Gastric myeloid sarcoma mimicking pseudoachalasia in non-leukemic context: a singular case report.

Introduction and importance: Myeloid sarcoma (MS) is a rare tumour associated with acute myeloid leukaemia (AML) and occasionally occurs independently. It typically affects skin, bone, lymph nodes, and rarely the gastrointestinal tract, with gastric cases being extremely rare. Notably, no reported instances associate pseudoachalasia with gastric myeloid sarcoma. Case presentation: A 20-year-old male presented with severe dysphagia, refractory vomiting, and weight loss. Diagnosed with type III achalasia via oesophageal tests, subsequent gastroscopy revealed a large gastric mass, later identified as gastric myeloid sarcoma through histopathology. Clinical discussion: MS, characterized by immature blast cells, poses diagnostic challenges without typical leukaemia symptoms. Diagnosis involves immunohistochemistry, employing markers like CD33, CD34, and CD43. Optimal treatments, such as chemotherapy or stem cell transplantation, aim to delay leukaemia progression. Gastric primary de-novo myeloid sarcoma is exceedingly rare, emphasizing the need for tailored treatment strategies. Conclusion: Gastric myeloid sarcoma is an exceptionally rare tumour, especially without concurrent acute myeloid leukaemia (AML), complicating its diagnosis. This case represents the first globally documented instance of gastric myeloid sarcoma causing pseudoachalasia. Documenting this unique clinical presentation is crucial for a better grasp of gastric myeloid sarcoma's diverse manifestations.