Adenocarcinoid tumor of the rectum: a rare finding in a patient with recurrent fistulizing perianal Crohn’s disease

Malignancy in patients with Crohn’s colitis is well described; however, adenocarcinoid tumor associated with Crohn’s disease is very rare with only four cases reported in the literature [1]. This is the first reported case of an adenocarcinoid tumor arising in a fistulous tract.

A 48-year-old man presented with diarrhea and a chronic perirectal fistula. Colonoscopy showed pancolitis with aphthous ulcers and pseudopolyps. Clinical and endoscopic findings were consistent with Crohn’s disease. Treatment with immunosuppressive agents was recommended, but the patient refused because of the potential side effects and sulfasalazine was therefore prescribed. He initially achieved clinical remission but experienced a recurrent perirectal abscess and fistulous drainage, for which he received a few short courses of antibiotics. A repeat colonoscopy showed mild pancolitis with inflammation of the distal rectum and a fistulous tract ([Fig. 1]). Rectal biopsies showed moderately differentiated adenocarcinoma with extensive mucin and signet-ring cells present ([Fig. 2]). Staging showed no evidence of metastases and he underwent abdominoperineal resection followed by adjuvant chemotherapy. Pathology from the surgical specimen showed active colitis, cryptitis, and transmural inflammation with noncaeseating granulomas, further substantiating the diagnosis of Crohn’s disease.

Fig. 1 Endoscopic image of the rectum in a 48-year-old man with Crohn’s disease showing a fistulous tract and distal inflammation.

Fig. 2 Histopathological appearance of the original rectal biopsy showing a signet-ring cell pattern in an apparent moderately differentiated adenocarcinoma (hematoxylin and eosin [H&E] stain, magnification × 400).

Two years later, he developed small-bowel obstruction, which required ileocecectomy. Small-bowel mesenteric deposits were seen during laparotomy; pathological examination of these showed metastatic adenocarcinoid tumor with signet-ring cell features ([Fig. 3]); immunohistochemical stains for both CK20 and chromogranin were positive. Adenocarcinoid had not been suspected after his initial surgery, but immunohistochemical staining of tissue from the original rectal tumor confirmed this had been the diagnosis ([Fig. 4]).

Fig. 3 Histopathological appearance of the mesenteric deposits found during surgery 2 years later showing an organoid and trabecular pattern consistent with metastatic adenocarcinoid (hematoxylin and eosin [H&E] stain, magnification × 100).

Fig. 4 Appearance of the original specimen stained immunohistochemically for chromogranin showing positive staining of small nests adjacent to the signet-ring cells, which confirmed the diagnosis of an adenocarcinoid tumor (magnification × 200).

Adenocarcinoid tumor, or goblet-cell tumor, is a rare malignancy that comprises features of both adenocarcinoma and carcinoid. Most adenocarcinoid tumors arise in the appendix and only six cases have previously been reported in the rectum, none of which were associated with Crohn’s disease [2]. Most patients with rectal adenocarcinoid present with rectal bleeding; symptoms of carcinoid syndrome are rare [3]. The management and prognosis of adenocarcinoid tumors are most dependent on the glandular component [3].

Malignancy arising in fistulous tracts in Crohn’s disease is rare, with only 61 cases reported from 1950 to 2008 [4]. We hypothesize that malignant transformation arises from chronic bacterial colonization and fistulous tract inflammation. This is the first reported case of adenocarcinoid arising in a fistulous tract in Crohn’s disease. Malignancy, including adenocarcinoid, should be considered in patients with recurrent fistulizing disease.

Endoscopy_UCTN_Code_CCL_1AF_2AH

• References

• 1 Cioffi U, De Simone M, Ferrero S et al. Synchronous adenocarcinoma and carcinoid tumor of the terminal ileum in a Crohn’s disease patient. BMC Cancer 2005; 5: 157
• 2 Wakahara T, Yamamoto S, Fujita S et al. A case of advanced rectal adenocarcinoid tumor with long-term survival. Jpn J Clin Oncol 2010; 40: 690-693
• 3 Ranganath R, Ramakrishnan A, Ayyappan A et al. Adenocarcinoid tumors of the gastrointestinal tract: case report and review of the literature. Internet J Surg 2007; 10 DOI: 10.5580/cd2.
• 4 Thomas M, Bienkowski R, Vandermeer TJ et al. Malignant transformation in perianal fistulas of Crohn’s disease: a systematic review of literature. J Gastrointest Surg 2010; 14: 66-73