Case Example: Increasing Shoulder Pain in a Child
Presentation. A 15-year-old male child had a 3-month history of increasing shoulder pain that became worse with activity and also kept him awake at night. He did not report any systemic symptoms (fever, chills, fatigue) and had not lost any weight.
Management. The history of increasing pain, particularly during rest and at night, in a child is concerning and warrants a plain radiograph for further investigation (moderate evidence). The radiographs (Figure 1) demonstrated a destructive lesion of the proximal humerus with an incomplete periosteal reaction and a poorly defined interface between the bone and tumor in the intramedullary canal. An MRI is indicated, given the combination of pain (moderate evidence), periosteal reaction (moderate evidence), and permeative borders (moderate evidence). An MRI (Figure 2) confirmed the presence of an aggressive neoplasm. The patient was referred to a sarcoma center where a biopsy demonstrated a high-grade osteosarcoma. The sarcoma center completed staging and treated the patient with neoadjuvant chemotherapy and limb-sparing surgical resection and reconstruction.
Radiograph of the left shoulder demonstrating a proximal humerus lesion with a periosteal reaction and a wide zone of transition at the bone-tumor interface.
MRI demonstrating a solid and heterogeneous lesion in the proximal humerus with soft-tissue extension that should cause concern for a primary sarcoma of bone.
Case Example: Incidental Finding in a Patient With Knee Pain
Presentation. A 54-year-old woman had a 9-month history of medial-sided left knee pain. She stated that the pain was exacerbated by activity, was not present with rest, and did not wake her at night. She took acetaminophen and nonsteroidal anti-inflammatories as needed with relief of symptoms.
Management. Given a clinical presentation suggestive of mild knee degenerative joint disease, a plain radiograph was obtained (Figure 3). The radiographs demonstrated a radiodense lesion in the distal femoral diaphyseal-metaphyseal junction, most consistent with a low-grade cartilaginous neoplasm, favoring benign enchondroma. No concerning features such as a periosteal reaction, poorly defined borders, or a soft-tissue mass was present. Clinically, her pain was explained by early and mild degenerative changes and was unlikely to be due to this lesion. None of the characteristics of her radiographic or clinical presentation justify advanced imaging. The most appropriate management is another plain radiograph in 3 months with continued surveillance to confirm stability every 3 to 6 months for 2 years. Discussion with a musculoskeletal radiologist or orthopaedic oncologist should be considered.
Radiograph of the distal femur demonstrating modest degenerative changes of the knee joint and a calcified intramedullary lesion consistent with an enchondroma.
Case Example: Soft-tissue Mass in a Thigh
Presentation. A 67-year-old woman had a subtle fullness in her right thigh. She stated that she first noticed this about 2 months ago and thought it may be enlarging. It was not painful at rest but was tender when compressed. On examination, there was a palpable mass on the medial aspect of the thigh >5 cm in diameter. The mass flattened when the knee was extended and there were no over-riding skin changes.
Management. Plain radiographs may be obtained during the initial evaluation of soft-tissue tumors (Figure 4). In this case, they revealed a soft-tissue density that was isointense with muscle, did not show any internal calcifications, and did not demonstrate an adjacent cortical reaction. At this point, the differential diagnosis remains wide and further imaging is warranted. Ultrasounds are a cost-effective and noninvasive intervention that can distinguish between benign and malignant entities (moderate evidence). However, they are more accurate in superficial lesions and may be inadequate in deep or large tumors such as this one. An MRI would be the study of choice in tumors larger than 5 cm (strong evidence) because it is able to reliably identify neoplastic tissue and distinguish between solid and cystic areas (moderate evidence) (Figure 5). If there is a question about the aggressiveness of the lesion, intravenous contrast may be used to determine whether the tumor is benign or malignant (strong evidence) because malignant tumors routinely demonstrate a heterogeneous signal (strong evidence). CT scans may be used in place of MRI in patients with contraindications (pacemaker, cerebral aneurysm clips). In this case, the MRI is highly suggestive of a malignancy, and the patient was referred to a sarcoma center before biopsy or additional imaging. A core needle biopsy was done, in line with the anticipated limb-sparing incision with guidance from the treating surgeon, and demonstrated a high-grade undifferentiated pleomorphic sarcoma. The patient was enrolled in a clinical trial and treated with neoadjuvant radiation before surgical excision.
Radiograph of the distal femur demonstrating a subtle soft-tissue mass without internal calcification.
This project was supported by the American Academy of Orthopaedic Surgeons Quality and Patient Safety Action Fund with equal contributions from the American Academy of Orthopaedic Surgeons and Musculoskeletal Tumor Society.
This Clinical Practice Guideline was approved by the Musculoskeletal Tumor Society Executive Committee on February 19, 2018, and endorsed by the American Academy of Orthopaedic Surgeons Board of Directors on June 9, 2018.
Participating Societies: Musculoskeletal Tumor Society, American Academy of Orthopaedic Surgeons, American College of Radiology. Guideline Development Participants: Benjamin J. Miller, MD, MS (Chair), Kenneth R. Gundle, MD, Carlos M. Pereira Betancourt, MD, Ahmet Salduz, MD, Ana Cecilia Belzarena Genovese, MD, Mark D. Murphy, MD, Michael Mulligan, MD, Kurt R. Weiss, MD, Lukas M. Nystrom, MD, Matthew R. DiCaprio, MD, Eric R. Henderson, MD, and Catherine C. Roberts, MD. Staff of the AAOS: Kaitlyn Sevarino, MBA, Jayson N. Murray, MA, Kyle Mullen, MPH, Anne Woznica, MLIS, AHIP, and Mary DeMars.
J Am Acad Orthop Surg. 2019;27(22):e1001-e1008. © 2019 American Academy of Orthopaedic Surgeons