What large cells with multiple nuclei are noted in bone marrow core biopsy close to the endosteum?

The presence of large cells with multiple nuclei in bone marrow core biopsy near the endosteum can be attributed to osteoclasts. Osteoclasts are specialized multinucleated cells that derive from monocyte/macrophage lineage and play a crucial role in bone resorption. Their characteristic multiple nuclei result from the fusion of precursor cells, making them distinguishable in histological examinations.

These cells are typically found in close proximity to the bone surface, including the endosteal surface, where they are involved in the breakdown of bone tissue. This process is vital for normal bone remodeling and maintaining calcium homeostasis in the body. The identification of these multinucleated cells can aid in understanding various bone diseases, including conditions resulting in increased bone resorption, like osteoporosis.

In contrast, megakaryocytes are large cells responsible for platelet production, but they are not multinucleated in the same context and location as osteoclasts. Adipocytes are fat cells and are usually not multinucleated, while fibroblasts are involved in connective tissue formation and repair, also lacking the multinucleated characteristic seen in osteoclasts. Therefore, the identification of osteoclasts aligns correctly with the question's criteria.