Colonic inflammatory myofibroblastic tumour presenting as 'pyrexia of unknown origin': report of a rare disease and its unique presentation.

An intra-abdominal inflammatory myofibroblastic tumour (IMT) belongs to a rare group of diseases initially described as an inflammatory pseudotumour. Even though it is seen more often in children, its incidence in adults is even rarer. Clinical presentations can vary depending on its site and inherent tumour properties. The colon is an uncommon site for IMT and pyrexia of unknown origin (PUO) as its dominant clinical presentation is even rarer. A 27-year-old woman presented with PUO. She was evaluated under the department of internal medicine before undergoing an 18F-fluorodeoxyglucose positron emission tomography-computed tomography scan. This showed an intensely enhancing descending colon mass. An image-guided biopsy of this lesion was reported as IMT. She underwent a left hemicolectomy and complete excision of the tumour, following which her symptoms resolved completely. The patient has been disease-free at a 6-month follow-up and is asymptomatic at 1 year.