Tuberculous (TB) lymphadenitis is lymph node involvement by Mycobacterium tuberculosis and is the most common form of extrapulmonary TB. Cervical lymphadenopathy (60-90%) is the most common presentation — particularly posterior triangle and jugular chain. The most characteristic imaging finding of TB lymphadenitis is peripheral rim enhancement (central caseous necrosis) and nodal matting. Caseous necrosis represents the central necrosis phase of granulomatous inflammation and is the key differentiating point from non-caseating granulomas in sarcoidosis. Increased frequency in endemic regions, HIV-positive individuals, and immunosuppressed patients. Treatment is prolonged multi-drug antibiotic regimen (6-9 months).
Age Range
15-50
Peak Age
30
Gender
Equal
Prevalence
Uncommon
M. tuberculosis reaches lymph nodes via lymphatic spread or hematogenous route. Granuloma formation — organized structures of epithelioid histiocytes, Langhans giant cells, and lymphocytes develop. Central caseous necrosis (cheese-like necrosis) occurs in granuloma centers — this lipid-rich necrotic material appears as low-density central area on CT and does not enhance. Peripheral granulomatous tissue receives vascular supply and enhances — creating rim enhancement. Matting results from caseous necrosis breaching lymph node capsule to involve adjacent nodes and surrounding soft tissue — perinodal inflammatory reaction connects nodes. In chronic TB, calcification develops — dystrophic calcium deposition within caseous material. Paradoxical reaction (transient LAP increase after treatment initiation) represents immune reconstitution inflammatory syndrome (IRIS).
Peripheral rim enhancement (central caseous necrosis), nodal matting, and perinodal inflammatory changes are three cardinal findings of TB lymphadenitis whose combined presence strongly supports diagnosis.
Peripheral rim enhancement and central low-density area (caseous necrosis) on contrast-enhanced CT. Nodes are matted and perinodal inflammatory changes (fat plane effacement, soft tissue thickening) are prominent. Multiple nodes are involved in clusters. Calcification may be seen in chronic form. Perinodal abscess/phlegmon may develop.
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Multiple matted lymph nodes with peripheral rim enhancement and central necrosis in cervical region, consistent with tuberculous lymphadenitis.
Matted, hypoechoic lymph nodes on ultrasonography. Intranodal necrosis — anechoic or hypoechoic central area. Perinodal inflammatory changes — edema and thickening in surrounding soft tissue. Sinus tract formation (fistulization) may be seen in chronic cases. Calcific foci show acoustic shadowing.
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Matted, multiple lymph nodes with intranodal necrosis and prominent perinodal inflammatory changes — consistent with TB lymphadenitis.
Peripheral vascularity and avascular necrotic center on Doppler. Perinodal inflammatory tissue shows vascularity increase. Irregular vascular distribution in matting areas. Decreased vascularity in fistulized areas.
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Avascular necrotic center with peripheral vascularity increase and perinodal inflammatory vascularity in lymph nodes.
Peripheral diffusion restriction (viable granulomatous tissue) and central high ADC (caseous necrosis) on DWI. ADC values 0.8-1.2 peripherally, >1.5 × 10⁻³ mm²/s centrally. Heterogeneous diffusion pattern in matting areas. Rim enhancement on post-contrast T1. High signal in necrotic center on T2.
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Peripheral diffusion restriction and central high ADC in lymph node, consistent with granulomatous lymphadenopathy with caseous necrosis.
Moderate FDG uptake on PET-CT (SUVmax usually 3-8). Rim-shaped uptake pattern may be observed — peripheral uptake and central photopenic area. Uptake is prominent in active TB, decreases with treatment. PET-CT may be used for treatment response monitoring.
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Rim-shaped FDG uptake in cervical lymph nodes consistent with active granulomatous lymphadenopathy — TB lymphadenitis should be primarily considered.
Calcified lymph nodes in chronic/treated TB on non-contrast CT. Calcification may be coarse or eggshell (peripheral) type. Completely calcified nodes show high density throughout. Partial calcification may coexist with necrosis areas.
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Calcified lymph nodes in cervical/mediastinal region, consistent with chronic granulomatous lymphadenopathy (treated TB).
Criteria
Prominent rim enhancement, central necrosis, matting. Represents active infection period.
Distinct Features
Most characteristic imaging findings in this stage. Clinical symptoms prominent (fever, night sweats, weight loss). Treatment should be initiated.
Criteria
Liquefaction of caseous necrosis, abscess formation. Fluctuation clinically palpable. Fistulization may develop.
Distinct Features
Prominent low-density collection on CT, thin wall enhancement. Partially organized fluid collection on US. Drainage may be needed.
Criteria
Dystrophic calcification within caseous material. Usually represents treated or inactive TB.
Distinct Features
Calcified nodes on CT. Minimal or no enhancement — no active inflammation. No follow-up needed but reactivation should be monitored.
Distinguishing Feature
SCC metastasis shows similar central necrosis but no matting, ENE and primary tumor presence, perinodal inflammatory changes less prominent — TB shows matting, perinodal thickening, and clinical TB findings.
Distinguishing Feature
Sarcoidosis shows homogeneous enhancement, absence of necrosis, bilateral symmetric hilar LAP — TB shows rim enhancement, central necrosis, matting, and asymmetric involvement.
Distinguishing Feature
NHL shows conglomerate LAP but nodes merge rather than mat, sandwich sign, extranodal masses — TB shows matting with perinodal inflammation predominant, indistinct inter-nodal borders but no sandwich sign.
Distinguishing Feature
Cat scratch disease shows similar necrosis but usually single region, cat contact history, more acute presentation, and less prominent matting — TB shows multi-region involvement, matting, and chronic course.
Urgency
urgentManagement
medicalBiopsy
NeededFollow-up
specialist-referralMicrobiological diagnosis (AFB stain, culture, PCR) by FNA or excisional biopsy is mandatory in suspected TB lymphadenitis. Treatment is 6-9 month multi-drug regimen (2RHZE + 4RH). Paradoxical reaction (transient LAP increase after treatment start) may be IRIS and does not require treatment change. Treatment response assessed clinically and radiologically — nodes shrink over months but residual calcification may remain. Atypical presentations are common in HIV-positive patients and differential diagnosis is broader.
TB lymphadenitis is the most common form of extrapulmonary TB (40%). Diagnosis is made by FNAC (fine needle aspiration cytology) + AFB staining + culture + PCR. Treatment is 6-9 month anti-TB regimen (HRZE). Paradoxical reaction (temporary enlargement at treatment initiation) is common and should not be confused with malignancy. Atypical appearance and more widespread involvement are expected in HIV-positive patients.