30th April 2024

A 45-year-old male presents with a 3-month history of fatigue, night sweats, and a painless swelling in his neck.

A 45-year-old male presents with a 3-month history of fatigue, night sweats, and a painless swelling in his neck. He reports significant weight loss over the last month. He has no significant past medical history.

Investigations:

Haemoglobin: 115 g/L (130–170)

White cell count: 7.2 × 10^9/L (4.0–11.0)

Platelets: 150 × 10^9/L (150–400)

Lymph node biopsy: Histopathology shows Reed-Sternberg cells

Serum LDH: Elevated

Which additional investigation is most likely to assist in staging and treatment planning?