Mucinous Signet-Cell Adenocarcinoma of the Ileum: A Diagnostic Challenge-Case Report and Review of the Literature

Abstract

Malignancies of the small intestine are rare. Signet-ring cell carcinoma (SRCC) is one of the rarest forms of adenocarcinoma that can arise in the small intestines. We present a case of a patient who originally presented with abdominal pain and radiographic findings suggestive of ileal congestion. The ileal biopsy specimens were nonspecific, and the patient began a trial of corticosteroid treatment for suspected Crohn's disease. A repeat colonoscopy yielded biopsies that were positive for malignancy. The patient then underwent an exploratory laparotomy which led to the diagnosis of SRCC. Given their similar presentations and the extreme rarity of this unusual malignancy, it can be difficult to differentiate between new-onset Crohn's disease and SRCC. A review of the literature was conducted to provide us with an improved understanding of previously documented cases of SRCC.

Figure 1

Tubulovillous adenoma with high-grade dysplasia. Ileal polyp showing slender, fingerlike projections formed by fibrovascular cores and lined by high-grade dysplastic epithelium (arrows) (H&E stain, 2×).

Figure 2

Invasive signet-ring cell carcinoma of the ileum (arrow) arising from dysplastic epithelium (arrowhead) (H&E stain, 20×).

Figure 3

Invasive signet-ring cell carcinoma of the ileum with dissecting extracellular mucin pools. The tumor is seen invading the muscularis propria (H&E stain, 2×).

Figure 4

Image showing the signet-ring cell morphology at higher magnifications (H&E stain, 40×).