Myeloid sarcoma of the pancreas: A case report and literature review

INTRODUCTION: Myeloid sarcoma (MS) is an extramedullary mass, consisting of myeloid blasts with or without maturation, which efface the normal tissue architecture. It occurs mainly in lymph nodes, skin and soft tissue, testis, bone, peritoneum, and gastrointestinal tract, but rarely in the pancreas. Because their clinical courses, treatments, and prognoses are quite different, it is crucially important to distinguish between MS and pancreatic cancer. PATIENT CONCERNS: We herein report a rare case of acute myeloid leukemia (AML) which presented with a pancreatic mass that mimicked pancreatic cancer. Diagnosis: The diagnosis of MS was established based on immunohistochemical (IHC) analysis and bone marrow examination which revealed neoplastic cells with CD34+/CD117+. INTERVENTIONS: The patient was actively treated with chemotherapy. OUTCOMES: After 4 cycles of chemotherapy, the lesion in pancreas was significantly reduced, and the patient is still receiving further chemotherapy. CONCLUSION: When we encounter a patient suspected of pancreatic cancer with blood cell abnormalities and no significant increase in carbohydrate antigen 19-9 (CA19-9), we need to be aware of the possibility of pancreatic MS. Preoperative pathological biopsy and IHC are indispensable. Misdiagnosis is common if we rely solely on imaging.