Primary extraskeletal osteosarcoma of small bowel mesentery presenting with acute bowel obstruction

Extraskeletal osteosarcoma of the small bowel mesentery is an exceedingly rare condition. It is an aggressive malignant neoplasm of mesenchymal origin characterized by osteoid formation. Final diagnosis is often made by histopathological analysis. However, we believe that prospective radiological diagnosis may be possible through careful analysis of densities (ossification) within the mesenteric mass. To the best of our knowledge, there is no current literature describing the radiological approach to making a prospective diagnosis of this condition. We present the 12th case of extraskeletal osteosarcoma worldwide and describe a radiological approach that is potentially useful in making a prospective diagnosis.

Principles of Surgical Management of Small Intestinal NET

Introduction: Small-intestinal neuroendocrine tumors (siNETs) account for 25% of gastroenteropancreatic NETs. Multiple siNETs appear to develop in a limited segment of the small bowel (SB), 89% of them being located in the ileum, most often within 100 cm of the ileocecal valve (ICV). According to the European Neuroendocrine Tumor Society (ENETS) and the American Joint Committee on Cancer (AJCC), all localized siNETs should be considered for radical surgical resection with adequate lymphadenectomy irrespective of the absence of lymphadenopathy or mesenteric involvement. Surgical management of siNETs: The preoperative workout should include a precise evaluation of past medical and surgical history, focusing on the symptoms of carcinoid syndrome (flush, diarrhea, and cardiac failure). Morphological evaluation should include a CT scan including a thin-slice arterial CT, a PET/CT with 68 Ga, and a hepatic MRI in cases of suspected metastasis. Levels of 24 h urinary 5-hydroxyindoleacetic acid are needed. Regarding surgery, the limiting component is the number of free jejunal branches allowing a resection without risk of short small bowel syndrome. The laparoscopic approach has been poorly studied, and open laparotomy remains the gold standard to explore the abdominal cavity and entirely palpate the small bowel through bidigital palpation and compression. An extensive lymphadenectomy is required. A prophylactic cholecystectomy should be performed. In case of emergency surgery, current recommendations are not definitive. However, there is expert agreement that it is not reasonable to initiate resection of the mesenteric mass without comprehensive workup and mapping. Conclusion: The surgery of siNETs is in constant evolution. The challenge lies in the ability to propose a resection without imposing short small bowel syndrome on the patients. The oncological benefits supported in the literature led to recent changes in the recommendations of academic societies. The next steps remain the dissemination of reproducible quality criteria to perform these procedures.

Primary extraskeletal osteosarcoma of sigmoid mesocolon: a case report and a review of the literature

Background Extraskeletal osteosarcoma (ESOS) is a rare mesenchymal malignancy, which produces osteoid, bone, or chondroid material and is located in the soft tissue without attachment to skeletal bones and periosteum. One of the things that ESOS originated from mesentery is much rarer. Case presentation A 75-year female had a history of pain in the left lower abdomen for more than 4 months. Abdominal computerized tomography (CT) and magnetic resonance imaging revealed a large, irregular, and solid-cystic mass (largest diameter was 11.5 cm). The tumor was radically removed during an open operation. It was composed of abundant osteoid and polyhedral-shaped tumor cells with high atypia and high mitotic activity microscopically. The final pathological diagnosis was osteoblastic osteosarcoma, arising from the sigmoid mesocolon with negative margins. A 9-month follow-up by CT exhibited signs of peritoneal metastasis. Conclusions Given the rarity of cases of mesenteric ESOS, diagnosis mainly depended on pathology findings or should be taken into consideration when the mesenteric mass was found. Its most effective treatment had not been determined, with surgical excision being generally accepted. Ensuring negative surgical margins may be an important factor affecting prognosis.

Sclerosing Mesenteritis, a Rare Cause of Mesenteric Mass in a Young Adult: A Case Report

Sclerosing mesenteritis (SM) is a rare fibroinflammatory disorder that involves mesenteric adipose tissue, more frequently localized in the small intestine, with an insidious clinical presentation having symptoms related to mass effect, usually resulting in bowel obstruction, mesenteric ischemia, as well as rapid weight loss. We report a case of a 23-year-old male presenting with palpable abdominal mass, mesogastric pain, and a history of rapid weight loss, who underwent exploratory laparoscopy. A hemorrhagic and gelatinous nodular tumor mass of the mesentery was identified and the surgical procedure was converted to a laparotomic approach. Histologically, the mass was composed of a proliferation of bland-looking spindle cells with slightly eosinophilic cytoplasm and elongated normochromatic nuclei with mild nuclear atypia, haphazardly set in a collagenized stroma; fat necrosis and inflammatory cells (lymphocytes, plasma-cells, and histiocytes) were also evident. The diagnosis of sclerosing mesenteritis was made. Our case emphasizes that histology remains pre-eminent for a correct diagnosis of SM, as pre-operative radiological-based diagnosis is non-specific.

Intra-abdominal EWSR1/FUS-CREM-rearranged malignant epithelioid neoplasms: two cases of an emerging aggressive entity with emphasis on misleading immunophenotype

CREB family (CREB1, ATF1, and CREM) gene fusions are defining markers in diverse mesenchymal neoplasms (clear cell sarcoma, angiomatoid fibrous histiocytoma, and others). However, neoplasms harboring EWSR1-CREM/FUS-CREM fusions are rare and poorly characterized. We describe two cases (55-year-old male with 7.5 cm renal mass and 32-year-old female with 5.5 cm mesenteric mass) illustrating their misleading immunophenotypes. Histologically, both showed eosinophilic and focally clear epithelioid cells arranged into sheets, nests, and trabeculae. Immunohistochemistry showed ALK, EMA, and AE1/AE3 immunoreactivity suggesting ALK-rearranged renal cell carcinoma (Case 1) and coexpression of keratin, EMA, synaptophysin, and chromogranin-A, suggesting neuroendocrine neoplasm (Case 2). Targeted RNA sequencing revealed EWSR1-CREM (Case 1) and FUS-CREM (Case 2) fusions. These cases add to the spectrum of CREM fusion-positive intra-abdominal epithelioid neoplasms. Their unusual immunophenotype and unexpected sites represent major pitfalls, underline a wide differential diagnosis, and emphasize the value of molecular testing in correctly diagnosing them.

Feline mesothelioma: case report and review of cytologic, immunocytochemical, histopathologic, and immunohistochemical findings

Mesotheliomas are uncommon neoplasms that arise from mesothelial cells in either the abdominal or thoracic cavities and are rarely diagnosed in cats. A 10-y-old spayed female domestic shorthair cat was presented to the Louisiana State University oncology service for evaluation of a large amount of abdominal effusion. Abdominal ultrasound identified a large mesenteric mass with numerous ill-defined nodules. An abdominocentesis was performed with cytologic and immunocytochemical findings consistent with a neoplastic effusion, with large clusters of epithelioid cells that exhibited strong cytoplasmic expression of pancytokeratin, vimentin, and Wilms tumor 1 antigens. Further testing was declined, and meloxicam was prescribed until the cat died 23 d after initial presentation. Upon postmortem examination, the omentum was contracted into a firm mass adhered to multiple organs and accompanied by numerous small white nodules throughout the abdominal cavity. On histopathology and immunohistochemistry, neoplastic cells were found throughout the abdominal cavity; 60–95% exhibited moderate-to-strong cytoplasmic immunoreactivity for cytokeratin, vimentin, and Wilms tumor 1 protein. The final diagnosis was an epithelioid mesothelioma. Our case illustrates the utility of cytology, immunocytochemistry, and its relation to histology and immunohistochemistry. We also reviewed the reported cases of feline mesothelioma.

A Unique Presentation of a Paraganglioma and Its Consequences

Introduction: Paragangliomas (PGL) are extremely rare tumors arising from extra-adrenal neural crest cells with an incidence of 0.8 per 100,000 person-years. Sympathetic chain PGLs usually arise in the abdomen, with about 75% of them arising intra-abdominally [2]. On CT or MRI, PGLs are usually have homogenous enhancement or central areas of low attenuation. The consequences of PGLs are many, and one complication that is rarely noted is glycemic disturbances with catecholamine excess. Here, we present a case of a radiographically unique appearing PGL that resulted in dramatic improvement of diabetes after resection. Case: 41 year old male with a past medical history of diabetes, CKD and developmental delay presented with hyperglycemia. Patient’s home regimen of Glargine 15 units qHS and Humalog 5 units TID AC had run out a few days prior. Patient had Hemoglobin A1c of 11.8% mg/dL and a C-peptide of 0.4 ng/ml. Endocrine was initially consulted for glucose management. Hospital course was complicated by abdominal pain and CT imaging showed low attenuation splenic masses, retroperitoneal lymphadenopathy and a large, necrotic appearing mesenteric mass consistent with lymphoma. MRI reaffirmed mass with peripheral enhancement and central necrosis consistent with neoplasm. Patient underwent biopsy of lymphadenopathy, which came back benign and then went for biopsy of mass. As the needle entered the mass, the patient became acutely hypertensive and tachycardic. He received phentolamine with good response and labs were drawn for catecholamine producing tumor. Plasma norepinephrine level was 6048 pg/ml and a chromogranin level of 4788 ng/ml. An MIBG scan revealed focal uptake at the lesion without evidence of metastasis. In the subsequent weeks, he was alpha- and then beta-blocked and underwent resection of mass that was complicated by transient hypotension and hypoglycemia. Eventually, patient’s blood pressure was controlled and insulin requirements dropped precipitously to just requiring 4 units of glargine by discharge. Discussion: This patient had a mass on CT scan that appeared to be consistent with lymphoma as opposed to PGL that led to biopsy and subsequent catecholamine crisis. Fortunately, this was controlled and subsequent resection led to improvement in the patient’s glycemic control. It has been thought that glucose intolerance in PGL patients is due to impaired insulin release through desensitization of the beta-adrenergic receptor. Furthermore, Catecholamines, as counter-regulatory hormones, have been well documented to raise blood sugar on this basis as well. Fortunately for our patient, he survived an initial biopsy and post-operatively, was able to actually have an improvement in his glycemic control. It also is a reminder to always do a screen for PGL before doing a needle biopsy of a compatible abdominal mass.

Predicting symptomatic mesenteric mass in neuroendocrine tumors using radiomics

Metastatic mesenteric masses of small intestinal neuroendocrine tumors (SI-NETs) are known to often cause intestinal complications. The aim of this study was to identify patients at risk to develop these complications based on routinely acquired CT scans using a standardised set of clinical criteria and radiomics. Retrospectively, CT scans of SI-NET patients with a mesenteric mass were included and systematically evaluated by five clinicians. For the radiomics approach, 1081 features were extracted from segmentations of the mesenteric mass and mesentery, after which radiomics models were created using a combination of machine learning approaches. The performances were compared to a multidisciplinary tumor board (MTB). The dataset included 68 patients (32 asymptomatic, 36 symptomatic). The clinicians had AUCs between 0.62–0.85 and showed poor agreement. The best radiomics model had a mean AUC of 0.77. The MTB had a sensitivity of 0.64 and specificity of 0.68. We conclude that systematic clinical evaluation of SI-NETs to predict intestinal complications had a similar performance than an expert MTB, but poor inter-observer agreement. Radiomics showed a similar performance and is objective, and thus is a promising tool to correctly identify these patients. However, further validation is needed before transition to clinical practice.

Primary Extraskeletal Osteosarcoma of Sigmoid Mesocolon: A Case Report and a Review of the Literature

Background: Extraskeletal osteosarcoma (ESOS) is a very rare mesenchymal malignancy, characterized by the production of osteoid, bone or chondroid material and typically located in the soft tissue without attachment to skeletal bones and periosteum. One of the things that ESOS originated from mesentery is much rarer. Case presentation: A 75-year female with a more than 4-months history of pain in the left lower abdomen. Abdominal computerized tomography and magnetic resonance imaging revealed a large, irregular and solid-cystic mass, which largest diameter was 11.5cm. The tumor was radically removed during open operation. The tumor was composed of abundant osteoid and polyhedral-shaped tumor cells with high atypia and high mitotic activity microscopically. The final pathological diagnosis was osteoblastic osteosarcoma, arising from the sigmoid mesocolon with negative margins. The patient was followed up 5 months after surgery and found no signs of systemic metastasis Conclusion: Given the rarity of cases of mesenteric ESOS, diagnosis mainly depended on pathology findings or should be taken into consideration when the mesenteric mass was found. Its most effective treatment had not been determined, with surgical excision was generally accepted. Negative surgical margin may be an important factor affecting the prognosis.