Orthopedic Surgery for Glomus Tumor 

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.^[1]

Glomus tumors are benign hamartomas originating from the glomus body. The 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 (see an example shown below). The glomus body is responsible for thermoregulation.

Frequency

Glomus tumors are rare. Congenital, familial, and multiple lesions are extremely rare.^[2]

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 (see first image below).^{[3, 4]} Other sites include the wrist, forearm, and foot,^[5] but 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.^[6] Intraosseous glomus tumors (see second image below), which arise from bone, are similarly rare. Fewer than 20 cases of glomus tumor in bone have been reported in the literature.^{[7, 8, 9, 10, 11]}

The rate of multiple tumors is 25%.^[12]

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.

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

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.^{[13, 14]} Findings 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.

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.^[3] Pain related to glomus tumors 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.^[15] Some 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.^[16]

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 rare familial, multiple glomus tumors may have a family history of similar lesions.^{[2, 12]}

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, as shown below. It may be associated with deformity of nail growth. Placement of the affected part in cold water may reproduce symptoms.

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 pain resolves probably because of the vascular nature of the tumor.^[17]

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

Differential diagnosis

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 cyst
• Enchondroma
• Osteoid osteoma
• Ingrown toenail
• Chronic osteomyelitis
• Entrapment neuropathy
• Clinical depression
• Metastatic tumor

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 4 diagnostic features are a sharp round or oval lesion, a diameter less than 2 cm, a homogeneously opaque center, and a small area of peripheral radiolucency.

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 need to be excised for cosmetic purposes.