Hematology Oncology · Year 2 · from Hematology Oncology

Case 3: Follicular Lymphoma

Patient Presentation

Demographics: 58-year-old male

Chief Complaint: Incidentally discovered lymphadenopathy during routine physical

History of Present Illness: During a routine physical examination, the patient's physician noted enlarged lymph nodes in his neck and groin. The patient had noticed some neck fullness but attributed it to weight gain. He is completely asymptomatic with no fever, night sweats, weight loss, or fatigue. He has no prior history of lymphoma and no family history of hematologic malignancy.

Physical Examination:

  • Vital signs: BP 128/78, HR 72, RR 14, Temp 36.8C
  • General: Well-appearing man in no distress
  • HEENT: Bilateral cervical lymphadenopathy (2-3 cm, rubbery, non-tender)
  • Axillae: Small bilateral lymphadenopathy
  • Cardiac: Regular rhythm
  • Lungs: Clear
  • Abdomen: No hepatosplenomegaly
  • Inguinal: Bilateral lymphadenopathy (2 cm)

Workup and Results

Laboratory:

  • WBC: 7,400/uL with normal differential
  • Hemoglobin: 14.5 g/dL
  • Platelets: 225,000/uL
  • LDH: 185 U/L (normal)
  • Beta-2-microglobulin: 2.8 mg/L (mildly elevated)

Excisional Lymph Node Biopsy:

  • Nodular/follicular growth pattern
  • Mixture of centrocytes (small cleaved cells) and centroblasts
  • Centroblasts <15 per high-power field

Immunohistochemistry:

  • CD20: Positive
  • CD10: Positive
  • BCL2: Positive (aberrant)
  • BCL6: Positive
  • CD5: Negative
  • Cyclin D1: Negative
  • Ki-67: 20%

FISH:

  • t(14;18) IGH-BCL2: Positive

Grading:

  • Follicular lymphoma, Grade 1 (0-5 centroblasts/HPF)

PET-CT Staging:

  • Multiple FDG-avid lymph nodes above and below diaphragm
  • Largest node 4 cm in right groin
  • Bone marrow involvement (confirmed on biopsy)

Clinical Image

Histologic section of follicular lymphoma demonstrating characteristic nodular/follicular architecture with neoplastic follicles composed of centrocytes and centroblasts, BCL2 positive staining confirms aberrant overexpression.

Diagnosis

Follicular Lymphoma, Grade 1, Stage IVA

Key features:

  • t(14;18) BCL2-IGH translocation
  • Indolent lymphoma
  • Stage IV (bone marrow involvement)
  • Asymptomatic at presentation
  • Low FLIPI score (good prognosis)

Treatment Plan

  1. Initial approach - Watch and Wait:
  • No treatment indication currently
  • Patient is asymptomatic
  • No cytopenias, no bulky disease, no impending organ compromise
  1. Indications for treatment (when to start):
  • Symptomatic disease
  • Cytopenias from marrow involvement
  • Rapid progression
  • Bulky disease or impending organ compromise
  • Patient preference
  1. When treatment needed:
  • Bendamustine + Rituximab (BR) preferred for most
  • OR R-CHOP for aggressive presentation
  • Rituximab maintenance after chemoimmunotherapy
  1. Surveillance:
  • Physical exam and labs every 3-6 months
  • CT scan if clinical change
  • Watch for symptoms of transformation (sudden growth, B symptoms, rising LDH)
  1. Prognosis:
  • Indolent course with median survival >15 years
  • NOT curable with standard therapy but long survival expected
  • Risk of transformation to DLBCL (~2-3% per year)

Teaching Points

  1. Follicular lymphoma is defined by t(14;18) BCL2-IGH translocation causing BCL2 overexpression
  2. BCL2 prevents apoptosis, leading to accumulation of long-lived B cells
  3. Watch and wait is appropriate for asymptomatic patients - treatment does not improve survival
  4. Grading based on centroblast count; Grade 3B is treated like DLBCL
  5. Transformation to aggressive DLBCL occurs at 2-3% per year
  6. Rituximab maintenance prolongs remission after chemoimmunotherapy
  7. Disease is typically incurable but most patients live many years

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