Myelofibrosis: This condition is characterized by the replacement of bone marrow with fibrous tissue, leading to ineffective hematopoiesis and resulting in pancytopenia. Hepatosplenomegaly is common due to extramedullary hematopoiesis.

Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can cause hepatosplenomegaly and pancytopenia due to marrow infiltration by lymphoma cells.
Chronic Lymphocytic Leukemia (CLL): CLL can lead to pancytopenia due to bone marrow infiltration and splenomegaly due to the accumulation of malignant cells.
Myeloproliferative Neoplasms (MPN): Conditions like Polycythemia Vera, Essential Thrombocytosis, and Primary Myelofibrosis can present with hepatosplenomegaly and, in advanced stages, pancytopenia due to marrow fibrosis or ineffective hematopoiesis.

Sepsis: Although less common as a primary cause of pancytopenia with hepatosplenomegaly, sepsis can lead to bone marrow suppression and multi-organ dysfunction, including liver and spleen enlargement. Missing this diagnosis can be fatal.
Tuberculosis: Disseminated TB can cause hepatosplenomegaly and pancytopenia due to bone marrow involvement. It's crucial not to miss this diagnosis due to its treatability with antimicrobial therapy.
Histiocytosis: Rare conditions like Langerhans cell histiocytosis can infiltrate the bone marrow, liver, and spleen, leading to pancytopenia and organomegaly. Early diagnosis is critical for effective treatment.

Gaucher's Disease: A genetic disorder leading to the accumulation of glucocerebroside in cells, causing hepatosplenomegaly and pancytopenia due to marrow infiltration.
Niemann-Pick Disease: Another genetic disorder that can cause hepatosplenomegaly and pancytopenia due to the accumulation of sphingomyelin in cells.
Kala-Azar (Visceral Leishmaniasis): A parasitic infection that can cause hepatosplenomegaly and pancytopenia, more common in endemic areas.