Residency · Residency · Medicine Pediatrics

Lymphadenopathy: Benign to Malignant Across Ages

Overview

Lymphadenopathy is palpable enlargement of lymph nodes (>1 cm in most locations; >1.5 cm inguinal; >0.5 cm epitrochlear; >1 cm supraclavicular is always abnormal) In children, lymphadenopathy is overwhelmingly reactive and self-limited (>95% benign) In adults, the probability of malignancy increases significantly, especially with advancing age. The Med-Peds physician must develop an age-adjusted differential and know when to pursue biopsy versus observation.

Anatomy and Distribution

Localized Lymphadenopathy

Cervical: most common site in children; reactive to upper respiratory infections, pharyngitis, dental infections; in adults also consider head/neck malignancy, lymphoma, TB. Supraclavicular: always concerning at any age; left (Virchow node) associated with intra-abdominal malignancy; right with thoracic malignancy; biopsy rate should be high. Axillary: cat scratch disease, breast pathology (adults), skin infections, lymphoma. Inguinal: common and often reactive in both ages; STIs in adolescents/adults; lower extremity infections. Epitrochlear: unusual; consider lymphoma, sarcoidosis, secondary syphilis; non-specific hand/forearm infections.

Generalized Lymphadenopathy

Defined as lymphadenopathy in >= 2 non-contiguous regions. Differential: EBV, CMV, HIV, SLE, sarcoidosis, serum sickness, lymphoma, leukemia, drug reactions (phenytoin, allopurinol), storage diseases in children (Gaucher, Niemann-Pick)

<image>Anatomical diagram showing lymph node drainage regions with associated differential diagnoses by location for both pediatric and adult patients</image>

Differential Diagnosis by Age

Infants and Young Children

Reactive lymphadenopathy: most common; responds to frequent viral infections. Bacterial lymphadenitis: acute, tender, erythematous; S. aureus and Group A Strep most common; may develop abscess. Atypical mycobacterial lymphadenitis: non-tender, unilateral cervical, violaceous skin discoloration; excision preferred over antibiotics. Kawasaki disease: unilateral cervical node >1.5 cm is one of the diagnostic criteria. Cat scratch disease (Bartonella henselae): regional lymphadenopathy proximal to scratch site; may suppurate. Malignancy: neuroblastoma (abdominal mass + cervical nodes), leukemia (generalized + systemic symptoms), lymphoma.

School-Age Children and Adolescents

Reactive remains most common. EBV (infectious mononucleosis): generalized, especially posterior cervical; fatigue, pharyngitis, hepatosplenomegaly. Lymphoma: Hodgkin lymphoma peaks in adolescence; painless, firm, rubbery nodes; B symptoms (fever, night sweats, weight loss) TB: chronic cervical (scrofula); consider in endemic areas or high-risk populations. Cat scratch disease. Toxoplasmosis: posterior cervical nodes in immunocompetent adolescents.

Adults

Reactive lymphadenopathy still common but malignancy must be excluded more aggressively. Lymphoma: Hodgkin (bimodal: young adult and >55) and non-Hodgkin. Metastatic carcinoma: head/neck cancer (cervical), breast (axillary), lung (supraclavicular), GI (left supraclavicular) HIV: persistent generalized lymphadenopathy may be presenting sign. Sarcoidosis: bilateral hilar and peripheral lymphadenopathy. Autoimmune: SLE, rheumatoid arthritis (Felty syndrome), dermatomyositis. Drug reactions: phenytoin (pseudolymphoma), allopurinol, carbamazepine.

Clinical Assessment

History

Duration (acute <2 weeks, subacute 2-6 weeks, chronic >6 weeks); Associated symptoms: fever, weight loss, night sweats (B symptoms), fatigue, pruritus. Infectious exposures: cat scratch, tick bite, TB contacts, travel, sexual history. Medications; Immunization status; Family history of malignancy, autoimmune disease.

Physical Examination

Size: >2 cm in any age raises concern; >1 cm supraclavicular always concerning. Consistency: soft/mobile = reactive; firm/rubbery = lymphoma; hard/fixed = metastatic carcinoma. Tenderness: tender = infection/inflammation; non-tender = more concerning for malignancy. Matting: nodes stuck together — TB, lymphoma, metastatic disease. Location: supraclavicular, epitrochlear, and popliteal nodes are concerning regardless of size. Associated findings: hepatosplenomegaly, rashes, joint involvement, oral lesions.

Red Flags Requiring Urgent Evaluation

Supraclavicular lymphadenopathy at any age; Fixed, hard, non-tender node >2 cm; B symptoms (unexplained fever, night sweats, >10% weight loss); Generalized lymphadenopathy with hepatosplenomegaly; Lymphadenopathy increasing in size over 2+ weeks despite antibiotics; Abnormal CBC (cytopenias, blasts, markedly elevated WBC); Age >40 with persistent unexplained lymphadenopathy.

<image>Clinical decision framework for lymphadenopathy evaluation showing when to observe, perform laboratory workup, image, or proceed directly to biopsy based on age, location, size, and associated features</image>

Diagnostic Workup

Laboratory Studies

Initial: CBC with differential, ESR/CRP, peripheral smear. Directed by clinical suspicion: EBV/CMV serologies, HIV, Bartonella antibodies, PPD/IGRA, toxoplasma IgM/IgG. If malignancy suspected: LDH, uric acid, comprehensive metabolic panel, flow cytometry (peripheral blood) Autoimmune workup: ANA, RF if systemic features.

Imaging

Ultrasound: first-line for superficial lymphadenopathy; distinguishes reactive (oval, preserved hilum, <2 cm) from suspicious (round, loss of hilum, irregular borders, necrosis, calcification) CT with contrast: neck, chest, abdomen, pelvis for staging or deep lymphadenopathy. PET-CT: staging for lymphoma; may guide biopsy to most metabolically active node. Chest X-ray: mediastinal lymphadenopathy (lymphoma, sarcoidosis, TB)

Biopsy

Excisional biopsy: gold standard for definitive diagnosis; preserves architecture for lymphoma subtyping. Core needle biopsy: acceptable in adults when excision is difficult; less ideal for initial lymphoma diagnosis. Fine needle aspiration (FNA): useful for metastatic carcinoma and infection; NOT adequate for primary lymphoma diagnosis (cannot assess architecture) When to biopsy: Persistent/progressive lymphadenopathy >4-6 weeks without clear infectious etiology. Supraclavicular node at any age. B symptoms, abnormal labs, or suspicious imaging. In children: lower threshold if node >3 cm, hard/fixed, or systemic symptoms. In adults: lower threshold overall; any node >2 cm persisting >3-4 weeks.

Specific Conditions

Cat Scratch Disease

Bartonella henselae; 7-12 day incubation after cat scratch/bite. Regional lymphadenopathy (axillary, epitrochlear, cervical), often with visible inoculation papule. Diagnosis: Bartonella antibody titers, PCR; histology shows granulomas with stellate microabscesses. Usually self-limited over 2-4 months. Antibiotics (azithromycin) shorten duration in some studies but not always necessary. Complications: encephalitis, neuroretinitis, hepatosplenic disease (immunocompromised)

Kikuchi-Fujimoto Disease

Histiocytic necrotizing lymphadenitis; most common in young Asian women; Tender cervical lymphadenopathy with fever; self-limited over 1-4 months; Can mimic lymphoma or SLE histologically; No specific treatment; may recur.

Castleman Disease

Unicentric: localized, often mediastinal; surgical excision curative. Multicentric: generalized; associated with HHV-8 and HIV; treat with anti-IL-6 (siltuximab) or rituximab.

Rosai-Dorfman Disease

Sinus histiocytosis with massive lymphadenopathy; painless bilateral cervical. More common in children and young adults of African descent. Usually self-limited; treatment for symptomatic or organ-threatening disease.

<image>Histopathologic patterns of lymph node biopsy findings comparing reactive follicular hyperplasia, granulomatous disease (TB and cat scratch disease), and Hodgkin lymphoma with Reed-Sternberg cells</image>

Clinical Pearls

Supraclavicular lymphadenopathy is NEVER normal — biopsy even in children. In a child with bilateral small (<1 cm), soft, mobile cervical nodes and no systemic symptoms, observation is appropriate — these are "shotty" reactive nodes. EBV-associated lymphadenopathy can persist for weeks to months; avoid unnecessary biopsy if monospot is positive and patient is improving. Lymph node biopsy for suspected lymphoma should be excisional, NOT FNA — architecture is essential for subtyping and prognosis. Steroid trial before biopsy can obscure lymphoma diagnosis — avoid empiric steroids unless life-threatening airway/organ compromise. Night sweats in lymphoma are drenching (soaking bedclothes), not just mild warmth. In adults >40 with a new, persistent cervical node, always examine the oropharynx, nasopharynx, and larynx — head/neck squamous cell carcinoma is common.

References

• Mohseni S, Shojaiefard A, Khorgami Z, et al. Peripheral Lymphadenopathy: Approach and Diagnostic Tools. Iran J Med Sci. 2014;39(2 Suppl):158-170.
• Twist CJ, Link MP. Assessment of Lymphadenopathy in Children. Pediatr Clin North Am. 2002;49(5):1009-1025.
• Ferrer R. Lymphadenopathy: Differential Diagnosis and Evaluation. Am Fam Physician. 1998;58(6):1313-1320.
• Gaddey HL, Riegel AM. Unexplained Lymphadenopathy: Evaluation and Differential Diagnosis. Am Fam Physician. 2016;94(11):896-903.

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