A 40-year-old man presents with bright red blood per rectum, severe perianal pain, and a palpable tender lump at the anal verge. The lump has a dusky appearance. The most likely diagnosis is:
- A First-degree internal haemorrhoid
- B Perianal abscess
- C Thrombosed external haemorrhoid ✓
- D Anal fissure
Correct answer: C. Thrombosed external haemorrhoid
Explanation
A painful, tender, dusky, firm lump at the anal verge following an episode of straining is characteristic of a thrombosed external haemorrhoid (perianal haematoma). It arises from rupture of venous plexuses below the dentate line, forming a haematoma in the subcutaneous tissue. First-degree internal haemorrhoids do not prolapse and are not palpable externally. Perianal abscesses are fluctuant with surrounding cellulitis. Anal fissures present with a linear tear and pain on defaecation.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.