Extensive squamous metaplasia in the rectum stained with a Lugol’s solution in patient with ulcerative colitis and primary sclerosing cholangitis

A case of extensive squamous metaplasia in a patient with longstanding ulcerative colitis and primary sclerosing cholangitis is presented. The patient was a 52-year-old man with a 20-year history of pancolitis who was referred for surveillance colonoscopy. No suspicious lesions had been found on previous examinations. Inspection of the rectum revealed a whitish epithelium lining the distal portion of the bowel, which was almost complete in circumferential extent and approximately 2 cm long at its maximum extent ([Fig. 1]). Lugol’s solution, known for its interaction with glycogen in a squamous epithelium, was used as a stain. An irregular border between the rectal mucosa and the metaplastic epithelium was clearly demarcated, and details of the surface of the latter could be easily observed ([Fig. 2]). As expected, histopathology confirmed the presence of squamous epithelium in the rectum.

Fig. 1 A whitish epithelium in the distal rectum adjacent to the inflamed rectal mucosa.

Fig. 2 The rectal mucosa and the squamous metaplasia stained with Lugol’s solution.

Although extremely rare, squamous metaplasia and squamous carcinoma of the rectum have been observed in longstanding ulcerative colitis [1] [2] [3]. In addition to chronic inflammation, human papilloma virus infection may play a role in the metaplasia – dysplasia – carcinoma sequence [1]. To the best of our knowledge, the combination of ulcerative colitis, squamous metaplasia, and primary sclerosing cholangitis has not been previously described.

Endoscopy_UCTN_Code_CCL_1AD_2AD

• References

• 1 Cheng H, Sitrin MD, Satchidanand SK et al. Colonic squamous cell carcinoma in ulcerative colitis: report of a case and review of the literature. Can J Gastroenterol 2007; 21: 47-50
• 2 Fu K, Tsujinaka Y, Hamahata Y et al. Squamous metaplasia of the rectum associated with ulcerative colitis diagnosed using narrow-band imaging. Endoscopy 2008; 40 (Suppl. 02) E45-46
• 3 Lord JD, Upton MP, Hwang JH. Confocal endomicroscopic evaluation of colorectal squamous metaplasia and dysplasia in ulcerative colitis. Gastrointest Endosc 2011; 73: 1064-1066