According to the University of Washington School of Medicine, bone lucencies can be caused by a variety of factors, such as cysts, cancer, benign tumors or infection. Healio goes on to point out that fractures also cause bone lucencies.
Dr. Joseph Accurso on HealthTap describes lucencies as areas on an X-ray where the bone is less dense, which can be a sign of bone lesions. Many other factors can cause bone lucencies. The University of Washington School of Medicine explains that one of these major factors is tumors, whether benign or malignant. Some of the most common bone tumors are caused by osteoblastoma, myeloma, chondroblastoma, hemangloma and enchondroma.
When bone lucencies are caused by fractures, Healio makes the correlation between these bone breaks and a Vitamin D deficiency.
Wikipedia says that osteoblastoma, one of the causes of bone lucency, occurs when abnormal bone-like tissue grows around the bones, creating tumors. Although these tumors are considered benign, they can interfere with the body's movement depending on their placement, such as if they are located on the spinal cord or nerve roots. This cancer is heralded by bone pain, swelling and tenderness. It is a very rare disease and even more rarely fatal. Doctors mostly treat it with surgery.