Non-Langerhans cell histiocytosis is a rare disease which seldom affects adults. We report a case of a 32-year-old Bulgarian woman living with HIV. She developed severe anemia, extreme splenomegaly, requiring splenectomy and vertebral tumor formations leading to fracture. The diagnosis was confirmed by histological examination of the spleen, but subsequently questioned and a cumulative disease was discussed. After genetic testing, a cumulative disease was ruled out and the condition was determined to be Non-Langerhans cell histiocytosis. According to literature data, the disease has a high mortality rate. However, in our case, we should also note that there was a delay in diagnosis by several months due to difficulties in the clarification of the hematological disorder.