2nd August 2023

A 48-year-old woman presents with a 9-month history of constipation and bloating. This has progressively worsened

A 48-year-old woman presents with a 9-month history of constipation and bloating. This has progressively worsened to the point where she only opens her bowels once a week. She has tried all types of laxatives with minimal effect. She has no history of weight loss, melaena, or rectal bleeding. A recent transvaginal ultrasound scan was normal. Blood tests, including a tumour marker screen, thyroid function tests and haematinics, are normal. A CT abdomen and pelvis revealed no masses, although there was evidence of an enlarged sigmoid colon (greater than 6 cm diameter) and rectum, with no acute features. She immigrated from Brazil 6 months ago.

What is the most likely diagnosis?

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