Oh node: Extranodal nodular involvement of chronic lymphocytic leukemia in the colon

A 64-year-old male patient with a known diagnosis of chronic lymphocytic leukemia (CLL) was referred to the gastroenterology department for a follow-up colonoscopy. A previous routine colonoscopy 4 years prior found benign polyps in the colon, and the patient was recommended to have a repeat colonoscopy within 3 years. In the interim, the patient had no new gastrointestinal symptoms. However, he was diagnosed with CLL based on flow cytometry approximately 1 year after his first colonoscopy. At diagnosis, his CLL was Rai Stage 1, and he did not meet any criteria for treatment initiation. The repeat colonoscopy was notable for continuous diffuse nodularity without bleeding throughout the colon from the cecum to the rectum, with only relative sparing of the transverse colon as seen in Image 1. Multiple cold forceps biopsies were obtained of nodularities in the cecum/ascending colon, transverse colon, descending colon, and rectum. The biopsies were sent for histology to evaluate for suspected lymphoid aggregates but also to rule out polyposis syndrome. Histology showed submucosal atypical lymphoid infiltrate present as expansile nodules. The lymphocytes were small in size with dense chromatin and scant cytoplasm. Immunohistochemistry was diffusely positive for CD5, CD20, and CD23, and negative for BCL-1. Scattered reactive T cells were positive for CD3. P53 was wild-type. Ki-67 showed a variable proliferation rate of 10%–30%. All colonic biopsies showed similar findings consistent with the patient's known CLL. Despite these striking incidental clinical findings, the patient remains asymptomatic without cytopenias or constitutional symptoms. On exam he has stable supraclavicular lymphadenopathy with a palpable lymph node measuring approximately 3 cm in diameter that is non-tender and mobile. His white blood cell count is relatively stable, fluctuating between 18 and 43 × 109/L. Other routine lab work, including renal function and hepatic function, also all remain stable. No additional imaging studies have yet been performed. Therefore, the decision was made to continue clinically monitoring this patient without initiating treatment, as per standard of care.1 Extranodal involvement of CLL presenting as nodularity has been described in several organs, including the skin,2 kidneys,3 and cardiac valves.4 Gastrointestinal manifestations of CLL are rare. One report of extranodal involvement in the gastrointestinal tract described a patient who had a positive fecal test for occult blood prompting colonoscopy, which showed a normal-appearing colon but with CLL involvement on histology of biopsies.5 Another reported on a single 6 mm polyp in the ascending colon revealing intestinal infiltration of CLL on biopsy.6 To our knowledge, this is the first report of diffuse nodularity resulting from intestinal infiltration of CLL. The authors declare no conflicts of interest. Data sharing is not applicable to this article as no new data were created or analyzed in this study.