Conservative treatment in uterine perivascular epithelioid cell tumor of uncertain malignant potential: a case report.

INTRODUCTION: Perivascular epithelioid cell tumors are uncommon mesenchymal tumors. The genital tract is the most common extrarenal location. Preoperative diagnosis is rarely achieved owing to non-specific symptoms and imaging features. Consensus on treatment strategies remains elusive. Case presentation We report the case a 38 year-old north African woman with a primary sterility, who was diagnosed with a uterine Perivascular epithelioid cell tumor of uncertain malignant potential on a resection specimen of an intracavity polypoid mass. Immunohistochemistry confirmed the diagnosis and we opted for conservative surgery to preserve the patient's fertility desires. CONCLUSION: Uterine perivascular epithelioid cell tumor is a rare entity that warrants consideration in the differential diagnosis of uterine tumors. Treatment modalities, follow-up protocols, and prognosis remain ambiguous. Given their unpredictable behavior, accurate diagnosis and long-term monitoring are imperative.

Gastrointestinal Stromal Tumor (GIST) Masquerading as a Pancreatic Pseudocyst: A Rare Case Report.

Despite their relative rarity, gastrointestinal stromal tumors (GIST) are the most common type of mesenchymal tumor in the gastrointestinal (GI) tract. Here, we describe a rare case of a 62-year-old hypertensive female presenting with abdominal pain and a palpable mass, initially suspected to be a pancreatic pseudocyst based on radiological findings. Subsequent histopathological (HPE) examination following surgical resection revealed a large cystic lesion originating from the stomach, characterized as a malignant epithelioid GIST. Based on these findings and taking into consideration the symptomatology of the patient, the decision was made to post the patient for an upfront, open surgical exploration without pre-operative biopsy studies. Frozen section facilities were kept on standby considering the differential diagnosis. Since the frozen section revealed a gastric GIST, a decision was made to perform subtotal gastrectomy, followed by gastrojejunostomy (GJ) and jejunojejunostomy (JJ). In addition, the part of the cyst adherent to the left lobe of the liver was dealt with with a non-anatomical wedge resection. Immunohistochemical (IHC) analysis showed positivity for Cluster of Differentiation 117 (CD117) with negativity for Cluster of Differentiation 34 (CD34), Desmin, and Discovered On Gastrointestinal Stromal Tumors 1 (DOG-1). The tumor exhibited aggressive features, including high mitotic activity, i.e., >5/10 high power field (hpf), hemorrhagic areas, and infiltration into the liver parenchyma. The patient then received adjuvant imatinib-based chemotherapy and was maintained on strict follow-up.

Case report: Solitary fibrous tumor of the paracervical uterus combined with vaginal wall adenocarcinoma.

Background: Solitary fibrous tumors are rare mesenchymal tumors that typically occur in the pleura. Solitary fibrous tumors of the uterine cervix are uncommon. We report the first case of a patient who underwent total hysterectomy for vaginal wall adenocarcinoma and was found to have a concurrent solitary fibrous tumor in the paracervical-uterus. Case presentation: A 51-year-old woman was admitted to our hospital due to contact bleeding. A gynecological examination revealed nodules of 3.0 × 1.0 cm on the vaginal wall, and a colposcopy with biopsy revealed adenocarcinoma of the vaginal wall. After the recommended staging examinations, the patient underwent total hysterectomy, double adnexectomy, pelvic lymph node dissection, and vaginal wall resection. During surgery, a nodule measuring approximately 2 × 2 cm was found in the middle of the mass in the left paracervical region. Subsequent postoperative histopathological examination confirmed an solitary fibrous tumor of the uterine cervix with adenocarcinoma of the vaginal wall. The patient was followed up for 46 months after hospitalization, and no recurrence or distant metastases were observed. Conclusion: In rare cases, solitary fibrous tumors may form large masses in the cervical or vaginal wall. They can easily be misdiagnosed as benign or malignant cervical tumors before and during surgery. Postoperative pathology and immunohistochemistry are helpful for diagnosis. Most solitary fibrous cervical tumors are benign, occasionally with low malignant potential, and surgical treatment is feasible and effective.

A Gastrointestinal Stromal Tumor (GIST) and a Pseudocyst of the Pancreas: A Peculiar Case of Both Co-existing in the Same Patient.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal (GI) tract, typically originating from the interstitial cells of Cajal. The clinical presentations are variable according to their size and shape but rarely present as a palpable abdominal mass. Pancreatic pseudocysts are common complications of chronic pancreatitis characterized by fluid collections surrounded by a non-epithelialized wall of fibrous and granulation tissue. Patients may present with non-specific symptoms like abdominal pain, nausea, and vomiting and they generally have a history of acute pancreatitis. Small pseudocysts often resolve spontaneously, but larger ones often become symptomatic and may lead to complications. It is rare to find both a GIST of the stomach and a pseudocyst of the pancreas in the same patient. We present a unique case of a giant GIST and a pancreatic pseudocyst in a 72-year-old male who was experiencing abdominal pain and distension. Imaging revealed a massive lesion originating from the posterior gastric wall, which resembled a pseudocyst, along with a distinct cystic lesion adjacent to the pancreatic body. During surgical exploration, a complex interplay of both pathologies was discovered, requiring a comprehensive resection approach. The successful outcome highlights the importance of careful evaluation and personalized management in such rare cases.

Desmoid Tumor of the Rectus Abdominis Muscle: A Case Report.

Desmoid tumors, also referred to as aggressive fibromatosis, represent an uncommon form of fibroblastic proliferation. These neoplasms may arise within any musculoaponeurotic structure throughout the body. They are classified as benign due to several distinctive features: histologically, they exhibit regular mitotic activity and are devoid of metastatic potential. Computed tomography (CT) remains the definitive modality for precise diagnosis, and surgical excision is strongly advised. This account details the manifestation of a desmoid tumor located in the anterior abdominal wall of a 31-year-old female patient who notably lacks any prior surgical interventions. The surgical intervention entailed the excision of the neoplasm and subsequent reconstruction of the abdominal wall utilizing a polypropylene mesh. Postoperatively, the patient was released from the medical facility after a period of three days, having experienced no post-surgical complications. This was followed by a six-month interval free of any adverse events.

A Giant Malignant Solitary Fibrous Tumor of the Pancreas: A Case Report and Review of the Literature.

We present a case report of a giant solitary fibrous tumor (SFT) with a review of the literature and discuss its biological features and diagnosis. A 43-year-old man presented to our emergency department with abdominal pain and distension with an evolution of two days. Contrast-enhanced computed tomography (CT) showed a large, well-circumscribed semisolid mass (12 cm x 10 cm x 12 cm) localized in the pancreatic head. The histological diagnosis obtained by endoscopic ultrasound-guided trans-duodenal tumor biopsy with fine-needle aspiration showed proliferating short spindle-shaped cells, suggesting a mesenchymal neoplasia of low grade. We proceeded to a Whipple surgical technique. The histopathological study of the resected tumor confirmed proliferating spindle-shaped cells in the tissue, and one mitotic figure was observed in 10 high-power fields (HPFs). Immunostaining was positive for CD34 and STAT-6. The histological diagnosis was a malignant pancreatic SFT. In the six months posterior to the surgical procedure, the patient has been free of recurrent disease. Preoperative diagnosis is difficult and requires comprehensive evidence including clinical, immunohistochemistry, and histological features. Since there are currently no recognized best practices, we advise total surgical excision and careful clinical monitoring.

Spindle Cell Lesions with Oncogenic EGFR Kinase Domain Aberrations: Expanding the Spectrum of Protein Kinase-Related Mesenchymal Tumors.

EGFR aberrations are reported in a subset of myofibroblastic lesions with kinase domain duplication (EGFR-KDD) and exon 20 mutations being assigned to infantile fibrosarcomas (IFS), mesoblastic nephroma, and fibrous hamartoma of infancy (FHI), respectively. In this retrospective study, we correlated molecular findings with the histomorphology of 14 myofibroblastic lesions harboring such genetic changes identified by NGS. We additionally performed DNA methylation profiling (DNAmp) and immunohistochemistry. Lesions were from 10 males and 4 females with a mean age of 3 years (range, 0.3-14) and occurred subcutaneously in the upper limbs (n = 5), lower limbs (n = 3), back/thorax (n = 5), and the nasal cavity (n = 1). Eleven were cured by surgery, including 1 relapsed case. Two patients were lost to follow-up. One case was very recent, and the patient was biopsied. Histologically, the lesions showed a wide spectrum varying from classic FHI (n = 9) to IFS (n = 1) or lipofibromatosis-like tumors (LFT-like) (n = 2) or dermatofibrosarcoma protuberans-like (DFSP-like) (n = 1) to a predominantly myxoid spindle cell lesion (n = 1). Immunohistochemically, all neoplasms stained with CD34, whereas S100 was positive in 2/14. EGFR expression was observed in 9/10 cases. Molecularly, the IFS and 1 LFT-like harbored EGFR-KDD, whereas an exon 20 mutation was identified in all FHI, 1 LFT-like, the DFSP-like, and in predominant myxoid spindle cell lesion. By DNAmp, all but 2 cases formed a well-defined cluster, demonstrating that these lesions are also epigenetically related. In conclusion, EGFR kinase domain aberrations found in FHI, IFS, LFT-like, DFSP-like, and a spindle cell lesion with a predominant myxoid stroma of children and adolescents showed that these neoplasms with a broad morphologic spectrum belong to the group of protein kinase-related lesions with a distinct epigenetic signature. Molecular analyses, including DNAmp, help to identify and characterize this emerging category and become mandatory when targeted treatment is considered.

18F-AlF-NOTA-octreotide PET/CT in the localization of tumor-induced osteomalacia: case series and literature review.

Introduction: This study explores tumor-induced osteomalacia (TIO) through a case series and literature review, assessing the diagnostic potential of 18F-AlF-NOTA-octreotide (18F-OC) positron emission tomography/computed tomography (PET/CT). Methods: We analyzed TIO patients who underwent 18F-OC PET/CT. Parameters such as tumor dimension, the maximum standardized uptake value (SUVmax), the mean standardized uptake value (SUVmean) and metabolic tumor volume (MTV) were meticulously assessed. Clinical features and imaging characteristics pertinent to TIO were reviewed. Results: 6 patients with clinical suspicion of TIO exhibited hypophosphatemia (0.25 to 0.64 mmol/L), elevated alkaline phosphatase (ALP) levels (142 to 506 U/L), and increased parathyroid hormone (PTH) levels (92.9 to 281.7 pg/mL). Of these patients, two underwent FGF-23 testing, with results of 3185.00 pg/ml and 17.56 pg/ml, respectively. Conventional imaging modalities depicted widespread osteoporosis, with several cases demonstrating fractures indicative of osteomalacic and associated pathological fractures. Subsequent 18F-OC PET/CT facilitated the accurate localization of causative tumors, with histopathological examination confirming the diagnosis of phosphaturic mesenchymal tumor (PMT). The interval from initial clinical presentation to definitive TIO diagnosis spanned approximately 2.5 years (range: 1 - 4 years), with tumors varying in size (maximum diameter: 7.8 to 40.0 mm), SUVmax (5.47 to 25.69), SUVmean (3.43 to 7.26), and MTV (1.27 to 18.59 cm3). Conclusion: The implementation of whole-body 18F-OC PET/CT imaging emerges as a critical tool in the identification of occult tumors causing TIO. Future investigations incorporating a broader cohort are imperative to further delineate the diagnostic and therapeutic implications of 18F-OC PET/CT in managing TIO.

From Black Stools to Gastrointestinal Stromal Tumor (GIST): A Case Report and Literature Review on This Unsuspected Danger.

This case report presents the clinical details of a 42-year-old female without previous medical issues who presented with upper gastrointestinal bleeding (UGIB) characterized by melanotic stools. Initial examination revealed mild anemia and subsequent endoscopy identified a 4 cm submucosal gastric mass displaying recent bleeding indicators. Subsequent surgical pathology confirmed a high-grade gastrointestinal stromal tumor (GIST) of grade 2 with a heightened risk of recurrence. The significance of this case lies in underscoring the necessity of considering GIST in the differential diagnosis of UGIB, particularly among middle-aged individuals with no identifiable risk factors such as recent or chronic non-steroidal anti-inflammatory drug (NSAID) use, peptic ulcer disease, or alarm symptoms. Early detection and prompt surgical intervention assume paramount importance in enhancing patient outcomes. While complete resection stands as the cornerstone of treatment, adjuvant imatinib therapy is recommended for high-risk patients to mitigate the risk of recurrence.

Emerging Role of Gallium-68 DOTANOC PET/CT Guided Radiofrequency Ablation in the Treatment of Tumor-induced Osteomalacia.

Tumor-induced osteomalacia (TIO) is a rare acquired form of hypophosphatemia that can be cured when the tumor responsible is completely removed. These tumors can be small and located in anatomically challenging areas, rendering surgery both risky and extensive. Radiofrequency ablation (RFA) has been explored as an effective treatment option for such tumors. We present a case of a 35-year-old man exhibiting clinical and biochemical features consistent with TIO. The culprit lesion was not detectable on the whole-body computed tomography (CT) scan. Gallium (Ga-68) DOTANOC positron emission tomography (PET)/CT showed increased uptake in the left acetabulum and magnetic resonance imaging (MRI) confirmed the location of the tumor. Given the risky anatomical location, we opted for less-invasive RFA. Following an unsuccessful attempt at CT-guided RFA of the lesion, we used real-time Ga-68 DOTANOC PET/CT guidance for precise imaging during the ablation procedure. Our patient achieved complete remission both clinically and biochemically after RFA. This response was also evident by the absence of tracer uptake in follow-up imaging. In conclusion, DOTANOC PET/CT-guided RFA can serve as a safe and effective treatment for patients with tumors causing TIO. This modality proves valuable when surgical resection is not a viable option.

Intracranial Phosphaturic Mesenchymal Tumors: A Systematic Literature Review of a Rare Entity.

BACKGROUND: Phosphaturic Mesenchymal Tumors (PMTs) are rare mesenchymal neoplasms known for producing Tumor-induced Osteomalacia (TIO). TIO is an uncommon paraneoplastic syndrome characterized by radiographic evidence of inadequate bone mineralization and analytical abnormalites. METHODS: We sought to present a case of TIO caused by skull base PMT with intracranial extension, manifesting with pain, progressive weakness, and multiple bone fractures. Furthermore, a systematic review was performed, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A search was conducted in PubMed database with title/abstract keywords "Phosphaturic mesenchymal tumor" and "Osteomalacia." Search results were reviewed looking for intracranial or skull base tumors. RESULTS: Our systematic review included 29 reported cases of intracranial PMT. In the reviewed cases there was a significative female predominance with 22 cases (75,86%). Osteomalacia was presented in 25 cases (86,20%). Bone fractures were present in 10 cases (34,48%). The most common site of involvement was the anterior cranial fossa in 14 cases (48,27%). Surgery was performed in 27 cases (93,10%) with previous tumor embolization in 4 cases (13,79%). Total recovery of the presenting symptoms in the first year was achieved in 21 cases (72,41%). Recurrence of the disease was described in 6 cases (25%). CONCLUSIONS: Skull base PMTs with intracranial extension are extremely rare tumors. Most patients are middle-aged adults with a PMT predominantly located in anterior cranial fossa. Surgery is the current treatment of choice with optimal outcome at 1-year follow-up, although recurrence could be present in almost 25% of the cases.

Incidental finding of an angiomyxoma of the urinary bladder: A case report of a rare but aggressive tumour.

Angiomyxoma is a rare mesenchymal tumor arising in the pelvic and perineal regions. Diagnosis of urinary bladder angiomyxoma is difficult, as it lacks typical signs and symptoms, and relies on immunochemistry. We present the case of a 53 year old patient presenting with an incidental finding of bladder tumor during an ultrasound. After a complete transurethral resection was performed, the pathology report led to angiomyxoma diagnosis. After 6 weeks a secondary TURB, along with a CT urogram showed no evidence of residual volume. Transurethral resection seems to be a safe and effective treatment of urinary bladder angiomyxoma.

KIT-SNAP-tag/cell membrane chromatography model coupled with liquid chromatography-mass spectrometry for anti-GIST compound screening from Evodia rutaecarpa.

Gastrointestinal mesenchymal tumors, as the most common mesenchymal tumors in the gastrointestinal tract, are adjuvantly treated with multi-targeted tyrosine kinase inhibitors, such as imatinib and sunitinib, but there are problems of drug resistance and complex methods of monitoring therapeutic agents. The pathogenesis of this disease is related to mutations in tyrosine kinase (KIT) or platelet-derived growth factor receptor α, an important target for drug therapy. In recent years, the screening of relevant tyrosine kinase inhibitors from traditional Chinese medicine has become a hotspot in antitumor drug research. In the current study, the KIT-SNAP-tag cell membrane chromatography (KIT-SNAP-tag/CMC) column was prepared with satisfying specificity, selectivity, and reproducibility by chemically bonding high KIT expression cell membranes to the silica gel surface using the SNAP-tag technology. The KIT-SNAP-tag/CMC-HPLC-MS two-dimensional coupling system was investigated using the positive drug imatinib, and the results showed that the system was a reliable model for screening potential antitumor compounds from complex systems. This system screened and identified three potential active compounds of evodiamine (EVO), rutaecarpin (RUT), and dehydroevodiamine (DEVO), which possibly target the KIT receptor, from the alcoholic extract of the traditional Chinese medicine Evodia rutaecarpa. Then, the KD values of the interaction of EVO, RUT, and DEVO with KIT receptors measured using nonlinear chromatography were 7.75 (±4.93) × 10-6, 1.42 (±0.71) × 10-6, and 2.34 (±1.86) × 10-6 mol/L, respectively. In addition, the methyl thiazolyl tetrazolium assay validated the active effects of EVO and RUT in inhibiting the proliferation of high KIT-expressing cells in the ranges of 0.1-10 µmol/L and 0.1-50 µmol/L, respectively. In conclusion, the KIT-SNAP-tag/CMC could be a reliable model for screening antitumor components from complex systems.

Clinical Characteristics of Malignant Phosphaturic Mesenchymal Tumor Causing Tumor-Induced Osteomalacia.

CONTEXT: Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome usually caused by oversecretion of fibroblast growth factor 23 (FGF23) from a phosphaturic mesenchymal tumor (PMT). PMTs are usually benign neoplasms but some of them show malignant characteristics. OBJECTIVE: The aim of this study was to compare the clinical characteristics of benign and malignant PMTs inducing TIO. METHODS: On March 31, 2023, we performed a systematic review of individual patient data analysis in Medline, Google Scholar, Google book, and Cochrane Library using the terms "tumor induced osteomalacia," "oncogenic osteomalacia," "hypophosphatemia," with no language restrictions and according to Preferred Reporting Items for Systematic reviews and Meta-Analyses criteria. RESULTS: Overall, we collected data from 837 patients with TIO in which the diagnosis of benign and malignant PMT was specified. Of them, 89 were affected by malignant PMT and 748 by benign PMT. Patients with malignant PMTs were younger and presented bone pain, functional impairment, and bone deformities more frequently. Malignant PMTs showed higher values of intact FGF23 and a higher mortality rate. CONCLUSION: The study results identify the clinical characteristics of patients with malignant TIO, permitting the early identification of patients with PMT at increased risk of malignancy. This may significantly improve the diagnostic approach to disease. Further experimental studies are mandatory to clarify the role of FGF23 in the pathogenesis of malignancy in PMTs.

Clinical Significance of SOX10 Expression in Human Pathology.

The embryonic development of neural crest cells and subsequent tissue differentiation are intricately regulated by specific transcription factors. Among these, SOX10, a member of the SOX gene family, stands out. Located on chromosome 22q13, the SOX10 gene encodes a transcription factor crucial for the differentiation, migration, and maintenance of tissues derived from neural crest cells. It plays a pivotal role in developing various tissues, including the central and peripheral nervous systems, melanocytes, chondrocytes, and odontoblasts. Mutations in SOX10 have been associated with congenital disorders such as Waardenburg-Shah Syndrome, PCWH syndrome, and Kallman syndrome, underscoring its clinical significance. Furthermore, SOX10 is implicated in neural and neuroectodermal tumors, such as melanoma, malignant peripheral nerve sheath tumors (MPNSTs), and schwannomas, influencing processes like proliferation, migration, and differentiation. In mesenchymal tumors, SOX10 expression serves as a valuable marker for distinguishing between different tumor types. Additionally, SOX10 has been identified in various epithelial neoplasms, including breast, ovarian, salivary gland, nasopharyngeal, and bladder cancers, presenting itself as a potential diagnostic and prognostic marker. However, despite these associations, further research is imperative to elucidate its precise role in these malignancies.

Cytopathology of mesenchymal tumors of the thyroid gland: analysis of 12 cases from multinational institutions with review of the literature.

INTRODUCTION: Mesenchymal tumors of the thyroid gland are extremely rare. We report the cytomorphologic characteristics of 12 mesenchymal tumors occurring in the thyroid gland and highlight the diagnostic difficulties encountered in their cytologic evaluation. MATERIALS AND METHODS: The cytopathology and surgical pathology archives from 5 large institutions were searched for thyroid mesenchymal tumors that had an FNA available for review. Clinicopathologic and cytomorphologic characteristics for each case were evaluated. RESULTS: Twelve cases of mesenchymal tumors occurring in the thyroid were identified in our search. Patient age ranged from 28 to 84 years (median, 60 years). The cases occurred in 7 women and 5 men. The tumor size ranged from 1.4 to 14 cm (median, 3.3 cm). The tumors were as follows: hemangioma (n = 4; 33.3%), angiosarcoma (n = 2; 16.7%), schwannoma (n = 2; 16.7%), solitary fibrous tumor (n = 2, 16.7%), metastatic synovial sarcoma (n = 1, 8.3%) and metastatic pleomorphic rhabdomyosarcoma (n = 1, 8.3%). The cytomorphologic features of the tumors were similar to those of their counterparts occurring in different sites. An accurate diagnosis was achieved in six primary thyroid mesenchymal cases (60%). Five patients (41.7%) underwent total thyroidectomy, and 3 patients received partial thyroidectomy (25%). Three patients (25%) did not receive a thyroidectomy and subsequent surgical information was not available in 1 case (8.3%). CONCLUSIONS: Mesenchymal tumors of the thyroid are extremely uncommon. Cytologic diagnosis of these tumors is often challenging due to the morphologic overlap with diverse epithelial and non-epithelial thyroid lesions. Ancillary studies such as immunohistochemistry and molecular studies are essential for accurate diagnosis.

Surgical management of craniospinal axis malignant peripheral nerve sheath tumors: a single-institution experience and literature review.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is an exceedingly rare and aggressive tumor, with limited literature on its management. Herein, we present our series of surgically managed craniospinal MPNSTs, analyze their outcomes, and review the literature. METHODS: We retrospectively reviewed surgically managed primary craniospinal MPNSTs treated at our institution between January 2005 and May 2023. Patient demographics, tumor features, and treatment outcomes were assessed. Neurological function was quantified using the Frankel grade and Karnofsky performance scores. Descriptive statistics, rank-sum tests, and Kaplan-Meier survival analyses were performed. RESULTS: Eight patients satisfied the inclusion criteria (4 male, 4 female). The median age at presentation was 38 years (range 15-67). Most tumors were localized to the spine (75%), and 3 patients had neurofibromatosis type 1. The most common presenting symptoms were paresthesia (50%) and visual changes (13%). The median tumor size was 3 cm, and most tumors were oval-shaped (50%) with well-defined borders (75%). Six tumors were high grade (75%), and gross total resection was achieved in 5 patients, with subtotal resection in the remaining 3 patients. Postoperative radiotherapy and chemotherapy were performed in 6 (75%) and 4 (50%) cases, respectively. Local recurrence occurred in 5 (63%) cases, and distant metastases occurred in 2 (25%). The median overall survival was 26.7 months. Five (63%) patients died due to recurrence. CONCLUSIONS: Primary craniospinal MPNSTs are rare and have an aggressive clinical course. Early diagnosis and treatment are essential for managing these tumors. In this single-center study with a small cohort, maximal resection, low-grade pathology, young age (< 30), and adjuvant radiotherapy were associated with improved survival.

Giant middle mediastinal lesions: when tumor size correlates with mesenchymal origin-a retrospective single-center analysis.

Background: The International Thymic Malignancy Interest Group (ITMIG) proposed an internationally accepted division of the mediastinum into three compartments based on computed tomography (CT): anterior (prevascular), middle (visceral) and posterior (paravertebral) compartment. There is no generally accepted definition for the term "giant" when applied to middle mediastinal lesions. We defined the term "giant" and described our surgical experience in treating patients with giant lesions of the middle mediastinum. Methods: CT imaging of patients operated in our center from January 2016 to August 2021 for mediastinal lesions was reviewed. Lesions were categorized to one of the ITMIG-defined compartments. Lesion size at diagnosis was measured at its largest diameter on axial CT imaging. Giant middle mediastinal lesions were defined as lesions having a size ≥90th percentile of our middle mediastinal lesion cohort. Patients with giant middle mediastinal lesions were further analyzed. Results: Thirty-six patients (23%) had lesions located in the middle mediastinal compartment. Most common diagnoses were mediastinal cysts (n=10, 28%), metastatic lesions (n=6, 17%), lymphomas (n=5, 14%), and sarcomas (n=3, 8%). Ninetieth percentile lesion size was 73 mm. As per definition, four patients had giant middle mediastinal lesions. All these four lesions were of mesenchymal origin including oesophageal leiomyoma, synovial sarcoma, leiomyosarcoma and undifferentiated round cell sarcoma. Resection was performed through posterolateral thoracotomy or sternotomy, with or without cardiopulmonary bypass. Conclusions: The term "giant" could be defined as a mass larger or equal to 73 mm. This definition selected specifically lesions with mesenchymal origin and may therefore guide diagnostic algorithm and patient management.

Current therapies and future prospective for locally aggressive mesenchymal tumors.

Locally aggressive mesenchymal tumors comprise a heterogeneous group of soft tissue and bone tumors with intermediate histology, incompletely understood biology, and highly variable natural history. Despite having a limited to absent ability to metastasize and excellent survival prognosis, locally aggressive mesenchymal tumors can be symptomatic, require prolonged and repeat treatments including surgery and chemotherapy, and can severely impact patients' quality of life. The management of locally aggressive tumors has evolved over the years with a focus on minimizing morbid treatments. Extensive oncologic surgeries and radiation are pillars of care for high grade sarcomas, however, play a more limited role in management of locally aggressive mesenchymal tumors, due to propensity for local recurrence despite resection, and the risk of transformation to a higher-grade entity following radiation. Patients should ideally be evaluated in specialized sarcoma centers that can coordinate complex multimodal decision-making, taking into consideration the individual patient's clinical presentation and history, as well as any available prognostic factors into customizing therapy. In this review, we aim to discuss the biology, clinical management, and future treatment frontiers for three representative locally aggressive mesenchymal tumors: desmoid-type fibromatosis (DF), tenosynovial giant cell tumor (TSGCT) and giant cell tumor of bone (GCTB). These entities challenge clinicians with their unpredictable behavior and responses to treatment, and still lack a well-defined standard of care despite recent progress with newly approved or promising experimental drugs.

Gastrointestinal Stromal Tumors: Recurrence and Survival Analysis of 49 Patients.

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor originating from the gastrointestinal tract and have a broad spectrum of clinicopathological features affecting disease management regarding the treatment modalities. Methods: A retrospective study of 49 patients who underwent surgery for gastrointestinal tumors between 2008 and 2016 was conducted. Clinical, pathological, and immunohistochemical features of patients with and without recurrence were statistically analyzed. Results: Twenty-nine (59.1%) patients had gastric; 16 (32.6%) had small intestinal; 3 (6.1%) had mesenteric; and 1 (2.2%) had rectal GISTs. Microscopic tumor necrosis and tumor ulceration were also significant for disease recurrence (P = 0.005, P = 0.049). High-risk patients according to Miettinen's risk classification were more likely to develop a recurrence (P < 0.001). Additionally, high-grade tumors were also a risk factor for recurrence (P < 0.001). Ki-67 levels were available in 40 patients and the mean Ki-67 level was 16.8 in patients with recurrence, which was a significant risk factor in regression analysis (HR: 1.24, 95%, CI: 1.08-1-43). Five-year disease-free survival rates of non-gastric and gastric GISTs were 62.3% and 90%, respectively (P = 0.044). Conclusion: Larger tumors and higher mitotic rates are more likely to develop recurrence. High Ki-67 levels were also associated with recurrence.