dedifferentiation
Process where well-differentiated neuroendocrine tumors transform into poorly differentiated or anaplastic forms.
Full Definition
Dedifferentiation in neuroendocrine tumors refers to the pathologic process whereby well-differentiated NETs with low proliferative activity transform into poorly differentiated neuroendocrine carcinomas with high-grade features. This transformation may occur spontaneously over time or following treatment pressure, resulting in loss of neuroendocrine differentiation markers, increased mitotic activity, and more aggressive clinical behavior. Dedifferentiated tumors typically lose somatostatin receptor expression, making them unsuitable for peptide receptor-targeted therapies. Recognition of dedifferentiation is crucial as it necessitates a change in treatment approach from NET-specific therapies to aggressive chemotherapy regimens used for high-grade neuroendocrine carcinomas.
Usage
Usage note: Important prognostic factor requiring change in therapeutic approach.
In Context
- "Biopsy of the new liver lesion showed dedifferentiation with loss of chromogranin staining." — pathology report
- "Dedifferentiation was suspected given the rapid disease progression and loss of octreotide avidity." — oncology consultation