Orthopedic Surgery for Glomus


Background

Glomus tumors are benign hamartomas originating from the glomus body. [1The glomus body is a neuromyoarterial apparatus composed of vascular structures, nerve cells, and smooth-muscle cells. It is found in the dermis throughout the body, with the highest concentrations being in the hands and feet. The glomus body is responsible for thermoregulation.

Wood first described the clinical findings associated with glomus tumor in 1812. He presented cases of painful subcutaneous nodules that were characterized by pain and temperature sensitivity and that were curable with excision. [2]

Pathophysiology and Etiology

In a glomus tumor, elements of the normal glomus body, vascular structures, nerve cells, and smooth-muscle cells are affected by marked hypertrophy, which leads to a nodulelike structure. The lesion sometimes appears as a locally enlarging mass. No evidence of mitosis is observed in the structure.

A few case reports have described glomus tumors possessing malignant potential. [34Findings included the following:

  • Large size
  • Deep location
  • Infiltrative growth
  • Mitotic activity
  • Nuclear pleomorphism
  • Necrosis

Some reports mention metastases and death from the disease. Glomangiosarcoma is a rare malignant variant that may metastasize.

No risk factors for the formation of glomus tumors are known.

Epidemiology

Glomus tumors are rare. Congenital, familial, and multiple lesions are extremely rare. [5 The incidence of multiple tumors is 25%. [6]

Glomus tumors are most commonly found in distal extremities in the nail bed and subcutaneous tissues of the distal phalanx. About 75% of glomus tumors occur in the hand, and 60% are subungual. [789Other sites include the wrist, forearm, [10and foot, [11but the tumor can occur anywhere in the body.

Glomus tumors have also been described at unusual sites, such as the patella, tendons, bone, eyelid, colon, rectum, kidney, and cervix. [12Intraosseous glomus tumors, which arise from bone, are similarly rare: Fewer than 20 cases of glomus tumor in bone have been reported in the literature. [1314151617]

Glomus tumors mostly occur in middle age, especially in the fourth and fifth decades of life. However, they have been described in all age groups. No clear sex predilection has been reported for glomus tumors in general; however, subungual glomus tumors appear to be more common in women than in men.

Prognosis

The outcome after complete excision with removal of the fibrous capsule is usually excellent, and pain relief occurs immediately after surgery. [18Recurrences are rare if the capsule is completely excised.

In a retrospective multicenter study that included 72 patients with surgically excised digital glomus tumors (mean  follow-up, 5.4 years), Kim et al investigated risk factors for recurrence and assessed complication and recurrence rates according to surgical approach and method. [19At final follow-up, recurrence was observed in 6.9% of patients and postoperative complications in 12.5%. Recurrence rates were higher, though not significantly so, in a group with pulp lesions treated via a direct approach and in a surgical loupe group. A nail-sparing approach and microscopic excision did not reduce nail deformities. No significant predictors of recurrence were identified.


History

Symptoms are often present for a long time before the patient seeks medical attention, and the diagnosis can be delayed for several years if the tumor is not suspected.

Pain is the usual presenting symptom of a glomus tumor. [7This pain related can be excruciating and intermittent. The worst pain may occur at night, and it may disappear when a tourniquet is applied to the hand proximal to the lesion. This palliation reflects the vascular nature of the tumor and the consequent effect of ischemia. [20Some have proposed that the exquisite pain may be associated with the presence of nerve fibers that contain pain neurotransmitter substance P, which has been identified in the tumor. [21]

Patients also have temperature sensitivity, especially when they are exposed to cold. The classic triad of sensitivity to cold, pain, and point tenderness is not always found.

Patients with the rare familial multiple glomus tumors may have a family history of similar lesions. [56]

Physical Examination

Local soft-tissue tenderness and thickening may be present. A mass is sometimes detectable in the area of tenderness. When the lesion is superficial, it may be visible as a small red-blue nodule or a bluish area beneath the skin or fingernail (see the image below). It may be associated with deformity of nail growth. Placement of the affected part in cold water may reproduce symptoms.

Subungual hue seen with a superficial glomus tumorSubungual hue seen with a superficial glomus tumor.

On clinical examination, a positive result with the Love test and the Hildreth sign suggest the diagnosis. To perform the Love test, a fine instrument, such as a pin or a toothpick, is used to elicit point tenderness in the affected region; this maneuver elicits no pain in the area immediately adjacent to the pinpoint area. The Hildreth sign is the disappearance of pain after a tourniquet is placed on the extremity proximal to the lesion. The vascular nature of the tumor is probably the reason why the pain resolves. [22]

On occasion, a patient may present with multiple nodular glomus tumors.


Diagnostic Considerations

Intraosseous glomus tumors should be included in the differential diagnosis of bone lesions. Plain radiography depicts these tumors as well-circumscribed, punched-out lesions with a sclerotic rim, especially in those arising in the finger.

Differential diagnoses of intraosseous glomus tumors can include the following entities:

Epidermal inclusion cysts are most commonly associated with trauma in superficial bones such as the calvaria, phalanx, hand, and foot. They are caused by the implantation of epithelium under the skin, which leads to the formation of cysts with secondary bone erosion. Pain over the lesion is common. However, point tenderness and sensitivity to cold, as observed with the classic glomus tumor, may not be present.

Enchondroma most often affects the cartilage that lines the inside of the bones. The bones that this benign tumor most commonly involves are the miniature long bones of the hands and feet. However, this lesion may also affect other bones, such as the femur, humerus, and tibia.

Osteoid osteoma is a benign bone lesion that is usually found in the diaphyses and the metaphyses of long bones, particularly at the distal end. It typically causes dull pain, which is worst at night and which lasts 20-30 minutes. The classic radiologic appearance of an osteoid osteoma is a radiolucent nidus surrounded by a dramatic, reactive sclerosis in the cortex of the bone. The four diagnostic features are as follows:

  • Sharp round or oval lesion
  • Diameter less than 2 cm
  • Homogeneously opaque center
  • Small area of peripheral radiolucency.



Laboratory Studies

The diagnosis of glomus tumor is primarily clinical, and laboratory workup usually is not needed. If the diagnosis is uncertain in view of the patient's history and physical findings, imaging studies are needed to assess the distal phalanx and the distal interphalangeal (DIP) joint. Various imaging modalities have been used to diagnose glomus tumors (see Imaging Studies). [23242526]

Imaging Studies

Results of plain radiography are often unremarkable, but radiographs may show a well-circumscribed osteolytic lesion with a sclerotic border or a soft-tissue mass causing bone erosion.

Computed tomography (CT) is indicated for accurately assessing tiny abnormalities of the cortex of the distal phalanx. CT scans demonstrate a nonspecific nodule or mass, either in the soft tissue or within the bone.

For the initial workup, color Doppler ultrasonography (US) is an appropriate first test. US may be helpful for depicting a cystic or a vascular component of a tumor. US and Doppler study yield better visualization of the tumors than standard radiology does; however, these sonographic methods are highly operator-dependent. [27]

Magnetic resonance imaging (MRI) offers whole imaging of the soft parts of the nail unit and the underlying bone. MRI may be performed to localize the tumor before surgery. On T1-weighted images, a glomus tumor appears as a dark, well-delineated mass. T2-weighted images are best for visualizing glomus tumors, which appear as bright and well-delineated masses (see the image below). [25 Because the lesion is richly vascularized, it demonstrates marked contrast enhancement on MRI performed after an intravenous injection of gadolinium-based contrast material.

Intraosseous glomus tumor appears as a bright, welIntraosseous glomus tumor appears as a bright, well-delineated mass on a T2-weighted MRI.

Magnetic resonance angiography (MRA) is especially helpful in diagnosing small lesions that may be missed with other imaging studies. [2328]

Histologic Findings

On gross examination, a glomus tumor appears as a well-encapsulated soft-tissue lesion. On microscopic evaluation, the tumor usually occurs at the dermal-subepidermal junction and consists of markedly hypertrophied elements of the normal glomus body surrounded by a fibrous capsule. A normal glomus body is made up of vascular structures, smooth-muscle cells, and nerve cells surrounded by uniform epithelioid cells, also known as glomus cells. [29]

Glomus tumor cells stain positively for smooth-muscle actin and weakly express desmin. These cells have also been shown to express CD34. [30]

Glomus tumors with malignant potential may show nuclear atypia, mitotic activity, or necrosis.

TREATMENT AND MANAGEMENT


Approach Considerations

Surgical excision of the tumor is the mainstay of treatment. Indications for surgical excision include local symptoms of pain and temperature sensitivity that are bothersome to the patient or that interfere with daily activities. Lesions associated with nail deformities may have to be excised for cosmetic purposes.

Medical Therapy

Although surgical excision is the only definitive treatment, pain relief should be provided until the procedure is performed. To destroy the tumor, therapeutic alternatives to surgical excision include sclerotherapy with sodium tetradecyl sulfate or laser treatment with an argon, carbon dioxide, or neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. [22313233 In one study, intralesional injections of hypertonic sodium chloride solution given in four sessions over 6 months were found to be effective. [34]

Surgical Therapy

Complete surgical excision provides definitive treatment. For multiple glomus tumors, excision may be difficult because the tumors may be poorly circumscribed. Excision should be limited to symptomatic lesions. [223536]

Because excision is a minimally invasive procedure, no specific preoperative workup is indicated if the diagnosis is clinically evident. The most crucial and challenging preoperative detail is exact localization of the glomus tumor. Magnetic resonance imaging (MRI) may be helpful in this regard. [25]

In lesions on the trunk or an extremity, careful localization and marking are essential for complete and successful excision. The use of methylene blue just before surgery can be helpful.

Because multiple tumors occur in 25% of cases, careful clinical examination and, possibly, radiographic investigation should be conducted to look for additional tumors.

Lesions in the nail bed are exposed after the nail is removed. A longitudinal incision is made in the sterile matrix, and the matrix is elevated on either side to expose the lesion. The entire flap, including the nail plate, nail bed, and periosteum, should be elevated to excise the circumscribed lesion on the undersurface of the flap or in the bone. Proximal lesions at the level of the germinal matrix should be exposed with a dorsolateral incision made at the junction with the glabrous skin. The flap is then replaced; it can be held with nylon sutures.

Complete excision with removal of the entire capsule should be ensured to prevent recurrences.

Pain relief is usually achieved immediately after surgical excision. If symptoms persist after 3 months or recur, exploration should be repeated. Persistence may be due to incomplete excision or multiple lesions, which affect 25% of patients. The incidence of recurrent symptoms is about 15%.

Garg et al described good results with a nail-preserving modified lateral subperiosteal approach to subungual glomus tumors in 30 patients. [37At follow-up, all patients experienced relief of their preoperative symptoms, and all of the treated fingers had normal function. None of the patients showed evidence of nail or fingertip deformity or experienced tumor recurrence.

Complications

Incomplete excision of the tumor capsule may cause symptoms to persist.

If the tumor extends into the germinal matrix of the nail bed, it may affect nail growth.

Lu et al reported a case of rupture of a subungual glomus tumor and subsequent finger infection.


Approach Considerations

Surgical treatment of fibrous dysplasia is indicated in the prevention or treatment of fractures or major deformity. [27 The most common surgical indications are fracture of a weightbearing bone and progressive disease. Asymptomatic patients do not need treatment. A needle biopsy can be performed if there is doubt about the diagnosis before the initial management. Upper-extremity lesions rarely require surgical management. Nevertheless, vascularized bone grafting has been proposed. [28]

There are no specific contraindications for surgical intervention in patients with fibrous dysplasia. However, care must be used in the skeletally immature patient. Internal fixation of long bones with intramedullary nails may be proposed.

In the future, effective nonsurgical treatments may be possible. Because the risk of local recurrence is high, the decision to treat must be made with informed consent to avoid inappropriate expectations. In general, the goals of surgery should be to stabilize the bone and relieve pain, rather than to excise the involved bone. The condition often is found incidentally, and the need for prophylactic treatment may be difficult to accept for an asymptomatic or minimally symptomatic patient.

Medical Therapy

Although there is no specific medical therapy for fibrous dysplasia, studies have shown decreased pain after treatment with bisphosphonates, which inhibit bone resorption by virtue of their action on osteoclasts. [29203031 

The most common drug therapy is intravenous (IV) pamidronate. An IV infusion of pamidronate (total dose of 1 mg/kg/day over 3 days, repeated every 3-6 months) has been proposed. The total dose must be administered over a 4-hour period. Vitamin D and calcium supplements must be added to the regimen. This therapy in children seems to be safe, but longer follow-up is needed to confirm the absence of collateral effects on the growth plate. An increased growth-plate thickness has been reported in children treated with bisphosphonates. [9]

The PROFIDYS study (Oral Bisphosphonate Effect on Osseous Symptoms in Fibrous Dysplasia of Bone) is a double-blind study evaluating the long-term safety and results of treatment with an oral bisphosphonate (risedronate), which was initiated in 2007. The study is evaluating bone pain and the evolution of osteolytic lesions in patients with fibrous dysplasia.

Majoor et al evaluated the biochemical (bone turnover markers [BTMs]) and clinical (pain reduction) outcome of bisphosphonate therapy in 11 patients with McCune-Albright syndrome and 30 patients with polyostotic fibrous dysplasia who were treated for a median of 6 years (range, 2-25 years). [32​ Their data suggested that long-term bisphosphonate therapy was beneficial and safe in the majority of patients with polyostotic fibrous dysplasia. The only prognostic factor found to influence the outcome of bisphosphonate therapy was a high skeletal burden score.

Wang et al retrospectively studied laboratory and clinical findings in 22 cases of polyostotic fibrous dysplasia associated with McCune-Albright syndrome, with the aims of (1) evaluating the efficacy and safety of bisphosphonate therapy and (2) comparing the efficacy of different bisphosphonates (ie, pamidronate and zoledronic acid) in this setting. [33​ They found bisphosphonate treatment to be safe and well tolerated and to cause no obvious impairment in patients' linear growth. Zoledronic acid was similar to pamidronate in terms of controlling disease activity.

Surgical Therapy

If surgical treatment is required for fibrous dysplasia in long bones, intramedullary nailing is recommended. [34This technique provides good stabilization and could prevent deformation.

Conservative treatment, use of plates, curettage, or bone grafting should be discouraged. [111635Deformity-correction surgery is indicated in patients with mechanical axis deviation of the lower limbs.

The dysplastic bone in fibrous dysplasia can be quite difficult to ream. Fibrous dysplasia is associated with a high tendency of bone bleeding during surgery. [11]

Gui et al reported their experience with a navigation system they developed for use in conjunction with computer-aided recontouring in the surgical treatment of complex craniofacial fibrous dysplasia. [36Surgical outcomes were assessed by superimposing postoperative computed tomography (CT) scans onto preoperative CT scans. The authors found that navigation-guided recontouring improved the accuracy and safety of the surgical treatment of complex craniofacial fibrous dysplasia.

Multiportal combined transorbital-transnasal endoscopic resection of fibrous dysplasia of the skull base and orbit has been described. [37]

Long-Term Monitoring

The main role of follow-up is to prevent deformity as a result of the disease. The authors recommend yearly radiographs of the involved area or areas until skeletal maturity. Because fibrous dysplasia rarely undergoes remission, it is appropriate to monitor disease progression periodically, especially in the skeletally immature patient. Once skeletal maturity has been achieved, it is unusual for monostotic fibrous dysplasia to progress.

Early intervention with internal fixation of involved bones may be important in the prevention of deformity. Referral to an endocrinologist for endocrine and metabolic testing is suggested so that endocrine anomalies can be diagnosed and treated.


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