Signet ring cell

In histology, a signet ring cell is a cell with a large vacuole. The malignant type is seen predominantly in carcinomas. Signet ring cells are most frequently associated with stomach cancer,^[1] but can arise from any number of tissues including the prostate,^[2] bladder, gallbladder,^[3] breast, colon,^[4] ovarian stroma and testis.^[5]

Signet ring cell, as seen in a case of colon adenocarcinoma with mucinous features, showing a tumor cell with a vacuole of mucin. H&E stain.

Signet ring for comparison.

Types

The NCI Thesaurus identifies the following types of signet ring cell

• Castration cell, a non-malignant cell arising in the anterior pituitary gland under certain abnormal hormonal conditions.
• Neoplastic thyroid gland follicular signet ring cell
• Signet ring adenocarcinoma cell
• Signet ring melanoma cell
• Signet ring stromal cell

Appearance

The name of the cell comes from its appearance; 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 a finger hole and the nucleus mimics the appearance of the face of the ring in profile.

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  Gastric signet ring cell carcinoma. H&E stain.
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  A signet ring-like foamy macrophage, which may mimic a cancer cell, but the texture of the nucleus is similar to that of a normal macrophage.
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  High magnification micrograph showing signet ring cells, with clear cytoplasm, in metastatic breast carcinoma. H&E stain.
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  Signet ring cells (magenta) stained with PAS in a gastric signet ring cell carcinoma.

Diagnostic significance

A significant number of signet ring cells, generally, are associated with a worse prognosis.^[6][7]

Classification of carcinomas

SRC carcinomas can be classified using immunohistochemistry.^[8]

See also

• Signet ring cell carcinoma