Perform a biopsy and culture all tumors treated operatively.
Rheumatologic workup should be considered with suggestive synovitis pattern (i.e., atraumatic ulnar wrist swelling in young patient).
Nonhealing wound or chronic infection can mimic a soft tissue tumor.
Consider checking the adjacent joint for satellite lesions when resecting a giant-cell tumor of the tendon sheath.
Pyogenic granuloma has a relationship with inflammatory bowel disease and pregnancy.
Atypical mycobacterial infection mimics soft tissue masses and must be specifically cultured.
Ultrasound is particularly useful when there is a suggestion of a foreign body which is not confirmed by plain radiographs.
Masses of the forearm, wrist, and hand are one of the most common presenting conditions seen in an upper extremity surgeon’s office. The vast number of masses that occur within the soft tissues of the forearm and hand are benign. However, the treating surgeon must be familiar with a large differential diagnosis. Tumors may originate from any of the elements of soft tissue in the upper extremity, including synovium, fat, skin, lymphatics, nerves, blood vessels, or bone. A high index of suspicion for such masses is necessary so that an appropriate workup and treatment plan can be formulated when indicated. The goal of this chapter is to familiarize the reader with the more common types of hand and forearm masses and to present a logical approach to rendering appropriate diagnosis and treatment.
Assessment of Masses in the Upper Extremity
A detailed history and physical examination are the essential starting points when a patient presents with an upper extremity mass. If a classic history can be obtained for a common tumor, then physical examination alone can confirm the diagnosis. This might obviate the need for a biopsy. It is important to ask when the mass was first noticed. Was there any history of trauma? Has the mass changed in size, shape, color, or consistency? Is the mass growing? If so, how fast? It is also important to identify any “red flags” that might be more suggestive of malignancy. Has the patient had any constitutional symptoms, such as fever, weight gain, weight loss, fatigue, night sweats, or pain awakening from sleep? Past medical history is important, as many common conditions seen in the hand surgeon’s office manifest with a soft tissue mass. Examples of these conditions include rheumatoid arthritis, Dupuytren’s contracture, gout, and infection. Moreover, since metastatic disease can manifest in the hand, history of any prior malignancies should also be sought. Obtaining a good family history might lead one to the diagnosis of a hereditary condition such as neurofibromatosis.
Physical examination should include the entire upper extremity. The size, shape, and consistency of the lesion should be noted. Location of the lesion, any skin induration or discoloration, and neurovascular involvement are important. Plain radiographs are recommended in all cases beyond the most straightforward diagnoses. Even though these masses are present in the soft tissues, radiographs can often reveal mass effect on the underlying bone or calcifications within the soft tissues. If there is any concern at all for malignancy, more advanced imaging should be obtained. Although computed tomography (CT) and bone scan both can have a role, magnetic resonance imaging (MRI) has become the test of choice for delineating the anatomy of the lesion. The additional use of gadolinium may enhance the image, which is particularly valuable for a malignancy workup. More recently, Cheng and colleagues reported their experience with ultrasound in the diagnosis of soft tissue tumors of the hand and forearm. They found ultrasound to be reliable in determining whether a lesion was cystic or solid, and where the lesion was located relative to other structures.
Principles of Biopsy
Once an appropriate radiographic workup has been completed and a limited differential diagnosis has been compiled, a biopsy is often indicated. Though certain common diagnoses, such as ganglion cysts, are obvious, most solid tumors seen by the hand surgeon warrant biopsy or excision (or both). Certain red flags, such as rapidly increasing size or recurrence after initial biopsy, are suggestive of malignancy and are of concern. This type of information helps determine the type of biopsy to be performed.
The techniques used to perform a biopsy of a lesion vary from needle biopsies that can be performed in the clinic setting, to open surgical biopsies that must be done in the operating suite. Small, clearly benign lesions can be addressed with an excisional biopsy, in which the entire tumor is removed. However, if there is any question about the diagnosis and whether it is malignant, an incisional biopsy is indicated. An incisional biopsy is performed by surgically removing only a portion of the lesion, with the intention of coming back to address the remainder of the tumor once a diagnosis has been established. Most orthopedic oncologists recommend that incisional biopsies be performed only by surgeons who are comfortable doing the definitive resection.
When performing a biopsy, certain principles should be applied. First and foremost, longitudinal skin incisions are always preferred if there is any chance that the lesions could be malignant. Second, in contrast to standard surgical techniques, the surgical dissection when performing the biopsy should attempt to stay within a single compartment instead of proceeding within an internervous plane. Last, it is prudent to culture all biopsy specimens, as indolent infection can often be confused with neoplasm.
Masses in the upper extremity can be separated into tumor-mimicking lesions, benign tumors, and malignant tumors. Box 24-1 lists the most common soft tissue masses of the upper extremity. The remainder of the chapter focuses on the defining characteristics of each of these individual tumors.
Giant-cell tumor of the tendon sheath (fibrous xanthoma)
Congenital arteriovenous malformation
Neurilemmoma (benign schwannoma)
Calcifying aponeurotic fibroma
Dermatofibroma (cutaneous fibrous histiocytoma)
Sweat gland tumors
Malignant skin tumors
Basal cell carcinoma
Squamous cell carcinoma
Malignant fibrous histiocytoma
Malignant peripheral nerve sheath tumors
Non-neoplastic conditions can mimic tumors. Rheumatoid arthritis (RA) and gout can both manifest as a solitary soft tissue mass. Rheumatoid arthritis has several characteristics that can confuse the unsuspecting surgeon. Isolated soft tissue swelling associated with synovitis, particularly in the prestyoid recess of the wrist in a young female, can be a cardinal presenting sign of RA. Rheumatoid nodules can also present as a solitary finding, though this is rare. These nodules result from rheumatoid factor and immunoglobulin G (IgG), causing small vessel arteritis, which results in tissue necrosis and subsequent granulation tissue. Despite surgical excision, these nodules typically recur, unless medical intervention with disease-modifying agents is implemented. They may be seen in advanced rheumatoid disease.
Gout and pseudogout are two other common diseases that can manifest with soft tissue lesions. Gout occurs as the result of a disorder in the metabolism of purines associated with DNA synthesis. Pseudogout is the result of accumulation of calcium pyrophosphate crystals within the joints and soft tissues. Pseudogout is classically seen on the ulnar side of the wrist. When calcifications are noted on plain radiographs in the location of the triangular fibrocartilage complex (TFCC), pseudogout should be prominent on the list of differential diagnoses. As with RA, gout and pseudogout can manifest for the first time with isolated swelling and synovitis that could be indicative of neoplasm. With longstanding disease, patients can develop tophi, which are accumulations of the monosodium urate crystals (gout) ( Fig. 24-1 ) or calcium pyrophosphate crystals (pseudogout) within the soft tissues. In most cases, a thorough history reveals the previous diagnosis of gout/pseudogout, allowing the current diagnosis to become obvious. It is important to diagnose this prior to biopsy, as surgical treatment of a tophus may be unnecessary and may result in clinical flareup of the gouty condition. In the rare case of a tophus that begins to break through the skin, a debulking procedure may be entertained, and in the most severe cases amputation may be required.
Ganglion cysts are discussed in detail as they are the most common soft tissue masses of the hand and wrist. Other conditions that manifest as soft tissue masses include Dupuytren’s contracture, tendon sheath fibroma, and localized calcium deposits, such as those that form secondary to a hematoma. Unusual entities such as atypical mycobacterial infection may be seen in immunocompromised hosts. Herpetic whitlow is also seen in the hand and manifests with a classic vesicular appearance that should not be drained because it spreads the lesion ( Fig. 24-2 ). Foreign body reaction can develop in an occult scenario, sometimes months or years later. Skin lesions are also included in this chapter as they are common.
According to Galen, the word ganglion means “anything gathered into a ball.” Ganglion cysts are widely acknowledged as the most common soft tissue mass in the upper extremity, comprising approximately 15% to 60% of all soft tissue masses in the upper extremity. , They are synovial cysts that arise from the synovial lining of either a joint or a tendon sheath. It has been suggested that these masses are actually herniations of the synovial lining that fluctuate in size as a result of a one-way valve that forms at the joint of origin.
As with most benign soft tissue masses, the clinical presentation of a ganglion is as a painless mass. However, when it becomes large enough to exert a mass effect on surrounding structures such as the terminal branch of the posterior interosseous nerve at the level of the wrist capsule, pain can be present. Patients often report some pain with full flexion or extension of the wrist and weight bearing, as with doing pushups. Patients classically report a mass that may wax and wane in size, or spontaneously decompress. There is often no history of trauma, although they are often seen in the young female population with ligamentous laxity, particularly of the scapholunate ligament. Ganglion cysts should not be confused with a carpometacarpal boss or with extensor tenosynovitis.
Diagnosis of a ganglion is usually straightforward. The patient presents with a mass that is typically nontender, but is either cosmetically or functionally bothersome. It is sometimes correlated with antecedent trauma or repetitive microtrauma, but often there is no clear cause. On physical examination, it is a well-circumscribed lesion with smooth borders and is sometimes multilobuled. Because these lesions are filled with a gelatinous fluid, if large enough, transillumination is diagnostic ( Fig. 24-3 ).
Ganglion cysts are most often found in characteristic locations. The dorsal wrist ganglion most often arises from the scapholunate interval ( Fig. 24-4 ). On the volar surface of the wrist, the radioscaphoid joint, scaphotrapeziotrapezoid joint, and the flexor carpi radialis tendon are the most common origins ( Fig. 24-5 ). An Allen’s test is important when evaluating volar carpal ganglions, as the radial artery is usually intimately associated with the ganglion. A volar ganglion should not be confused with a pseudoaneurysm of the radial artery. It is important to recognize that the surface location of these masses does not always correspond with their joint of origin, such that a mass that appears on the middle or ulnar side of the dorsum of the wrist may still originate from the scapholunate interval when one traces it down to its origin. Ganglia may be found in Guyon’s canal and may cause intrinsic dysfunction in the hand secondary to compression of the motor branch of the ulnar nerve. Figure 24-6 represents the authors’ case of a ganglion cyst found to cause intrinsic paralysis in an avid drummer. Recovery was complete after excision of the ganglion.
Two other common examples of a ganglion are the retinacular cyst and the mucous cyst. A retinacular cyst is a ganglion that originates from a tendon sheath, most often on the flexor tendon sheath. Classically, these appear at the volar side of the proximal interphalangeal (PIP) or metacarpophalangeal (MCP) joint and arise from the A2 or A1 pulleys ( Fig. 24-7 ). Triggering may be seen in association with these cysts, although it is not common. Mucous cysts form in association with degenerative osteoarthritis at the distal interphalangeal (DIP) joint. They typically form at the dorsal base of the distal phalanx and are associated with an underlying osteophyte and a nail deformity ( Fig. 24-8 ).
Another rare variant of the ganglion is the intraosseous ganglion. , These variants are often found incidentally on radiographs, most commonly within the scaphoid and lunate. In these cases, it is difficult to determine if the intraosseous ganglion is the cause of wrist pain. Nuclear bone scan imaging can be used to detect metabolic activity associated with these entities to determine whether the cyst is the cause of the patient’s pain. If the surgeon believes that the intraosseous cyst is the cause of the patient’s pain, these lesions can be successfully treated with curettage and bone grafting. The authors believe that arthroscopy in this setting is a useful adjunctive tool, especially for assessing the scapholunate ligament in association with a radial-sided intraosseous lunate cyst.
Treatment of ganglion cysts varies. Nonoperative care may include aspiration of the cyst with or without injection of a corticosteroid. Aspiration of these cysts usually reveals a straw-colored thick, mucinous fluid, which confirms the diagnosis. The recurrence rate of dorsal wrist ganglion cysts after aspiration is 60% with a single aspiration, though repeated aspirations have achieved up to 85% cure rates. In 1963, Bruner anecdotally reported cure rates in 14 of 15 retinacular cysts. Aspiration is not recommended in volar wrist ganglia because of their proximity to the radial artery. Our preferred technique is surgical excision if the ganglion is large or symptomatic. When excising a ganglion, a portion of the joint capsule is also excised in order to decrease the chance of recurrence. The surgical excision of a dorsal wrist ganglion can be performed with either an open or arthroscopic technique. The arthroscopic technique has the theoretical advantage of causing less postoperative pain and allowing for smaller incisions. Arthroscopic resection is most suitable if the ganglion arises from the scapholunate interval so it can be decompressed when the 3–4 radiocarpal arthroscopic portal is established surgically. The recurrence rate with either open or arthroscopic technique is similar, at between 2% and 10%. When surgical excision of the mucous cyst is undertaken, it is imperative that the underlying osteophyte also be removed to limit recurrence. For retinacular cyst excision, a small noncritical window of flexor sheath is usually excised.
Surgical treatment of ganglion cysts, though routine, is not without complications. Watson and colleagues reported a case of scaphoid rotary subluxation after ganglion excision, presumably caused by overzealous intercarpal ligament resection. Dorsal sensory branches of the radial nerve are at risk during the dissection of a dorsal wrist ganglion. Mucous cysts, when they occur, are often associated with attenuation of the skin overlying the cyst. In severe cases, this attenuation of skin may require skin grafting or a rotation flap.
Ganglion cysts in the pediatric population warrant special consideration. Although much less common than in young adults, their natural history appears to be different. In 1989, Rosson and Walker reported on a series of 29 ganglion cysts in patients younger than 15 years old, and saw 20 of 29 resolve without any treatment within 2 years. In a similar study, Wang and Hutchinson followed 14 children under the age of 10, and found that 11 of 14 cysts spontaneously resolved within 2 years. For this reason, observation is recommended initially for ganglion cysts in children.
Giant-Cell Tumors of the Tendon Sheath
Giant-cell tumors of the tendon sheath (GCTTS) are the next most common soft tissue tumors of the upper extremity, after ganglions. These benign tumors are known by a number of different names, including fibrous xanthoma, localized nodular tenosynovitis, and benign synovioma. They are commonly classified into nodular and diffuse varieties, with the diffuse type being closely related to pigmented villonodular synovitis (PVNS). There is a slight female predominance (3 to 2), and they most commonly occur in the fifth and sixth decades of life.
Clinically, they manifest as a painless soft tissue mass, oftentimes having been present for many years. They can be found on either the dorsal or volar side of the hand or digit. Most commonly they are found on the volar aspect of the digit, at the level of the proximal phalanx ( Fig. 24-9 ). As with ganglion cysts, they can uncommonly cause a local mass effect, compressing neurovascular structures to cause numbness or sensitivity distal to the lesion. Ward and coworkers reported one case of GCTTS manifesting as acute carpal tunnel syndrome. Similarly, longstanding tumors can cause erosion of adjacent bone, which can be appreciated on plain radiographs. Histologic examination reveals that these lesions are very similar to PVNS. Foam cells with small nuclei and lipid-laden granules within the cytoplasm are characteristic. These cells are accompanied by brown deposits of hemosiderin.
Treatment for GCTTS is surgical excision ( Fig. 24-10 ). Meticulous technique is imperative in order to completely excise the mass. Identification of the neurovascular bundles in the digit proximal to the lesion is imperative prior to excision. For this reason, extensile incisions are utilized. The authors have operated on cases in which the digital nerve was found to be volar to the lesion and the artery either midsubstance or dorsal. Recurrence rates for these tumors is high—up to 50% —but can be diminished with good technique. Gholve and colleagues examined the treatment of a pediatric population with GCTTS treated with surgical excision, and at 2-year follow-up there were no episodes of recurrence. They attributed their success to “meticulous dissection and excision” under loupe magnification. Surgical dissection may require evaluation of joint involvement, as GCTTS may extend intra-articularly and require arthrotomy for complete excision.