Malignant bone tumors in children: It’s hard to miss a zebra

The report by Dhinsa, Mahon, and Strahlen­dorf in the May issue of the BCMJ [2020;62:130–133] regarding the delays in the early recognition of solitary childhood neoplasms such as osteosarcoma troubled me. The marked delays documented by the authors in their review could have been avoided if more attention had been paid to all the symptoms at initial presentation by the first caregiver, as well as there being a thoughtful and complete physical examination of the patient before any investigations.

Too often modern medical practice counsels one to follow established algorithms and test results rather than old-fashioned question-and-answer patient interviews and direct physical examination. Their report only confirms my suspicion. To me, it always seemed that if you knew the right questions to ask then the correct diagnosis was more likely to be pursued. As well, the accurate physical examination of the musculoskeletal system appears to be a lost art.

The clinical suspicion and recognition of an underlying bone neoplasm as an explanation for persistent limb pain in children is not quite as difficult as their article suggests. Before ordering a plethora of imaging studies, a few typical and characteristic symptoms should be recognized, and a thoughtful physical exam completed. Because too often even academic physicians and paramedical personnel miss the key questions, I offer a few of these clues.

First, a differential diagnosis should be established based on any commonly occurring painful regional problems such as muscular injury, chronic insertional tendinitis, tendon rupture, meniscal injury, Osgood-Schlatter disease, stress fracture, bursitis, etc., then a physical examination of the painful limb completed searching for these diagnoses while recalling basic musculoskeletal anatomy.

If a possible malignancy remains a high contender, then consider the following:

• All children with significant lower limb pain will limp, have difficulty with stairs, and stop running.
• In the upper extremity, bone pain will inhibit strength and limb use.
• All bone malignancies demonstrate pain at rest.
• While this limb pain is always present, at times it may be ignorable.
• The typical pain is dull, aching, centrally within the limb, and poorly localized. It is not superficial.
• The limb is not tender and is not restricted in motion.
• Local redness and heat are never observed.
• Rest alone does not relieve the limb pain.
• Simple analgesics do not relieve the pain.
• A sling or brace or compression bandage is unhelpful.
• Applying heat, massage, stretching, or transcutaneous stimulation does not help.
• Evening pain interferes with achieving an easy sleep.
• Night pain often wakes even a sound sleeper.
• Morning limb pain is noticed upon waking and rising.
• A palpable soft tissue mass is a late and ominous sign.

If you pay attention to the clues and follow the details, an early correct diagnostic outcome is likely to be achieved.
—Richard Dewar, MD, FRCSC
Retired Clinical Associate Professor of Orthopaedic Surgery, University of Calgary, Foothills Hospital and Alberta Children’s Hospital

This letter was submitted in response to “Sometimes we need to think of zebras: An observational study on delays in the identification of bone tumors in children.”