Gastrointestinal Diagnostic Pathology Textbook 2026-2027

Move from specimen context to a defensible final report

This organ-based guide develops a repeatable method for interpreting mucosal biopsies, resections, inflammatory patterns, precursor lesions, and neoplasms across the alimentary tract. It connects normal regional histology with mechanisms of injury, architecture-first differential diagnosis, focused ancillary testing, molecular classification, staging, and integrated reporting. The scope is calibrated for AP residents who need a rigorous sign-out framework that remains useful from first preview through multidisciplinary discussion.

The Mucosa-to-Molecule Diagnostic Map makes the reasoning sequence visible: specimen context, dominant pattern, differential split, ancillary pivot, diagnostic trap, and report anchor.

Use the book to strengthen these daily diagnostic capabilities:

Specimen orientation, biopsy handling, and resection grossing - recognize when sampling or artifact limits interpretation

Normal regional histology and reactive change - separate expected variation from clinically meaningful injury

Esophageal, gastric, small-intestinal, appendiceal, colorectal, and anal lesions - organize site-specific differentials from low power to high power

Inflammatory bowel disease, infection, ischemia, and medication injury - integrate chronicity, activity, distribution, and clinical context

Dysplasia, carcinoma, neuroendocrine, mesenchymal, and lymphoid tumors - classify lineage, grade, extent, and staging features

Special stains, immunohistochemistry, in situ methods, and molecular assays - order focused panels while conserving tissue

Mismatch repair, HER2, EBV, and other biomarkers - connect valid test interpretation with inherited-risk and therapeutic consequences

Synoptic reporting, digital workflows, and multidisciplinary correlation - deliver complete reports with calibrated certainty

Adopt a consistent architecture-first sequence for gastrointestinal specimens and carry each case from slide pattern to clinically actionable sign-out.