Primary Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Stomach

Extraskeletal Ewing Sarcoma of the Gastrointestinal and Hepatobiliary Tract: Deceptive Immunophenotype Commonly Leads to Misdiagnosis

Ewing sarcoma (ES) is an uncommon mesenchymal neoplasm that typically develops as a bone mass, although up to 30% arise in extraskeletal sites. ES of the gastrointestinal (GI) and hepatobiliary tract is rare and may be misdiagnosed as other, more common neoplasms that occur in these sites. However, the correct classification of extraskeletal ES is important for timely clinical management and prognostication. We reviewed our experience of ES in the GI and hepatobiliary tract in order to further highlight the clinicopathologic features of these neoplasms and document the potential for misdiagnosis in this setting. The archives and consultation files of 6 academic institutions were retrospectively queried for cases of ES occurring in the GI and hepatobiliary tract. The histologic slides and ancillary studies were reviewed and clinical data were retrieved for each case through the electronic medical records, when available. Twenty-three patients with ES in the GI and/or hepatobiliary tract were identified from 2000 to 2022. Of these, 11 were women and 12 were men with a median age of 38 years (range, 2 to 64). Tumor locations included the pancreas (n=5), liver (n=2), stomach (n=3), colorectum (n=3), and small intestine (n=5), as well as tumors involving multiple organs, pelvis and retroperitoneum (n=5). Tumor size varied between 2 cm and 18 cm. Twenty were primary and 3 were metastases. Of the 23 cases, only 17% were initially diagnosed as ES. The most common misdiagnoses involved various forms of neuroendocrine neoplasia due to expression of synaptophysin and other neuroendocrine markers (22%). A wide variety of diagnoses including GI stromal tumor was considered due to aberrant CD117 expression (4%). The diagnosis of ES was ultimately confirmed by detection of the EWSR1 rearrangement in 22 cases. The remaining case was diagnosed using traditional immunohistochemistry. Follow-up information was available in 20 cases, with follow-up time varying between 2 and 256 months. Six patients with follow-up died of disease between 6 and 60 months following initial presentation. Our data indicate ES in the GI and hepatobiliary tract is commonly misdiagnosed leading to a delay in therapy. In light of the attendant therapeutic and prognostic implications, ES should be considered in the differential diagnosis of any GI or hepatobiliary tumor with epithelioid and/or small round cell morphology.

Gastrointestinal Ewing Sarcoma: A Clinicopathological and Molecular Genetic Analysis of 25 Cases

Occurrence of extraskeletal Ewing sarcoma (ES) in the gastrointestinal (GI) tract is extremely rare. Here, we report 25 cases of ES arising primarily in the GI tract with a focus on the clinicopathological and molecular features, differential diagnosis, and biological behavior. Thirteen patients (52%) were male, and 12 (48%) were female with age ranging from 9 to 59 years (mean: 36.2 years; median: 38 years). Twenty-one tumors (84%) occurred in the small intestine, 3 (12%) in the stomach, and 1 (4%) in the anal canal. At operation, 8/18 (44.4%) patients presented with abdominopelvic disseminated disease. Tumor size measured from 2 to 25 cm (mean: 8.2 cm; median: 6 cm) in maximum size. Microscopically, the tumors were composed of infiltrative small round, ovoid, or short spindle cells arranged mostly in lobular and solid sheet-like patterns with a rich capillary vasculature. Focal formation of Homer Wright-type rosettes and pseudoalveolar architecture was noted each in 2 (8%) cases and 3 (12%) cases. Besides CD99 (25/25; 100%), Fli-1 (15/15, 100%), and NKX2.2 (14/16; 87.5%), the tumor cells also showed variable staining of CD117 (14/17; 82.4%). Of 25 cases, 23 (92%) demonstrated EWSR1 rearrangement by fluorescence in situ hybridization analysis. The 2 cases with negative fluorescence in situ hybridization results were found to harbor EWSR1::ERG and EWSR1::FLI1 fusion by further RNA sequencing, respectively, with a median follow-up of 12 months (range: 1 to 42 months), 5/19 (26.3%) patients developed visceral metastasis and 12/19 (63.2%) patients died of the disease (range:1 to 33 months; median: 9 months). This study showed that GI ES had a predilection for the small intestine, although other sites of the GI tract could also be involved. GI ES had a poor prognosis with a high rate of mortality, particularly in patients with abdominopelvic disseminated disease. In light of appropriate therapeutic strategies and prognostic considerations, it is essential not to misdiagnose GI ES as gastrointestinal stromal tumor owing to the expression of aberrant CD117.

Surgical management of primary gastric Ewing-like sarcoma at the lesser curvature

We report the case of a 65-year-old female who presented with a 6-month history of epigastric pain and dyspepsia. Computed tomography of the abdomen and pelvis showed an enhancing nodular lesion and an indeterminate 4 mm lymph node on the lesser curvature of the stomach raising concerns for gastric malignancy. Upper gastrointestinal endoscopy revealed a 10 cm malignant appearing lesion along the gastric lesser curvature. Histopathology demonstrated spindled and small round blue cell tumor with immunohistochemistry staining consistent with Ewing-like sarcoma. After multidisciplinary team discussion the patient was arranged for neoadjuvant chemotherapy with early re-imaging, followed by consideration of gastrectomy. This case highlights the unusual diagnosis of primary gastric Ewing-like sarcoma and the management of this rare condition.

Extraskeletal Ewing sarcoma of the stomach: A rare case report

BACKGROUND

Extraskeletal Ewing sarcoma (EES) is a rare and highly malignant small round cell tumor associated with a poor clinical outcome. Ewing sarcoma (ES) involving the stomach is an uncommon presentation and can be easily confused with other small round cell tumors. We herein present a rare case of ES involving the gastric area.

CASE SUMMARY

We report a case of gastric ES in a 19-year-old female patient who initially presented with a complaint of a tender epigastric mass for 5 d. Contrast-enhanced abdominal computed tomography revealed a soft-tissue-density mass with a diameter of 8.5 cm between the liver and stomach; the mass was connected to the gastric antrum. Then, the mass was surgically excised completely. Upon histopathological, immunophenotype and molecular analysis, the mass was identified to be a primary gastric ES.

CONCLUSION

EES is an aggressive tumor with poor prognosis. Therefore, early diagnosis and timely intervention are essential for a good prognosis. It is imperative for us to raise awareness about this rare tumor. Surgical resection is still the best treatment option.

Ewing sarcoma of the jejunum: A case report and literature review

BACKGROUND

Ewing sarcomas (ESs) are highly aggressive malignancy and are predominant in the long bones of extremities of children and young adults with a slight male predilection and rarely presents at extra skeletal locations.

CASE SUMMARY

A 55-year-old woman came to our hospital after finding elevated tumor biomarkers during her physical examination. Her enhanced computed tomography scan showed a jejunal mass. The patient underwent laparoscopic enterectomy. The mass was later diagnosed as ES, evidenced by fluorescence in situ hybridization whereby the GLP ES breakpoint region 1 probe was used, showing that more than 10% of the cells showed a red-green-yellow signal proving the breakpoint rearrangement of the ES breakpoint region 1 gene in chromosome 22.

CONCLUSION

We describe a case of localized ES at the jejunum in China based on the literature.

Primary gastric Ewing sarcoma/primitive neuroectodermal tumor

A rare and highly malignant small round cell tumor, Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) usually occurs in the pelvis, long-axis bones, and femur. In contrast, extraosseous ES is more often found in the paraspinal region, limbs, and retroperitoneum, but is extremely rare in the stomach. We report a case of a 55-year-old woman who presented with fatigue, fever, and black stool. Preoperative computed tomography (CT) imaging showed a large ulcerative lesion of approximately 5.5 × 5.0 cm in the stomach and irregular thickening of the ulcer wall. Upper endoscopy revealed a large, irregular ulcer in the posterior wall of the stomach. Histopathological examination suggested that the mass with the largest diameter (7.5 cm) was ES. Immunohistochemistry indicated positivity for CD99. Enhanced CT of the whole body was performed but no definite masses were found in other organs, and the patient was diagnosed with primary gastric ES. The patient underwent radical distal gastrectomy with Roux-en-Y gastrojejunostomy, but refused chemoradiotherapy.

Primary epithelioid rhabdomyosarcoma of the stomach: a case report and review of literature

BACKGROUND

Epithelioid rhabdomyosarcoma is a rare tumor that generally occurs in the bladder, the parotid gland, or the skin of the neck. We describe an unusual case of primary epithelioid rhabdomyosarcoma of the stomach and review the literature.

CASE PRESENTATION

A 64-year-old woman presented with a lesion at the gastroesophageal junction. Histopathological examination showed irregularly sized round cells with low cytoplasmic content and eccentric nuclei. Mitotic figures were present. Fibrovascular septa and areas of necrosis were observed between tumor cells. Tumor cells were strongly positive for MyoD1, desmin, and myogenin, and weakly positive for actin, CD56, and PGP9.5. The ki-67 index was ≥90%.

CONCLUSIONS

Primary epithelioid rhabdomyosarcoma of the stomach is extremely rare. Better awareness of this entity is necessary for early diagnosis and treatment.

Primary Ewing's sarcoma/primitive neuroectodermal tumor of the ileum: case report of a 16-year-old Chinese female and literature review

Background

Ewing’s sarcoma (ES) and primitive neuroectodermal tumors (PNET) are closely related tumors. Although soft tissue ES/PNET are common in clinical practice, they are rare in the small intestine. Because of the absence of characteristic clinical symptoms, they are easily misdiagnosed as other benign or malignant diseases.

Case presentation

Here, we present the case of a 16-year-old female who complained of anemia and interval hematochezia. Her serum test results showed only a slight elevation of CA-125 and a low level of hemoglobin. Computer tomography and magnetic resonance imaging revealed a cystic and solid mass in the lower abdominal quadrant and pelvic region, which prompted suspicion of a malignant gastrointestinal stromal tumor of the small intestine. After resection, the tumor’s histology and immunohistochemistry (positive for CD99, vimentin and synaptophysin) results suggested ES/PNET. Fluorescent in situ hybridization tests proved the breakpoint rearrangement of the EWSR1 gene in chr 22.Ultrastructural analysis revealed neurosecretory and glycogen granules in the tumor cell cytoplasm.

Conclusions

Together, these data supported the diagnosis of a rare case of localized ES/PNET in the small intestine without adjuvant chemo- or radiotherapy. To our knowledge, this is the first report from China of a primary small bowel ES/PNET in the English-language literature. In addition, on the basis of findings from previous publications and the current case, the optimal treatment for localized gastrointestinal ES/PNET is discussed.