Nuclear Medicine · Supplementary · from Nuclear Medicine
Case 3: PET/CT for Lymphoma Staging
Patient Presentation
Demographics: 22-year-old male college student
Chief Complaint: "I've had a lump in my neck for about 6 weeks and I've been having drenching night sweats."
History of Present Illness: A 22-year-old male college student presents after noticing a painless, progressively enlarging mass in his left neck 6 weeks ago. He initially attributed it to a swollen gland from a viral illness, but it has continued to grow. Over the past 3 weeks, he has developed drenching night sweats requiring him to change his sheets, unintentional weight loss of 5 kg (8% body weight), and intermittent fevers up to 38.5°C, predominantly in the evening. He also reports generalized pruritus without rash and an unusual symptom of sharp left neck pain after drinking alcohol (pathognomonic for Hodgkin lymphoma, though rare).
He was seen by his campus health center, which obtained a CT scan showing bulky mediastinal and left cervical lymphadenopathy. He was referred to hematology-oncology, and an excisional biopsy of the left cervical node was performed.
Pathology revealed classical Hodgkin lymphoma, nodular sclerosis subtype. He has been referred for F-18 FDG PET/CT for staging.
Past Medical History:
- No significant medical history
- No prior malignancy
- Up to date on immunizations including HPV
Medications:
- None
- Acetaminophen PRN for fevers
Social History:
- College junior, biology major
- Non-smoker
- Social alcohol (reported alcohol-induced lymph node pain)
- No illicit drug use
- Lives in dormitory
Family History:
- No family history of lymphoma or hematologic malignancy
- Maternal grandmother: breast cancer at age 70
Physical Examination
- Vital Signs: BP 118/72 mmHg, HR 82 bpm, RR 14/min, Temp 37.8°C, SpO2 99% on room air, Weight 58 kg (baseline 63 kg 2 months ago)
- General: Thin young male, appears fatigued, no acute distress
- Lymph nodes:
- Left anterior cervical chain: 4 cm firm, non-tender, rubbery, mobile mass
- Left supraclavicular: 2 cm firm node
- Right cervical: no palpable lymphadenopathy
- Bilateral axillary: no palpable lymphadenopathy
- Bilateral inguinal: small (<1 cm), soft, mobile nodes (likely reactive)
- HEENT: Oropharynx clear, no Waldeyer ring involvement
- Cardiovascular: Regular rate and rhythm, no murmurs
- Lungs: Clear bilaterally, no dullness to percussion
- Abdomen: Soft, non-tender, no hepatosplenomegaly, no palpable masses
- Skin: No rashes, excoriations from scratching on bilateral forearms
Workup and Results
Laboratory Studies:
| Test | Result | Reference Range |
|---|---|---|
| WBC | 11,800/µL | 4,500-11,000/µL |
| Hemoglobin | 11.2 g/dL | 13.5-17.5 g/dL |
| Platelets | 442,000/µL | 150,000-400,000/µL |
| ESR | 68 mm/hr | 0-15 mm/hr |
| LDH | 312 U/L | 140-280 U/L |
| Albumin | 3.2 g/dL | 3.5-5.0 g/dL |
| Alkaline phosphatase | 98 U/L | 44-147 U/L |
| Uric acid | 7.8 mg/dL | 3.5-7.2 mg/dL |
| Hepatitis B surface antigen | Negative | Negative |
| HIV | Negative | Negative |
| Beta-hCG | <1 mIU/mL | <5 mIU/mL |
Pathology:
- Excisional biopsy: Classical Hodgkin lymphoma, nodular sclerosis subtype
- Reed-Sternberg cells positive for CD30 and CD15
- Negative for CD20 (excludes nodular lymphocyte-predominant HL)
- EBV (EBER) in situ hybridization: Negative
Imaging/Additional Studies:
- F-18 FDG PET/CT (Staging):
- Left cervical chain: Multiple intensely FDG-avid nodes, largest 4.2 x 3.1 cm, SUVmax 14.8
- Left supraclavicular: FDG-avid node, 2.3 cm, SUVmax 11.2
- Mediastinum: Bulky anterior mediastinal mass measuring 10.2 x 7.8 cm (mediastinal mass ratio 0.38 -- bulky disease), SUVmax 16.4, encasing but not compressing great vessels
- Bilateral hilar: Mildly FDG-avid nodes, largest 1.8 cm, SUVmax 8.2
- Spleen: Diffusely increased FDG uptake, SUVmax 5.4 (above normal liver background of 3.2), no focal lesions
- Subdiaphragmatic: No FDG-avid lymphadenopathy
- Bone marrow: No focal FDG-avid osseous lesions
- Liver, lungs, other organs: No evidence of extranodal disease
- Deauville Score (baseline): 5 (intense uptake above liver, as expected for staging)
Clinical Image
Diagram showing maximum intensity projection (MIP) image from F-18 FDG PET/CT in a patient with Hodgkin lymphoma, demonstrating FDG-avid cervical, supraclavicular, mediastinal, and hilar lymphadenopathy with the Deauville five-point scale for response assessment. Source: Educational illustration.
Diagnosis
Classical Hodgkin Lymphoma, Nodular Sclerosis Subtype, Stage IIBS (B Symptoms: Fevers, Night Sweats, Weight Loss >10%; S: Splenic Involvement; Bulky Mediastinal Disease)
Key Diagnostic Criteria:
- Reed-Sternberg cells on biopsy (CD30+, CD15+)
- PET/CT demonstrating FDG-avid disease above and below the diaphragm (cervical, supraclavicular, mediastinal, hilar = above; splenic involvement = below) -- Stage III
- B symptoms present: fevers >38°C, drenching night sweats, weight loss >10% in 6 months
- Bulky mediastinal disease (>10 cm or mediastinal mass ratio >0.33)
- Diffuse splenic FDG uptake above liver background indicating involvement
- International Prognostic Score (IPS): 3 points (albumin <4, hemoglobin <10.5 -- borderline, WBC >15,000 -- no; stage IV -- no; age >45 -- no; male -- yes; lymphocyte count -- adequate)
Treatment Plan
- Chemotherapy: ABVD regimen (doxorubicin, bleomycin, vinblastine, dacarbazine) for 6 cycles, with consideration of escalation to BEACOPP if interim PET shows inadequate response
- Interim PET/CT: After 2 cycles of ABVD (PET-2) to assess early metabolic response using Deauville criteria; Deauville 1-3 = adequate response (continue ABVD, may omit bleomycin); Deauville 4-5 = inadequate response (escalate to BEACOPP or alternative)
- End-of-treatment PET/CT: After completion of chemotherapy to confirm complete metabolic response (Deauville 1-3)
- Consolidative radiation: Involved-site radiation therapy (ISRT) 30 Gy to bulky mediastinal disease if complete metabolic response achieved; consider omission if PET-2 negative (per RAPID/RATHL trial data)
- Fertility preservation: Urgent sperm banking before chemotherapy initiation (ABVD has lower gonadotoxicity than BEACOPP but counseling still recommended)
- Pre-treatment: Echocardiogram (baseline for doxorubicin), PFTs (baseline for bleomycin), hepatitis B/C screening, HIV testing, port placement
- Supportive care: Antiemetics, growth factor support if needed, Pneumocystis prophylaxis if BEACOPP escalation, psychosocial support and academic accommodations
Key Learning Points
- F-18 FDG PET/CT is the standard of care for initial staging and response assessment in Hodgkin lymphoma, replacing CT-only staging which misses metabolically active disease in normal-sized nodes and splenic involvement
- The Deauville five-point scale (1=no uptake, 2=uptake ≤ mediastinum, 3=uptake > mediastinum but ≤ liver, 4=uptake moderately > liver, 5=uptake markedly > liver or new lesions) provides a standardized framework for response assessment
- Interim PET/CT after 2 cycles (PET-2) is a powerful prognostic tool: a negative PET-2 predicts >90% progression-free survival and may allow treatment de-escalation (bleomycin omission or fewer cycles)
- PET/CT has largely replaced bone marrow biopsy for staging in Hodgkin lymphoma, as it has high sensitivity for marrow involvement (focal FDG-avid osseous lesions)
- Bulky mediastinal disease is an important prognostic factor in Hodgkin lymphoma and may influence decisions regarding consolidative radiation therapy