IMAGING CHARACTERISTICS OF RARE HISTOLOGICAL SUBTYPES IN RECTAL CANCER: A LITERATURE REVIEW
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Abstract
Background: Rectal cancer is predominantly adenocarcinoma; however, rare histological subtypes such as mucinous adenocarcinoma, signet-ring cell carcinoma, squamous cell carcinoma, adenosquamous carcinoma, and neuroendocrine tumors exhibit more aggressive behavior, rapid progression, and poorer prognosis. These entities often present with complex imaging features and may be underdiagnosed.
Objectives: To describe and analyze the imaging characteristics of rare histological subtypes of rectal cancer and correlate them with histopathological findings to support diagnosis and treatment planning.
Methods: A retrospective descriptive study of rare rectal cancer cases collected at Tam Anh General Hospital, Ho Chi Minh City. Imaging features on CT and MRI were analyzed and compared with histopathological results.
Results: Each subtype demonstrated characteristic imaging findings: mucinous adenocarcinoma showed high T2 signal and low diffusion restriction; signet-ring cell carcinoma presented with diffuse concentric wall thickening (“target sign”); squamous and adenosquamous carcinomas showed heterogeneous features; neuroendocrine tumors appeared as small submucosal hypervascular lesions. MRI demonstrated high diagnostic value in differentiating these subtypes.
Conclusions: Recognizing imaging features of rare histological subtypes in rectal cancer is crucial for early diagnosis, biopsy guidance, and appropriate treatment planning, ultimately improving patient outcomes.
Keywords
Rectal cancer, rare histology, MRI, CT, mucinous adenocarcinoma, signet-ring cell carcinoma, neuroendocrine tumor
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References
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