aplastic

Aplastic is an adjective used in biology and medicine to describe tissue, organs, or cells that have failed to form or develop as normal. The term derives from the Greek a-, meaning without, and plasis, meaning formation or molding.

In medical usage, aplasia and related aplastic conditions refer to the absence or failure of development. Aplasia denotes failure of an organ or tissue to develop fully, which may be congenital or acquired. Aplastic generally describes a process in which tissues or marrow fail to maintain or form new cells. A well-known example is aplastic anemia, a condition in which bone marrow does not produce enough blood cells, leading to pancytopenia and increased risk of infection or bleeding.

Aplastic conditions may be caused by genetic disorders, toxins, radiation, infections, or autoimmune processes, and they can range from partial to complete lack of formation. Diagnosis typically involves clinical evaluation and laboratory tests, including blood counts and marrow biopsy. Treatment varies with cause and severity and may include supportive care, immunosuppressive therapy, or stem cell transplantation.

In related terminology, aplasia refers to the absence of development of an organ or tissue, while the term aplastic is used to describe the non-formed or failed-formation state. The term can appear in various medical contexts, including descriptions of tissue underdevelopment or loss in clinical reports.