Signet ring cell carcinoma

Signet ring cell carcinoma, abbreviated SRCC, is a type of malignant epithelial neoplasm that is typically arises from the stomach.

General

• It has been said that there are two types of pathologists... those that have missed SRCs and those that will miss SRCs.

Differential diagnosis

It may arise from the:

• Stomach.
• Small intestine
• Large intestine.
• Breast
• Pancreas.
• Urinary bladder.
• Prostate gland
• Lung.

Microscopic

Features:

• Signet ring cells resemble signet rings.
  • They contain a large amount of mucin, which pushes the nucleus to the cell periphery.
  • The pool of mucin in a signet ring cell mimics the appearance of the finger hole.
  • The nucleus mimics the appearance of the face of the ring in profile.
• Signet ring cells are typically 2-3x the size of a lymphocyte.
  • Smaller than the typical adipocyte.
• Often have a crescent-shaped or ovoid nucleus.
  • Capillaries sectioned on their lumen have endothelial cells - the nuclei of these are more spindled.

Note:

• SRCs are usually close to friend, i.e. they are adjacent to another SRC.
  • This helps differentiate SRCs from capillaries sectioned on their lumen.
• The mucin is often clear on H&E... but maybe eosinophilic.

DDx:

• Fat atrophy.

Images:

• Signet rings (engravingarts.com).
• SRCs (H&E) by Nephron (WC).
• SRC AL-PAS stain (WC).
• SRC H&E stain (WC).

Stains

• PAS stain +ve.
• Alican blue-PAS stain +ve.

IHC

• AE1/AE3 +ve.
• CK7 +ve.