Pure erythroid leukemia is a rare entity that represents less than 5% of pediatric acute myeloid leukemias and is classified according to the World Health Organization (WHO) within the group of unspecified acute leukemias. A clinical case of a 5-year-old patient admitted with septic arthritis in the Pediatric Hospital, he also presenting with fever and anemia, for which a medullogram and immunophenotype were performed and erythroleukemia was diagnosed. It can be concluded that it is necessary for its diagnosis to integrate clinical, morphological and immunophenotypic, genetic and molecular studies.

Primary Immune Thrombocytopenia (ITP) is an acquired coagulation disease characterized by a decrease in platelets below 100 x 109/L in the absence of other causes of thrombocytopenia and that may be preceded by viral processes or vaccination. A 16-year-old male adolescent who presented a febrile syndrome was diagnosed as part of the studies as an infection by cytomegalovirus, later he began to present purpuric hemorrhagic manifestations on the skin and mucous membranes, for which a medulogram was performed and the diagnosis of Primary ITP was made. Conclusions: an adolescent who developed a TIP after cytomegalovirus infection, requiring treatment with steroids and valganciclovir for its management.