Rare Tumor Type Research Articles

Giant skull base periosteal chondroma treated with endonasal endoscopic surgery: illustrative case.

Intracranial chondroma is an extremely rare type of tumor composed of mature hyaline cartilaginous tissues. No previous cases of skull base periosteal chondroma have been presented. A 31-year-old male had progressive memory loss and diminished motivation for the previous 1.5 years. Magnetic resonance imaging revealed a giant tumor with partial calcification arising from the upper clivus and extending to the prepontine cistern. Compression of the brainstem and hypothalamus was significant. Surgery was performed and intentionally limited to an intracapsular resection with endoscopic endonasal surgery (EES), and the brainstem and hypothalamus were successfully decompressed. Pathological examination findings showed a composition of hyaline cartilage with chondrocyte clusters. Genetic testing with next-generation sequencing indicated alternations in IDH1 R132C, KDR Q472H, IDH2 I142L, and TP53 P72R. On the basis of these findings, a diagnosis of periosteal chondroma was made. Postoperatively, complete relief from all symptoms was noted, and MRI one year later showed no evidence of tumor regrowth. This is the first known report of skull base periosteal chondroma. Genetic testing was useful for confirming the diagnosis, and EES was effective for treatment. Should such a tumor show adhesion to an important structure, an intracapsular excision can be beneficial for avoiding complications.

Sinonasal Glomangiopericytoma with Skull Base Involvement: A Diagnostic Dilemma.

Introduction: Glomangiopericytoma (GPC) is a rare type of neoplasm with hemangiopericytoma-like vasculature and perivascular hyalinization of capillary-sized veins. CD34 and S100 protein staining might be positive in a small percentage of GPC. Solitary fibrous tumors (SFTs) present clinically like GPC. However, challenges remain when differentiating GPC from SFT. Case Presentation: A 37-year-old male, smoker, presented with 3 years history of right-sided epistaxis and nasal congestion. He was also complaining of hyposmia but no headaches or visual complaints. On nasal endoscopy, he was found to have a right-sided nasal mass occupying the ethmoid cavity. Computed tomography showed a right sinonasal mass abutting the anterior skull base and magnetic resonance imaging demonstrated a hyperintense, enhancing mass within the right ethmoid cavity, superior septum, and anterior skull base. The patient underwent endoscopic resection with gross total resection and skull base reconstruction. Postoperative pathology initially was thought to be an SFT; however, subsequent STAT6 expression was negative, and therefore GPC diagnosis was confirmed. At the most recent follow-up (6 months), the patient remained free of local disease. Discussion: SFT, unlike GPC, stains strongly for CD34, in this case, due to strong CD34, the diagnosis of SFT was initially made. Nuclear STAT6 expression is highly specific and sensitive for SFT. This later returned as negative; therefore, GPC was confirmed. Conclusion: We present a case of sinonasal GPC with skull base involvement that was treated with endoscopic resection. At the most recent follow-up (6 months), the patient remained free of local disease.

Epithelioid Hemangioma Masquerading as Traumatic Lesion: A Rare Case Report with Diagnostic Workup

Abstract Wells and Whemser first identified epithelioid hemangioma (EH) as angiolymphoid hyperplasia in 1969. It is a rare type of vascular tumor that primarily affects men in their middle ages. Typically, it appears as a single or few reddish-to-brown nodules. EHs of the oral cavity have only seldom been reported up to this point. Histologically, it is distinguished by lobular vessel configuration, tombstone-like epithelioid cells lining the vessel wall, and a persistent inflammatory infiltration predominately made up of eosinophils. Although the terms EH and epithelioid hemangioendothelioma are sometimes confused, the two are distinct based on histopathology and a number of immunohistochemistry (IHC) markers, including high Ki67 index and ERG positivity observed later. Local trauma to a nearby vessel may be one of the etiopathogeneses for this entity. This is a rare case report of EH that was identified with the use of a panel of IHC markers and hematoxylin and eosin histology.

Pathogenesis, diagnosis and treatment of primary renal well-differentiated neuroendocrine tumors: a review of the literature.

Neuroendocrine tumors (NETs) are a rare type of neoplasm that originate from neuroendocrine cells and peptide neurons. Primary renal well-differentiated NETs are extremely rare, and only a few cases have been reported worldwide. In this study, we present a new case of primary renal well-differentiated NET at our institution, followed by a literature review. A systematic search was conducted using various search terms to identify relevant literature on primary renal well-differentiated NETs from 2021 to present. The study analyzed the clinical features, age, gender, tumor size, location, gross pathology, light microscopy, and immunohistochemical results of 32 cases of primary renal well-differentiated NETs. The findings suggest that these tumors are rare and have nonspecific clinical and imaging features. The diagnosis heavily relies on immunohistochemical analysis. Primary renal well-differentiated NETs are associated with low malignant potential and a favorable prognosis. Surgical resection is the preferred treatment, and long-term follow-up is necessary to monitor the patient's condition.

Hemangioendothelioma: A Rare Entity at an Unusual Location

Abstract Epithelioid hemangioendothelioma (EHE) is a rare type of vascular tumor that behaves in a manner halfway between benign hemangiomas and malignant angiosarcomas. It is histologically distinguished by angiocentricity and solid, cord-like arrangements of epithelioid cells with intracytoplasmic lumina containing red blood cells. Although uncommon in childhood, it can develop at any age and affects both sexes equally. Accurate diagnosis may require further evaluation with tru-cut biopsy due to its potential for false-positive metastatic cancer diagnoses. Treatment approaches vary based on symptomatology, ranging from regular follow-ups for asymptomatic patients to surgical resection with embolization for symptomatic cases. With the help of this case, we want to discuss the importance of considering EHE in the differential diagnosis of vascular lesions and the significance of tailored treatment strategies based on individual patient characteristics.

Clinical Presentation, Approach and Outcome of Gliosarcoma: A Series of 12 Cases

Gliosarcoma (GSM) is a rare and aggressive type of brain tumour with limited treatment options and a poor prognosis. The present case series aimed to provide further insights into the clinical features, treatment outcomes, and prognosis of GSM. Medical records of 12 histologically confirmed cases of GSM were analysed from 2018 to 2022, revealing a male predominance and a median age of 54 years. The most common symptoms were headache and vomiting due to raised intracranial pressure. All patients underwent maximal safe resection followed by concurrent chemoradiation and adjuvant chemotherapy with Temozolomide (TMZ). KaplanMeier analysis showed a median Progression-free Survival (PFS) and overall survival of 8 and 12 months, respectively. The study revealed that the optimal treatment for primary GSM remains a therapeutic dilemma due to the rarity of the disease and the heterogeneity of the patient population and treatment regimens employed. The present study provides valuable insights into the clinical presentation and management of primary GSM in India and highlights the need for further research to improve outcomes for these patients.

Triple-Negative Breast Cancer: A Rare Tumor Type Presenting in Pregnancy-Case Report

Introduction: Breast Cancer diagnosis during pregnancy is a relatively rare event, affecting about 1 in 1,000 pregnancies and representing 0.1% or less of all cancers. However, when it occurs, it is found to be more aggressive with the worst prognosis during pregnancy. Most notable reasons include delayed diagnosis due to changes in breast parenchyma in pregnant and lactating women, and the higher incidence of the poor prognostic subtype (triple-negative) among premenopausal patients. Aim: We present a 28year old nullipara with triple-negative right breast cancer in the third trimester of pregnancy. Methodology: Description of a successfully managed breast cancer disease in pregnancy and the histological diagnosis.

Spindle cell rhabdomyosarcomas: With TFCP2 rearrangements, and novel EWSR1::ZBTB41 and PLOD2::RBM6 gene fusions. A study of five cases and review of theliterature.

Spindle-cell/sclerosing rhabdomyosarcomas (SS-RMS) are clinically and genetically heterogeneous. They include three well-defined molecular subtypes, of which those with EWSR1/FUS::TFCP2 rearrangements were described only recently. This study aimed to evaluate five new cases of SS-RMS and to perform a clinicopathological and statistical analysis of all TFCP2-rearranged SS-RMS described in the English literature to more comprehensively characterize this rare tumour type. Cases were retrospectively selected and studied by immunohistochemistry, fluorescence in situ hybridization with EWSR1/FUS and TFCP2 break-apart probes, next-generation sequencing (Archer FusionPlex Sarcoma kit and TruSight RNA Pan-Cancer Panel). The PubMed database was searched for relevant peer-reviewed English reports. Five cases of SS-RMS were found. Three cases were TFCP2 rearranged SS-RMS, having FUSex6::TFCP2ex2 gene fusion in two cases and triple gene fusion EWSR1ex5::TFCP2ex2, VAX2ex2::ALKex2 and VAX2intron2::ALKex2 in one case. Two cases showed rhabdomyoblastic differentiation and spindle-round cell/sclerosing morphology, but were characterized by novel genetic fusions including EWSR1ex8::ZBTB41ex7 and PLOD2ex8::RBM6ex7, respectively. In the statistical analysis of all published cases, CDKN2A or ALK alterations, the use of standard chemotherapy and age at presentation in the range of 18-24 years were negatively correlated to overall survival. EWSR1/FUS::TFCP2-rearranged SS-RMS is a rare rhabdomyosarcoma subtype, affecting predominantly young adults with average age at presentation 34 years (median 29.5 years; age range 7-86 years), with a predilection for craniofacial bones, rapid clinical course with frequent bone and lung metastases, and poor prognosis (3-year overall survival rate 28%).

Mutational Signature Changes in Patients With Metastatic Squamous Cell Carcinoma of the Anal Canal.

We examined the concordance of genetic mutations between pretreatment tumor tissue and posttreatment circulating tumor DNA (ctDNA) in patients with metastatic squamous cell carcinoma of the anal canal (SCCA) and assessed the impact of therapy on this concordance. We analyzed next-generation sequencing reports from pretreatment tumor tissue and posttreatment ctDNA in 11 patients with metastatic SCCA treated at Vanderbilt University Medical Center between 2017 and 2021. Among the mutations identified in posttreatment ctDNA, 34.5% were also found in pretreatment tumor tissue, while 47.6% of pretreatment tumor tissue mutations were found in posttreatment ctDNA. Four patients had preservation of potentially actionable mutations in both pretreatment tissue and posttreatment ctDNA, while 7 patients had newly identified mutations in posttreatment ctDNA that were not present in pretreatment tumor tissue. Patients with SCCA demonstrate a high degree of temporal mutational heterogeneity. This supports the hypothesis that ctDNA can serve as a real-time tracking mechanism for solid tumors' molecular evolution in response to therapy. Our findings highlight the potential of ctDNA in identifying emerging actionable mutations, supplementing information from tissue-based genomic assessments. Further research, ideally with larger and multi-institutional cohorts, is needed to validate our findings in this relatively rare tumor type.

High-grade HER2-positive mucoepidermoid carcinoma of the breast: a case report and review of the literature

BackgroundMucoepidermoid carcinoma of the breast is a rare special type of salivary gland-like tumor of the breast, usually displaying triple-negative phenotype. To date, only 64 cases have been reported in the English literature. Herein, we report the first case of mucoepidermoid carcinoma of the breast with human epidermal growth factor receptor 2 gene amplification.Case presentationA 58-year-old Caucasian woman treated with breast-conserving surgery, radiotherapy, and chemotherapy for an invasive breast carcinoma of no special type, relapsed 20 years later in the ipsilateral left breast. Histological examination of the core needle biopsy of the relapse deferred to the surgical specimen for the definitive diagnosis, because of the broad differential diagnosis. On the resected specimen we observed the presence of a poorly differentiated carcinoma with mucoepidermoid carcinoma of the breast typical features consisting of epidermoid, intermediate and mucinous cells lacking true keratinization, in keeping with the latest World Health Organization diagnostic criteria. The mucoepidermoid carcinoma of the breast was weakly estrogen receptor and androgen receptor positive and progesterone receptor negative, but exceptionally showed human epidermal growth factor receptor 2 gene amplification. Mastermind-like transcriptional coactivator 2 gene translocations were not detected by fluorescent in situ hybridization. The patient received adjuvant chemotherapy with anti-human epidermal growth factor receptor 2 therapy but no endocrine therapy. After 61 months of follow-up, no signs of local or distant recurrence were observed.ConclusionsMucoepidermoid carcinoma of the breast is a very rare entity. Despite being most frequently triple negative, the standard evaluation of receptor status is mandatory, as well as strict application of World Health Organization diagnostic criteria for correct patient management.

Diagnosis and treatment of intravenous leiomyomatosis

Intravenous leiomyomatosis is a rare type of tumor that is histologically benign but biologically invasive. It originates from the smooth muscle of the uterine or the uterine vein. It can grow through the uterus and extend into the pelvic cavity, or grow along the veins without invading the wall of the venous vessel itself. The tumors are estrogen-dependent and can metastasize through the bloodstream. Thus, in addition to continuous growth, some tumors exhibit isolated growths in the venous system and heart chambers or show disseminated growth in the lungs, although distant metastasis to other regions usually do not occur. Currently, there is limited research on this disease, the majority of which are case reports, surgical experience summaries, and differentiation from ordinary gynecological myomas in terms of pathogenesis and radiological diagnostic experience. There are two main theories on the origin of the disease: uterine smooth muscle and smooth muscle of the uterine veins. Some studies have verified the role of estrogen, progesterone receptor-related pathways, and angiogenesis in the development of the disease. The clinical symptoms of this disease are varied, depending on the affected area. In the early stages, when the tumor only affects the pelvic cavity, patients show mild symptoms resulting from pelvic organ compression. When it progresses to the inferior vena cava and heart, patients show more complex symptoms resulting from venous return obstruction, cardiac obstruction, and hemodynamics appearing. Different institutions have proposed different disease staging and classification strategies for different clinical purposes. Some are based on the affected area of the lesion; others are based on the size of the tumor. Although surgery remains the main treatment for this disease, the specific surgical approach, adjuvant drug therapy, and prognosis still need further exploration.

Ileocecal Intussusception of the Adult Induced by the Gastrointestinal Stromal Tumor of the Ileocecal Valve - A Case Report

Abstract Adult intussusception is a rare entity which is distinct frompaediatric cases in incidence, aetiology, and management. It represents 5% of all intussusceptions and is the cause of 1% of allintestinal obstructions, 0,08% of all abdominal surgeries and 0,003-0,02% of all hospital admissions. Ileocolic intussusceptionin adults is a unique variant in which nearly 100% of cases havea malignant lead point. In our report, we described a case of apatient with ileocecal intussusception caused by a rare type of the gastro intestinal tumor. The female patient was admitted to hospital for occasional pain in the lower right quadrant of the abdomen followed by abdominal discomfort and appearance of blood in thestool. The result of CT scan of the abdomen and pelvis showed atumor mass and intussusception at the ileocecal junction, whichwas confirmed peroperatively. Open right hemicolectomy wasperformed adhering to oncological principles. The final pathologic diagnosis indicated the gastrointestinal stromal tumor of theileocecal valvе. The diagnosis of intussusception in adults is delicate, and timely surgical treatment can be vital. Patients with thepalpable abdominal mass, digestive tract obstruction, gastroin-testinal bleeding, or lead point computed tomography must undergo a surgical examination. Given a high risk of malignancy,primary surgical resection using oncologic principles presents the best option for the treatment of ileocecal intussusception inadults.

Unusual Case of Primary Hepatic Squamous Carcinoma on 18F-FDG PET/CT.

Primary hepatic squamous carcinoma is an extremely rare liver tumor type with high malignancy and poor prognosis. We present 18F-FDG PET/CT findings of primary squamous carcinoma of the liver in a 65-year-old man, who was admitted to the hospital with subxiphoid pain in the epigastric region radiating to the left lower back for 2 months. 18F-FDG PET/CT demonstrated a large heterogeneous mild enhancing mass in the left lobe of the liver, with intense circumferential 18F-FDG activity.

Case Report: Remarkable breakthrough: successful treatment of a rare intracranial mesenchymal, FET::CREB fusion-positive tumor treated with patient-tailored multimodal therapy

BackgroundIntracranial mesenchymal tumors are a rare type of neoplasm (0.3% of all soft tissue tumors) characterized by a fusion of a FET family gene (usually EWSR1, rarely FUS) to CREB family genes (CREB1, ATF1, and CREM) with a slow-growing and favorable prognosis. Mesenchymal tumors are most frequently localized in the subcutaneous tissue (typically in the limbs and hands) of young adults and have rarely been diagnosed in the central nervous system. Surgery is the gold standard treatment; adjuvant radiation therapy and chemotherapy with sarcoma-based regimens have been used in rare cases when complete surgical excision was not recommended. In terms of prognosis, these tumors show a tendency for local relapse. The longest patient outcomes reported in the literature are five years.Case descriptionThis case describes a 27-year-old woman with unconventional extracranial metastatic sites of myxoid intracranial mesenchymal tumor FET::CREB fusion-positive and high expression of PD-1 (40%) and PD-L1 (30%). Based on clinical, molecular, and histological characteristics, she underwent various local and systemic therapies, including surgery, proton beam therapy, the use of immune checkpoint inhibitors, and chemotherapy. These treatments led to a complete remission of the disease after eight years from tumor diagnosis.ConclusionsOur case sheds light on the importance of precision medicine and tailored therapy to explore new treatment opportunities for rare or unknown tumor entities.

Bilateral Gonadoblastoma in a 13-Year-Old Female with Turner Syndrome and Y Chromosome: A Case Report

Abstract Introduction/Objective Gonadoblastoma is a relatively rare type of ovarian tumor that has a high risk for patients with 45X/46XY. It is derived from the Y chromosome at its long arm GBY region, which contains the most likely candidate gene called testis-specific protein Y-encoded (TSPY). Methods/Case Report In this case report, we present a case of a 13-year-old girl with Turner syndrome whose cytogenetic test showed 45X with monosomy X and a siodicentric Yq chromosome. As she carried a high risk for the development of gonadoblastoma due to the presence of the Y chromosome and clinically had premature ovarian failure, she received further imaging studies, which did not reveal obvious ovarian masses. She underwent resections of bilateral fallopian tubes and ovaries. Bilateral fallopian tubes were unremarkable. However, within the bilateral ovarian tissue, foci of gonadoblastoma were found (0.5 to 0.6 cm), composed of large round germ cells (confirmed by positive OCT 3/4 and SALL4 stains) intermingled with oval-shaped sex cord-stromal cells forming tubular/cribriform structures (confirmed by positive staining for inhibin, calretinin, and FOXL2). The stromal cells of gonadoblastoma, but not germ cells, were positive for androgen receptor staining, while both components were negative for estrogen receptor staining. No invasive germ cell tumor or sex cord tumor was present. Results (if a Case Study enter NA) N/A Conclusion The positive androgen receptor staining in stromal cells of the gonadoblastoma supports the view that the Y chromosome-driven androgen system may play a role in the development of gonadoblastoma in a bi-cellular pattern.

Rapidly growing massive abdominal sarcomatoid carcinoma on F18-FDG PET-CT scan

Sarcomatoid carcinoma is a rare type of tumour and most commonly arises in the lungs. However, rarely can it also be found in the abdomen. Sarcomatoid tumours are aggressive with large tumoural volume showing cancerous epithelial cells mixed with sarcomatous (nerve, muscle, fat etc.) features on histopathology. Most of the carcinosarcomas arise in the background of pleomorphic adenoma, originating from a myoepithelial precursor. These tumours are resistant to treatment and rapidly metastasize. We present a unique case of hepatocellular sarcomatoid sarcoma, evaluated through F18-FDG PET/CT. Keywords: Sarcomatoid sarcoma, 18F FDG PET-CT, massive abdominal mass.

High Efficacy and Safety of Nanobody Based Anti-BCMA CAR-T Cell Therapy in Treating Patients with Relapsed or Refractory Multiple Myeloma

Introduction Refractory or relapsed (R/R) multiple myeloma (MM) is often associated with a poor prognosis following chemotherapy or even transplantation. BCMA-targeted CAR-T therapy has demonstrated notable efficacy in R/R MM. In the past, the overall response rate (ORR) was relatively low at around 60%, but in recent years, advancements in the manufacturing of BCMA-CAR-T products have led to a substantial improvement in efficacy. Here we explore the efficacy and safety of nanobody-based anti-BCMA CAR-T cell therapy in R/R MM from a clinical trial (https://clinicaltrials.gov NCT04447573). Methods Autologous peripheral blood lymphocytes were collected from patients, who subsequently underwent intravenous fludarabine (30mg/m 2/d) and cyclophosphamide (300mg/m 2/d) lymphodepletion chemotherapy from day-5 to day -3. The SL-BCMA CAR molecule, an anti-BCMA CAR-T cell product generated by Senlang Biotechnology, features a structure that includes dual nanobody VHHs targeting BCMA (dVHHs), CD8α hinge region, CD8α transmembrane domain (TMD), co-stimulatory domain (4-1BB), and CD3 zeta domain (CD3ζ). Among them, dVHHs consist of two different VHHs connected by short peptides. The CD8α hinge region provides an effective spatial architecture for the binding of dVHHs and BCMA protein. The first signal of CAR-T cell activation is completed along with the intracellular CD3ζ domain. The 4-1BB intracellular co-stimulatory domain provides co-stimulatory signals for the activation of CAR-T cells. Under the dual signal stimulation, CAR-T cells are activated and expanded. After the BCMA CAR-T cells infusion on day 0, patients underwent evaluations, including immunoglobulin fixed electrophoresis, free light chains in blood and urine, bone marrow penetration, and whole-body PET CT to evaluate the efficacy at the first month, second and third month, and every three months thereafter. Results From April 2021 to May 2023, 21 R/R MM patients in our hospital were treated with SL-BCMA CAR-T, including 10 males and 11 females. The median age is 57 years (30-73 years). Among them, there were 2 cases with Plasma cell leukemia, 10 had extramedullary multiple lesions, and 2 had paralysis caused by central nervous system infiltration. Pre-CAR-T, 11 patients had a prior transplant history including 10 who relapsed after autologous transplantation and 1 who relapsed after allogeneic transplantation. One patient had a rare type of anaplastic Plasma cell tumor. Seven patients presented high-risk factors characterized by FISH abnormalities such as t (4; 14) (p16; q32), t (14; 16) (q32; q23), and 3 had TP53 mutations. The median BCMA expression rate among 19 patients was 53.3% (range: 18.5% -100%), while the remaining 2 patients displayed non-BCMA expression. The median BCMA CAR-T cell dose was 1*10 6/Kg (0.3-2*10 6/Kg). One month following BCMA-CAR-T cell infusion, the ORR was 95%(20/21), and the CR rate was 38% (8/21). The patient who initially showed no response achieved a partial response following a second infusion of BCMA-CAR-T cells. One died at about 2.5 months due to lung infection. Evaluations conducted at the three-month mark showed an ORR of 95% (19/20) and a CR rate of 80% (16/20). One patient relapsed at the second month and underwent salvage allogeneic hematopoietic stem cell transplantation. For the long follow-up data, the median duration of remission was 11 months. Of the 7 deaths, 2 were attributed to infection during disease control, and 5 were due to disease progression. (Figure 1) In terms of side effects, 6 patients developed grade 2 cytokine release syndrome (CRS), and only 1 patient developed grade 3 CRS. Only one patient had grade 1 neurotoxicity. Conclusions The clinical trial demonstrated that BCMA CAR-T therapy, composed of dual nanobody VHHs targeting BCMA (dVHHs), exhibits a high ORR with a manageable safety profile in treating R/R MM patients. This extends even to high-risk patients, such as those with extramedullary lesions, cytogenetics high-risk groups, and patients with plasma cell leukemia or anaplastic plasma cell tumor.

Immunotherapy in SMARCB1 (INI-1)-deficient sinonasal carcinoma: Two case reports

BACKGROUND SMARCB1/INI-1 deficient sinonasal carcinoma (SDSC) is a rare subset of sinonasal undifferentiated carcinoma with a poor prognosis. Here, we present two case reports of SDSC patients. We also review the literature on this tumor. This is the first published report of SDSC treatment with immunotherapy. CASE SUMMARY Here we present two patient cases of SDSC in which initial consultation and diagnosis were complicated but SDSC was ultimately diagnosed. One patient received a traditional treatment of surgery and adjuvant chemoradiotherapy, while the other patient received additional immunotherapy; the prognoses of these two patients differed. We review previous diagnostic literature reports and SDSC treatments and provide a unique perspective on this rare type of tumor. CONCLUSION SDSC is a rare, diagnostically challenging carcinoma with a consistently poor prognosis, early distant metastases, and frequent recurrence. Timely diagnosis and intervention are critical for treatment, for which the standard of care is surgery followed by adjuvant chemoradiotherapy, though immunotherapy may be an effective new treatment for SDSC.

Clinical significance of PDGFRβ gene testing in hematological tumors

To explore the clinical and laboratory characteristics of hematological tumors with different types of abnormalities in platelet derived growth factor β (PDGFRβ) gene. A retrospective analysis was carried out on 141 patients with abnormal long arm of chromosome 5 (5q) and comprehensive medical history data from Changhai Hospital Affiliated to Naval Medical University from 2009 to 2020, and their clinical data were collected. R-banding technique was used for chromosomal karyotyping analysis for the patient's bone marrow, and fluorescence in situ hybridization (FISH) was used to detect the PDGFRβ gene. The results of detection were divided into the amplification group, deletion group, and translocation group based on FISH signals. The three sets of data column crosstabs were statistically analyzed, and if the sample size was n >= 40 and the expected frequency T for each cell was >= 5, a Pearson test was used to compare the three groups of data. If N < 40 and any of the expected frequency T for each cell was < 5, a Fisher's exact test is used. Should there be a difference in the comparison results between the three sets of data, a Bonferroni method was further used to compare the data. In total 98 patients were detected to have PDGFRβ gene abnormalities with the PDGFRβ probe, which yielded a detection rate of 69.50% (98/141). Among these, 38 cases (38.78%) had PDGFRβ gene amplifications, 57 cases (58.16%) had deletions, and 3 (3.06%) had translocations. Among the 98 cases, 93 were found to have complex karyotypes, including 37 cases from the amplification group (97.37%, 37/38), 55 cases from the deletion group (96.49%, 55/57), and 1 case from the translocation group (33.33%, 1/3). Analysis of three sets of clinical data showed no significant gender preponderance in the groups (P > 0.05). The PDGFRβ deletion group was mainly associated with myeloid tumors, such as acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) (P < 0.001). The PDGFRβ amplification group was more common in lymphoid tumors, such as multiple myeloma (MM) (P < 0.001). The PDGFRβ translocation group was also more common in myelodysplastic/myeloproliferative tumors (MDS/MPN). Tumors with PDGFRβ gene rearrangement may exhibit excessive proliferation of myeloproliferative tumors (MPN) and pathological hematopoietic changes in the MDS, and have typical clinical and hematological characteristics. As a relatively rare type of hematological tumor, in addition to previously described myeloid tumors such as MPN or MDS/MPN, it may also cover lymphoid/plasma cell tumors such as multiple myeloma and non-Hodgkin's lymphoma.

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.