Prostatic carcinoma variants
Signet ring carcinoma

Authors: Komal Arora, M.D. (see Authors page)

Revised: 9 August 2016, last major update March 2012

Copyright: (c) 2003-2016,, Inc.

PubMed search: prostatic signet ring carcinoma
Cite this page: Signet ring carcinoma. website. Accessed October 26th, 2016.
Definition / General
Case Reports
  • Similar to traditional adenocarcinoma - hormonal therapy, radiation, surgery
Micro Description
  • Solid, acinar, single-line patterns
  • Primarily composed of tumor cells with signet ring pattern (at least 25%) due to intracellular accumulation of mucin compressing the nucleus into a crescent shape
Micro Images

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Various images

Positive Stains
  • PSA (variable in some studies), AE1/AE3, CAM 5.2, Ki-67 (mean 8%), PAS-diastase, mucicarmine (50%), Alcian blue (60%), α-methylacyl coenzyme A racemase (P504S) and cytokeratin 5/6
Negative Stains
  • Bcl2 (rare cells positive), CEA (80%)
Electron Microscopy Description
  • Intracytoplasmic lumina lined by microvilli
Differential Diagnosis
  • Artifactual changes in lymphocytes post TURP: no classic adenocarcinoma, CD45+, negative for mucin, PSA, PAP (Am J Surg Pathol 1986;10:795)
  • Benign signet ring change: no classic adenocarcinoma, negative for mucin, PSA, PAP (Am J Surg Pathol 2002;26:1066)
  • GI primary: much more common; no typical prostatic adenocarcinoma, positive GI workup (abdominal CT, colonoscopy, esophagogastroduodenoscopy); PSA-, PAP-
  • Mucinous carcinoma with signet ring cells: > 25% of tumor is extracellular mucin and < 25% of tumor cells feature signet rings