Location Has Prognostic Impact on the Outcome of Colorectal Mucinous Adenocarcinomas.

Mucinous (colloid) adenocarcinomas (MAs) are a rare histological subtype of tumors defined by extracellular mucin comprising more than 50% of the tumor. These tumors are on a continuum of mucin-producing malignancies with signet ring cell adenocarcinomas (SRCCs), which instead produce intracellular mucin. Mucin-containing cancers occur primarily in the stomach and colon, where for SRCCs, outcomes are relatively worse in the proximal stomach and the rectum.

Malignant Transformation of Long-Standing Ileal Crohn's Disease Likely Favors Signet Ring Cell Adenocarcinoma Histology.

Signet ring cell adenocarcinomas (SRCCs) are a rare and aggressive histological subtype of adenocarcinomas typically with poor prognosis usually secondary to late stage at detection. In the small bowel, they constitute only 1% of all malignancies. In the last decade, there have been multiple case reports and small case series that have identified SRCCs, typically in the ileum, in patients with Crohn's disease.

Epidemiology of Undifferentiated Carcinomas.

Undifferentiated carcinomas are rare cancers that lack differentiation, such that they cannot be classified into any conventional histological subtype. These cancers are uniquely codified and are contrasted to carcinomas with an ascertained histology that are grade classified as poorly differentiated, undifferentiated, or anaplastic. Given their rarity, there are no standardized overviews of undifferentiated carcinomas in the literature, and it is unknown if their classification indicates a unique prognosis profile.