Imaging Gallery

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Glomus tumors are rare benign neoplasms arising from the glomus body, a specialized arteriovenous anastomosis involved in thermoregulation. In the hand, these tumors most commonly occur in the subungual region (50-75% of cases), particularly in the fingertips. Despite their small size (usually less than 10 mm), glomus tumors cause disproportionately severe pain, exquisite point tenderness, and marked cold sensitivity—a clinical triad that is virtually pathognomonic.

The diagnosis is primarily clinical, supported by imaging (MRI or ultrasound), and treatment is complete surgical excision, which is curative and provides dramatic symptom relief in over 90% of cases.

Epidemiology

Incidence: Rare, exact incidence unknown (estimated less than 2% of all soft tissue tumors)

Key Demographics:

• Age: 20-50 years (peak incidence 30-40 years)
• Gender: Female predominance (3:1 ratio for solitary lesions)
• Location: Fingers greater than hand greater than other sites
• Subungual: 50-75% of hand glomus tumors
• Thumb: Most common digit affected

Australian Context: Patients often endure prolonged diagnostic delay (average 5-7 years) before referral to hand surgeon. Awareness of the clinical triad by GPs can expedite diagnosis.

Anatomy and Pathophysiology

Normal Glomus Body:

• Specialized arteriovenous anastomosis (Sucquet-Hoyer canal)
• Concentrated in distal extremities (fingertips, palms)
• Function: Thermoregulation via shunting blood flow
• Richly innervated by sympathetic nerve fibers
• Located in dermis and subcutaneous tissue

Components:

1. Afferent arteriole: Brings arterial blood
2. Glomus cells: Modified smooth muscle cells surrounding anastomosis
3. Efferent venule: Drains blood to venous system
4. Nerve supply: Extensive unmyelinated nerve fibers (explains pain)

Tumor Pathology:

• Benign neoplasm of glomus cells
• Well-circumscribed, encapsulated
• Size: Typically 3-10 mm (rarely larger)
• Three histologic types:
  1. Glomus tumor proper (75%): Predominantly glomus cells
  2. Glomangioma: Vascular component prominent (20%)
  3. Glomangiomyoma: Smooth muscle component (5%)

Pain Mechanism:

• Extensive unmyelinated nerve fibers within and around tumor
• Pressure on nerves causes severe pain
• Temperature changes (cold) cause vasoconstriction, increased pressure
• Mechanical pressure (Love's test) reproduces pain

Clinical Variants

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Solitary Glomus Tumor (90% of cases):

• Single lesion
• Subungual or fingertip location typical
• Female predominance
• Sporadic occurrence
• Symptomatic (pain, cold sensitivity)

Multiple Glomus Tumors (10% of cases):

• Multiple lesions, may be hundreds
• Often extradigital locations
• Male predominance
• Autosomal dominant inheritance (some families)
• Less painful than solitary lesions
• Associated with NF1 in some cases

Glomangiomatosis:

• Rare diffuse form
• Involves entire digit or hand segment
• Presents in childhood
• More vascular, may have mass effect

Classic Symptom Triad

Physical Examination

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Inspection:

• Subungual lesions:
  • Bluish-red discoloration through nail (40-60% of cases)
  • Nail ridging or deformity (pressure erosion of bone)
  • Visible mass if nail removed
• Extraungual lesions:
  • Small nodule, skin-colored to bluish
  • May not be visible externally
• Nail changes: Longitudinal ridging, thinning over tumor

Palpation:

• Point tenderness: Exquisite tenderness at tumor site
• Size: Often impalpable due to small size
• Consistency: Firm if palpable
• Mobility: Attached to deeper structures

Special Tests:

Love's Test (Pinprick Test):

• Apply pressure to suspected area with blunt object or pinhead
• Positive: Severe pain elicited at exact tumor location
• Specificity: High for glomus tumor
• Technique: Systematic palpation of entire nail bed, note exact pain point

Hildreth's Test (Tourniquet Test):

• Apply finger tourniquet to occlude venous return
• Palpate suspected area with Love's test
• Positive: Pain relieved with tourniquet inflation
• Mechanism: Reduces venous pressure, decreases tumor engorgement
• Less reliable than Love's test, not routinely necessary

Cold Sensitivity Test:

• Immerse digit in ice water or apply ice
• Positive: Severe pain within seconds
• Highly specific for glomus tumor
• Patients often refuse test due to anticipated pain

Transillumination:

• Negative (unlike mucous cysts)
• Solid mass does not allow light transmission

Differential Diagnosis

The classic triad (severe pain, cold sensitivity, point tenderness) makes glomus tumor diagnosis straightforward despite its rarity.

Imaging

MRI (Gold Standard)UltrasoundPlain Radiographs

MRI - Investigation of Choice:

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Protocol:

• Dedicated small field-of-view imaging of affected digit
• T1-weighted sequences: Isointense to muscle
• T2-weighted sequences: Hyperintense (high signal)
• Post-contrast T1 with fat saturation: Intense enhancement
• High-resolution (3T preferred over 1.5T for small lesions)

Findings:

• Well-circumscribed, homogeneous mass
• Size: Typically 3-10 mm
• Location: Subungual (nail bed) or pulp
• T1: Isointense to muscle
• T2: Hyperintense (bright)
• T1+C: Intense homogeneous enhancement
• Bone: May show pressure erosion (scalloping) of distal phalanx

Sensitivity and Specificity:

• Sensitivity: 85-95% for lesions greater than 2 mm
• Specificity: 50-75% (other vascular lesions may mimic)
• Negative MRI: Does not exclude glomus tumor (sensitivity not 100%)

Utility:

• Confirm suspected diagnosis
• Localize tumor pre-operatively (guide surgical approach)
• Distinguish from other subungual lesions
• Assess for multiple lesions

MRI is highly sensitive but clinical diagnosis remains paramount. Negative MRI with classic triad should still prompt surgical exploration.

High-Resolution Ultrasound:

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Protocol:

• High-frequency linear probe (greater than 15 MHz)
• Doppler assessment for vascularity
• Dynamic scanning with pressure

Findings:

• Hypoechoic, well-defined mass
• Hypervascularity on Doppler (distinguishes from other lesions)
• Size typically 3-10 mm
• Location in nail bed or pulp

Advantages:

• Lower cost than MRI
• No contraindications (pacemaker, claustrophobia)
• Dynamic real-time imaging
• Office-based in some centers

Limitations:

• Operator-dependent
• Less sensitive for small lesions (less than 3 mm)
• Difficult if lesion deep to nail
• Limited availability of high-frequency probes

Sensitivity: 70-85% (operator-dependent)

Useful alternative when MRI unavailable or contraindicated, but MRI remains gold standard.

Plain Radiographs (AP and lateral digit):

Limited Diagnostic Value:

• Tumor not visible on X-ray (soft tissue lesion)
• May show secondary bone changes:
  • Pressure erosion of distal phalanx (scalloping)
  • Well-defined lytic defect
  • Thinning of cortex
• Bone changes present in only 20-40% of cases

Utility:

• Rule out other bony pathology (enchondroma, osteochondroma)
• Document bone involvement pre-operatively
• Generally not necessary for diagnosis

Indications:

• Atypical presentation
• Concern for bony tumor
• Pre-operative planning if bone erosion suspected

Radiographs are low-yield for diagnosis but may be obtained as part of routine workup.

Biopsy

Not Routinely Indicated:

• Clinical diagnosis with imaging confirmation usually sufficient
• Risk of incomplete excision with biopsy
• May cause bleeding, hematoma
• Tumor small, excision is both diagnostic and therapeutic

Consider Biopsy If:

• Atypical imaging features raising concern for malignancy
• Large lesion (greater than 2 cm) suggesting alternative diagnosis
• Multiple lesions with uncertain diagnosis

Histopathology (after surgical excision):

• Well-circumscribed mass
• Three cell types:
  1. Glomus cells: Uniform, round, centrally located nuclei
  2. Vascular component: Capillary-sized vessels
  3. Smooth muscle: Surrounding vessels
• Immunohistochemistry:
  • Glomus cells: Positive for smooth muscle actin (SMA), vimentin
  • Negative for S100, cytokeratin, desmin
• No mitoses, no atypia (benign)

Limited Role

Observation:

• Not recommended for symptomatic lesions
• Pain quality of life impairment significant
• No spontaneous resolution
• Progressive bone erosion may occur

Indications for Non-Operative Approach:

• Incidental finding, asymptomatic (rare)
• Patient refuses surgery
• Significant comorbidities precluding surgery
• Diagnostic uncertainty (may observe with interval imaging)

Medications:

• Analgesics: Limited efficacy for neuropathic-type pain
• Gabapentin/pregabalin: Minimal benefit
• NSAIDs: Ineffective for symptom control
• Calcium channel blockers (nifedipine): Anecdotal reports, weak evidence

Pre-operative Counseling

Realistic Expectations:

• Surgery highly successful (greater than 90% cure rate)
• Complete symptom relief typical
• Recurrence low (less than 10%, usually incomplete excision)
• Nail may not grow back normally if matrix damaged
• Small scar at surgical site

Surgical Risks:

• Incomplete excision (recurrence)
• Nail deformity
• Infection (rare)
• Prolonged pain (if nerve injury)
• Cold intolerance may persist briefly even after excision

Indications

Symptomatic Glomus Tumor:

• Classic triad (pain, cold sensitivity, point tenderness)
• Confirmed or suspected on imaging
• Failed observation (if attempted)

Relative Indications:

• Incidental finding with mild symptoms
• Patient preference for definitive treatment

Surgical Approaches

Subungual ApproachTransungual ApproachExtraungual Approach

Subungual (Nail Bed) Approach - Most Common:

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Indications:

• Subungual glomus tumor (50-75% of hand cases)
• Tumor distal to lunula
• Identified on MRI or ultrasound

Technique:

1. Anesthesia: Digital block (avoid epinephrine in some centers)
2. Tourniquet: Finger tourniquet for hemostasis
3. Nail removal:
   • Elevate nail plate from nail bed with freer elevator
   • Complete nail plate removal
   • Preserve nail matrix proximally (avoid permanent deformity)
4. Tumor identification:
   • Often visible as bluish-red lesion in nail bed
   • Correlate with pre-operative imaging and point tenderness
   • May require meticulous exploration if not immediately visible
5. Excision:
   • Careful dissection around tumor capsule
   • Complete excision en bloc (avoid rupture or piecemeal removal)
   • Preserve nail bed germinal and sterile matrix
   • Remove small margin of surrounding nail bed if adherent
6. Hemostasis: Release tourniquet, meticulous hemostasis
7. Nail bed repair: Absorbable 6-0 or 7-0 sutures if nail bed defect
8. Nail plate replacement: Replace nail plate as biologic dressing (or silicone conformer)
9. Closure: Non-adherent dressing, protective splint

Key Technical Points:

• Tourniquet essential for visualization
• Complete excision critical (recurrence if incomplete)
• Protect germinal matrix (avoid permanent nail deformity)
• Tumor may be very small (3-5 mm), requires meticulous search

This approach provides excellent exposure and is the gold standard for subungual tumors.

Transungual (Through-Nail) Approach:

Indications:

• Tumor proximal to nail fold (under lunula)
• Tumor not accessible via standard subungual approach
• Revision surgery for recurrence

Technique:

1. Nail fold reflection:
   • Make incision along lateral nail folds
   • Reflect eponychium proximally
   • Exposes proximal nail plate and matrix
2. Partial nail plate removal: Remove proximal portion only if needed
3. Matrix incision: Longitudinal incision over tumor (identified by MRI/palpation)
4. Tumor excision: As per subungual approach
5. Matrix repair: Meticulous closure with fine absorbable sutures
6. Eponychium replacement: Return eponychium to anatomic position
7. Closure: Nail plate or conformer, non-adherent dressing

Risks:

• Higher risk of nail deformity (working through matrix)
• More complex dissection
• Longer healing time

Reserved for proximally located tumors not accessible via simpler approach.

Extraungual (Fingertip Pulp) Approach:

Indications:

• Tumor in fingertip pulp (not under nail)
• Lateral or volar digital location
• MRI/ultrasound localization confirms extraungual position

Technique:

1. Incision: Directly over tumor (guided by point tenderness and imaging)
   • Transverse, oblique, or lazy-S incision
   • Avoid volar longitudinal incisions (painful scar, contracture)
2. Dissection: Through subcutaneous tissue to tumor
3. Tumor excision: Complete excision with capsule intact
4. Neurovascular preservation: Protect digital nerves and arteries
5. Hemostasis: Meticulous (release tourniquet)
6. Closure: 5-0 or 6-0 nylon, minimize tension

Advantages:

• No nail involvement
• Direct access
• Lower risk of nail deformity

Location-Specific Incisions:

• Lateral: Midaxial incision
• Volar: Transverse or oblique (never longitudinal)
• Dorsal (extraungual): Curvilinear or transverse

Approach dictated by tumor location confirmed on imaging.

Intraoperative Challenges

Tumor Not Visible:

• Small size (3-5 mm) may make identification difficult
• Correlate with pre-operative imaging (measure distance from landmarks)
• Use Love's test intraoperatively (without tourniquet, patient awake)
• Meticulous exploration of entire nail bed
• Consider ultrasound-guided localization (wire or dye injection pre-op)

Multiple Tumors:

• Glomangiomatosis or multiple glomus tumors
• May require extended exploration
• Consider interval imaging if symptoms persist

Bone Involvement:

• Pressure erosion of distal phalanx
• Curettage of bone if tumor adherent
• Usually no bone grafting needed (remodels)

Post-operative Management

Immediate Post-operative (0-2 weeks):

• Bulky protective dressing
• Elevate hand above heart level (reduce swelling, pain)
• Pain management: Typically minimal after tumor removed
• Dressing change at 48-72 hours
• Monitor for hematoma, infection

Early Rehabilitation (2-6 weeks):

• Suture removal at 10-14 days
• Gentle active motion as tolerated
• Protect nail bed (avoid trauma)
• Scar massage once wound healed

Nail Regrowth (3-6 months):

• Nail grows approximately 1 mm per week
• Full nail regrowth takes 3-6 months
• May have ridging or irregularity initially
• Usually normalizes by 6-12 months

Return to Activities:

• Light activities at 2 weeks
• Full unrestricted activities at 6 weeks
• Avoid forceful gripping until nail fully regrown

Outcomes

Symptom Relief:

• Pain relief: Immediate and dramatic in greater than 90% of cases
• Cold sensitivity: Resolves in greater than 85%
• Patient satisfaction: Extremely high (greater than 95%)

Recurrence:

• Overall recurrence rate: 5-10%
• Cause: Incomplete excision (tumor cells left behind)
• Risk factors: Poorly localized tumor, surgeon inexperience, multiple tumors
• Management of recurrence: Revision excision (usually successful)

Nail Deformity:

• Transient nail changes: 30-40% (ridging, irregular growth)
• Permanent nail deformity: Less than 5% (germinal matrix injury)
• Cosmetically acceptable: Most cases

Management of Recurrence

Evaluation:

• History: Recurrent pain, cold sensitivity
• Examination: Point tenderness at or near original site
• MRI: Localize recurrent tumor
• Consider alternative diagnoses (neuroma, scar tenderness)

Revision Surgery:

• Indications: Symptomatic recurrence
• Pre-operative imaging: Essential for localization
• Technique: Re-explore original site, wider excision
• Success rate: Greater than 90% for first revision
• Counsel patient: Slightly higher risk of nail deformity with revision

Service Delivery

Referral Pathway:

1. GP Presentation: Patient with chronic fingertip pain and cold sensitivity
2. Initial Assessment: Clinical diagnosis suspected based on triad
3. Imaging: MRI hand (high-resolution, contrast-enhanced)
4. Referral to Hand Surgeon: Public or private hand surgeon
5. Surgery: Day surgery under local anesthetic with sedation
6. Follow-up: Wound check, assess symptom resolution

Diagnostic Delay:

• Common issue: Average 5-7 years from symptom onset to diagnosis
• Reasons: Rarity of condition, lack of GP awareness, normal radiographs
• Impact: Prolonged suffering, psychological distress
• Education: Increased GP awareness of classic triad can reduce delay

Funding

Private health insurance may cover gap payments for surgery. Public hospital surgery is available (wait times variable by state).

Pathology:

• Excised specimen sent for histopathology
• Confirms diagnosis, rules out malignancy

Hand Therapy

Limited Role:

• Pre-operative: None
• Post-operative: Wound care education, scar management
• Usually not required for routine uncomplicated cases
• May benefit if persistent stiffness or nail issues

Glomus tumors are rare benign neoplasms arising from the glomus body, a specialized arteriovenous anastomosis involved in thermoregulation. They occur most commonly in the subungual region (50-75% of hand cases), affecting women more than men (3:1), with peak incidence at 30-40 years.

The classic clinical triad—severe paroxysmal pain, exquisite point tenderness (Love's test positive), and marked cold sensitivity—is virtually pathognomonic and allows clinical diagnosis even before imaging. Despite their small size (typically 3-10 mm), glomus tumors cause disproportionately severe pain that significantly impacts quality of life.

MRI is the gold standard investigation, demonstrating a well-circumscribed T2-hyperintense lesion with intense enhancement on post-contrast T1 sequences. Sensitivity is 85-95%, but negative MRI with classic triad should still prompt surgical exploration. Plain radiographs show bone erosion (scalloping of distal phalanx) in only 20-40% of cases.

Surgical excision is the treatment of choice, providing immediate dramatic pain relief in greater than 90% of cases. The key surgical principle is complete en bloc excision to prevent recurrence. Surgical approach depends on tumor location: subungual (nail removal, tumor excised from nail bed), transungual (for proximal lesions under lunula), or extraungual (direct approach for pulp/lateral tumors).

Outcomes are excellent with high patient satisfaction (greater than 95%), immediate pain relief, and resolution of cold sensitivity in greater than 85%. Recurrence occurs in 5-10% due to incomplete excision and is managed with revision surgery (successful in greater than 90%). Nail deformity is usually transient (30-40%) with permanent deformity rare (less than 5%) if germinal matrix protected during surgery.

The major clinical challenge is diagnostic delay (average 5-7 years from symptom onset to diagnosis) due to the rarity of the condition and lack of awareness. Increased recognition of the classic triad by general practitioners can expedite diagnosis and referral, reducing patient suffering.