A glomus tumor is a rare growth that originates from specialized cells in the glomus body, a structure found in the skin. While these tumors are uncommon, accounting for less than 2% of all soft tissue tumors, they are typically benign.
Understanding Glomus Tumors
Glomus tumors develop from glomus bodies, which are modified smooth muscle cells that play a role in regulating skin temperature. These microscopic structures are part of the dermis and help control blood flow to the skin’s surface. While glomus bodies are distributed throughout the body, they are highly concentrated in the fingers and toes, particularly under the fingernails.
Glomus tumors are usually small, often less than 7 millimeters in diameter, and are frequently solitary. They commonly appear in the hands and feet, with a significant number, around 65%, found beneath the fingernail. The exact cause of glomus tumor proliferation is not fully understood, though some cases are linked to genetics or trauma.
Are Glomus Tumors Malignant?
Glomus tumors are overwhelmingly benign. The occurrence of malignant glomus tumors is exceedingly rare. When malignancy does occur, these tumors are typically locally infiltrative.
Distinguishing features of a malignant glomus tumor often include a size greater than 2 centimeters, a deep or visceral location, and infiltrative growth patterns. Despite their aggressive local behavior, metastases from malignant glomus tumors are extremely rare, though when they do occur, they can be serious.
Symptoms and Impact on Health
Even though most glomus tumors are benign, they can significantly affect a person’s health due to their characteristic symptoms. The most common symptom is intense pain, which is often disproportionate to the tumor’s small size. This pain can be excruciating and is frequently described as throbbing or lancinating.
Patients commonly experience heightened sensitivity to cold temperatures, with pain often worsening when the affected area is exposed to cold water. Tenderness to touch is also a hallmark symptom, where even light pressure on the tumor can cause severe discomfort. If the tumor is located under the fingernail, a bluish discoloration or a deformity of the nail plate, such as changes in color, splitting, or thickening, may be observed. These symptoms arise from the tumor’s rich vascularity and its proximity to nerve endings, leading to nerve compression and irritation. The constant pain and sensitivity can severely disrupt daily activities and diminish quality of life.
Diagnosis and Treatment
Diagnosing a glomus tumor typically begins with a thorough physical examination and a review of the patient’s symptoms. Specific clinical tests, such as Love’s test, which involves applying pinpoint pressure to the suspected area to elicit intense pain, and Hildreth’s sign, where pain and tenderness decrease after applying a tourniquet, can aid in diagnosis. Because of their small size and rarity, glomus tumors can sometimes be difficult to detect clinically, leading to diagnostic delays.
Imaging techniques are frequently used to confirm the diagnosis and pinpoint the tumor’s exact location. High-resolution ultrasound can identify the tumor as a hypoechoic nodule with prominent hypervascularity. Magnetic Resonance Imaging (MRI) is considered the preferred imaging modality, showing the tumor as a well-defined nodule with low to intermediate signal intensity on T1-weighted sequences, high signal intensity on T2-weighted sequences, and strong, uniform enhancement after contrast administration due to its vascular nature. X-rays may occasionally show subtle bone erosion in cases where the tumor has been present for an extended period. The definitive diagnosis is confirmed through histopathological examination of the excised tissue.
The primary treatment for symptomatic solitary glomus tumors is complete surgical excision. This procedure aims to alleviate pain and minimize recurrence. For tumors located under the nail, a total nail avulsion followed by excision is often performed, although nail-preserving techniques also exist.
Pain relief is usually immediate following successful surgical removal. The success rate of surgical treatment in achieving symptom resolution is high, with many patients experiencing complete relief within 2-4 weeks. Recurrence rates for subungual glomus tumors after surgical excision generally range from 2% to 13%, with incomplete excision being a common reason for recurrence. In cases of recurrence, further surgical treatment is often effective.
Long-Term Outlook
The long-term outlook for individuals with glomus tumors is generally positive, especially after complete surgical removal. With the tumor fully excised, symptoms typically resolve, allowing patients to return to their normal activities without the debilitating pain and sensitivity. While recurrence is possible, particularly if the initial excision was incomplete, it is often manageable with additional treatment. The prognosis is favorable, reinforcing that these tumors, while painful, do not typically pose a life-threatening risk in the long run.