Metastatic colon cancer mimicking Crohn's disease

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

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.

Metastatic Gastric Signet Ring Cell Carcinoma Mimicking Crohn's Disease

Signet-ring cell carcinoma (SRCC) is an adenocarcinoma characterized by mucin-producing cells and most commonly arises in the stomach. Colonic SRCC can share features of colitis, including long segments of concentric bowel wall thickening and ulcerated mucosa with regions of sparing. We describe a rare case of metastatic gastric SRCC mimicking Crohn’s disease. Our patient underwent 2 colonoscopies, and biopsies revealed chronic active inflammation with no evidence of malignancy. The diagnosis of SRCC was only made after colectomy was performed for recurrent bowel obstruction.

Signet-ring cell carcinoma of colorectum--current perspectives and molecular biology

PURPOSE

Colorectal signet-ring cell carcinoma (SRCC) is rare, and very little detailed information on the molecular biology of the disease is available.

METHODS

The literature on the clinical, pathological and, in particular, the molecular biology of this rare entity was critically reviewed. The reviewed articles take into account a total of 1,817 cases of SRCC, but only 143 cases have molecular data available. The characteristics of two patients with colorectal SRCC were also discussed.

RESULTS

Colorectal SRCC mostly occurs in younger patients, is larger and has different site predilection compared with conventional colorectal adenocarcinoma. It can occur as one of the synchronous cancers in the colorectum. The cancer is usually diagnosed at advanced stages because of the late manifestation of symptoms, and aggressive treatment strategy is required. Limited reports in the literature have shown that the variant of colorectal cancer demonstrated a different pattern of genetic alterations of common growth kinase-related oncogenes (K-ras, BRAF), tumour suppressor genes (p53, p16), gene methylation and cell adhesion-related genes related to the Wingless signalling pathway (E-cadherin and beta-catenin) from conventional colorectal adenocarcinoma. Colorectal SRCC also showed high expression of mucin-related genes and genes related to the gastrointestinal system. There was also a higher prevalence of microsatellite instability-high tumours and low Cox-2 expression in colorectal SRCC as opposed to conventional adenocarcinoma.

CONCLUSIONS

Colorectal SRCC has unique molecular pathological features. The unique molecular profiles in SRCC may provide molecular-based improvements to patient management in colorectal SRCC.

A primary adenocarcinoma of the transverse colon mimicking Crohn's disease: a case report and literature review

Diarrhoea and weight loss are presenting features of both Crohn's disease and colorectal cancer; however, the two conditions can usually be distinguished on the basis of characteristic patterns of abnormalities observed at the time of initial blood testing and imaging. In patients with suspected Crohn's disease these are often considered sufficient grounds to commence empirical treatment before the results of histology are available. This case report describes a 45-year-old man whose initial clinical, endoscopic and radiological investigations were strongly suggestive of a diagnosis of Crohn's disease, but who subsequently was found to have an adenocarcinoma of the mid-transverse colon. He went on to have an emergency extended right hemi-colectomy.