We will be performing site maintenance on AAOS.org on February 8th from 7:00 PM – 9:00 PM CST which may cause sitewide downtime. We apologize for the inconvenience.

Joel Mayerson, MD

AAOS Now

Published 12/1/2014

Lumps, Bumps, and What to Do with Them

JAAOS article examines “Diagnosis and Management of Soft-tissue Masses”

Nearly every orthopaedist—as well as other providers of musculoskeletal care—has encountered patients who have soft-tissue masses of the extremities. The November issue of the Journal of the AAOS (JAAOS) takes a look at how orthopaedic surgeons and others can properly diagnose and manage these lumps and bumps. AAOS Now Editor-in-Chief Designee Eeric Truumees, MD, recently spoke with lead author Joel Mayerson, MD, to uncover more information about the approach to soft-tissue masses, imaging recommendations, and promising research for the future.

Dr. Truumees: Do any benign soft-tissue lesions degenerate into malignancies?

Dr. Mayerson: Most benign soft-tissue masses do not undergo malignant degeneration. In rare instances—such as a well-differentiated liposarcoma/atypical lipomatous tumor—malignant transformation can occur, but usually only when the tumor has been allowed to grow for a long time.

Dr. Truumees: I’ve seen infections develop in patients with bursitis. Are these patients at risk of neoplastic degeneration?

Dr. Mayerson: There is no risk of neoplastic degeneration associated with bursitis.

Dr. Truumees: How does the approach to soft-tissue tumors differ with locally aggressive lesions like desmoid tumors compared to less aggressive lesions or malignancies with high metastatic potential?

Dr. Mayerson: Desmoid tumors are benign and have no metastatic potential, but they are extremely locally invasive with a very high recurrence rate. Because of this, management of desmoid tumors has changed. Easily resectable primary tumors should be excised. If the tumor recurs, multimodal management—including radiation therapy and/or various chemotherapy modalities—should be considered.

Many orthopaedic oncologists are now recommending observation of clinically and radiographically stable desmoid tumors that are not near neurovascular structures. This is a markedly different recommendation than for any type of soft-tissue sarcoma. No one would recommend observation for a sarcoma.

Dr. Truumees: You point out the myth that only painful lesions should cause worry and note that smaller sarcomas are often painless if they aren’t compressing neurologic structures. What brings these patients to a physician?

Dr. Mayerson: The most common presentation of a soft-tissue sarcoma is a painless growing mass. They are usually more firm than muscle. A painful soft-tissue mass is often less likely to be malignant than if it were painless. The caveat to this is a malignant peripheral nerve sheath tumor.

Most patients seek care from their local physician once they notice a mass or they notice that it is growing. Most orthopaedic oncology surgeons are willing to see patients within their referral base whenever a referring physician calls. The key is to recognize that the mass is more firm than muscle and growing; therefore, it should be considered a sarcoma until proven otherwise.

An excisional biopsy should not be performed by someone not trained in the management of musculoskeletal tumors unless a definitive diagnosis can be made on MRI prior to the surgery. An example of this would be a lipoma for a benign tumor that could be treated with excisional biopsy.

Dr. Truumees: You state that larger masses, above 5 cm, deep to the fascia, and firmer than the surrounding muscle should raise suspicion for malignancy. When masses do not meet those criteria, how worried should the evaluating physician be? 

Dr. Mayerson: A soft, painless mass that is less than 5 cm, superficial to the fascia, and not bothersome to the patient can be observed over a couple of months to evaluate for growth. If the lesion grows, it should be referred to a musculoskeletal oncologist; if it remains stable, observation can continue.

Any mass larger than 5 cm that is questionably firm should be evaluated with an MRI scan. A mass deep to the fascia with indistinct borders and close to 5 cm in size should also be evaluated with an MRI. In younger children, where a cyst is possible (such as in the popliteal fossa), ultrasound can be used as a screening test to determine whether an MRI is necessary.

Stable masses that do not demonstrate worrisome characteristics can be followed with MRIs at 3- to 6-month intervals for 1 to 2 years. If the MRI raises concerns, the mass should be biopsied. Any mass deep to fascia should have an MRI prior to any attempted biopsy. Lesions consistent with a benign mass such as lipoma that are radiographically stable can be observed.

Dr. Truumees: What should the orthopaedist consider when ordering an MRI—such as contrast elements, size, and the need for postcontrast images?

Joel Mayerson, MD
Fig. 1 Axial T1-weighted gadolinium-enhanced MRI demonstrating a solid component mass (arrow) with heterogeneous enhancement, indicating a cystic lesion with solid components that raise suspicion for sarcoma. Reproduced from Mayerson JL, Scharschmidt TJ, Lewis VO, Morris CD: Diagnosis and Management of Soft-Tissue Masses, J Am Acad Orthop Surg 2014;22(11): 742-750.

Dr. Mayerson: Gadolinium contrast dye should be added for further evaluation of tissue content versus fluid content (Fig. 1). Whenever possible, the entire segment of the affected body part should be included in the MRI scan (ie, the entire arm for arm soft-tissue mass). I typically use postcontrast images on the diagnostic MRI to help identify where the biopsy should be. I also use postcontrast images to help differentiate between a seroma and a recurrent mass during long-term surveillance follow-up.

Dr. Truumees: You discuss the utility of ultrasound as an inexpensive and accessible tool to evaluate soft-tissue masses. Do you perform ultrasound assessment in the office or do you refer it out?

Dr. Mayerson: I refer this test to the radiologists at our institution.

Dr. Truumees: PET-CT can image a tumor and assess metabolic activity. Who typically orders this test? 

Dr. Mayerson: Patients who have been referred by a medical oncologist will often have a PET-CT scan. Most other physicians and specialists refer to their local musculoskeletal oncologist immediately and do not order this very expensive test. I will order the PET-CT when I believe it will possibly change management of the patient.

Dr. Truumees: What laboratory or staging studies should be ordered?

Dr. Mayerson: No laboratory values are helpful in diagnosing soft-tissue sarcoma. We often obtain a complete blood count with differential, erythrocyte sedimentation rate, and C-reactive protein to help in evaluation of a mass that could be an infection masquerading as a tumor. Staging studies for a soft-tissue sarcoma can include a CT scan of the chest, abdomen, and pelvis, and/or a PET-CT scan. Abdominal or pelvic CT scans are only ordered for specific tumors that have the propensity to metastasize to the retroperitoneum. Most musculoskeletal oncologists follow the guidelines published by the National Comprehensive Cancer Network.

Dr. Truumees: Some physicians who refer patienst to a musculoskeletal oncologist want to provide as much information as possible, so they order needle biopsies or perform them themselves. Is this a good idea?

Dr. Mayerson: Many studies, including two national studies from the Musculoskeletal Tumor Society, report high complication rates for biopsies performed at a nontertiary sarcoma referral center (including up to 4 percent unnecessary amputations). These rare tumors are best managed when the biopsy is performed by the physician who is going to treat the problem. For this reason, nearly all orthopaedic oncologists would rather have the patient referred immediately after an imaging study documents a potentially malignant mass or the physical exam and history raise flags for malignancy.

Dr. Truumees: What tests and therapies on the horizon might affect the evaluation and management of soft-tissue tumors?

Dr. Mayerson: Molecular testing is expanding rapidly. New genetic abnormalities are being identified for many different types of soft-tissue sarcomas and may be used for diagnostic purposes. Specific targeted therapy is being tested in national clinical trials as an adjunct to traditional chemotherapy.

An example of a revolutionary new treatment can be seen in the use of a tyrosine kinase inhibitor for gastrointestinal stromal tumor. To date, however, none of these new targeted therapy agents has become standard of care. All of them are currently under investigation.

The advent of better technology is improving radiation therapy with more targeted beams that can kill the tumor without causing as much damage to the surrounding normal soft tissues. This can diminish long-term complications such as fibrosis and lymphedema.

Megaprosthetic implants have made limb salvage commonplace. These prostheses are very cosmetic and work well for patients who are not very active. From a functional standpoint, patients who want to be very active and participate in sporting activities that involve running, jumping, twisting, and turning are often better off with an amputation.

If above-knee amputation is necessary, rotationplasty may be used to provide function that approximates a below-knee amputation. This markedly decreases the energy expenditure to ambulate with the prosthesis and results in improved functional capacity. Rotationplasty is best performed in young children who would have a potentially significant leg length discrepancy with traditional limb salvage methods and those who want to pursue vigorous sports.

A new clinical trial by the national cooperative research groups of the Children’s Oncology Group and the National Radiation Group is studying the benefits of pazopanib, a new drug. This is another tyrosine kinase inhibitor that may improve disease-free and overall survival rates when added to traditional chemotherapy and radiation therapy. This is the first national study to include both children and adults in the same treatment protocol. My partner, Thomas J. Scharschmidt, MD, is national coprinicpal investigator on this study.

The Sarcoma Advanced Research Consortium is also conducting studies. Whenever possible, every sarcoma patient should be part of a clinical trial, because this is the only way that we can study rare tumors and make advances in patient care.

Dr. Mayerson’s coauthors for “Diagnosis and Management of Soft-tissue Masses” include Dr. Scharschmidt; Valerae O. Lewis, MD, and Carol D. Morris, MD, MS. A link to the article can be found here.