Primary gastric Ewing sarcoma/primitive neuroectodermal tumor

Abstract

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.

Extraskeletal Ewing sarcoma of the stomach: A rare case report

“…ES is a highly malignant and small round cell tumor. It comprises classic ES of the bone, EES, and peripheral PNETs of the bone and soft tissue[ 1 ]. Primary gastric ES is exceptionally rare.…”

“…Czekalla et al [ 6 ] first reported a case of gastric ES in 2004, and few cases have been reported in the literature so far. We summarize the reported cases of primary gastric ES in Table 1 , describing their clinical presentation, immunohistochemistry findings, treatment and outcome[ 1 , 4 , 6 - 15 ]. The rare occurrence of EES in the stomach may be related to its origin from primitive tumor cells.…”

“…EES grows slowly, and the mass diameter can exceed 20 cm; however, patients often do not exhibit any evident clinical symptoms[ 21 ]. Ye et al [ 1 ] summarized 12 cases of primary gastric ES and found that it tends to occur more often in women, has nonspecific clinical manifestations, and predominantly presents as single tumors larger than 5 cm in diameter. Therefore, primary gastric ES is difficult to detect and diagnose early.…”

“…Ewing sarcoma (ES) is a rare and highly malignant small round cell tumor[ 1 ]. It is characterized by different degrees of neuroectoderm differentiation and an EWSR1-ETS fusion protein[ 2 ].…”

18F-fluorodeoxyglucose positron emission tomography / computed tomography in primary Ewing sarcoma of the lung

“…According to https://www.genecards.org, tartrate-resistant acid phosphatase has marked expression in bone, stomach, colon, liver, kidney, lung, pancreas, and prostate. The same organs/tissues, including bone and lung, are referred to in the scientific literature as loci for primary Ewing sarcoma of soft tissue [7,17,18,19,20,21]. As TRAP has a promotive effect on cancer cell elongation, proliferation, migration, and invasion [22], we can propose that TRAP inhibitors may be possible therapeutic agents.…”