A 26-year-old male presents with fatigue, night sweats, and a painless neck mass; what is the next best step in evaluation?

• A. Bone marrow biopsy and aspiration
• B. Lymph node biopsy
• C. Chest CT scan
• D. Reexamine in 2-4 weeks

Answer: (B)

This presentation raises strong suspicion for lymphoma in a young adult with a painless neck mass and systemic symptoms like fatigue and night sweats. The key step is to obtain a tissue diagnosis from the enlarged lymph node to confirm lymphoma and determine the subtype, which drives treatment.

An excisional lymph node biopsy is the best option because it provides full nodal architecture, allowing pathologists to identify malignant cells such as Reed-Sternberg cells and to perform necessary immunophenotyping. This architectural detail is essential for distinguishing lymphoma from benign reactive hyperplasia or infection and for accurate subtyping, which guides therapy.

Other tests have roles after diagnosis: imaging like chest CT helps stage disease and assess mediastinal involvement, and bone marrow biopsy can be indicated if there is suspicion of marrow involvement or certain subtypes, but they do not establish the initial diagnosis. Waiting or rechecking in a few weeks would delay needed evaluation and treatment.