Tumors and Tumorous Conditions of the Hand

Lipoma

Although lipomas are more common elsewhere in the body, they are also found in the hand and are common solid cellular hand tumors ( Fig. 78.1 ). 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, bulging mass, or they can be nonpalpable, occurring deep in the palm, arising in Guyon’s canal, the carpal tunnel, or the deep palmar space. Usually, a painless mass is present that impairs grasp. Lateral deviation of the fingers may also be present when the tumor is located between the metacarpophalangeal joints .

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.

Intraneural Lipofibromas

Intraneural lipofibromas or lipofibromatous hamartomas (LFHs) are rare benign tumors that usually involve the median nerve; one third of individuals also have macrodactyly. Males and females are equally afflicted, and nearly three fourths of LFH 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. 78.2 ). Microscopically, fibroadipose tissue is seen infiltrating the epineurium, separating and compressing the fascicles. A conservative approach should be taken in treating these tumors. Histologic examination is definitive for LFH tumors; however, biopsy is rarely necessary because T1- and T2-weighted MRI showing characteristic low-intensity serpentine nerve bundles embedded within abundant hyperintense adipose material, with fine, fibrous tissue septa coursing along the median nerve, is pathognomic ( Fig. 78.3B and C ). If extrinsic neural compression exists, surgical decompression should be performed by fasciotomy or carpal tunnel release ( Fig. 78.3D and E ). Intraneural excision may debulk the tumor, but this procedure is not recommended because intraneural fibrosis can increase the neural deficit. Malignant transformation has not been reported; however, intractable pain and expanding tumor size or increased firmness may warrant tumor biopsy and excision. If a digital nerve is involved, en bloc excision with nerve grafting may be performed ( Fig. 78.4 ).

Giant Cell Tumor of the Tendon Sheath (Xanthoma)

Giant cell tumors of tendon sheaths were first described by Targett in 1897, and some consider these to be the most common solid cellular hand tumors ( Fig. 78.5 ). The reported age distribution is 8 to 80 years, although most present in middle-aged patients. These tumors may occur anywhere in the hand but more commonly present as firm lobulated masses on the lateral side of the hand (index and middle fingers more so than the thumb).

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

The lesions are benign, but recurrence is noted in up to 40% of patients (10% to 20% more commonly reported) 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, tendon involvement, 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 should be removed during the marginal tumor resection.

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 histologic appearance. All tumors of fibrous origin may involve the hand and although most are benign, they are frequently 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.

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 has also 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. 78.6 ). The tumor is usually 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.

Desmoid Tumor

Extraabdominal desmoid tumors are benign, rare, aggressive, and infiltrative lesions that make surgical excision difficult and recurrence common. There is no sex predilection, and the tumors more commonly affect the forearm than the hand ( Fig. 78.7 ). Tumor excision is the mainstay of treatment; however, disease-free margins may be difficult to obtain. Nonetheless, recurrence rates in the forearm and hand are 60% and 33%, respectively. Disease recurrence is more common in younger patients. Adjunctive radiation treatment does not appear to decrease the recurrence rate but does increase the 5-year disease-free interval. Hence, radiation therapy may be reasonable for patients with incomplete excision or in whom tumor resection resulted in substantial morbidity.

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. 78.8 ), where enlargement may produce grotesque finger angulation and gigantism. They are usually 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.

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. The glomus body 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 or a variant. Glomus cells are specialized perivascular muscle cells that are round or oval and have a dense, granular cytoplasm. The etiology for glomus tumors is unknown, but trauma and genetic mutations have been implicated. Nonmyelinated nerve fibers that are intermixed with thick-walled capillaries are postulated to be responsible for the lancinating pain.

Pain, cold sensitivity, and point tenderness are the characteristic of glomus tumors (described by Wood in 1812 and histologically clarified by Barre and Masson in 1924). Glomus tumors may be solitary or multiple. The lesions arise mainly in women (75%) and occur at an average age of 46 years (18 to 72 years). Seventy-five percent are subungual in location (Trehan et al.) ( Fig. 78.9 ). Although they occur more often in the hand, up to 25% may be located elsewhere, and a diagnosis requires a high index of suspicion. Multiple lesions are associated with neurofibromatosis I and may be nontender, making their diagnosis sometimes elusive. Direct pressure on the tumor by a small, firm object causes excruciating pain (Love test), whereas pressure applied slightly to one side of it elicits no pain. Elimination of the pin-point tenderness with tourniquet-induced ischemia (Hildredth test) is also characteristic of glomus tumors. Immersing the involved hand or digit in ice water also exacerbates the discomfort, and a red, opaque dot seen with transillumination of the finger pad may be a useful additional test for some glomus tumors.

Glomus tumors are usually less than 1 cm in diameter, often being only a few millimeters in diameter. High-Tesla MRI scans may prove helpful in diagnosing these rare tumors, with a cold T1 and bright T2 signal being classic but nondiagnostic. Moreover, smaller tumors, those with atypical pathology or location, and tumors not suspected clinically may produce a false-negative MRI study. Trehan et al. found that 33% of histologically proven glomus tumors had negative MRI studies.

Most of these tumors are benign; however, if the lesion exceeds 2.0 cm and histologic parameters suggest malignancy, then metastatic rates exceed 25%. Most of these tumors can be removed under local anesthesia and should be accurately localized by marking the lesion(s) just before surgery. Meticulous and complete excision of the usually well-encapsulated lesions is normally curative, although reoperation rates of 12% to 24% have been reported. Unrecognized synchronous satellite lesions may explain tumors developing in new sites; however, recurrence has been associated with tumor beneath the nail bed and those poorly differentiated from the tumor bed. A retrospective, multicenter study of 72 patients (Kim et al.) found a recurrence rate of 6.9%. No significant difference in outcomes were noted between microscopic procedures and loupe procedures, and no risk factors for recurrence were noted.

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 forms a soft, collapsible mass ( Fig. 78.10 ). Calcifications may be 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 is usually curative if the tumor is fairly well localized ( Fig. 78.11 ); however, in diffuse lesions, persistence rather than recurrence is common. If complete excision is impossible, tumor debulking should be the emphasis of the procedure.

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. 78.12 ) and are rarely 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 a centrally located tumor. Two types of Schwann cells are present: hypercellular (Antoni A) cells, which are arranged in palisades and are 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 are frequently misdiagnosed as ganglions and are rarely multifocal. With careful microsurgical technique, these tumors can usually 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.

Osteoid Osteoma

Osteoid osteomas are characterized by pain that gradually increases from mild to severe and is usually worse at night. Although dramatic pain relief can be obtained from salicylates, a small proportion of patients get no or only partial relief with nonsteroidal antiinflammatory medications. In one study, more than half of upper extremity osteoid osteomas occurred in the wrist and hand; the lesion occurred twice as often in men as in women, and the average age at diagnosis was 19 years (range 4 to 40 years). Some osteoid osteomas of the phalanges are painless, presumably because of the lack of nerve fibers trapped within the tumor. Generalized swelling of the involved part and tenderness to pressure are frequent findings. The carpus, especially the scaphoid, may be the site of involvement. The radiographic appearance depends on the area of bone involved. A small oval or round sclerotic nidus ( Fig. 78.13 ) is surrounded first by an area of less dense bone, similar to a halo, and then by an area of sclerotic bone. Lesions in cortical bone or near the cortex may exhibit extreme sclerosis, requiring special imaging studies to reveal the nidus. A bone scan can be helpful in making the diagnosis. Treatment consists of creating a cortical window for complete removal of the nidus; recurrence may be expected if excision is incomplete. CT-guided radiofrequency ablation may also be used successfully for tumor management.

Enchondroma

Enchondromas are the most common and destructive primary bone tumors of the hand ( Fig. 78.14 ). The most common location is the proximal metaphysis of the proximal phalanx, where the enchondroma is eccentric and expansile ( Fig. 78.15 ). Occasionally, some enlargement of the finger is seen if the loculated medullary tumor has expanded the bony cortex. Pathologic fracture is a common complication because only minimal trauma is required to fracture the thin shell of bone. The fracture is usually allowed to heal before the tumor is excised. For tumor excision, a window is typically made where the cortical bone is expanded maximally and is the weakest, and the soft, blue, friable cartilaginous material is curetted thoroughly. Although the lesion may be treated successfully by curettage alone, we prefer to fill the cavity with bone graft and verify the filling by intraoperative imaging. Curettage and cementation supplemented with Kirschner wires, calcium phosphate defect packing, high-speed burring, and curettage with alcohol irrigation have also been described. Amputation may be necessary if all useful finger function has been lost. Malignant degeneration of an isolated enchondroma is rare; however, when these tumors are found in multiplicity, as in Ollier disease and Maffucci syndrome, the incidence of sarcomatous degeneration increases. Only multiple enchondromas are associated with Ollier disease, and symmetric hemangiomas visible on the hand and legs are associated with Maffucci syndrome. The diagnosis can usually be made from radiographs and the physical examination, but other destructive lesions, such as inclusion cysts, giant cell tumors, and aneurysmal bone cysts, should be considered.

Benign Osteoblastoma

Benign osteoblastomas are rare, but when they do arise they commonly occur in the small bones of the hands and feet. They are similar in appearance clinically and histologically to osteoid osteomas. In general, osteoblastomas tend to be larger than osteoid osteomas, cause less pain, and are more expansile radiographically ( Fig. 78.16 ). These tumors have a ground-glass appearance, producing gross metacarpal deformities, although the cortical shells remain intact. Histologically, areas of mature bone, osteoid, and plump osteoblasts are seen. Treatment is with curettage and bone grafting. Locally aggressive or recurrent lesions may require excision and interpositional bone grafting.

Aneurysmal Bone Cyst

Aneurysmal bone cysts typically begin as eccentric ballooning lesions (metaphyseal, not epiphyseal) that enlarge to become centrally located, causing pain and limitation of motion ( Fig. 78.17 ). Radiographically, they are almost indistinguishable from giant cell tumors or enchondromas. Tremendous cortical expansion and loss of mechanical stability make en bloc resection and autogenous bone grafting the treatment of choice for tubular bone involvement.