This is a fairly common reason for a referral to a musculoskeletal specialist. In this situation, the patient suffers either a minor injury or develops symptoms related to non-neoplastic musculoskeletal pathology. As part of the primary physician's investigation of the injury or symptoms, radiographs are taken, showing a bone lesion in the symptomatic anatomical site. Often, the primary physician tells the patient that he or she has a bone tumor, causing considerable anxiety about the diagnosis while waiting to consult with the musculoskeletal specialist.
Most frequently, this clinical scenario involves the shoulder and the knee. The prevalence of incidental findings at these two joints is related to the fact that they are a common location of benign late lesions, such as enchondromas, and are also common locations for pain caused by non-neoplastic conditions, such as rotator cuff tendonitis and chondromalacia patella. The most important aspect of determining the diagnosis in this situation is to take a careful history and perform a physical examination that determines the source of the patient's symptoms.
Carefully evaluate the history of pain. If the abnormal radiograph was part of a work-up after a traumatic injury, find out whether the trauma was mechanically significant or simply drew the patient's attention to a pre-existing painful condition. Was there pain prior to the injury? Has the pain abated since the injury? Probe for symptoms that might suggest neoplasia, such as pain at rest, night pain, and pain that is not associated with mechanical stress to the region.
If there is no history of trauma and the abnormal radiograph was occasioned by the onset of spontaneous pain, concentrate on eliciting features related to musculoskeletal pain symptoms common to the affected anatomical region. Exacerbating factors are important: Rotator cuff pain is worse with overhead activity and internal or external rotation of the shoulder; patella-femoral pain worsens with stair climbing or sitting down and standing up from a sitting position. Determine if the patient has pain at other anatomical site. Osteoarthritis of the knee, for example, may be associated with pain at other large joints. Also, metastatic disease in one skeletal site may be accompanied by pain at other locations.
During the physical examination, determine whether aspects of musculoskeletal pathology other than neoplastic conditions are causing the patient's pain. A bone tumor in the proximal humerus may cause pain with overhead lifting, but unless it is locally advanced, it probably will not result in the weakness and pain with shoulder rotation that is usually observed with rotator cuff tendonitis. An aggressive or malignant bone tumor in the distal femoral region may cause pain while walking or at rest, but it is not likely to result in the specific joint line tenderness observed in a meniscal tear or osteoarthritis.
Evaluate the patient for evidence of arthritis at other typical sites, such as limitation of hip internal rotation and pain on stressing of the carpo-metacarpal joints of the thumb. Determine whether the tenderness present in the region is associated with the bony lesion or is at the joint.
Analyze the plain radiograph to determine if the bony abnormality warrants further investigation or if it has the features of a latent, incidental bone lesion that is unlikely to have caused the patient's symptoms. The most common latent, incidental lesions are enchondromas, bone infarcts, non-ossifying fibromas, and small regions of fibrous dysplasia.
Observation is the best investigation for latent, incidental lesions. The risk of observation is that the bony mass has been misdiagnosed as a latent lesion when it is, in fact, an aggressive or even malignant tumor. With proper analysis of the plain radiograph, the clinician will be certain that the lesion is at worst a low-grade bone sarcoma and that disease progression will result in local growth of the lesion rather than metastasis.
If it appears that the pain is related to non-neoplastic musculoskeletal causes, reassure the patient about the bone tumor and recommend that he or she obtain treatment for the actual pathology. Advise the patient to return for follow-up radiographs, even if it is evident that the lesion is probably benign and latent. Confirmation that the lesion has not progressed on follow-up radiographs taken over the 2 years following presentation is final evidence that the lesion is not active. The first follow-up radiograph should be within 3 months of the initial consultation. If there are no radiographic change observed in the lesion at 3 months, follow up is lengthened to 6 months, and then 1 year. Once the lesion shows no change over 2 or 3 years, regular visits can be suspended.
The Other Presenting Complaints