Foot and Ankle Tumors

Foot and Ankle Tumors

J.C. Neilson, MD

Joseph Benevenia, MD

Valdis M. Lelkes, MD

Dr. Neilson or an immediate family member has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research-related funding (such as paid travel) from Musculoskeletal Transplant Foundation and serves as a board member, owner, officer, or committee member of Musculoskeletal Transplant Foundation. Dr. Benevenia or an immediate family member has received royalties from Rutgers University/CreOsso LLC; is a member of a speakers’ bureau or has made paid presentations on behalf of the Musculoskeletal Transplant Foundation; serves as a paid consultant to or is an employee of Merete and Onkos; serves as an unpaid consultant to Implant Cast and the New Jersey Orthopaedic Society; has stock or stock options held in CreOsso LLC; has received research or institutional support from CreOsso, Merete Medical, and the Musculoskeletal Transplant Foundation; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research-related funding (such as paid travel) from Implantcast, Merete, and Onkos; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons, the Musculoskeletal Transplant Foundation, and the Musculoskeletal Tumor Society. Neither Dr. Lelkes nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.


The evaluation, diagnosis, treatment, and referral of patients with a tumor of the foot or ankle are important in clinical practice. Orthopaedic surgeons should be vigilant to detect these tumors. A foot or ankle tumor is classified as benign or, less often, malignant and may occur within the soft tissue or bone. A mass can develop in the foot as a result of a posttraumatic or neuropathic condition or because of bone or soft-tissue infection.


Tumors of the foot or ankle are rare, and their incidence has not been well studied. In a retrospective review of 2,660 musculoskeletal tumors at any anatomic site that were surgically treated at a tertiary center over 20 years, 153 tumors were in the bone or soft tissue of the foot or ankle (5.75%; mean patient age, 33.2 years).1 Sixty of the foot and ankle tumors (39.2%) were considered to be malignant, and the remaining 93 were considered to be benign. Eighty patients (52.3%) had a soft-tissue tumor, of which giant cell tumor of the tendon sheath and pigmented villonodular synovitis were the most common. The remaining 73 patients (47.7%) had a bone tumor; giant cell tumor was the most common type.

Patient Evaluation


Radiographic analysis is important in the evaluation of both soft-tissue and bone tumors. Radiographs can indicate the aggressiveness of an osseocentric tumor. A permeative pattern suggests an aggressive, often malignant process. A geographic pattern often is characterized by a thin, eggshell-like margin of bone around the tumor and connotes a less aggressive process. This observed difference is explained by the response of the bone to the tumor. The bone is able to respond to and even contain a relatively slow-growing, unaggressive tumor. Some types of tumors are most likely to occur in a diaphyseal, metaphyseal, or epiphyseal area, but because the foot bones are small and irregular, the specific origin of a tumor can be difficult to identify. Periosteal elevation may be the result of a mass effect from tumor, and subperiosteum elevated off the bone usually indicates a relatively aggressive tumor. The pattern of periosteal elevation is described as a sunburst, onion skinning, or a Codman triangle.

The matrix of any lesion can give important clues to its origin. Cartilage tumors often have a lucent appearance and over time become mineralized in a punctate pattern. Fibrous dysplasia typically has a ground glass radiographic appearance. In comparison with normal bone, other tumors are more or less lucent or have mixed lucency; this characteristic often is helpful in the differential diagnosis of primary and metastatic tumors of bone. Cortical destruction also can indicate a relatively aggressive tumor. Extraosseous mineralization may appear adjacent to a bone lesion or in some soft-tissue masses. The most commonly seen forms of extraskeletal bone are phleboliths in an arteriovascular malformation or synovial sarcoma, mineralization of the necrotic center of soft-tissue sarcoma, peripheral mineralization of myositis ossificans, or cloudlike mineralization of an extraskeletal osteosarcoma. Radiographs can differentiate soft-tissue masses within different tissue planes by the density of air, fat, water (muscle), and bone.

CT is helpful for evaluating the character of mineralized structures, which have many characteristics in common with those of bone, as seen on plain radiographs. CT of the chest, abdomen, and pelvis is an important part of the workup for a patient with suspected metastatic carcinoma to bone.2 Although CT angiography is an effective tool for a patient who cannot undergo MRI, usually MRI is superior for precise evaluation of tumors and important surrounding structures in the foot and ankle. Obtaining high-quality MRI results for small structures in areas
such as the forefoot requires the use of small coils and a high-Tesla machine. MRI with gadolinium contrast is recommended for all soft-tissue and most bone lesions because this technique shows the amount of blood flow to a mass. By enhancing the rim of a cystic structure such as a ganglion, as well as some arteriovascular malformations and bone cysts, MRI can differentiate between a fluid-filled and a solid mass. Diffusion-weighted MRI sequences are most commonly used to assess the tumor response to radiation, chemotherapy, or ablative treatment. Magnetic resonance angiography has supplanted traditional angiography for most tumor indications, and it is useful for evaluating the blood supply to the foot before resection or reconstruction. The soft-tissue detail provided by a high-quality MRI is critical to the surgical resection of soft-tissue and bone tumors of the foot and ankle.3

Technetium Tc-99 bone scanning is useful for evaluating a stress fracture or a stress reaction that can masquerade as an osseous lesion of the foot. Whole body scanning is commonly used to identify malignant metastasis to bone, but it must be interpreted with caution because some tumors, such as multiple myeloma, eosinophilic granulomas, and large renal cell cancers, may not show significant uptake.

The use of ultrasonography in the diagnosis and management of soft-tissue tumors is constantly evolving. Ultrasonography is used to differentiate solid and fluid-filled masses, and it is an excellent tool for measuring flow in vascular anomalies. The usefulness of ultrasonography increases with the surgeon’s experience with this modality. In the treatment of tumors, ultrasonography most commonly is used for guidance during soft-tissue biopsy or the treatment of a vascular anomaly.

Positron emission tomography (PET) is useful in the evaluation of many but not all types of malignancies. Inclusion of the lower extremities is not standard during PET staging of many cancerous conditions, and whole body PET should be specified if PET evaluation is appropriate for the patient’s lesion. PET is rarely ordered by a physician other than an oncologist. PET can be useful for evaluation of the lymphatic spread of hidradenocarcinoma, melanoma, or epithelioid sarcoma, usually in conjunction with lymphoscintigraphy and sentinel node resection.4 Although PET-MRI is a promising tool for identifying tumor metastasis at diagnosis and during subsequent staging, its use has not yet been completely validated.5

Laboratory Evaluation

Laboratory testing is not necessary for most tumors of the foot and ankle. However, inflammatory markers, white blood cell analysis, and cultures are appropriate if an infectious origin is suspected. Complete blood cell counts are useful for identifying leukemia or lymphoma and may reveal anemia in a patient with multiple myeloma or a widely metastatic cancer. Protein electrophoresis and light chain evaluations can be diagnostic for multiple myeloma. Some other primary cancers have blood markers, such as prostate-specific antigen. Metabolic analysis can reveal kidney or liver damage, malnutrition, or electrolyte abnormalities.2 Calcium levels should be checked in all patients with metastatic disease to the bone because increased bone turnover can lead to increased serum calcium or to cardiac conditions including fatal arrhythmias.


Pathologic analysis should be performed for all masses. An excision, incision, or needle technique can be used, depending on the size, location, and imaging characteristics of the lesion as well as the experience of the surgeon. Excisional biopsy is appropriate if a cuff of normal tissue can be obtained around the lesion to ensure negative margins. This saves the patient from a wider re-excision if the lesion is determined to be malignant by pathology. Incisional biopsy should be considered for a relatively large mass, which should be presumed to be malignant until histologic analysis proves otherwise. In general, biopsies should be performed or guided by a surgeon trained in treating primary malignant tumors of the extremity. Frozen section should be obtained during an open biopsy to determine whether lesional tissue is obtained and thereby increase the likelihood of a correct diagnosis. A needle biopsy can be done with or without imaging guidance. Ultrasonography or CT can be used to increase the likelihood of obtaining tissue from the lesion by targeting solid, nonnecrotic areas and correlating these findings with those of contrast-enhanced MRI. A thoughtful approach to needle biopsy is essential because bleeding from deep or subcutaneous vessels could allow tumor tissue to spread along uninvolved tissue planes and thereby increase the resection area.6 Fine-needle aspiration biopsy can be used in many masses, but this technique is operator dependent. Core biopsy allows more tissue to be obtained, but its use is limited to tumors large enough to accommodate the throw of the needle.

The small amount of subcutaneous tissue in the foot and ankle often allows relatively early identification of a mass. Usually, a mass smaller than 3 cm is benign. A mass larger than 3 cm is more likely to be malignant. However, a recent study found that malignant bone tumors in the foot are 5 to 30 times smaller than those in other skeletal areas.7 All biopsies should be done with great care; an inexpert biopsy can increase the likelihood that a secondary surgical procedure, tissue transfer, or amputation will be required.8

Feb 27, 2020 | Posted by in ORTHOPEDIC | Comments Off on Foot and Ankle Tumors

Full access? Get Clinical Tree

Get Clinical Tree app for offline access