How to differentiate and manage a cervical mass in an adult patient with no significant medical history, suspected to be either a cervical tuberculous abscess or scrofula?

Differentiating and Managing Cervical Tuberculous Abscess vs Scrofula

Scrofula and cervical tuberculous abscess are the same entity—both terms refer to tuberculous cervical lymphadenitis—so the real clinical challenge is distinguishing tuberculous from nontuberculous mycobacterial (NTM) lymphadenitis, which fundamentally changes management. 1

Critical Distinction: Age-Based Epidemiology

The patient's age is the single most important differentiating factor:

• In adults (your patient): >90% of culture-proven mycobacterial cervical lymphadenitis is due to Mycobacterium tuberculosis (tuberculous/scrofula) 1
• In children: Only ~10% is tuberculous; ~80% is NTM (primarily MAC) 1

Therefore, in an adult with cervical mycobacterial lymphadenitis, you should presume tuberculosis until proven otherwise. 1

Initial Risk Stratification for Malignancy (Critical First Step)

Before pursuing infectious workup, you must first rule out malignancy, as any neck mass in an adult should be considered malignant until proven otherwise 2. Your patient is at increased risk if the mass has been present ≥2 weeks, is >1.5 cm, firm/hard, fixed to tissues, or accompanied by constitutional symptoms 2, 1.

Mandatory High-Risk Workup:

• CT neck with contrast (or MRI) immediately 2
• Visualization of larynx, base of tongue, and pharynx (flexible laryngoscopy) to exclude primary malignancy 2, 1
• Fine-needle aspiration (FNA) if diagnosis remains uncertain after imaging 2, 1

Do NOT give empiric antibiotics unless clear bacterial infection signs (warmth, erythema, fever, tenderness) are present 2, 1—this delays cancer diagnosis and does not help mycobacterial infections.

Differentiating Tuberculous from NTM Lymphadenitis

Once malignancy is excluded and mycobacterial infection suspected:

Clinical Features Favoring Tuberculosis (Scrofula):

• Adult patient (>90% probability) 1
• History of TB exposure or immigration from endemic areas (Southeast Asia, Mexico) 3, 4
• Systemic symptoms may be present 4
• Bilateral or mediastinal node involvement possible 1
• HIV co-infection common 4
• Chest X-ray may show pulmonary TB 1

Clinical Features Favoring NTM:

• Pediatric patient (80% probability in children) 1
• Insidious onset, rarely systemic symptoms 1
• Unilateral involvement (95%) 1
• Nodes may enlarge rapidly, rupture, form sinus tracts 1
• Normal chest X-ray 1
• No TB exposure history 1

Tuberculin Skin Test (PPD) Interpretation:

• Not diagnostic for either condition 1
• Children with NTM can show reactions ≥10 mm in up to one-third of cases 1
• Negative PPD does NOT rule out tuberculosis, especially in immunocompromised patients 1

Diagnostic Approach

Step 1: Obtain Tissue Diagnosis

FNA is the first-line diagnostic modality 1, 2:

• Look for granulomas, caseating necrosis, acid-fast bacilli (AFB) 1, 5
• Send aspirate for AFB smear and mycobacterial culture 5
• Sensitivity is lower for cystic masses (73% vs 90% for solid) 1

If FNA is non-diagnostic, proceed to excisional biopsy 5:

• Provides tissue for histopathology and culture 1, 5
• Critical caveat: Avoid incision and drainage or incomplete excision—this causes chronic fistula formation 1
• Preauricular node excision risks facial nerve injury 1

Step 2: Microbiologic Confirmation

• Mycobacterial culture is definitive but only positive in 50-82% of excised nodes 1, 5
• Culture distinguishes M. tuberculosis from NTM species 1
• Molecular testing (PCR, GeneXpert) can provide rapid TB diagnosis 5

Step 3: Ancillary Testing

Based on clinical suspicion 1:

• HIV testing (scrofula strongly associated with HIV) 4
• Chest X-ray (pulmonary TB in ~50% of scrofula cases) 1
• Contact tracing if TB confirmed 1

Management: The Critical Difference

Tuberculous Lymphadenitis (Scrofula):

Medical management with anti-tuberculous chemotherapy is highly effective 3, 5:

• Standard 4-drug regimen (rifampin, isoniazid, pyrazinamide, ethambutol) 5, 6
• Duration: 6-9 months 5
• Public health notification and contact tracing required 1
• Surgery NOT indicated unless diagnosis uncertain 3

NTM Lymphadenitis:

Surgical excision is the primary treatment 1:

• Complete excision of involved nodes 1
• Antimicrobial therapy has variable efficacy and is NOT first-line 1, 3
• No public health implications (not contagious) 1

Common Pitfalls to Avoid

• Assuming cystic masses are benign: Continue evaluation until diagnosis obtained 1, 2—HPV-positive oropharyngeal cancer commonly presents as cystic cervical metastases 2
• Incomplete surgical excision or incision/drainage: Leads to chronic fistula formation 1
• Empiric antibiotics without infection signs: Delays cancer diagnosis 2, 1
• Relying on PPD alone: Not diagnostic for either TB or NTM 1
• Assuming negative cultures rule out mycobacterial disease: Only 50-82% culture-positive even with compatible histology 1, 5

Clinical Algorithm Summary

1. Rule out malignancy first: CT with contrast + laryngoscopy + FNA if high-risk features 2, 1
2. If mycobacterial infection suspected: FNA for AFB smear/culture and histology 1, 5
3. In adults, presume tuberculosis: Obtain HIV test, chest X-ray, initiate contact tracing 1, 4
4. If FNA non-diagnostic: Excisional biopsy (complete excision, avoid I&D) 1, 5
5. Await culture results: M. tuberculosis → medical therapy; NTM → surgical excision primary treatment 1, 3
6. If culture-negative but granulomas present: High suspicion for TB in adults—consider presumptive anti-TB treatment 5