Bone tumors of the hand and wrist are rare overall. Primary malignant bone tumors in the distal upper extremity are far more uncommon. Most surgeons lack experience with such tumors; therefore, misdiagnosis and mismanagement can occur and result in disastrous and potentially fatal outcomes. Clinicians should have a thorough understanding of the principles of tumor evaluation and management before caring for patients with bone lesions of the hand and wrist. In general, only surgeons who are comfortable with the principles of musculoskeletal oncology and limb salvage surgery should initiate surgical management.
Evaluation of the patient with a bone tumor begins with a focused history and physical examination. The patient should be questioned regarding the onset and duration of pain, swelling, functional limitations, constitutional symptoms, and weight loss. Family history, exposure to radiation, and personal history of malignancy are also sought. The physical examination findings in a patient with a bone tumor are often nonspecific; however, rapid enlargement of a firm, tender mass are concerning features that warrant prompt evaluation. Patients should be examined for regional lymphadenopathy, asymmetric limb swelling, and associated skin changes. Laboratory analysis can help identify metabolic abnormalities, an occult malignancy, or an inflammatory process associated with a mass in the upper extremity.
An accurate differential diagnosis is initiated after plain radiography. Critical information is gained regarding the biologic nature of a lesion based on the interaction between the lesion and the host. Most benign bone lesions are slow-growing, providing the host with an opportunity to develop a well-defined sclerotic rim around the lesion. Most aggressive bone lesions, in contrast, are rapidly progressive and are therefore poorly marginated. Aggressive lesions are also characterized by cortical destruction, periosteal reaction, and adjacent soft tissue mineralization. One should also consider the possibility of an infection, since osteomyelitis may mimic the clinical and radiographic features of an aggressive tumor.
At least two orthogonal views of the involved area should be obtained for accurate characterization of the bone lesion. A chest radiograph is also recommended before biopsy when a malignant bone tumor is suspected owing to the potential for pulmonary metastasis.
Computed tomography (CT) provides detailed information of mineralized structures. CT is the preferred technique for evaluating the cortical integrity of bone and is valuable when determining the stage of the lesion. Chest CT is recommended for staging purposes in all patients with a documented extremity sarcoma.
Magnetic resonance imaging (MRI) has been integral in both the diagnosis and staging of tumors of the upper extremity. The clarity of soft tissue anatomy combined with the ability to create multiplanar reconstructions has made MRI the preferred imaging technique for evaluating the soft tissue extent of a bone tumor. The extent of the tumor in the medullary canal is also well visualized on MRI and is helpful when planning the level of skeletal resection. Image clarity has improved dramatically with the introduction of high-resolution 1.5-Tesla magnets and dedicated extremity coils. In the setting of a malignant neoplasm, MRI is useful for assessing tumor response to neoadjuvant chemotherapy.
Ultrasound has been used more frequently in musculoskeletal oncology with the increasing availability and sophistication of sonographic technology. Ultrasound is less expensive than either CT or MRI, but the technique provides less clarity in delineating anatomic structures. Ultrasound is occasionally helpful in differentiating a fluid-filled from a solid tumor and can be helpful during core needle biopsy. The technique is highly user-dependent.
Radionuclide scintigraphy, or bone scan imaging, is very sensitive for identifying a musculoskeletal lesion and the presence of a skeletal metastasis, which has prognostic and treatment ramifications. However, increased radionuclide uptake is a nonspecific finding.
If the diagnosis is not known following non-invasive diagnostic imaging, the surgeon should obtain a representative tissue sample as the final diagnostic step. The biopsy should preferably be performed by the surgeon who will perform the definitive treatment at an institution capable of integrating medical oncologic treatment and pathologic tissue evaluation. However, surgeons who adhere to strict oncologic principles and follow recommended limb salvage approaches may perform an open biopsy without additional morbidity. It is essential to place the skin incision such that it can be incorporated into future limb salvage incisions. The biopsy tract is presumed to contain residual malignant cells and must be excised en bloc at the time of the definitive resection.
Biopsy options include incisional, excisional, or core needle ( Table 64-1 ). The choice of technique is dictated by the clinical scenario, radiographic characteristics, and anatomic location of the lesion. Open incisional biopsy is the gold standard for most lesions in which the nature of the lesion is unknown. Open excisional biopsy is performed through the reactive zone of a lesion. Core needle biopsy has gained in popularity because of its reliability in obtaining a representative tissue sample, low cost, and reduced risk of adjacent compartment contamination. Needle biopsy can be performed in the office setting with the aid of fluoroscopy or in an interventional radiology suite under CT, MRI, or ultrasound guidance.
Several staging systems for musculoskeletal tumors have been described in the literature. In 1979, the Musculoskeletal Tumor Society (MSTS) adopted a classification system for bone sarcomas, which accounts for the tumor grade, site, and presence or absence of metastases ( Table 64-2 ). This system is most commonly used. The American Joint Committee on Cancer (AJCC) system is also used and takes into account the size of the tumor and differentiates between pulmonary and nonpulmonary metastases.
The grade of the tumor is classified as either low- or high-grade based on its potential for metastasis. The designation of grade is determined by the pathologist and the surgeon, taking into consideration the histologic characteristics, radiographic features, and clinical findings. Low-grade lesions are histologically well differentiated with few mitoses or moderate nuclear atypia. High-grade lesions are histologically poorly differentiated and characterized by frequent mitoses, significant atypia, and necrosis.
The site or location of the lesion is classified as intra- or extracompartmental, based on the absence or presence of tumor extension into an adjacent anatomic compartment. In general, tumors that are contained within an anatomic compartment are amenable to en bloc resection with an adequate tissue margin. Extracompartmental tumors, by definition, are no longer contained within the usual barriers of an anatomic region, and resection of multiple compartments or amputation is required to obtain an adequate margin. The introduction of CT and MRI in the preoperative planning process has afforded an accurate prediction of tumor stage.
Finally, systemic staging is performed for all patients with a confirmed primary bone malignancy. A lesion is designated as MSTS stage III when a regional or distant metastasis is identified regardless of the tumor grade or site of the primary tumor. Most malignant bone tumors metastasize hematogenously. The lung is the most common site of distant metastasis; therefore, a chest CT should be routinely ordered. Consultation with a medical oncologist for systemic staging and treatment is imperative. Most cancer centers have a multidisciplinary musculoskeletal tumor board for guidance.
DEFINITIVE TREATMENT OVERVIEW
In musculoskeletal oncology, “function is secondary to survival.” Eradication of malignant disease is more important than the function of the remaining limb. However, there are cases in which aggressive resection—and the associated morbidity—is unnecessary. Therefore, the surgeon must achieve the correct balance for each patient, erring on the side of preserving life when feasible.
In biopsy-confirmed benign bone tumors of the hand and wrist, local treatment is generally sufficient. Options include intralesional curettage and marginal excision. Adjuvant treatment with polymethylmethacrylate (PMMA), phenol, or cryotherapy to prevent recurrence has been described for certain benign aggressive tumors.
Treatment of a primary malignant bone tumor generally involves wide or radical en bloc resection. Preoperative consultation with a musculoskeletal oncologist is important in determining the role, if any, for preoperative neoadjuvant and/or postoperative chemotherapy and radiation therapy. The specific surgical strategy is based on the tumor type, anatomic location, and stage. A description of specific benign and malignant tumors and current recommended treatment practices is presented in the following sections.
BENIGN BONE LESIONS
Benign primary bone tumors are generally self-limiting and are thus treated with intralesional or marginal resection. Curettage is the simplest intralesional procedure. In the digits, this is typically performed by means of a midaxial approach directly over the lesion. Fluoroscopy is helpful for confirming the location of the lesion and the adequacy of the tumor removal. Representative tissue samples should be routinely sent to pathology for permanent sectioning to confirm the diagnosis. Adjuvant treatment is recommended for benign aggressive tumors associated with a high recurrence rate (i.e., aneurysmal bone cyst and giant cell tumor of bone).
Enchondroma is a benign, slow-growing cartilage tumor. Approximately 40% arise within the small bones of the hand. It is the most common osseous tumor in the hand. Enchondroma has a predilection for the phalanges and metacarpals. The proximal phalanx is the most common site overall. The least common sites are the distal phalanx and the carpus. The solitary enchondroma is considered a hamartoma that has arisen from persisting cartilaginous islands from the growth plate. Multiple enchondromas are seen in both Ollier’s disease and Maffucci’s syndrome. Ollier’s disease is also known as multiple enchodromatosis. Maffucci’s syndrome is the presence of multiple enchondromas and hemangiomas. Both conditions are associated with malignant transformation of an enchondroma to a chondrosarcoma. The possibility of sarcomatous transformation within an isolated preexisting enchondroma is remote, and the resulting malignancy generally has minimal metastatic potential.
An enchondroma of the hand is usually asymptomatic, but patients can present with pain, swelling, and deformity following a pathologic fracture ( Fig. 64-1 ). An enchondroma is a common coincidental radiographic finding.
Most surgeons treat an enchondroma of the hand with an intralesional procedure. Curettage is the mainstay of surgical management. Autogenous cancellous bone graft or allograft is used by some authors to fill the osseous void; however, satisfactory results have been reported with curettage alone. Cemented internal fixation has been advocated to reconstruct large cavitary defects, theoretically providing immediate mechanical support and permitting early mobilization. Recurrence can occur with incomplete tumor removal. Periodic radiographic follow-up is recommended. In most cases of enchondroma, a pathologic fracture is permitted to heal with nonoperative management before definitive treatment of the enchondroma. An asymptomatic enchondroma without impending fracture may be treated with observation and radiographic surveillance.
An osteochondroma is a benign osteocartilaginous mass that occurs in well-recognized locations in the upper extremity. A predilection for the metaphysis of long bones has been described. Isolated lesions in the hand occur most often in the distal aspect of the proximal phalanx; however, most lesions arise in patients with multiple hereditary exostoses (MHE).
Patients typically present with a firm, painless mass in childhood, which may increase in size during pubertal growth. The tumor can cause angular or rotatory deformities or can impair function because of irritation of adjacent tendinous or neurovascular structures. Treatment is generally directed at symptom relief with marginal excision. Lesions of the distal radius or ulna may cause deformity and loss of forearm rotation. Associated subluxation or dislocation of the radial head has also been described with severe bowing of the forearm. Digital lesions may cause angular or rotational deformities with secondary triggering, loss of finger motion, and functional compromise. Asymptomatic lesions with classic radiographic features may be observed. Sarcomatous transformation of an osteochondroma can occur. Clinical features suggestive of malignant degeneration are enlargement of the mass and pain, particularly at night.
Osteoid osteoma is an uncommon, benign lesion that rarely occurs in the hand and wrist, accounting for approximately 5% of lesions at all sites. Osteoid osteoma is characterized by a nidus (typically less than 1 cm) surrounded by a sclerotic rim of reactive bone. Patients often present with dull, aching pain classically relieved by nonsteroidal anti-inflammatory medication. Patients may report a gradual progression of symptoms over months or years, and the diagnosis is often missed initially. Tenderness to direct palpation of the lesion with soft tissue swelling may be present. Plain radiographs may demonstrate a sclerotic nidus. Bone scan imaging can be helpful in identification of occult lesions, since osteoid osteomas are characterized by an intense focal area of increased uptake. CT scan is useful for definitive diagnosis ( Fig. 64-2 ).