Tumors involving the hand are classified in a manner similar to that for tumors involving the rest of the body. Benign tumors are classified as latent, active, or aggressive, according to their local biological activity (Table 77-1). Benign latent tumors are those in which tumor growth has occurred during childhood or adolescence and has subsequently entered an inactive or healing phase. Solitary and unicameral bone cysts are examples of benign latent tumors. A benign active tumor continues to enlarge and, although it is well encapsulated, may have an irregular or lumpy border. Most benign tumors of the hand fall into this category. A benign aggressive tumor, although nonmetastasizing and innocent appearing on histological sections, is locally destructive and is surrounded by a thin, tenuous capsule that may not contain all the tumor cells. A giant cell tumor of bone often behaves in this aggressive manner. A wide margin often is necessary for complete eradication of benign aggressive tumors.

TABLE 77-1 Classification of Benign Tumors

STAGE	TYPE
1	Latent
2	Active
3	Aggressive

Modified from Enneking WE: Musculoskeletal tumor surgery, New York, 1983, Churchill Livingstone.

Malignant tumors are classified as low grade (I), high grade (II), or associated with metastasis (III) (Table 77-2). Most malignant tumors of the hand are low-grade tumors and are classified further, according to the degree of local extension, as either intracompartmental (A) or extracompartmental (B). In the hand, each ray forms a distinct compartment. The individual phalanges are not considered separate compartments, but rather they, along with their corresponding intrinsic muscles, are included in the ray compartment. The ray compartment includes the flexor tendon and sheath of each finger as far proximally as the midpalmar space and the extensor tendon as far as the metacarpophalangeal joint. Each metacarpal is a separate compartment. If a tumor involves the palmar space or the loose areolar tissue on the dorsum of the hand, it is considered extracompartmental because proximal spread is unobstructed. Tumors arising in the digits remain confined to that compartment for long periods and then extend into the palm.

TABLE 77-2 Classification of Malignant Tumors

STAGE	TYPE
IA	Low grade, intracompartmental
IB	Low grade, extracompartmental
IIA	High grade, intracompartmental
IIB	High grade, extracompartmental
III	Either grade with regional or distant metastasis

Modified from Enneking WF, Spanier SS, Goodman MA: The surgical staging of musculoskeletal sarcoma, Clin Orthop Relat Res 153:106, 1980.

Diagnosis

Usually a thorough history, physical examination, and plain radiographs are all that are necessary to determine adequately the diagnosis and appropriate treatment of benign-appearing tumors in the hand. If a more aggressive process is present, causing considerable pain, inflammation, a large tumor, or bony destruction, further diagnostic and staging studies are warranted before biopsy or a definitive surgical procedure. Local imaging studies, including bone scans, angiograms, CT, and MRI, are more helpful in surgical planning than in obtaining a specific diagnosis. A metastatic workup is indicated in most malignant lesions and a chest CT is necessary for those tumors with a propensity for metastasizing to the lungs.

Treatment

Generally, hand tumors are treated surgically. Biopsy rarely is needed in most tumors because complete excision usually is indicated, and the entire tumor is available for microscopic study. Incisional biopsy is advised if a malignant tumor is suspected, or if the morbidity of surgical excision outweighs the morbidity caused by the tumor itself, as may be true in some benign neural tumors. Incisions should be made directly over the mass to be harvested for biopsy and should be oriented so as not to jeopardize hand function or interfere with complete removal of the tumor. The way in which a tumor is removed depends on its location, aggressiveness, potential for metastasizing, and, at times, sensitivity to adjuvant chemotherapy and radiation therapy. The various surgical margins are summarized in Table 77-3.

TABLE 77-3 Classification of Surgical Margins

TYPE	PLANE OF DISSECTION
Intracapsular	Piecemeal, debulking, or curettage
Marginal	Shell out (en bloc) through pseudocapsule or reactive zone
Wide	Intracompartmental (en bloc) with cuff of normal tissue
Radical	Extracompartmental (en bloc) with entire compartment

Modified from Enneking WE: Musculoskeletal tumor surgery, New York, 1983, Churchill Livingstone.

Benign soft tissue tumors are treated by excisional biopsy (marginal excision). Benign tumors of bone often are treated by curettage (intracapsular) and, occasionally, bone grafting. Malignant tumors require a wide excision in which a 2-cm tumor-free cuff of tissue is removed with the tumor. Malignant tumors involving the distal phalanx can be treated with a transdiaphyseal amputation through the middle phalanx. Malignant tumors of the middle phalanx can be treated with a transdiaphyseal amputation through the proximal phalanx. If the malignant tumor involves the proximal phalanx, a ray amputation usually is required. Malignant tumors of the metacarpals, especially if large and extracompartmental, often require adjacent amputations to achieve adequate surgical margins. Grade IIB lesions involving the hand may require amputation through the distal third of the forearm at a level just proximal to the musculotendinous junctions. Reconstruction after wide or radical excisions for malignant tumors of the hand should be delayed until tumor-free margins have been documented.

Benign Tumors (Table 77-4)

Lipoma

Although lipomas are more common elsewhere in the body, they also are found in the hand and are common solid cellular hand tumors (Fig. 77-1). These lightly encapsulated tumors are composed of mature fatty tissue in which the central lipid droplet and peripherally located nucleus form the characteristic signet-ring cell. They arise from mesenchymal primordial fatty tissue cells. These tumors can be superficial, arising from the subcutaneous tissues and having the characteristic signs of a soft, fluctuant, bulging mass, or they can occur deep in the palm, arising within the Guyon canal, the carpal tunnel, or the deep palmar space. Usually, a painless mass is present that impairs grasp. Lateral deviation of the fingers also may be present when the tumor is located around the metacarpophalangeal joints.

TABLE 77-4 Benign Tumors of the Hand

FIGURE 77-1 A and B, Palmar lipoma with significant dorsal prominence of the middle finger causing interference with grasp and finger adduction. C, Tumor with extensive lobulation around digital nerves and flexor tendons. D, Complete excision of lipoma with surgical sparing of flexor tendons and digital nerves. E, Closure of Bruner incision that allowed complete tumor excision.

Median or ulnar nerve compression from these tumors can cause muscular weakness or diminished sensibility. Lipomas project through spaces of least resistance, and those deep palmar space lesions tend to present distally between the fingers and thumb because of the unyielding overlying palmar aponeurosis. Careful dissection is necessary for removal because the tumor often envelops digital nerves and is much larger than is clinically apparent. Recurrence after marginal excision is unlikely.

Infiltrating Lipomas

Infiltrating lipomas are rare tumors that usually occur in adults. Two types, intermuscular and intramuscular, have been reported. Intermuscular lipomas grow between large muscles and arise from septa; intramuscular lipomas arise between muscle fibers. Despite tissue infiltration, no malignant transformation has been reported; however, these uncommon, nonencapsulated, benign tumors have a recurrence rate of 60%.

Lipoblastomas

Lipoblastomas are rare, benign tumors composed of immature, spindle-shaped cells that occur in children younger than 7 years old. Two forms of this tumor exist; one is deeply seated and poorly circumscribed, and the other is more superficial and well circumscribed. Not all lipoblastomas follow the usual slow growth pattern, and absence of cellular atypia and mitosis is necessary to differentiate them from the exceptionally rare congenital liposarcomas. Surgical excision after MRI to assess the extension of the mass usually is necessary. A recurrence rate of 14% after excision has been reported.

Intraneural Lipofibromas

Intraneural lipofibromas are rare benign tumors that usually involve the median nerve. Patients present within the first 3 decades of life with a mass located in the palmar aspect of the hand or wrist, possibly with altered median nerve function (Fig. 77-2). Microscopically, fibroadipose tissue is seen infiltrating the epineurium, separating and compressing the fascicles. A conservative approach should be taken in treating these tumors. Incisional biopsy may be necessary for diagnosis. If extrinsic neural compression exists, surgical decompression should be performed by fasciotomy or carpal tunnel release. Intraneural excision may debulk the tumor, but this procedure is not recommended because intraneural fibrosis can increase the neural deficit. Malignant transformation is rare; however, intractable pain may result from some lesions and warrant tumor excision (Fig. 77-3). If a digital nerve is involved, en bloc excision with nerve grafting may be successful, although sensation would be altered (Fig. 77-4).

FIGURE 77-2 A, Intraneural lipofibroma of median nerve with palmar and distal forearm enlargement. B, Surgical exposure showing extensive main trunk and common digital nerve lipofibromatous changes after decompression and external neurolysis of the median nerve. C, Closer view of digital nerve enlargement.

FIGURE 77-3 A and B, Clinical views of a 25-year-old woman with intractable pain after multiple debulking procedures for a median nerve lipofibroma. C, Intraoperative nerve dissection in the distal forearm and hand. D, Gross specimen. (Note that pain relief was not complete and nerve excision should be the final step in this tumor management aside from malignant degeneration.)

FIGURE 77-4 A, Recurrent intraneural lipofibroma of ulnar digital nerve to small finger. B, Surgical exposure showing 4-cm segment of involved ulnar digital nerve with normal-appearing proximal and distal segments. C, En bloc excision of digital nerve and tumor with nerve graft placed in proximity. D, Nerve graft sutured in place.

Giant Cell Tumor of the Tendon Sheath (xanthoma)

Giant cell tumors of tendon sheaths were first described in 1915 by Beekman, and some consider these to be the most common solid cellular hand tumors (Fig. 77-5). The reported age distribution is 8 to 80 years. These tumors occur in the hand more frequently than in any other part of the body, and they occur more often as firm lobulated masses on the volar lateral side of the index and middle fingers. Multiple xanthomas may be associated with hypercholesterolemia.

FIGURE 77-5 A and B, Giant cell tumor on the flexor surface of the ring finger. C, Surgical dissection showing well-encapsulated giant cell tumor with typical yellowish brown color.

Xanthomas usually grow slowly and can remain the same size for many years. Pain and tenderness are rare. If xanthomas occur at a joint (often the proximal interphalangeal joint), they can become large enough to interfere with joint motion. They may rarely erode bone. Grossly, the tumors appear as well-encapsulated yellow or tan lobular masses. Histological sections reveal spindle cells, fibrous tissue, cholesterol-laden histiocytes, multinucleated giant cells similar to osteoclasts, and hemosiderin.

The lesions are benign, but 27% recur even after meticulous excision of the friable fragments. Risk factors for recurrence or persistence include adjacent degenerative joint disease, location at the finger distal interphalangeal and thumb interphalangeal joint, bony invasion, multifocal disease, and poor surgical technique. Excision often is difficult because the tumors may wind in and around the flexor tendons and their sheaths, the digital nerves, and even the extensor tendons and may involve three fourths of the circumference of involved digits; however, this benign lesion is considered surgically curable. Extensile surgical approaches are frequently required, and gentle blunt dissection should be performed to minimize fragmentation of the encapsulated tumor mass. Magnified vision is helpful to discover discolored synovial tumor, which must accompany the specimen.

Benign Tumors of Fibrous Origin

Fibrous tissue frequently proliferates in the hand as a response to local injury and is considered simple scar tissue; for this reason, the diagnosis of fibrous tumor must be made based on the appearance of the tumor, the age of the patient, the clinical behavior of the tumor, and its histological appearance. All tumors of fibrous origin may involve the hand; and although most are benign, they frequently are active or aggressive lesions with a tendency to recur after local excision. The differential diagnosis in benign fibrous tumors includes simple fibroma, recurring digital fibrous tumor of childhood, juvenile aponeurotic fibroma, Dupuytren contractures or nodules, fibromatosis or desmoid tumors, and pseudosarcomatous fasciitis. Fibromatosis or extraabdominal desmoid, and pseudosarcomatous fasciitis are especially aggressive tumors that usually involve the more proximal portions of extremities.

Recurring Digital Fibrous Tumor of Childhood or Infantile Digital Fibromatosis

In 1965, Reye described a benign fibrous tumor that develops in the fingers and toes of infants and young children. The distinguishing feature of this tumor is the presence of intracytoplasmic inclusion bodies within proliferating fibroblasts. These inclusion bodies are invisible with routine hematoxylin and eosin staining. A viral causative factor has been suggested, although this is uncertain. These tumors tend to be multicentric, occurring on several digits. The dermis appears to be the site of involvement with sparing of the overlying epidermis. No malignant potential is present, and spontaneous regression has been reported. A marginal excision is recommended when function seems compromised or appearance is bothersome, especially if tendons, joints, or nails are involved. Local recurrence after marginal excision is common, occurring in 60% of patients.

Juvenile Aponeurotic Fibroma or Calcifying Aponeurotic Fibroma

First described by Keasbey in 1953, juvenile aponeurotic fibroma is a benign fibrous tumor typically appearing in the hands or wrists of children and young adults. It also has been called calcifying aponeurotic fibroma because in older patients calcification of the cartilaginous component may be present, a feature that distinguishes it from other benign tumors of fibrous origin. Clinically, it is a painless, solitary, and mobile mass less than 4 cm in diameter, usually involving the palm (Fig. 77-6). The tumor usually is on the volar side of the hand and is connected to peritendinous tissues and fascia. It has no gender predilection and no tendency to involve the ulnar side of the hand, as do Dupuytren nodules. Juvenile aponeurotic fibromas tend to develop close to tendons and are able to infiltrate surrounding muscle and fat. On radiographs, calcifications can be seen within the soft tissue mass. Because juvenile aponeurotic fibroma has a distinct tendency for local recurrence after marginal excision, especially in younger children (50%), a wide excision, preferably without sacrifice of function, is recommended.

FIGURE 77-6 A, and B, Fibroma resulting in gradual pulp enlargement and sensory nerve compromise. C and D, Midline palmar oblique approach and exposure of well-encapsulated tumor in situ. E and F, Marginal excision of tumor and distal interphalangeal joint inspection for additional deposits.

Fibroma

Fibromas are rare in the hand and can be deep, arising from a joint capsule, or superficial. They tend to occur early in life, grow for a limited time, and then subside. There are no calcifications, as are seen in juvenile aponeurotic fibroma, unless they have been present for a long time. Clinically, these tumors are distinguishable from Dupuytren nodules because they occur earlier in life, tend not to multiply, have no predilection for the ulnar side of the hand, and are not associated with contractures. These tumors are well encapsulated and are easily dissected free from surrounding tissue by blunt dissection. They are firm, white, and composed of dense mature fibroblasts and fibrous tissue. Marginal extracapsular excision usually is curative.

Neurofibroma

Neurofibromas rarely exist as solitary lesions, and most that occur as multiple lesions are associated with neurofibromatosis or von Recklinghausen disease. The solitary form usually occurs in the first decade of life, and the multiple form frequently manifests after 30 years of age. These lesions in the hand involve the more distal digital nerves (Fig. 77-7), where enlargement may produce grotesque finger angulation and gigantism. They usually are centrally located, nontender, more nodular, and nonencapsulated and may involve the skin, making them less mobile than schwannomas. The lesion is not resectable without sacrificing nerve elements because the nerve fibers intersperse in the tumor mass. Often these involve cutaneous nerves where proximal and distal to the lesion the nerve caliber appears normal. The solitary and multiple forms are histologically indistinguishable; both have a plexiform mass of irregular, thickened nerve fibers separated by increased endoneural matrix. Malignant transformation in neurofibromatosis has been reported to occur in 15% of patients, and complete excision is necessary for lesions that enlarge and become painful.

FIGURE 77-7 Neurofibroma. A, Café au lait spot. B, Multiple palmar neurofibromas.

Glomus Tumor

A glomus body is a specialized neuromyoarterial receptor composed of an afferent arteriole, an anastomotic Sucquet-Hoyer canal, an afferent venule, actin-containing glomus cells surrounding the canals, intraglomerular retinaculum, and capsule. It functions as a dermal shunt that normally regulates skin temperature and blood pressure. Hyperplasia of one or more parts of the glomus body causes this tumor. Glomus cells are specialized perivascular muscle cells that are round or oval and have a dense, granular cytoplasm. Nonmyelinated nerve fibers that are intermixed with thick-walled capillaries are responsible for the lancinating pain.

Pain, cold sensitivity, and point tenderness are the characteristic symptoms of a glomus tumor, which was originally described by Wood in 1812 and histologically clarified by Masson in 1924. Direct pressure on the tumor by a small, firm object, such as a pinhead, causes excruciating pain (Love test), whereas pressure applied slightly to one side of it elicits no pain. Immersing the involved hand or digit in ice water also causes discomfort.

Glomus tumors usually are less than 1 cm in diameter, often being only a few millimeters in diameter, and may be visible through the overlying tissues as a deep red or purple discoloration. They occur more often in the hand (75%) than elsewhere and are located beneath the fingernail in 25% to 65% of patients (Fig. 77-8). Twenty-five percent are not subungual, however, and these may pose a difficult diagnostic problem. MRI and bone scans may prove helpful in diagnosing these tumors. Most of these tumors are benign; however, if the lesion exceeds 2.0 cm and histologic parameters suggest malignancy, then metastatic rates exceed 25%

FIGURE 77-8 A, Subungual glomus tumor with bluish discoloration. B, Nail removed and nail bed incised to expose underlying glomus tumor. C, Glomus tumor excised with preservation of nail bed. D, Nail bed sutured.

These tumors can be removed with the patient under local anesthesia and should be accurately localized by marking the lesion just before surgery. Meticulous and complete excision of the usually well-encapsulated lesions is curative, although reoperation rates of 12% to 24% have been reported most likely from incomplete tumor extirpation.

Hemangioma

The following remarks are limited to the cavernous hemangioma and do not include the capillary superficial infantile hemangioma, which tends to involute by age 7 years. A cavernous hemangioma can be slightly to moderately tender and may enlarge a digit with distended venous sinuses. It produces a bluish color when it occurs close to the surface, and it forms a soft, collapsible mass. Calcifications often are visible on radiographs. Custom-fitted compression garments can be a useful conservative treatment. Radiation therapy is discouraged. Surgery is the treatment of choice for cavernous hemangiomas if symptoms justify it. The tumor can be so extensive that a staged procedure is required for its removal. Sometimes vessel ligation can assist a second-stage lesion excision. A rare coagulopathy, Kasabach-Merritt syndrome, can occur with lesions larger than 5 cm as a result of secondary platelet sequestration. Early treatment is indicated with this syndrome. With careful tourniquet control, blood partially fills the sinuses and outlines the extent of the tumor at the time of surgical excision. Complete excision usually is curative if the tumor is fairly well localized (Fig. 77-9); however, in diffuse lesions, persistence rather than recurrence is common. If complete excision is impossible, tumor debulking should be the emphasis of the procedure.

FIGURE 77-9 A and B, Hemangioma of ring finger.

Lymphangioma

Lymphangiomas are benign soft tissue tumors that consist of an abnormal proliferation of lymph vessels and lymphoid tissue. They rarely occur in the hand. Their tendency to occur during childhood and to recur after excision and the pain associated with the condition make them especially troublesome for the patient, the patient’s parents, and the surgeon. They have no malignant potential, and overly aggressive surgery should be avoided because hypertrophic scarring may follow. Parents and surgeons should have realistic expectations and goals. Excisional biopsy is recommended for diagnostic confirmation and tumor debulking.

Neurilemoma (schwannoma)

Neurilemomas arise from Schwann cells or sheath cells (Fig. 77-10) and rarely are found in the hand despite being the most common solitary tumor of the peripheral nerves. Proliferation of the Schwann cells begins around one nerve fascicle and results in an eccentric or centrally located tumor. Two types of Schwann cells are present: hypercellular (Antoni A) cells, which are arranged in palisades, composed of plump and fusiform nuclei known as Verocay bodies, and hypocellular (Antoni B) cells, which are nonuniform cells dispersed in a myxomatous matrix. These tumors are not extremely tender and are more mobile at right angles to the course of the nerve than in line with the nerve. Neurilemomas frequently are misdiagnosed as ganglions and rarely are multifocal. With careful microsurgical technique, these tumors usually can be dissected from the surrounding nerve. Malignant degeneration is rare, and excision is curative. An alternative diagnosis or malignancy should be considered if the mass cannot be dissected free from the nerve trunk or is adherent to adjacent tissue. In such situations, incisional biopsy is indicated.