From the Guidelines
Signet ring cell carcinomas are a subtype of gastric adenocarcinoma characterized by their diffuse growth pattern and aggressive behavior, with a high propensity for early metastasis and poor prognosis, as noted in the most recent guidelines from the National Comprehensive Cancer Network 1.
Key Characteristics of Signet Ring Cells
- These cells have a large vacuole filled with mucin that pushes the nucleus to the periphery, creating a ring-like appearance resembling a signet ring.
- Signet ring cells are most commonly associated with gastric adenocarcinoma but can also be found in other cancers.
- They typically stain positive for mucin with special stains like PAS-D or mucicarmine.
Clinical Implications
- Signet ring cell carcinomas are generally more aggressive than non-signet ring cell variants, with a tendency for diffuse infiltration and early metastasis.
- These tumors often present at advanced stages due to their propensity for submucosal spread without forming distinct masses, making early detection challenging.
- At the molecular level, signet ring cell carcinomas frequently show E-cadherin mutations, particularly in gastric cancers, which contributes to their diffuse growth pattern and aggressive behavior, as supported by the Italian Research Group for Gastric Cancer guidelines 1.
Diagnosis and Treatment
- Recognition of these cells is crucial for accurate diagnosis and appropriate treatment planning.
- The Lauren classification, which includes the diffuse type that signet-ring cell carcinoma belongs to, is a widely used histological classification for both early and advanced gastric cancers 1.
From the Research
Signet Cell Features
- Signet-ring cell carcinoma (SRCC) is a poorly differentiated mucin-producing adenocarcinoma that may arise from many different organs, but all SRCCs share identical morphology 2
- Mucin profiles of gastric, colorectum, and breast SRCCs are distinct and maintained in metastases, which may be useful to identify the origin of a metastatic SRCC of unknown primary 2
- Signet ring cell carcinomas of the stomach, colorectum, and breast have distinct mucin expression patterns 2
- Depth of tumour invasion is predictive of lymph node metastasis in patients with signet ring cell histology 3
- Tumour size and lymphovascular invasion are independent risk factors for lymph node metastasis in signet ring cell carcinoma 4
- Mucin-poor signet ring cell carcinoma is a distinct subset of colorectal carcinoma with diffuse infiltration and minimal to no extracellular mucin, associated with dismal prognosis and aggressive clinical course 5
- Lymph node dissection is an important aspect of surgical treatment for advanced resectable gastric cancer, with D2 dissection being the standard of care in Japan 6
Key Characteristics
- Signet ring cell carcinoma is characterized by the presence of signet ring cells, which are mucin-filled cells with a distinctive appearance 2
- Mucin profiles can be used to distinguish between different types of SRCC, including gastric, colorectum, and breast 2
- Lymph node metastasis is a significant concern in signet ring cell carcinoma, with depth of tumour invasion and tumour size being predictive factors 3, 4
- Mucin-poor signet ring cell carcinoma is a distinct subset of colorectal carcinoma with a poor prognosis 5
Clinical Implications
- Accurate diagnosis and characterization of signet ring cell carcinoma are crucial for determining the appropriate treatment approach 2, 3, 4
- Lymph node dissection is an important aspect of surgical treatment for advanced resectable gastric cancer 6
- Mucin profiling may be useful in identifying the origin of a metastatic SRCC of unknown primary 2