Table 1 Histological subtypes of colorectal adenocarcinoma, adapted from the 5th edition of the World Health Organization (WHO) classification of tumors of the digestive system [24]
From: Colorectal liver metastases: radiopathological correlation
Mucinous Adenocarcinoma | > 50% of pools of extracellular mucin in tumors. |
|---|---|
Signet-ring cell carcinoma | Presence of > 50% of tumor cells with signet ring cell (prominent intracytoplasmic mucin vacuole that pushes the nucleus to the periphery). Poorly differentiated and poor outcome. |
Medullary carcinoma | Extremely rare. Sheets of epithelioid neoplastic cells with large vesicular nuclei, prominent nucleoli, and abundant cytoplasm. Associated with microsatellite instability and a better prognosis. |
Serrated adenocarcinoma | Glandular serration that can be associated with mucinous areas. |
Micropapillary adenocarcinoma | > 5% of the tumor showing small clusters of tumors cells with stromal spaces mimicking vascular channels |
Adenoma-like adenocarcinoma | > 50% of invasive areas showing an adenoma-like aspect. |
Adenosquamous | Characteristics of both adenocarcinoma and squamous cell carcinoma. |
Carcinoma with sarcomatoid component | Undifferentiated with sarcomatoid aspects including spindle cell components or rhabdoid features. |
Undifferentiated | Absence of morphological, immunohistochemical or molecular differentiation other than epithelial tumor. |