Is It Crohnʼs or Lymphoma: Which Is the Chicken and Which Is the Egg?

Abstract

Spontaneous fistulae in the GI tract are usually secondary to an inflammatory process, most commonly inflammatory bowel disease (IBD), although infection or malignancy are also reported etiologies. The GI tract is the most common site of extranodal lymphoma and is associated with widespread nodal disease. A 69-year old male with past medical history of lung cancer stage 1B status post resection 9 years ago presented for evaluation of crampy abdominal pain (AP) for the past few weeks. Physical exam was unremarkable, CT abdomen and pelvis showed possible Crohn's disease (CD) in the terminal ileum (TI) with enterocolonic fistula versus an infectious process. The patient persisted with AP after outpatient antibiotic therapy and was admitted for further evaluation. Laboratory studies revealed leukocytosis and elevated ESR and CRP. Colonoscopy showed mucosal thickening and edematous changes in the transverse colon with normal TI. CT enterography showed worsening inflammation of the TI with three fistulous tracts. The patient underwent a right hemicolectomy and resection of 70 cm of TI with takedown of multiple enteroenteric and enterocolonic fistulas. Mesenteric creeping fat was seen in the TI. Biopsy of the TI and colon showed multiple mucosal ulcerations and cobblestoning with active enteritis and transmural inflammation, however no granulomas were seen. Lymph nodes showed chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) on immunohistochemistry and flow cytometry. PET scan after surgery did not reveal any major hypermetabolic areas. Hematology recommended observation for CLL/SLL since the patient continued having normal CBC and no B symptoms or widespread lymphadenopathy. Follow up colonoscopy 5 months later showed ileitis at the TI with aphthous ulcers. The serum markers gASCA and ALCA were positive. The patient is currently having chronic diarrhea and GI is discussing starting treatment for CD. The increased risk for lymphoma secondary to CD has been reported, but usually after the use of immunosuppressants for CD treatment. CLL/SLL has been linked to autoimmune manifestations including IBD, which is thought to be caused by a dysregulated immune system. CLL/SLL causing lymphomatous colitis has also been reported to masquerade CD. The simultaneous presence of both entities in a patient with no recent history of immunosuppression would be extremely rare and it is not possible to identify which disease process is secondary to the other.2083 Figure 1. CT enterography showing fistulous tracts between the colon and TI