Bone marrow involvement in follicular lymphoma (FL) consists of large paratrabecular lymphoid aggregates and is seen in about 85% of cases. The aggregates that appear to wrap around or hug the bony trabeculae are especially suggestive of FL. In contrast to the paratrabecular location of lymphoma nodules, the benign lymphoid aggregates are usually central. The marrow aggregates of FL are largely composed of small centrocytes and rarely show centroblasts. The cellular composition may not reflect that seen in the lymph node. This bone core is from a 34-year-old male who presented with cervical lymphadenopathy and was diagnosed with FL. The image shows the characteristic paratrabecular infiltrate of follicular lymphoma when it involves the bone marrow. More often, the involvement is subtle and easy to overlook. Flow cytometry showed B-cell markers and CD10 on the tumor cells. Image courtesy of Ed Uthman, MD, Houston, USA.