Can early lymphoma preserve the fatty hilum, particularly in a patient with a short duration of symptoms and a history of Polycystic Kidney Disease (PKD), von Willebrand Disease (VWD), Mitral Valve Prolapse (MVP), and Premature Ventricular Contractions/Supraventricular Tachycardia (PVCs/SVT)?

Early Lymphoma and Fatty Hilum Preservation

Yes, early lymphoma can preserve the fatty hilum, but this feature significantly reduces the probability of lymphomatous involvement and should not delay tissue diagnosis when clinical suspicion exists. 1

Key Imaging Characteristics

The presence of an intact fatty hilum is the single most important benign feature in lymph node assessment, with high diagnostic accuracy:

• Preserved fatty hilum demonstrates 86-93% sensitivity and 96-100% specificity for excluding metastatic involvement 1
• The negative predictive value of a fatty hilum for malignancy is extremely high, with its absence carrying a 90-93% positive predictive value for malignancy 2
• However, up to 25% of clinically negative lymph nodes harbor micrometastases, meaning imaging features alone cannot definitively exclude malignancy 1

Critical Distinction: Hypervascularity vs. Fatty Hilum

The combination of hypervascularity WITH preserved fatty hilum favors a reactive rather than malignant process 1:

• Hypervascularity alone is not specific for malignancy, as reactive lymphadenopathy from infection or inflammation commonly demonstrates increased blood flow 1
• Reactive nodes from upper respiratory infections, dental processes, or other inflammatory conditions frequently show both preserved architecture and increased vascularity 2

When Short Duration Matters (and When It Doesn't)

While short symptom duration might suggest reactive etiology, the American College of Radiology advises against assuming benignity based solely on clinical presentation or duration 1:

• Lymphomas, particularly aggressive subtypes like diffuse large B-cell lymphoma, can present acutely with rapid growth 3, 4
• Follicular lymphoma demonstrates spontaneous regressions in up to 25% of cases, creating variable clinical courses that can be misleading 5
• Delaying tissue diagnosis can lead to subsequent relapses that are rarely amenable to successful secondary treatment 1

Recommended Diagnostic Algorithm

For any suspicious groin mass, regardless of fatty hilum preservation:

1. First-line: Ultrasound-guided fine-needle aspiration biopsy (US-FNAB) with 80-93% sensitivity and approaching 100% specificity 1

2. If US-FNAB is non-diagnostic: Core needle biopsy under imaging guidance 1

3. Only if above fail: Excisional biopsy at a specialized center by a surgeon capable of definitive resection 1

Red Flags Requiring Immediate Biopsy

Proceed directly to tissue diagnosis if any of the following develop 2:

• Progressive enlargement to >15 mm in short axis on follow-up imaging
• Loss of fatty hilum on serial imaging
• Development of irregular borders, necrosis, or extranodal extension
• Cortical thickness >3 mm
• Persistent B symptoms (fever, night sweats, weight loss)

Special Considerations for This Patient

Given the patient's comorbidities (PKD, von Willebrand disease, MVP, PVCs/SVT):

• Von Willebrand disease requires pre-procedural hemostatic evaluation and preparation before any biopsy procedure 6
• The bleeding disorder does NOT contraindicate necessary tissue diagnosis but requires appropriate management with desmopressin or factor replacement 6
• PKD and cardiac conditions do not alter the lymphoma diagnostic approach but may influence subsequent treatment intensity 5

Conservative Management Option

If imaging shows preserved fatty hilum, size <15 mm, and oval morphology, observation with close follow-up is reasonable 2:

• Repeat ultrasound in 4-6 weeks to assess for interval change
• Trial of antibiotics may help differentiate reactive from malignant causes if infection is suspected 1
• However, any progression or persistence beyond 6-8 weeks mandates tissue diagnosis 1, 2

Critical Pitfall to Avoid

The most dangerous error is assuming benignity based on reassuring imaging features alone, particularly in the groin where reactive nodes are common but lymphoma can present identically in early stages 1. The short duration of symptoms does not exclude lymphoma, as aggressive lymphomas can present acutely and early-stage follicular lymphoma may have preserved nodal architecture initially 5, 3.