Identification of Signet Ring Cell Change in Colonic Subserosa in the Setting ofClostridium difficileColitis

Abstract

Signet ring cell change of intestinal epithelial cells is a rare but well-known mimicker of signet ring cell carcinoma and is often associated with ischemic and/or pseudomembranous colitis. Instead, signet ring cell change involving nonepithelial cells in the subserosa of the intestine is an extremely rare finding with only a single case report in the literature to date. We report a new case of benign signet ring cell change localized in the subserosa of the large bowel incidentally identified in a resection specimen for Clostridium difficile colitis mimicking a metastatic signet ring cell carcinoma. Based on the morphologic features and immunohistochemical profile, we propose that these signet ring cells may possibly represent modified/degenerated fat cells. Furthermore, we discuss how to differentiate benign signet ring cells from a signet ring cell carcinoma.

Dystrophic Adipocytes Mimicking Metastatic Signet Ring Cell Adenocarcinoma: A Diagnostic Pitfall in a Cachectic Patient

“…However, our case shows an infiltrating pattern in the submucosal area where the signet ring-like cells are interspersed with chronic inflammatory cells and blood vessels and adjacent to nerves, raising the concern for perineural invasion. Similar to Khan and Ligatos' report of atrophic adipocytes in the setting of clostridium difficile colitis [ 6 ], our case also shows necrotizing changes and areas of ischemia, characterized by tan-maroon colonic serosa with tan white shaggy fibrous exudate and areas of transversely oriented linear ulcerations throughout the colonic mucosa.…”

“…However, a variety of benign conditions and malignant neoplasms beyond signet ring cell adenocarcinoma have now been reported with signet ring-like cells, thus leading to a differential diagnosis with potential diagnosis pitfalls. Nonneoplastic mimickers of signet ring cell adenocarcinoma have been described in gastric xanthomas [ 4 ], transurethral prostatectomy specimen [ 5 ], and pseudomembranous colitis [ 6 ]. While the majority of the reported cases of signet ring-like cells in the gastrointestinal tract involve epithelial cells that are adjacent to ischemic or injured areas, signet ring-like cellular changes involving nonepithelial cells are rare.…”

“…While the majority of the reported cases of signet ring-like cells in the gastrointestinal tract involve epithelial cells that are adjacent to ischemic or injured areas, signet ring-like cellular changes involving nonepithelial cells are rare. To the best of our knowledge, signet ring-like changes have only been reported in muciphages [ 7 ], schwannomas [ 8 ], two cases involving subserosal adipocytes (one being associated with chronic ischemic enteritis [ 9 ] and the other in the setting of clostridium difficile colitis [ 6 ]), and two cases of starvation-induced fat atrophy involving the omentum [ 10 ]. Here we report a case of a signet ring cell-like change involving adipocytes in a cachetic patient diagnosed with locally aggressive pancreatic adenocarcinoma with the concern for carcinomatosis.…”

Adipocyte Atrophy Mimicking Signet Ring Cell Carcinoma of the Gallbladder

“…Benign signet ring cell change is a well-recognised phenomenon, usually involving epithelial cells confined to the mucosa, which are suspected to arise from precursors with goblet cell differentiation [ 1 ]. In the gastrointestinal tract, they are typically associated with injurious stimuli such as ischaemia, traumatised polyps, or colitis (frequently pseudomembranous colitis) [ 1 , 2 ]. Their appearance is often difficult to distinguish on cytological grounds from signet ring cell carcinoma, with obvious implications for prognosis and further treatment.…”

“…Nonepithelial signet ring cell change is a much rarer entity first described in 2006 [ 1 ], with only a handful of case reports since published, principally involving mesenteric fat and with no previous reports of gallbladder involvement. In most cases, the cells of concern were identified as atrophic adipocytes which uniformly stain positively for S100 protein and variably for calretinin, but negatively for pancytokeratin markers, histiocyte markers, vascular markers, melanocyte markers, other mesothelial markers, and mucin [ 1 , 2 , 5 – 8 ]. The cells lack cytologic or nuclear atypia and generally retain their normal lobulated, circumscribed architecture, although occasional pseudoinfiltrative growth has been seen and the cells may also be seen within lymph nodes and around nerves [ 6 ].…”