title: Tumors of the alimentary tract.
abstract: Electron microscopy offers substantial aid in the diagnosis of gastrointestinal tract tumors, especially small-cell carcinoma and enterochromaffin-cell tumors. Tumors that are most difficult to classify by light microscopy--that is, poorly differentiated ones--may also have ultrastructural features by which the cell of origin can be determined. As always, the well-preserved tissue is more likely to retain diagnostic features than is the inadequately preserved.
mesh_terms: D002276:Carcinoid Tumor / Q000648:ultrastructure; D002277:Carcinoma / Q000648:ultrastructure; D003937:Diagnosis, Differential; D004759:Enterochromaffin Cells / Q000648:ultrastructure; D004848:Epithelium / Q000648:ultrastructure; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis / Q000648:ultrastructure*; D006801:Humans; D007124:Immunoenzyme Techniques; D008637:Mesenchymoma / Q000648:ultrastructure; D008854:Microscopy, Electron