Hereditary spherocytosis (HS) is the most prevalent red blood cell (RBC) membrane disorder. We report a rare case of acquired SPTB spherocytosis coinciding with a myelodysplastic syndrome associated U2AF1 mutation, neither found in germline DNA. The diagnosis was confirmed by Eosin-5-Maleimide binding assay and Next Generation Sequencing (NGS). The patient recovered quickly after splenectomy, which confirms that his myelodysplastic syndrome (MDS)-associated U2AF1 mutation did not affect the clinical picture. This case highlights the essence of thoroughly examining the etiology of hemolytic indices, despite bone marrow morphology and myeloid gene panel supporting a diagnosis of MDS with single line dysplasia.