Pathology Lecture ✦ Deluxe & Trusted
The professor collects her papers.
"Every cancer begins as a betrayal. In Margaret’s case, the betrayal started in a single crypt cell in her ascending colon. The cause? Sporadic. Bad luck. A base pair mismatch during replication. But one mutation in the APC gene—the 'gatekeeper' of the colon.
The pathologist (me) signed it out: 'Moderately differentiated adenocarcinoma of the colon, with lymphovascular invasion, metastatic to liver.'
A student in the front row stops taking notes. He’s just staring. pathology lecture
And the macrophages believed it.
"Margaret’s primary tumor was 7 cm. It had invaded the omentum—that fatty apron of the abdomen. That’s what she felt as a lump. The omentum tried to wall it off, but the tumor just grew inside it like ivy on a fence." Part 4: The Diagnosis (The Biopsy) The slide changes to a histology image: disorganized glands, dark purple nuclei, mitotic figures.
She turns off the projector. The room is silent. The professor collects her papers
Now. Turn to page 342. We will go over the molecular pathways of colorectal cancer. But first—any questions?"
"Margaret was a retired librarian. Non-smoker. Walked three miles a day. Six months ago, she noticed she felt full after eating only a few bites. She thought it was age. Three months ago, she noticed her stool was darker. She thought it was iron pills. Two weeks ago, she felt a lump in her right lower quadrant. She thought it was a muscle.
"So. What is pathology? It is not just slides and diagnoses. It is the story of a cell that forgot how to die. It is the story of a woman who gardened and read books and loved her family. And it is our job to understand the first story so we can help the second. The cause
That single cell grew into a 2 cm metastasis in the right lobe of the liver. That’s when Margaret’s alkaline phosphatase rose. That’s why she felt fatigue—cytokines from the tumor causing systemic inflammation. Cachexia began. Her body started breaking down its own fat and muscle, not because she wasn’t eating, but because the tumor released TNF-alpha and IL-6."
"Margaret chose palliative chemo. She had eight good months. Then the liver metastases grew. She developed ascites—fluid in the belly from portal hypertension. Then jaundice—the liver couldn’t clear bilirubin. Then confusion—ammonia from the gut bypassing the failed liver.
Stage IV. Incurable."
"This is Margaret’s biopsy. See the glands? They’re 'back-to-back'—no normal stroma between them. See the nuclei? They’re hyperchromatic, elongated, stratified. And here—a mitotic figure. That cell is in the middle of dividing wrong.
The autopsy—which I performed—showed a 4 cm liver metastasis that had replaced 60% of her liver parenchyma. The primary colon tumor had perforated silently, walled off by the omentum. And here’s what matters: we found two tiny metastases in her lungs, each 2 mm. Too small to see on CT. That’s why she didn’t respond fully to chemo—the disease was always one step ahead."