Refractory anaemia with ringed sideroblasts associated with marked thrombocytosis (RARS-T) is a rare entity belonging to myeloproliferative/myelodysplastic syndromes. Myelodysplastic syndrome (MDS) with isolated del(5q) is a category of MDS characterized by better prognosis and specific morphology. Herein we describe a 69-year-old male with anaemia and thrombocytosis presenting with coexisting features of both these rare diseases. After the description of the clinical data, we summarize the histopathologic, cytogenetic and molecular findings, as well as introduced treatment. Next, we discuss possible diagnostic options with reference to the relevant literature.