extramedulläre

Extramedullary refers to any tissue or tumor that grows outside of the bone marrow. Normally, blood cell production, also known as hematopoiesis, occurs within the medullary cavity of long bones. However, under certain conditions, such as in myelofibrosis or other myeloproliferative neoplasms, hematopoiesis can occur in extramedullary sites like the spleen, liver, or lymph nodes. This phenomenon is termed extramedullary hematopoiesis.

Extramedullary hematopoiesis is a compensatory mechanism where the body attempts to produce blood cells when the bone marrow is no longer functioning efficiently. While it can help maintain adequate blood counts, it can also lead to complications. Enlargement of the spleen (splenomegaly) and liver (hepatomegaly) are common consequences, which can cause abdominal discomfort, pain, and pressure on surrounding organs. In some cases, extramedullary masses can form in other locations, such as the central nervous system or skin, and these can be associated with specific symptoms depending on their location and size. The diagnosis of extramedullary hematopoiesis is typically made through imaging studies like ultrasound, CT scans, or MRI, and confirmed by biopsy if necessary. Treatment focuses on managing the underlying condition and alleviating symptoms caused by the extramedullary tissue.