Solitary rectal ulcer syndrome (SRUS) is an uncommon, chronic disorder of rectal mucosal prolapse that typically presents with rectal bleeding, mucus discharge, and straining, and can occasionally present as a polypoid mass rather than a discrete ulcer. Acute incarceration of SRUS through the anal canal, requiring emergency surgery, does not appear to have been previously reported. We describe an adolescent boy with a two-year history of biopsy-confirmed SRUS, managed conservatively with only partial symptomatic response, who presented with acute, irreducible incarceration of a large, actively bleeding polypoidal mass protruding through the anal canal. He underwent emergency examination under anaesthesia with complete transanal excision, achieving simultaneous diagnostic and therapeutic control, and histopathology confirmed SRUS without dysplasia or malignancy. He remained completely asymptomatic with no recurrence at long-term follow-up extending to nearly six years postoperatively. This case illustrates an apparently novel presentation of SRUS as an anorectal surgical emergency, supports complete transanal excision as effective definitive treatment, and is placed in the context of the wider published literature on polypoid and prolapse-related SRUS.