26th April 2024

A 60-year-old man presents with a 3-month history of altered bowel habits, predominantly constipation, and occasional rectal bleeding.

A 60-year-old man presents with a 3-month history of altered bowel habits, predominantly constipation, and occasional rectal bleeding. He also reports unintentional weight loss and generalised fatigue. On examination, he appears pale and has mild abdominal tenderness on the left side.

Investigations:

Haemoglobin 102 g/L (130–180)

White cell count 12.0 × 10^9/L (4.0–11.0)

Neutrophils 8.2 × 10^9/L (2.0–7.5)

Lymphocytes 2.1 × 10^9/L (1.1–3.3)

Monocytes 0.7 × 10^9/L (0.2–1.0)

Eosinophils 0.2 × 10^9/L (0–0.4)

Basophils 0.05 × 10^9/L (0–0.1)

Platelets 380 × 10^9/L (150–400)

Which is the most likely diagnosis?