Which of the following is NOT a cause of acquired aplastic anemia?

Acquired aplastic anemia is a condition characterized by the failure of bone marrow to produce sufficient blood cells, leading to anemia, neutropenia, and thrombocytopenia. The causes of acquired aplastic anemia are typically linked to exposures or conditions that damage the bone marrow cells.

Benzene exposure, chemotherapy agents, and certain infections like cytomegalovirus (CMV) are all known triggers of acquired aplastic anemia. Benzene, commonly found in various industrial settings, is a well-documented risk factor because it is toxic to hematopoietic stem cells in the bone marrow. Chemotherapy agents can lead to bone marrow suppression as they target rapidly dividing cells, including not only cancer cells but also normal hematopoietic cells. Infections like CMV can also contribute to bone marrow suppression, although the mechanisms may vary and often involve immune-mediated damage.

Thyroid disease, on the other hand, does not directly cause bone marrow failure or aplastic anemia. While severe hypothyroidism may lead to various hematological changes and some autoimmune thyroid disorders may have associated hematological issues, they are not typically considered direct causes of acquired aplastic anemia. Thus, of the options provided, thyroid disease stands out as the condition that is not