a 13-month-old child and share our experience with its management. Case Presentation: We report a case of a 13-month-old girl with a chief complaint of gradually progressive head size. There is a history of seizures once a week before admission. The head CT scan with contrast administration revealed non-communicating hydrocephalus with bone defect in the occipital region and an intraaxial tumor of the posterior fossa due to Ewing’s sarcoma. Conclusion: Primary cranial Ewing's sarcoma of the cranium is a rare occurrence; its extension to intraparenchymal is even rare. This diagnosis can be considered in the differential diagnosis in children with a tumor involving the skull with destruction of the bone.

Charcot neuroarthropathy in persons with diabetes: It's time for a paradigm shift in our thinking.

The aim of this paper is to review the recent literature regarding the epidemiology and surgical management of Charcot neuro-osteoarthropathy (CNO). We propose that a fundamental change in the approach and assumptions regarding the historical treatment of active CNO should be considered. Although the true incidence and prevalence of CNO in the US population with diabetes are not known, we estimated the incidence to be 27,602 per year and the prevalence to be 208,880 persons. In persons with diabetes, the incidence of CNO is higher than that of prostate, lung, kidney, and thyroid cancer, and in the entire US population, the incidence of CNO is higher than that of multiple myeloma, soft tissue sarcoma, and primary bone sarcoma. In persons with diabetes, the incidence of CNO is higher than fractures of the femoral shaft, distal femur, tibia, talus, calcaneus and Lisfranc ligament injuries. Surgical techniques have evolved over the past half century, and surgery is the standard for treating displaced fractures and intra-articular injuries. Since CNO is a fracture, dislocation, or fracture dislocation in patients with neuropathy, why do we treat CNO differently? Elsewhere in the skeleton displaced osseous and ligament injuries are treated surgically. Based on the information presented in this manuscript, we suggest that it is time for a paradigm shift in the treatment of persons with CNO. While uncommon, CNO in persons with diabetes is not rare. Given the advances in surgical techniques, surgical intervention should be considered earlier in persons with CNO who are at risk for developing deformity related foot ulceration.

Outcomes of proximal humeral reconstruction with cemented osteoarticular allograft in pediatric patients: a retrospective cohort study.

There is no agreement on the best choice of proximal humeral reconstruction following tumor resection in pediatric patients. We reviewed the functional outcomes, oncologic outcomes, and surgical complications in pediatric patients after proximal humeral reconstruction with cemented osteoarticular allograft. Eighteen patients aged 8-13 years who underwent proximal humeral osteoarticular allograft reconstruction following resection of primary bone sarcoma were included. The mean follow-up period was 88±31.7 months. At the last follow-up assessment, limb function was evaluated based on shoulder range of motion, Musculoskeletal Tumor Society score, and Toronto Extremity Salvage Score. Tumor recurrence and postoperative complications were extracted from the patients' medical records. Mean active forward flexion of the shoulder was 38°±18°. Mean active abduction was 48°±18°. Mean active external rotation was 23° ± 9°. The mean Musculoskeletal Tumor Society score was 73.4%±11.2%. The mean Toronto Extremity Salvage Score was 75.6%±12.9%. Local recurrence occurred in 1 patient. Metastasis developed after the operation in 2 additional patients. We recorded 6 postoperative complications in this series, including 1 superficial infection, 1 late-onset deep infection, 1 allograft fracture, 2 cases of nonunion, and 2 cases of shoulder instability. Two complications required allograft removal. In pediatric patients, reconstruction of the proximal humerus with cemented osteoarticular allograft results in acceptable oncologic and functional outcomes while the postoperative complication rate seems to be lower than that of other available techniques.

Extremely rare presentation of primary jejunal monophasic synovial sarcoma

Extremely rare presentation of primary jejunal monophasic synovial sarcoma

Intraoperative motive for incomplete resection in primary retroperitoneal sarcoma.

Surgical resection is the current standard of care for retroperitoneal sarcoma (RPS). Recent data suggests that up to 5% of patient have incomplete (R2) resection. The exact reason why patients scheduled for surgery with a curative intent to treat ended up with an R2 resection is largely unknown. To identify intraoperative findings responsible for incomplete (R2) resection in primary RPS. All records of consecutive patients scheduled for a non-metastatic primary RPS surgery between 1995 and 2020 in a tertiary care sarcoma centre were retrospective analyzed. Among the 347 patients scheduled for surgery, 13 (3.7%) had an incomplete (R2) resection. The reasons for incomplete surgery were intraoperative finding of vascular involvement of great vessels in 5 patients, previously undetected peritoneal metastases in 5 patients, invasion of contralateral kidney/ureter in 2 patients and the need to preserve both kidneys in 1 patient because of his past medical history. Among these patients, 3 had a laparotomy without resection and 10 had a partial resection (i.e. debulking surgery). Severe postoperative complications occurred in 5 patients. The median length of stay in hospital was 19days. After a median follow-up of 12months, the median survival of patients after incomplete resection was 18months. The 1-y, 5-y and 8-y overall survival (OS) for these patients were 46%, 14%, and 7%, respectively. Incomplete (R2) resection for a primary RPS surgery is rare in specialized sarcoma center. The next steps should be to identify the preoperative criteria that lead to this accurate selection and to define the best practice in front of a peroperative discovery of an unresectable RPS. III.

Synovial Sarcoma of the Descending Colon: Report of a Rare Case and Review of the Literature

Abstract Introduction/Objective Synovial Sarcoma is a mesenchymal malignancy that occurs primarily in the deep soft tissue near large joints of the extremities in young adults. Synovial sarcoma of the gastrointestinal tract is extremely rare. There is not enough literature to establish a consensus on management and treatment for colorectal synovial sarcoma. Methods/Case Report An 85-year-old male preresented with a positive cologuard test and the colonoscopy revealed a 12 mm polyp in the descending colon. Polypectomy was preformed. Histological examination exhibits spindle cell proliferation with fascicular growth pattern and with small nucleoli. There are collagen deposition, variable size of thick wall vessels and mixed inflammatory cells including lymphocytes, eosinophils and neutrophils in the background. Mitosis are identified. Immunohistochemical stains show tumor cells are negative for CD34, S100, DOG1, CD117, STAT6, Bcl-2, Desmin, and AE1/AE3, and focal positive for EMA, SMA and ALK. Immunohistochemical stain for SS18-SSX fusion protein is positive. Archer fusionplex targeted RNA sequencing (M23-1377) showed SS18:SSX2 fusion. A structural genomic alteration between the SS18 and SSX2 genes is detected [t(18;X)(q12.1;p11.22)]. These findings confirmed the diagnosis of synovial sarcoma. Results (if a Case Study enter NA) NA Conclusion Here we report a rare case of descending colon primary synovial sarcoma. Synovial sarcoma is generally considered as an aggressive and high-grade lesion with metastatic potential and its management is different from other colorectal neoplasms. This case report emphasies a wide differential diagnosis for colorectal lesions and prompt diagnosis and early management is important for better patient outcome.

Primary Chest Wall Ewing Sarcoma with Indolent Behavior in an Elderly Male

Abstract Introduction/Objective Ewing sarcoma (ES) is the second most common primary malignant bone tumor, primarily affecting children and young adults within the first two decades of life. Over 80% of cases are positive for CD99 and exhibit a characteristic t(11;22) translocation resulting in an EWSR1::FLI1 fusion. Extraosseous ES is extremely rare and most reported cases occur in patients less than 50 years old. We report an unusual case of extraosseous ES arising from the chest wall in an elderly male that showed slow interval progression on imaging studies. Methods/Case Report An 83-year-old male with a past medical history of COPD and tobacco use presented to the emergency department for a mechanical ground level fall and a worsening cough over the prior week. Of note, he was found to have a 6.1 cm pleural based mass seven years prior. The patient was ultimately discharged home with recommended oncologic follow-up for this long-standing chest wall mass due to an increase in size on imaging. A PET scan showed a hypermetabolic subpleural mass in the right lower chest wall measuring 7.6 cm with invasion through the adjacent ribs and intercostal spaces into the adjacent soft tissue. A core biopsy was performed, which demonstrated a small round blue cell tumor diffusely positive for CD99 and Bcl-2, lacking significant mitotic activity and necrosis. Given the unusual clinical features, a next generation sequencing (NGS) panel for sarcoma fusions was performed and identified an EWSR1::FLI1 fusion, supporting the diagnosis of ES/primitive neuroectodermal tumor (PNET). Results (if a Case Study enter NA) NA Conclusion ES is relatively common as a primary bone tumor in children and young adults, but is rare in the chest wall and pleura and is extremely rare in the elderly. The clinical course for ES is typically aggressive. Diagnosis of ES can be challenging as CD99 positivity is nonspecific. The characteristic t(11;22) EWSR1::FLI1 fusion can be identified through FISH or NGS. At 83 years old, this is, to our knowledge, the oldest patient reported in the literature with this diagnosis. The slow interval growth of this mass over a period of seven years is also unusual. These combined clinicopathologic features are exceedingly unique and expand upon the reported spectrum and behavior of the Ewing’s family of sarcomas. The use of broad NGS panels among pathologists may result in increased identification of ES in unusual clinical settings in the future, while also providing more confident pathologic classification in challenging situations.

Primary Epithelioid Sarcoma of Frontotemporal Scalp: a Rare Case Report with Recent Literature Review

Epithelioid sarcoma (ES) is a very rare and aggressive mesenchymal sarcoma subtype which represents less than 1% of soft tissue sarcomas (STS). According to the origin of the site, there are two types of ES: distal-type epithelioid sarcoma and proximal-type epithelioid sarcoma. The clinical diagnosis of ES mainly is confirmed by histopathology examination followed by immunohistochemistry. Radical excisional surgery is the best treatment option for epithelioid sarcoma. According to TNM staging, the treatment option will vary from surgery to surgery accompanied with radiotherapy and chemotherapy. Here in, we presented a 36-year-old man had non-healing ulcer in left frontotemporal scalp extending to involve left orbit. Histopathological confirmed epithelioid sarcoma. Magnetic Resonance Imaging (MRI) of Head and Neck revealed that there was mass in left frontotemporal scalp measuring 6.7 X 5.7 X 2.6 cm extending to zygomatic region and left orbit D/D malignant mass/sarcoma with bilateral (B/L) sinusitis. After that patient undergone for Wide Local excision (WLE) surgery on 11th September 2022. Adjuvant Radiation Therapy (RT) 6000 cGy radiation dose in 30 fractions (#) which was 200 cGy per fraction (#) were given during 22nd September to 10th November 2022 due to local advancement of disease. Patient was asked to follow up after 6 weeks after completion of RT. After 6 weeks of surgery, the patient was undergone for MRI and report revealed normal study.

The efficacy and safety of direct oral anticoagulants compared with low-molecular-weight heparin for venous thromboembolism prophylaxis after surgical resection of primary lower extremity bone or soft-tissue sarcoma.

The incidence of postoperative venous thromboembolism (VTE)and wound complications is greater after sarcoma resection. We sought to identify differences in postoperative VTE and bleeding complications with direct oral anticoagulants (DOACs)versus low-molecular-weight heparin (LMWH)following resection of lower extremity primary bone or soft tissue sarcoma. We retrospectively identified 2083 patients from the PearlDiver database who underwent resection of primary bone or soft tissue sarcoma of the lower extremity from January 2010 to October 2021 and prescribed LMWH or DOAC within 90-days postoperatively. The primary outcomes were comparison of postoperative incidence and odds of deep venous thrombosis(DVT), pulmonary embolism(PE), and bleeding complications within 90-days following resection. Patients prescribed DOACs had a greater odds of DVT (odds ratio [OR]: 1.60; 95% confidence interval [CI]: 1.06-2.41;p = 0.024) and PE (OR: 3.38;95% CI: 1.96-5.86;p < 0.001) within 90-days following resection of bone sarcoma when compared withthe LMWH cohort. Patients undergoing resection of soft tissue sarcomas also had greater odds DVT (OR: 1.65;95% CI: 1.09-2.49;p = 0.016) and PE (OR: 2.62;95% CI: 1.52-4.54;p < 0.001) in the DOAC cohort. There was no difference in the odds of bleeding complications. This study demonstrated an increased incidence and odds of VTE, but not bleeding complications, when using DOACs versus LMWH after primary bone or soft tissue sarcoma resection. Level III.

Challenges in primary orbital Ewing sarcoma: A case report

Primary Orbital Ewing Sarcoma (POES) is an exceptionally uncommon cancer. We present a case study of POES in a young woman that highlights the intricate diagnostic process, therapeutic interventions, and the essential role of a multidisciplinary healthcare team.

Pleomorphic liposarcoma of the extremity with solitary huge liver metastasis at initial diagnosis treated with conversion surgery combined with adjuvant chemotherapy: a case report

BackgroundPleomorphic liposarcoma is the rarest subtype of liposarcoma. Pleomorphic liposarcomas are generally unresponsive to chemotherapy and radiotherapy. Moreover, metastasis in the liver, as the first and sole site, from a primary extremity soft tissue sarcoma, including pleomorphic liposarcoma, is extremely rare. Information regarding the appropriate management of these lesions is limited.Case presentationA 50-year-old Japanese woman presented with a mass in the left thigh. Imaging examination revealed a soft tissue sarcoma on the left posterior thigh. The tumor was histologically diagnosed as pleomorphic liposarcoma. Computed tomography examination for assessment of metastases incidentally detected a huge liver mass. Wide excision of sarcoma was performed prior to chemotherapy. Right trisectionectomy was necessary to achieve hepatic clearance; however, the future liver remnant volume was insufficient. Therefore, we decided to administer anthracycline-based chemotheraphy to shrink the tumor. After seven courses of adriamycin-based chemotherapy, the liver tumor size was reduced from 211 mm × 106 mm × 180 mm to 105 mm × 66 mm × 90 mm. Finally, a right hemihepatectomy was performed. The patient was continuously monitored and was metastasis or local recurrence free within 5 months after liver surgery.ConclusionChemotherapy is effective in some cases for the treatment of unresectable liver metastases of pleomorphic liposarcoma, and complete resection is possible with conversion surgery. If the patient’s general condition permits, anthracycline-based chemotherapy can be used for the treatment of stage 4 pleomorphic liposarcoma.

An Unusual Differential Diagnosis of Sarcoma

Osteomyelitis is an uncommon cause of a soft tissue mass and is diagnosed clinically by a blend of radiology, histology, and microbiology. This case report outlines a case of melioidotic osteomyelitis presenting as a suspected sarcoma. The diagnosis of melioidotic osteomyelitis was done against the diagnosis of sarcoma only after radiological evaluation, microbiological evidence of Burkholeria pseudomallei and osteomyelitis confirmed on histology. It is an extremely rare mimic of primary sarcoma of bone and the presentation described in the present case report appears to be unique. Keywords: Osteomyelitis; Sarcoma; Burkholeria pseudomallei

Indicators of free radical oxidation in neutrophils of patients with primary and recurrent soft tissue sarcomas

Purpose of the study. To carry out a comparative analysis of lipid peroxidation intensity and antioxidant system indices in blood neutrophils of patients with primary and relapsed soft tissue sarcomas (STS) depending on sex and age.Patients and methods. Of the 81 patients included in the study, 48 had primary STS, 5 patients with continued growth, and 28 patients with recurrent STS. The patients were divided by sex and age; the level of lipid peroxidation products, superoxide dismutase (SOD) activity, total peroxidase activity (TPA), glutathione peroxidase (GPx) activity and reduced glutathione (RG) content in blood neutrophils were investigated by conventional spectrophotometric methods. The comparison groups (donors) consisted of 12 men and 17 women divided into the same age subgroups: ≤ 45 years and &gt; 45 years.Results. In donors, there was a multiple decrease in the SOD/TPA ratio with age, especially in women, and in men this was accompanied by an age-related decrease in GPx activity. In primary sarcomas in older women and in men with continued growth and recurrence, there was an increase in diene conjugates (DC). In men over 45 years of age, there was an increase in SOD, TPA, and GPx. Women of the older age group were characterized by activation of SOD and GPx, expressed in the relapsed process to a significantly greater extent than in men, and an increase in RG was observed in women. The increase in both components of the glutathione system and SOD activity was especially significant in the development of relapses in women for periods exceeding three years, which was accompanied by a decrease in DC content. Conclusions. Neutrophils are characterized by an increase in DC content in patients of both sexes in the older age group with primary and recurrent STS, with its highest content in men with continued growth and relapses. GPx activity, increased in both men and women in the older age group in all variants of STS development, may play an important role in the antioxidant protection of blood cells in STS. Thus, the most pronounced activation of GPx, accompanied by a maximum increase in reduced glutathione and activation of SOD, contributes to a decrease in the level of DC and the absence of MDA increase in women with slow development of recurrences.

High Grade Osteosarcoma at the Site of a Ceramic on Cross-Linked Polyethylene Cementless Hip Replacement: A Case Report and Review of the Literature

The following case report describes a 50-year-old male with a history of post-traumatic arthritis of the right hip after a previous open reduction of a traumatic hip dislocation as a young adult. He underwent an uncomplicated ceramic on highly cross-linked polyethylene primary total hip arthroplasty (THA), with unremarkable intra-operative pathology at that time. Three years postoperatively, the patient developed acute onset of hip and groin pain and associated radiographic findings which proved to be related to a high-grade osteosarcoma within the soft tissue juxtaposed to the ceramic on highly cross-linked polyethylene THA. While metal-associated primary bone sarcomas have been previously reported, we are unaware of any prior description of an osteosarcoma in the setting of a ceramic on highly cross-linked polyethylene articulation. This current report represents the first case of a primary osteosarcoma associated with this type of hip arthroplasty articulation.

Clinical characteristics and management of primary retroperitoneal sarcoma: A literature review.

Retroperitoneal sarcoma (RPS) is a rare tumor classified into many histological types. It is also often detected only after it has grown to a considerable size and requires extensive resection of the surrounding organs, making it difficult to offer optimal patient-tailored management. Evidence supporting specific treatment modalities for RPS is insufficient, owing to its rarity. The Japanese clinical practice guidelines for RPS were published in December 2021, with the aim of accumulating existing evidence and indicating the optimal practice for RPS. These guidelines provide important clinical questions (CQs) concerning the diagnosis and treatment of RPS. This review, with a particular focus on primary RPS, attempts to introduce clinical problems in the diagnosis and treatment of RPS and to assess those problems along with the CQs in the guidelines. According to these guidelines, although chemotherapy and radiotherapy are expected to have therapeutic effects, the level of evidence to support these treatments is not very high at present. Accordingly, complete resection of the tumor is the first and only option for managing primary RPS. However, as with other tumors, the demand for multidisciplinary treatment for RPS is increasing. These guidelines will undoubtedly represent a milestone in clinical practice in relation to RPS in the future, and further evidence is expected to be accumulated based on the CQs that have been proposed.

The use of the flow-void sign on MRI: highly sensitive sign in detecting bone metastases from renal cell carcinoma.

To evaluate a range of pathologically proven malignant bone tumours, including primary bone sarcoma and metastatic bone lesions, referred to a tertiary referral centre for the presence of the flow-void sign on MR imaging. A retrospective search was performed using the radiology information system and oncology database in our institution to identify patients over the age of 40years referred with a solitary bone lesion. Patients with a range of pathologically proven malignant bone tumours, including primary bone tumours and metastatic bone lesions, were included in the study. MRI images were reviewed for the presence of the flow-void sign. The presence and type of the flow-void sign were correlated with lesion size. Two hundred and sixty-six cases were included in the study. Overall, the flow-void sign was identified in 40.9% of cases. The flow-void sign was most frequently seen in renal cell carcinoma metastasis (90.0%). The sign is highly sensitive (90%) for renal cell carcinoma metastases with a high negative predictive value (98.09%). When the flow-void sign is identified, the lesion is almost three times more likely to represent a renal cell carcinoma metastasis than any other malignant tumour in patients over the age of 40years with a solitary bone lesion. The flow-void sign is highly sensitive for renal cell carcinoma bone metastases and could negate the need for biopsy in patients with a known history of renal cell carcinoma or in whom an occult renal cell carcinoma is subsequently identified.

Synovial Sarcoma of the Gastrointestinal Tract

We report the clinicopathologic and immunohistochemical features of 18 cases of confirmed primary synovial sarcoma of the gastrointestinal tract. The neoplasms arose in 10 women and 8 men ranging in age from 23 to 81 years (mean: 50; median: 57.5 years). The tumors for which size was known ranged from 1.8 to 15.0 cm (mean: 5.2; median: 5.1 cm). Microscopically, 14 synovial sarcomas were of the monophasic type, 2 were biphasic, and 2 were poorly differentiated. Immunohistochemical analysis of 4 cases showed strong, diffuse staining for SS18::SSX (4/4 cases). Pancytokeratin and EMA immunohistochemistry were performed on 13 and 9 tumors, respectively, and each showed patchy-to-diffuse staining. By reverse-transcription PCR, 3 cases were positive for the SS18::SSX1, and 2 cases were positive for the SS18::SSX2 gene fusion. Six cases contained an SS18 gene rearrangement by fluorescence in situ hybridization, and next-generation sequencing identified an SS18::SSX2 gene fusion in one case. Clinical follow-up information was available for 9 patients (4 months to 4.6 years; mean, 2.8 y; median: 29 months), and one patient had a recent diagnosis. Three patients died of disease within 41 to 72 months (mean, 56 months) of their diagnosis. Five patients were alive without evidence of disease 4 to 52 months (mean, 17.6 months) after surgery; of whom 1 of the patients received additional chemotherapy treatment after surgery because of recurrence of the disease. A single patient was alive with intraabdominal recurrence 13 months after surgery. We conclude that synovial sarcoma of the gastrointestinal tract is an aggressive tumor, similar to its soft tissue counterpart, with adverse patient outcomes. It is important to distinguish it from morphologically similar gastrointestinal tract lesions that may have different treatment regimens and prognoses.

EPID-25. SIX CONSECUTIVE CASES OF PRIMARY INTRACRANIAL SARCOMA IN CHILDREN IN TWO PRIVATE INSTITUTIONS FROM LIMA DURING COVID-19 PANDEMIC

Abstract INTRODUCTION Peruvian health system was severely impacted by COVID-19 pandemic. Public hospitals were saturated by patients with COVID-19 rapidly. Many patients had to seek medical attention for other health conditions in private institutions. This situation was also observed in pediatric patients with brain tumors. The objective of the present study was to describe clinical and neuroimaging characteristics from pediatric patients diagnosed with brain tumors in two private institutions fron Lima-Peru during COVID-19 pandemic. METHODS Descriptive study of cases of brain tumor in patients aged less than 18 years observed in two private institutions from Lima-Peru from March 2020 to December 2021. RESULTS Six consecutive cases of intracranial tumors were detected during a large part of COVID-19 pandemic's first year (October 2020 to March 2021), all of them with diagnosis of primary intracranial sarcoma . Before the pandemic, the last primary intracranial sarcoma in children operated occurred in June 2018, and was the only case that year. CONCLUSION The present study found an unusual frequency of primary intracranial sarcoma in children in two private institutions from Lima-Peru during COVID-19 pandemic.

EPID-24. CAPTURING EVOLVING DEFINITIONS OF 12 SELECT RARE CNS TUMORS: A TIMELY REPORT FROM CBTRUS AND NCI-CONNECT

Abstract BACKGROUND Incidence, prevalence, and survival are population-based cancer statistics that describe cancer burden. The National Cancer Institute’s Comprehensive Oncology Network Evaluating Rare CNS Tumors (NCI-CONNECT) specializes in research of 12 rare CNS tumor types to improve approaches to care and treatment. These tumors include atypical teratoid/rhabdoid tumors, brainstem and midline glioma, choroid plexus tumors, ependymoma, high grade meningioma, gliomatosis cerebri, medulloblastoma, oligodendroglioma/anaplastic oligodendroglioma, pineal region tumors, pleomorphic xanthoastrocytoma, CNS embryonal tumors, not elsewhere classified (NEC)/not otherwise specified (NOS), and primary CNS sarcoma. This study aimed to update incidence, prevalence, and survival statistics for these tumors. METHODS The Central Brain Tumor Registry of the United States (CBTRUS) database, a combined dataset of CDC’s National Program of Cancer Registries (NPCR) and NCI’s Surveillance, Epidemiology and End RESULTS (SEER) data, was used to calculate average annual age-adjusted incidence rates (AAAIR) per 100,000 population overall and by sex, race-ethnicity, and age (2008-2019). NPCR data were used to calculate relative survival (RS) estimates (2008-2018). Prevalence on December 31, 2019 was estimated using annual age-specific incidence and survival from CBTRUS and SEER, respectively. RESULTS AAAIR was 1.51 per 100,000 for these tumors combined, with highest incidence in ependymomas (AAAIR=0.41/100,000). Most tumor types were more common in males, adults (ages 40+ years) or children ages &amp;lt; 15 years, and non-Hispanic White individuals. Ependymomas were most prevalent (19,339 cases) followed by oligodendrogliomas (15,070 cases). RS for all subtypes combined at 1-, 5-, and 10-years was 86.6%, 71.9%, and 65.3%, respectively. Ependymomas had the highest RS (5-years=90.6%) and primary CNS sarcomas had the lowest RS (5-years=7.7%). CONCLUSIONS Incidence, prevalence, and survival patterns for these 12 selected rare cancer subtypes varied significantly by type. Population-based data are critical to guiding effective design of and accrual expectations for clinical trials in rare cancers.

Long-Term Survival after Primary Ewing's Sarcoma of the Skull with Intracranial Extension.

Primary Ewing's sarcoma of the skull is a very rare malignant neoplasm, predominantly occurring in children and adolescents. We describe here the clinical, neuroradiologic, and histopathologic features of a patient with primary Ewing's sarcoma of the skull and discuss the standards of therapy for this type of tumor. This 18-year-old male patient presented with a primary Ewing's sarcoma of the skull, involving the dura of the frontal and parietal lobes of the left cerebral hemisphere. He was treated with gross total surgical excision of tumor, skull reconstruction, chemotherapy, and irradiation. Twelve years after the surgery, the patient has no evidence of local recurrence or distant metastases. Radical surgical excision of the primary tumor with safety margins is thought to play a role in the favorable clinical course. The presented case is the longest surviving patient after treatment of primary Ewing's sarcoma of the skull bone. This rare type of tumor may allow better survival rates under adequate management than sarcoma elsewhere in the body.