Pathology for medical students

This article is an introduction to pathology for medical students.

Compentencies

Describing injuries

• Gross pathologic classification of injuries.

Pre-autopsy

• Filling in a death certificate.
  • Difference between manner of death, cause of death and mechanism of death.
  • World Health Organization standard for death certificates.

Autopsy

• Identifying medical examiner cases/coroner's cases.
• Getting an autopsy consent.
  • Understanding the hierarchy and knowing it must be followed strictly.
  • Knowing the difference between executer of the estate and power of attorney for health care decisions (not valid after death).
• Providing important clinical information.
  • Clinical history - past medical history.
  • Events leading-up to death.
  • Provisional/suspected cause of death.
• Value of doing an autopsy.
• Interpretation of autopsy reports.
  • Negative autopsy.
  • Inherited diseases, e.g. MEN 2A, ARVC.

Surgical pathology

• Ordering biopsies and laboratory tests.
  • Infectious cases - role of culture.
• Interpreting pathology reports.
• Importance of providing clinical information.
  • Consultant for a specialist should have a reason for referral - pathology is not different.

Cancer diagnoses

Definitions:

• Cancer.
  • Pathologic definitions of cancer.
• Tumour.
  • Not necessarily cancer.
  • Locally aggressive tumours, e.g. desmoid tumour.
  • Benign tumours.

Pitfalls:

• The -oma endings -- some are malignant:
  • Melanoma.
  • Mesothelioma.
  • Sarcoma.

Implication of not otherwise specified:

• Adenocarcinoma.
• Squamous cell carcinoma.

Prognostic factors:

• Stage & grade.
  • TNM staging system.
• Lymphovascular invasion.
• Perineural invasion.
• Margin status.
• Tumour size - understanding the rationale for diagnostic size cutoffs.

Techniques

• Immunohistochemical stains.
  • Cancers of unknown primary.
• Targeted therapies/molecular testing:
  • Receptors in breast cancer (ER, PR, HER2).
  • Lung cancer biomarkers (EGFR, ALK, PD-L1, ROS1).
  • BRAF testing in malignant melanoma.
  • MSI testing in colorectal cancer.

See also

• Basics.