Ewing's sarcoma of the lesser sac masquerading as a pancreatic tumor

Rare presentation in a rare case of pancreatic extraosseous Ewing's sarcoma: A case report

RATIONALE

Extraosseous Ewing's sarcoma is a rare tumor which is aggressive with poor prognosis; it can occur anywhere in the body, but scantily in the pancreas. Pancreatic Ewing's sarcoma is not reported commonly, with inconsistent clinical manifestations. In this regard, early recognition of this disease is very important for the patient's sake.

PATIENT CONCERNS

A 16-year-old boy presented with left lower quadrant abdominal pain for 2 months, and left flank pain with dysuria for 1 month.

DIAGNOSIS

Abdominal and renal ultrasonography found a mass between the spleen and left kidney as well as left renal pelvic dilatation. Abdominal computed tomography found a heterogenous mass derived from the tail of the pancreas. Serial examinations revealed that the mass was a pancreatic Ewing's sarcoma. Furthermore, no metastasis was documented.

INTERVENTIONS

The tumor was totally excised after 6 months of chemotherapy, which included 10 courses of neoadjuvant chemotherapy with vincristine, epirubicin, and cyclophosphamide, alternating with ifosfamide and etoposide. The patient completed consolidation chemotherapy with vincristine, epirubicin, and cyclophosphamide, alternating with ifosfamide and etoposide for 5 courses. Radiotherapy was applied to the tumor-involved region and tumor bed.

OUTCOMES

To date, the malignancy has not recurred since the treatment was completed 4 years ago. There are no complications from the treatment for the patient.

LESSONS

The pancreas is a very rare extraosseous location for Ewing's sarcoma. Pancreatic extraosseous Ewing's sarcoma should be regarded as a differential diagnosis of non-urinary originated left flank pain with dysuria in adolescents.

Intraabdominal lesser sac metastasis from Ewing's sarcoma: An exceptional localization

Ewing's sarcoma/primitive neuroectodermal tumor is rare and aggressive with a poor prognosis. Intraabdominal metastases are an uncommon condition. Metastasis in the lesser sac is an exceptional occurrence. To the best of our knowledge, this location has not been described previously. We report a case of a 15-year-old patient treated for Ewing's sarcoma of the left arm 6 years back. She had developed a suspicious mass in the lesser sac 6 years following her primary tumor. The histopathologic exam revealed a tumor with "small round cells" that were positive for CD99, confirming the relapse of Ewing's sarcoma. The relapse was successfully managed with chemotherapy and surgery. Intraabdominal, extraintestinal masses in patients treated previously for Ewing's sarcoma should be considered as Ewing's sarcoma relapse in the differential diagnosis. We fully describe the management of this atypical relapse, with different components of clinical, radiological, and histological findings.

Metastasis of Ewing Sarcoma to the Pancreas: Case Report and Literature Review

Ewing sarcoma (ES) is a highly aggressive malignant bone cancer. ES is part of the Ewing sarcoma family of tumors (ESFT), which express characteristic t(11;22) translocation as well as higher levels of CD99. Given that metastasis and tumor burden are significant prognostic factors in patient's response to treatment, prompt diagnosis is needed to effectively treat ESFT patients. However, the challenges in classifying and characterizing ESFT complicate effective management and treatment of ES. In this report, we present a rare case of ES metastasis to the pancreas. Upon review of the literature, we found 39 cases of ESFT involving the pancreas, but only 3 were metastatic to the pancreas while the remaining cases of ESFT primarily originated from the pancreas. Given the rarity of such metastasis, the positive outcome in our patient's case may explain the importance of prompt diagnosis in order to initiate appropriate treatment.