Gastric Leiomyosarcoma Research Articles

Gastric Leiomyosarcoma in Post-Gastrointestinal Stromal Tumor Era: Revisit.

Primary gastric leiomyosarcoma is an exceptionally rare disease. This review covers 41 post-gastrointestinal stromal tumor (GIST) era gastric leiomyosarcoma cases that are supported by immunohistochemistry markers. Other spindle cell lesions are also excluded through histological and immunohistochemistry evaluations. The patients range from 3 to 82 years old, with an average age of 54.6 years. The male-to-female ratio is 1.4:1, from diverse geographic areas. Patients may experience abdominal symptoms, and tumor sizes vary between 1cm and 22cm. Morphologically, tumors originate from the muscularis propria or the muscularis mucosae, well-circumscribed with spindle cells arranged in fascicule. Tumoral cells exhibit positivity for smooth muscle markers while being negative for GIST markers and others. The mitotic index ranges from 2 to 500/50 high power field. Ki-67 index varies from 15% to 70%. Management typically involves gastrectomy and other appropriate treatments, with tumor recurrence being uncommon. 56% of patients are alive, with 5 patients dying from this disease. Statistical analyses conducted on post-GIST era cases reveal that a mitotic index of ≥100/50 high power field, tumor recurrence, metastasis, or positive lymph nodes significantly correlate with prognosis.

A Case of Gastric Leiomyosarcoma Completely Resected by Endoscopic Submucosal Dissection after a Precise Preoperative Diagnosis.

A 68-year-old woman was diagnosed with leiomyosarcoma (LMS) based on preoperative biopsy of the gastric body. As tumor invasion confined to the submucosa with no breaking of the submucosal layer was confirmed on endoscopic ultrasonography (EUS), the patient underwent endoscopic submucosal dissection (ESD) for gastric LMS, resulting in complete tumor resection. No apparent recurrence was observed in the 2.5 years after treatment. This is an extremely rare case of gastric LMS that underwent ESD after a precise preoperative diagnosis, with no signs of recurrence after treatment. ESD may be an acceptable option for gastric LMS when EUS findings allow this treatment method.

The Landscape of Primary Gastric Leiomyosarcoma in Texas Population: Analysis of Texas Cancer Registry Data.

Introduction Primary gastric leiomyosarcoma is an extremely rare disease. There have been no previous studies regarding gastric leiomyosarcoma in the Texas population. Methods Anonymous data of gastric leiomyosarcoma from the Texas Cancer Registry (TCR) was used. Information collected included the primary tumor site, age at diagnosis, gender, race/ethnicity, diagnosis and treatments, tumor size, lymph node and metastasis status, grade and stage, body weight and height, public health regions and payer, metropolitan status, neighborhood poverty level, smoking status, survival interval, and cause of death for statistical analysis. Result Thirty-three cases from 2003-2019 were selected. Primary gastric leiomyosarcoma was more commonly diagnosed in patients over 50 years of age, females, and individuals of white race. The diagnosis was primarily based on histology, and the disease was typically treated with surgery and chemotherapy. At the time of diagnosis, 45.5% of patients were in the late stage, and 48.5% of patients died from gastric leiomyosarcoma with a mean survival interval of 15.3 months. BMI scores showed a positive correlation with survival intervals. Surveillance, Epidemiology and End Results (SEER) tumor staging was associated with the prognosis of gastric leiomyosarcoma. Conclusion There were multiple disparities among patients with primary gastric leiomyosarcoma in the Texas population. The SEER summary stage was associated with the prognosis of gastric leiomyosarcoma.

S4248 A Rare Case of Gastric Leiomyosarcoma With Peculiar Endoscopic Appearance

S4248 A Rare Case of Gastric Leiomyosarcoma With Peculiar Endoscopic Appearance

Primary gastric leiomyosarcoma: a case report and literature review

After separating gastrointestinal (GI) stromal tumors from true smooth muscle tumors of the GI tract, leiomyosarcoma (LMS) of the GI tract has become a rare tumor. Gastric LMS is extremely rare and accounts for 0.1% of all cases of LMS in the GI tract. There are few English-language reports of gastric LMS describing radiologic findings. Here, we report a case of gastric LMS and review the recent literature focusing on radiologic findings. An 80-year-old female patient was referred for evaluation of a gastric mass accompanied by severe anemia. The physical examination revealed no specific findings except for an anemic conjunctiva. Laboratory data showed a low hemoglobin level of 5.1 g/dL. Endoscopy revealed a huge subepithelial mass in the posterior wall of the gastric body. Contrast-enhanced computed tomographic images showed an intraluminal protruding enhancing mass with an internal stalk appearance in the gastric body. There was no internal necrosis or calcification. The patient underwent subtotal gastrectomy and was diagnosed with primary gastric LMS. The diagnosis of gastric LMS is challenging due to its rarity. Our case report suggests that the presence of an internal stalk or spouting appearance can help prompt the radiologist to consider gastric LMS in the differential diagnosis.

Digestive pseuodpolyposis as a form of presentation of digestive metastases of primary gastric leiomyosarcoma.

A 71-year-old male was diagnosed with gastric leiomyosarcoma in 2020 after biopsies of an ulcerated gastric lesion. Despite oncological treatment, he presented bone, liver and lung progression. Fourth line treatment with Pazopanib was started in 2022 with no evidence of intestinal or peritoneal metastases. He was attended in the Emergency Department in February 2023 due to symptoms of gastrointestinal bleeding with clinical and analytical repercussion with hemoglobin 5.8g/dl. Initially he presented hematemesis and subsequently hematochezia. An upper and lower endoscopic study was performed, revealing multiple sessile polypoid lesions with an irregular mucosal pattern of between 5-30 mm distributed throughout all explored sections at the gastric, duodenal and colic mucosal; some of them ulcerated with fibrin deposits on the surface and signs of recent hemostasis. The histological study demonstrated infiltration by spindle-shaped mesenchymal cells with atypical nuclei, a Ki-67 proliferation index >80%, and an immunohistochemical profile consistent with digestive metastases of primary gastric leiomyosarcoma. CT scan was performed confirming tumor progression with pulmonary, digestive, hepatic, bone, muscle and peritoneal dissemination of gastric leiomyosarcoma.

S3613 Gastric Spindle Cell Leiomyosarcoma Is Associated With Chronic Helicobacter pylori Infection

Introduction: Chronic Helicobacter pylori (HP) infection has been shown to be strongly associated with development of gastric malignancies, mostly gastric adenocarcinomas and lymphomas. We present a case of primary gastric leiomyosarcoma in a patient with persistent epigastric pain and HP infection. Case Description/Methods: A 59-year-old female presented to clinic with persistent, postprandial epigastric pain. Cardiopulmonary workup was negative. She had a history of esophageal leiomyoma resected endoscopically with negative margins 10 years ago. She was treated in the past for HP infection but never had repeat testing to confirm eradication. Abdominal computed tomography showed focal hepatic infiltration. She was advised to have a repeat upper endoscopy for surveillance but was lost to follow-up due to psychiatric comorbidities. She presented 6 years later with epigastric pain. Repeat CT abdomen showed a new 2.8 cm hypoattenuating lesion in the lesser curvature of the stomach. Patient did not follow up due to psychosocial issues. Two years later, she returned to clinic for epigastric pain and underwent repeat upper endoscopy and endoscopic ultrasound (EUS) with fine needle aspiration (FNA). EGD showed sub-gastric nodule attached gastric wall, about 30 mm in maximal dimension and gastric biopsy confirmed active HP infection. The EUS showed a 31.7x23.5 mm hypoechoic homogeneous gastric mass along the lesser gastric curvature. Cytology showed cellular spindle cell neoplasia with myogenic differentiation concerning for possible leiomyoma or leiomyosarcoma. Abdominal magnetic resonance imaging and chest computed tomography revealed no evidence of abdominal or thoracic metastasis. Subsequently, partial underwent sleeve gastrectomy. Pathology revealed Grade 1 myxoid leiomyosarcoma with negative margins. (Figure) Discussion: Prior studies demonstrated associations between HP infection and gastric malignancies - typically gastric adenocarcinoma or lymphomas. Few studies investigated the relationship between HP infection and gastric leiomyosarcomas.4,5 Importantly, this patient never had clearance of HP infection and may have allowed a leiomyosarcoma to develop. It is imperative that clinicians confirm eradication of HP infection given risk of leiomyosarcoma development in addition to other malignancies HP infections are known to cause.Figure 1.: Endoscopic and histologic examination of gastric leiomyosarcoma. (A) Endoscopic ultrasound visualization demonstrating tumor within lesser curvature of stomach. (B) Upper endoscopy revealing tumor approximately 4 cm from gastroesophageal junction. (C) Hematoxylin and eosin (H&E) stain of gastric tumor biopsy demonstrating spindle cell proliferation in a myxoid background with significant nuclear atypia and pleomorphism consistent with myxoid leiomyosarcoma. Magnification x400. (D) Immunohistochemical staining of gastric lesion biopsy demonstrating strong immunoreactivity to desmin. Not shown are positive stains for smooth muscle actin (SMA) as well as negative stains for Cytokeratin AE1/AE3, Myogenin, MyoD1, DOG-1, CD117, S100, SOX10, CD34, ALK-1 and ER. Positive and negative controls stained appropriately but are not included.

S2602 Gastric Leiomyosarcoma: A Rare Case of Upper GI Bleeding

Introduction: Leiomyosarcoma (LMS) is a tumor arising from parts of the body containing smooth muscle cells such as the uterus, stomach and walls of blood vessels. Primary gastric leiomyosarcomas are extremely rare, accounting for 0.1%-3% of gastrointestinal malignancies. They can be differentiated from Gastrointestinal Stromal Tumors (GIST) based on immunohistochemical staining that is positive for desmin and SMA and negative for staining of KIT (CD 117), CD 34, and DOG1.1. LMS is usually asymptomatic but can present with anorexia, weight loss, nausea, vomiting, or bleeding. Here we present a rare case of an aggressive LMS manifesting as hematemesis and melena. Case Description/Methods: A 76-year-old male with a past medical history of Hypertension, Bladder Cancer and Prostate Cancer presented with a chief complaint of three days of hematemesis and melena. Upper Esophagogastroduodenoscopy (EGD) done five months prior was notable for an esophageal ulcer and gastritis. Labs on admission were notable for Hg of 10.3. EGD was performed which showed a large polypoid mass at the gastroesophageal (GE) junction. Biopsies were notable for smooth muscle cells that tested positive for SMA and caldesmon but negative for desmin, CD34, CD117 and DOG-1 most consistent with leiomyosarcoma. Ultimately, the patient underwent surgical resection of a 8.5 × 7.2 × 3.3 cm tumor with negative surgical margins and no evidence of lymphovascular invasion. The patient did well post-operatively and has been following with oncology for further management (Figure 1). Discussion: Prior to 1998, gastrointestinal stromal tumors (GIST) were misdiagnosed as LMS due to lack of molecular markers. Since then there are only 10 reported cases of gastric leiomyosarcoma in the post-GIST era. On CT imaging LMS tends to show up as irregular central zones of low attenuation suggestive of extensive necrosis or hemorrhage. Endoscopically, LMS tends to appear mainly in the muscularis propria with increased vascularity and a heterogeneous appearance. For tumors greater than 2 cm surgical resection is the preferred method of treatment. For metastatic disease, however, there has been no clear benefit of adjuvant chemotherapy as there is a high risk of recurrence. Routine follow up for completely resected tumors consists of abdominal and pelvic imaging which should occur every three to six months for two to three years, and then annually. In conclusion, we highlight a rare case of an aggressive type of Leiomyosarcoma at the GE junction presenting as an upper GI bleed.Figure 1.: (1) Upper Endoscopy showing mass lesion at the gastroesophageal (GE) junction. (2) Axial computed tomography (CT) image showing mass lesion in the gastric cardia (3) Spindle cells with marked atypia, necrosis, rare mitosis and moderate pleomorphism (H and E, x20)

S3685 Unusual Stomach Mass: Gastric Metastasis of Malignant Leiomyosarcoma

Introduction: Metastases in the stomach are rare findings, and likely represent a progressive malignant disease. With reported incidence of 0.2%-0.7%, the tumor can spread through hematogenous, lymphatic direct and peritoneal dissemination. Gastric metastases of leiomyosarcoma (LMS), a rare malignant mesenchymal smooth muscle tumor, have only been documented in a handful of case reports. We present a case of metastatic leiomyosarcoma in the stomach presenting with gastrointestinal bleeding. Case Description/Methods: A 64-year-old male with history of metastatic LMS of his left lower extremity came with melena for 3 days. Hemoglobin on presentation was 8.7 g/dl from his baseline of 13-14g/dl. He was diagnosed with grade 3 LMS 3 years ago, involving femoral vessel wall and muscle of his left thigh. He underwent radical excision without any adjuvant chemo and radiotherapy despite recommendations. He subsequently developed metastasis to the lung two years later at which time he started chemotherapy. An esophagogastroduodenoscopy revealed a 6 mm mucosal nodule and a 3 cm mass with a clean based ulcer in the body of stomach. Biopsy, however, was negative for malignancy. He then underwent endoscopic ultrasound guided biopsy for cytology which revealed malignant spindle cell neoplasm in the background of lymphoid tissue consistent with metastatic LMS (Figure 1). Discussion: LMS, a malignant tumor of smooth muscle origin, represents 20%-30% of soft tissue sarcomas. Predominantly uterine in origin, it can arise from the peritoneum, extremities, and blood vessels. Primary gastric LMS has also been reported in literature, but they are extremely rare and now are considered a type of gastrointestinal stromal tumor. LMS has a rapid tendency to metastasize, with lung, peritoneum, bone, and liver being common targets. Some rare cases of LMS metastasizing to pancreas, stomach and oral cavity have been reported. In general, metastases to the stomach are uncommon. The most common gastric metastases come from breast, lung, renal cell cancer and malignant melanoma. Metastasis of LMS to gastric mucosa has been limited to only a handful of case reports with primary tumors arising from kidney, uterus, and broad ligaments. The lesions are described as nodules, submucosal tumors, and ulcerative lesions, most of which are asymptomatic but can present as GI bleeding and abdominal pain. These metastases typically portray a poor prognosis. Local excision of the primary lesion with hormonal therapy and chemotherapy is considered standard treatment.Figure 1.: A. Endoscopic appearance of the metastatic LMS as a gastric body mass with clean based ulcer B. Endosonographic image of the mass in the gastric image.

Minimally Invasive Endoscopic Treatment of Gastric Leiomyosarcoma: A Rare Case Report and Review of Literature

Background Since the c-kit was described in 1998, gastrointestinal LMS remains a relatively rare disease in the post-GIST era. Previous studies have reported that gastric LMS accounts for only 1% of gastric tumors. This report provides valuable endoscopic and endoscopic ultrasound data for rare diseases such as primary gastric leiomyosarcoma, which can add experience for clinical diagnosis to the current literature. Particularly, this case proved that the early-stage lesions can be treated with minimally invasive endoscopic treatment with high safety, good tolerance, and satisfactory clinical results. Case Presentation A 63-year-old female patient visited our hospital mainly because of “epigastric pain and discomfort for 2 months.” After hospitalization, the relevant examinations were performed, and laboratory examination showed no obvious abnormalities. Abdominal contrast-enhanced CT found slight thickening of the gastric body wall. Ultrasonic gastroscopy revealed a round protuberant mass that originated from the muscularis mucosa on the great curvature of the gastric body, with a largest diameter of 16 mm. After full communication with the patient and exclusion of contraindications, the patient successfully underwent diagnostic endoscopic submucosal dissection (ESD) surgery. The postoperative pathological findings, immunohistochemical staining panel and molecular detection all improved that the mass was leiomyosarcoma. After 18 months of follow-up, the patient was in good condition, and there was no relapse on gastroscopy and abdominal enhanced CT. Conclusion Gastrointestinal leiomyosarcoma can be successfully resected by minimally invasive endoscopic treatment with high safety, good tolerance, and satisfactory clinical results. This shows that ESD is an effective method for the treatment of these diseases and has promising prospects for clinical application.

Thorahcic SMARCA4-deficient undifferentiated tumors with ganglioneuroma and enchondroma: implications for SLC7A11 and ARID1A expression: a case report

BackgroundSWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4-deficient thoracic sarcoma (SMARCA4-DTS) is a rare disease that has recently been described as an entity. It is characterized by an aggressive clinical course and specific genetic alterations. As an immunohistological feature, the tumors are deficient in SMARCA4 and SMARCA2 and express sex-determining region Y (SRY)-box 2 (SOX2). Occasionally, there are cases that are less frequent and difficult to distinguish from SMARCA4-deficient non-small cell lung carcinoma (SMARCA4-dNSCLC). Therefore, the 5th edition of the World Health Organization (WHO) classification describes thoracic SMARCA 4-deficient undifferentiated tumors (SMARCA4-UT). In contrast, Carney’s triad is a syndrome that combines three rare soft tissue tumors: gastric leiomyosarcoma, pulmonary chondroma, and extra-adrenal paraganglioma. Protein kinase cAMP-dependent type I regulatory subunit alpha (PRKAR1A) has been proposed as the causative gene. Both diseases are valuable cases; moreover, there have been no previous reports of their coexistence.Case presentationA 43-year-old man visited our hospital because of respiratory distress. Computed tomography revealed a large mass measuring 55 mm in the upper lobe of the right lung and front mediastinum, with metastases in the surrounding lymph nodes. Needle biopsy was performed for diagnosis, and histological examination of the samples revealed monotonous epithelioid-like cells with loose binding and sheet-form proliferation. The tumor cells had distinct nuclei with some rhabdoid-like cells. Immunohistochemical analysis revealed that the tumor cells were positive for AE1AE3, SOX2, CD34, and p53 and negative for SMARCA4 and SMARCA2. The patient died 6 months after admission, without any treatment. Autopsy revealed ganglioneuroma and enchondroma suggestive of an incomplete Carney complex.ConclusionSMARCA4-UT is a rare and recently established disease. While it is difficult to diagnose, it is necessary to distinguish undifferentiated carcinoma, large cell carcinoma, Ewing sarcoma, and epithelioid sarcoma when diagnosing tumors involving the mediastinum. Moreover, cases of SMARCA4-UT with ganglioneuroma and enchondroma are very rare. We discuss and report a case of SMARCA4-UT in which we also examined ARID1A and SLC7A11expression.

S3189 Not Just a GIST: A Rare Case of Gastric Leiomyosarcoma

Introduction: Leiomyosarcoma (LMS) is a malignant neoplasm showing smooth muscle differentiation. Before the recognition of gastrointestinal stromal tumors (GISTs), leiomyoarcomas were commonly reported in the gastrointestinal tract due to misclassification. Now, these tumors are considered rare with only 16 cases of gastric LMS reported in the post-GIST era. We present the 17th case of primary gastric LMS. Case Description/Methods: An 81F with a history of GERD,CHF and Afib presented for evaluation of syncope. She had also suffered with increased fatigue, poor appetite, 30lb unintentional weight loss, and a “gnawing” post-prandial epigastric pain. Her last EGD was 4 years prior which showed non bleeding erosive gastropathy and a non obstructing Schatzki’s ring. Biopsies showed chronic gastritis without evidence of dysplasia or H. Pylori. On admission, pertinent labs included Hg of 11.5 g/dL, MCV 99.7 fL, WBC 11.02 k/uL, and albumin 2.8 g/dL. She underwent an EGD which showed a large, infiltrative, transmural, ulcerated, non-circumferential mass in the greater curvature of the stomach. EUS showed a hypoechoic lesion which appeared to extend to the cardia by extrinsic involvement of the gastric wall. Biopsies showed an ulcerated spindle cell neoplasm which stained negative for C-kit and DOG1, but were strongly positive for desmin. This conformed the diagnosis of gastric leiomyosarcoma. Discussion: Before the development of immunohistochemical staining for C-kit, many GISTs were misdiagnosed as LMSs and leiomyoblastomas. Now these tumors are considered rare with only 16 prior case reports. The diagnosis mainly relies on pathologic examination with SMA, desmin, and h-caldesmon are positive in the majority ( >70%) of LMSs. CD117 (KIT), DOG 1 and CD34 are negative. It is important to rule out Carney tried, which is a type of multiple endocrine neoplasia which encompasses LMSs, pulmonary chondroma, and extra-adrenal paragangliomas. Complete for LMS surgical resection with negative margins remains the gold standard of treatment. It is important to note that not every spindled lesion is a GIST, as diagnosis will change management. As opposed to GISTs, LMSs are not likely to respond to Imatinib. Due to concern for splenic invasion, neoadjuvant chemotherapy was pursued in our patient with Ifosfamide and doxorubicin prior to surgical resection. Due to her other comorbidities, she was felt to be too high risk for surgery and she eventually chose to pursue hospice.Figure 1.: Figure 1 1a: Ulcer in the incisura of the stomach 1b: Ulcer status post hemostatic clip and argon plasma coagulation (APC).

Giant gastric leiomyosarcoma: a rare case report

Leiomyosarkom en sık retroperitonda görülen düz kas orijinli nadir bir tümördür. Genelde 5. dekattan sonra kadın ve erkeklerde eşit oranda görülür. Visseral organlar arasında en sık uterusta izlenmekte olup, mide malign tümörlerinin %1’ini oluşturur. Burada mide yerleşimli dev bir leiomyosarkom olgusu literatür eşliğinde tartışıldı. 74 yaşında kadın hasta, gastrik tümöral lezyon nedeniyle genel cerrahi kliniğinde wedge rezeksiyon uygulandı. Materyalinin makroskopik incelemesinde 14x10x8,5 cm ölçülerinde yumuşak kıvamlı nodüler bir lezyon saptandı. Lezyon submukozal yerleşimli olup muskularis propriaya da uzanım göstermekte idi. Lezyonun histopatolojik incelemesinde eozinofilik sitoplazmaya sahip iğsi hücrelerin sellüler bir proliferasyonu görüldü. Bu hücrelerde mitoz, pleomorfizm ve nekroz izlendi. Yapılan immünhistokimyasal çalışmada SMA, desmin ve vimentin ile pozitif boyanma DOG-1 ve CD117 ile de negatif boyanma saptandı. Bu bulgular eşliğinde olguya leiomyosarkom tanısı verildi. Mide yerleşimli leiomyosarkomlar oldukça nadir görülmekle beraber submukozal tümöral lezyonların, özellikle de gastrointestinal stromal tümör (GİST)’ün , ayırıcı tanısında mutlaka akılda tutulmalıdır. Bu tümörlerin GİST’ten ayırımında immünhistokimyasal çalışma oldukça yararlıdır.

Metastatic leiomyosarcoma of the excluded stomach: a case report

Background: Leiomyosarcoma (LMS) represents about 1% of primary malignancies of the stomach, usually evolves with hepatic implants in 2-thirds of cases, and the outcome is frequently poor. With an insidious course, late diagnosis and misdiagnosis with other gastric neoplasia occur. Immunohistochemical evaluations are mandatory to confirm the diagnostic hypothesis. Surgical resection has been the more effective treatment of gastric LMS; however, recurrences after resections and distant metastases may develop in up to 50% of the patients. Doxorubicin, gemcitabine, and docetaxel are therapeutic options, with variable responses. Case presentation: The 52-year-old male herein described with a diagnosis of LMS in the gastric pouch and liver metastasis underwent a Roux-en-Y bypass to treat morbid obesity more than a decade ago. Persistent abdominal pain was a unique symptom, and he had liver metastasis at diagnosis. The initial hypothesis was a metastatic gastrointestinal stromal tumor (GIST) of the excluded stomach and the patient underwent a schedule with imatinib without significant response. After a complete revision of the anatomopathological findings, the patient underwent a new biopsy of the gastric mass, and the immunohistochemical data were consistent with LMS. Then doxorubicin replaced imatinib, later changed by gemcitabine associated with docetaxel. As last control found lesions in the central nervous system, he is under radiotherapy sessions. Conclusion: The diagnosis of gastric LMS often occurs at late stages because of the insidious clinical course. The rate of liver metastasis at diagnosis is high. Besides, the relatively poor response to the alternative management for non-surgical stages of the disease yields severe outcomes.

An Unusual Case of Gastric Leiomyosarcoma Presenting as a Giant Polyp

An Unusual Case of Gastric Leiomyosarcoma Presenting as a Giant Polyp

Gastric leiomyosarcoma: A common tumor in an uncommon location

A previously healthy 51-year-old female presented with gradually worsening, 10/10 non-radiating epigastric abdominal pain associated with nausea, bilious vomiting, and weight loss. Computed tomography (CT) of the abdomen with intravenous contrast showed a large 10.7 × 9.5 cm exophytic mass in the antrum/body of the stomach (Figure 1A). An upper endoscopic evaluation revealed a large fungating, infiltrative, and ulcerated mass in the gastric body (Figure 1B). Histopathology of the biopsied mass was notable for spindle cells with a fascicular pattern, moderate nuclear atypia, abundant eosinophilic cytoplasm, and numerous mitotic figures. Immunohistochemistry analysis revealed that the tumor was diffusely positive for smooth muscle actin (SMA) (Figure 2A), desmin (Figure 2B), and calponin (Figure 2C). Ki-67 stain (Figure 2D) showed a high labeling index of 60% indicating a high-grade leiomyosarcoma. There was a complete lack of reactivity with DOG-1 and CD-117 (c-KIT) which excluded the diagnosis of a gastrointestinal stromal tumor (GIST). No evidence of metastatic disease and no lymph node involvement were noted in the head, abdomen, or thorax on the respective CT scans which were done for staging. Due to the large size of the tumor, the patient was started on a neoadjuvant chemotherapy regimen consisting of doxorubicin, ifosfamide, and mesna to reduce tumor burden with a future plan for surgical excision.

2730 Unexpected Cause of Globus Pharyngeous: Gastric Leiomyosarcoma

INTRODUCTION: Soft tissue sarcomas (STS) are derived from smooth muscle cells and typically arise in adipose tissue, blood vessels or structural tissue surrounding the organs of the body. One of the most common types of STS is leiomyosarcoma (LMS) which account for 11% of all sarcomas diagnosed. Gastric LMS are exceptionally rare and make up 0.1% of all mesenchymal tumors of the stomach. CASE DESCRIPTION/METHODS: A 72 year-old male presented to the gastroenterology clinic with complains of globus pharyngeus, migrating abdominal discomfort and a 4-month 18 pound weight loss. Endoscopy revealed a large bloody friable mass in the posterior wall of the stomach. Biopsy demonstrated atypical spindle cell proliferation. Immunohistochemistry was positive for Smooth Muscle Actin (SMA), desmin and CD34; cKIT and DOG1 was negative. He was diagnosed with high grade LMS of the stomach with no metastasis after unremarkable positron emission tomography scan. The patient underwent total gastrectomy with splenectomy en-bloc resection to achieve wide negative margins. DISCUSSION: This case highlights an unexpected cause of globus pahryngeus: Gastric LMS which is important to differentiate from gastrointestinal stromal tumor (GIST) as its management and prognosis differ. LMS represent 0.1% of all gastric tumors, and 3% of all gastrointestinal malignancies. In contrast, GIST has annual incidence of 11-14.5 per million population. LMS and GIST appear similar on gross assessment and clinical symptoms and need to be differentiated via immunohistochemical staining. LMS are actin and desmin reactive with DOG1.1 typically being absent. Further, LMS lack cKIT and PDGFRα mutations that are seen in GIST. Management of GIST with tyrosine kinase is potentially lifesaving, whereas no such treatment exists for LMS where the cornerstone of treatment is surgery. Chemotherapy and radiation have been shown to be only helpful for palliative measures. They are intrinsically aggressive tumors and 90% are moderate to high grade at time of diagnosis with evidence of metastatic disease. We are far from understanding the pathology of LMS and its risk factors. This case confirms our present understanding of LMS; as shown by positive markers as well a diagnosis of high grade tumor on presentation. However, it also challenges our current understanding of LMS in its unusual symptomatology and lack of metastatic disease. Due to its low incidence, it is crucial to report cases such as this in order to further our understanding of the tumor.

2194 Prevention of Excessive Gas Accumulation With a Biliary Dilation Balloon During Endoscopic Cryotherapy

INTRODUCTION: Endoscopic cryotherapy for the treatment of premalignant and malignant conditions has been demonstrated to be an effective tool in esophageal malignancy. However, there is concern for perforation from gas production during cryotherapy. Here we describe the use of a biliary dilation balloon to prevent distal gas accumulation in Roux-en-Y anatomy. CASE DESCRIPTION/METHODS: This is a case of a 77-year-old male with history of total gastrectomy with Roux-en-Y esophagojejunostomy for remote history of gastric leiomyosarcoma and locally advanced esophageal cancer. Two years prior he underwent Endoscopic Submucosal Dissection (ESD) of an esophageal nodule previously biopsied positively for adenocarcinoma. One year ago a surveillance EGD/EUS with biopsy showed no evidence of residual disease at the ESD site. Repeat surveillance EGD/EUS early this year identified thickening of subepithelial layers with a 6mm hypoechoic lesion at the level of the ESD scar. A hybrid ESD and endoscopic mucosal resection (EMR) technique was performed to remove the nodule. Pathology showed invasive poorly differentiated adenocarcinoma with the deeper cauterized margin involved. Endoscopic cryoablation was planned for the remaining margins. Close examination of the ESD defect using EGD and EUS showed no evidence of recurrence. Cryotherapy was then prepared with the insertion of a biliary dilation balloon via a nasal trumpet. The balloon was endoscopically guided to the jejunum distal to the esophagojejunal anastomosis and inflated to prevent distal leakage of cooling gases. A decompression tube was placed in the esophagus proximal to the treatment area. Using the cryocatheter, 3 treatments of liquid nitrogen at -190⁰ C were sprayed over the ESD scar to achieve uniform white frost, each treatment lasting 30 seconds with 60 seconds of defrost time between. Throughout the treatment, suction was provided via the decompression tube and the abdomen was palpated without significant distention. The patient tolerated the procedure well without complication and was discharged home. DISCUSSION: Gas by-products are produced during cryotherapy, which in the case of a patient with a Roux-en-Y, causes substantial risk for perforation. With a distally inflated biliary dilation balloon, gas is prevented from accumulating in the small intestine where it may be difficult to suction, reducing the risk of perforation. This technique may be applied to similar cases where perforation risk is elevated.

Gastric leiomyosarcoma in a 3-year-old boy

Abstract A 3-year-old boy presented with anemia and a palpable abdominal tumor. The operative finding was a 10.5×9.6×4.6-cm tumor that infiltrated the anterior wall of the stomach. Local excision was performed. The tumor was histopathologically diagnosed as leiomyosarcoma with immunoreactivity for alpha-smooth muscle actin and muscle actin, but not for CD34, c-kit, and S-100. The tumor was characterized as highly malignant because of its size, high mitotic count, nuclear atypia, and high MIB-1 labeling index. After 6 months of follow-up, recurrence developed in the remnant stomach and liver metastasis was observed. Partial gastrectomy and lateral segment resection of the liver were performed. Subsequently, multiple recurrences in the remnant liver and peritoneal dissemination occurred. The patient underwent follow-up without adjuvant therapy and was well for more than 10 years after liver metastases and peritoneal dissemination after the initial surgery. This case represents the different biological behavior of pediatric gastrointestinal leiomyosarcoma compared to adult gastrointestinal leiomyosarcoma.

Gastric Leiomyosarcoma Associated with Hypoglycemia in Dog—A Case Report

Neoplasms of the digestive system are uncommon in dogs, and may be of epithelial, neuroendocrine, hematopoietic and mesenchymal origin. The leiomyosarcoma is a tumor of mesenchymal origin of smooth, malignant, slow-growing muscles. Paraneoplastic syndromes can affect different systems, being the most commonly found: hypercalcemia, hypoglycemia, cachexia and anemia. There are rare cases of mesenchymal tumors of the gastrointestinal tract in dogs that result in hypoglycaemia with clinical signs. The objective of this study is to report a case of gastric leiomyosarcoma associated with clinical hypoglycemia. The patient had neurological signs such as ataxia and seizures associated with hypoglycemia, which did not recur after surgical excision of the tumor. The definitive diagnosis was based on the histopathological and immunohistochemical examination of the tumor.