Lymphadenopathy

Section: Hepatobiliary Sub-section: Spleen Curriculum: Curriculum, page 92

Anatomy

• 300-500 LN in the body; approximately 1/3 of them are in the head & neck
• Normal lymphocytes circulate, passing from blood into & though the lymph nodes then into efferent lymphatics surveying for antigen for which they have a receptor; if this Ag is not present, then they leave the LN

• LN structure
  • Capsule
  • Afferent lymphatics → lymphatic fluid enters subcapsular sinus.
  • Cortex
    • In the absence of immune stimulation: the cortex contains “Primary follicles” (composed of B cells – virgin B cells or memory B cells)
    • With antigenic stimulation, the B cells are stimulated & this converts the primary follicle into a “secondary follicle” or “germinal centre”, surrounded by a mantle zone of transient small lymphocytes & a central replicating area
  • Paracortex = region surrounding & beneath germinal centres
    • Site of T cell homing; T cells replicate in response to antigen
  • Medulla = deep to cortex & paracortex – composed of medullary cords & sinuses,
    • Plasma cells aggregate at the cords and release their Immunoglobulins into efferent lymph
  • Medullary vessels: artery & vein @hilum
  • Efferent lymphatic(s) @hilum

Biopsy

•  Diagnosis
  • Need adequate tissue for histologic, immunologic, and molecular biologic assessment.
    • Excisional or incisional biopsy
    • Multiple core needle
  • FNA
    • FNΑ is neither adequate to exclude a diagnosis of lymphοma (eg, due to limited diagnostic material, sampling issues, loss of fragile cells during processing) nor does it enable definitive classification (because it disrupts the nodal architecture)
• Send
  • Fixed in Formalin
    • Histology
    • Can also do if required
      • Immunohistochemistry - can get information that you get form flow cytometry
      • Fluorescence in situ hybridization (FIЅH) - can get information detected by conventional karyotype
  • Fresh
    • Flow cytometry
    • Conventional Karyotyping
• Correlate with blood tests: PSA, Ca-125
• USS:
  • presence of echogenic hilum reflects nodal architecture; it’s absence is predictive of pathology
    • USS can be useful in identifying abnormal tissue & avoiding necrotic nodes
• If searching for a primary: (also see Axillary nodes Unknown Primary in Breast section)
  • PR
  • CT
  • TV USS
  • ± endoscopy if anaemic or symptomatic
  • ± PET
• Of all lymphadenopathy of unknown primary, adenocarcinoma is most common

Castleman disease

• aka: giant lymph node hyperplasia, angiofollicular hyperplasia, lymph node harmatoma, follicular lymphoreticuloma or benign giant lymphoma
• a rare and usually benign lymphoproliferative disease, cured by surgical resection

Lymphoma