Colonic NK/T-cell lymphoma mimicking Crohn’s disease

A 29-year-old man presented at another institution with bloody diarrhea. Colonoscopy showed multiple discrete ulcers in the ascending colon. Histological study revealed moderate chronic inflammation with negative stain for acid-fast bacilli. A computed tomographic scan showed asymmetrical thickening of the ascending colonic wall with no lymphadenopathy ([Fig. 1]). After a month’s trial of anti-tuberculosis medication, the diarrhea still persisted. Subsequent colonoscopy showed more extensive colonic ulcers from the sigmoid to the ascending colon ([Fig. 2]). The second histological study revealed more severe inflammation. At this point, Crohn’s disease was suspected, and the patient’s diarrhea partially improved after prednisolone treatment (40 mg/day). However, a month later, he developed sudden abdominal pain. He underwent an emergency right hemicolectomy as treatment for spontaneous ileal perforation ([Fig. 3]). Histological study demonstrated more severe ulcers with granuloma and reactive nodes. The patient was kept on prednisolone (40 mg/day) and azathioprine (2 mg/kg per day).

Fig. 1 Computed tomographic scan of the abdomen showed asymmetric bowel wall thickening at the ascending colon, the ileocecal valve (*), and the terminal ileum (arrow).

Fig. 2 Colonoscopy showed: a multiple discrete deep round ulcers at the sigmoid colon; b, c large well-defined colonic ulcers with intervening normal colonic mucosa at the transverse colon and the ascending colon.

Fig. 3 Colonic specimen shows multiple large ulcers with evidence of recent hemorrhage.

Two weeks later, the patient was referred to our hospital with more bloody diarrhea, fever, weight loss, and new-onset epistaxis. Physical examination showed a right nasopharyngeal mass. Serum LDH level was elevated at 552 U/L. Histological study of a specimen from the nasopharyngeal mass demonstrated small lymphoid cells with immunohistochemical staining reported as positive for CD3, CD56, and EBER, and negative for CD20 ([Fig. 4]). Similar to the nasopharyngeal mass, additional staining of the previous colonic specimen found a positive result for CD3, CD56, and EBER in a small number of small lymphoid cells ([Fig. 5]). Colonic NK/T-cell lymphoma was now diagnosed. Sadly, the patient died from an invasive fungal infection before chemotherapy could be given.

Fig. 4 a Histological section of the nasopharyngeal specimen shows a mass containing small lymphoproliferative cells. b Immunohistochemical study was positive for CD3, CD56, and EBER and negative for CD20.

Fig. 5 Immunohistochemical staining of the colonic specimen was positive for EBER cells among other inflammatory cells that had infiltrated the lamina propria.

Colonic NK/T-cell lymphoma is a rare and aggressive disease [1]. Due to the nonspecific clinical and endoscopic findings, its diagnosis is very difficult. Despite clinical signs suggesting lymphoma, histological analysis without special staining did not allow a confirmed diagnosis in some cases [2]. One fifth of patients with colonic NK/T-cell lymphoma were misdiagnosed as having Crohn’s disease and intestinal tuberculosis [3]. Severe ileocolonic ulcers with spontaneous perforation should prompt consideration of the possibility of a non-Crohn diagnosis such as NK/T-cell lymphoma.

Endoscopy_UCTN_Code_CCL_1AD_2AC

Competing interests: None

• References

• 1 Jiang M, Chen X, Yi Z et al. Prognostic characteristics of gastrointestinal tract NK/T-cell lymphoma: an analysis of 47 patients in China. J Clin Gastroenterol 2013; 47: e74-79
• 2 Zheng S, Xu H, Ouyang Q et al. A case of rapid growing colonic NK/T cell lymphoma complicated by Crohn’s disease. Chin J Cancer Res 2013; 25: 119-123
• 3 Mahuad CV, Bilbao ER, Garate GM et al. Primary NK/T cell lymphoma nasal type of the colon. Rare Tumors 2013; 5: e9