[Medical Human Story-Episode 80]_Part III: Can We Save the Kidney?

 

 The 6.6-Centimeter Discovery on Routine Screening

Prologue | Part 1 | Part 2 | Part 3 | Part 4 | Epilogue   

Part III: Can We Save the Kidney?

1. "Can we save the kidney?"

The moment I heard that question, I looked back at the screen.

The left kidney.

A mass extending from the interpolar region to the lower pole.

Approximately 59 x 66 x 57 mm.

It was well over 6 cm.

To the patient, that number felt overwhelming. But in surgical planning, a single number isn't everything. Where is that tumor located within the kidney? And what is its relationship to the normal renal parenchyma?

I moved the mouse, tracing the edges of the mass to inspect the surrounding structures.

"This is not a question that can be answered with a simple yes or no just by looking at the images."

The patient lowered his head. I continued.

"However, the images can provide a substantial amount of the information needed to plan the surgery."

He looked back up at me.

"Then what do you look for?"

"First, we look at the location of the tumor."

"We look at its relationship with the blood vessels."

"We look at how it relates to the inner architecture of the kidney."

"We check whether it has extended into the surrounding tissues."

"With that information, the Department of Urology will determine the actual feasibility of surgery."

He listened quietly. This time, his wife didn't ask a question either.

2. Why Surgery Cannot Be Decided Solely by Tumor Size

When a renal tumor is discovered, most people check its size first. How many centimeters? Is it 4 cm? 5 cm? 6 cm?

These numbers matter. Yet in surgical planning, size is merely a starting point. Even with identical 6 cm tumors, differences in location can entirely change the surgical difficulty and strategy.

·         A tumor situated on the outer surface of the kidney is different from one deeply embedded in the core.

·         A tumor at the lower pole differs from one at the upper pole.

·         A tumor close to the renal sinus differs from one near the renal capsule.

·         A tumor adjacent to major blood vessels differs from one that is not.

This is why, when a radiologist reviews pre-surgical imaging, they do not simply stop at:

“6.6 cm renal mass.”

The questioning continues:

·         Where is it?

·         How far does it extend?

·         What is it pushing against?

·         What is it invading?

·         And most importantly, what can be preserved?

[Insert Figure 1]

3. "Is it strictly confined within the kidney?"

It was the patient's question. I zoomed in on the CT scans once more.

"That is precisely what we must check first on current imaging."

In staging renal cell carcinoma, not only tumor size but also extension beyond the kidney is critical. Specifically, we must evaluate extension into the perirenal fat, invasion of the renal sinus, tumor thrombus in the renal vein or inferior vena cava, lymph node involvement, and distant metastasis.

While this patient's mass is large, the provided imaging evaluation shows no clear invasion of the renal vein or inferior vena cava, nor obvious perirenal invasion. I explained this to the patient.

"The fact that no major vascular invasion is clearly visible on the current images is crucial information for surgical planning."

He looked slightly relieved. But I immediately added:

"However, we cannot finalize the surgical approach based on this alone."

His expression turned serious again.

"Why?"

"Because actual surgery involves many more factors than what can be seen on imaging."

4. How Much Normal Kidney Can Be Saved?

This question is paramount in the treatment of kidney cancer. We have two kidneys. Yet neither kidney possesses infinite function on its own.

The goals of a surgeon differ significantly when considering a radical nephrectomy—removing the entire kidney—versus a procedure that removes the tumor while preserving as much healthy renal tissue as possible. Preserving renal function is a vital component of long-term patient management. Therefore, in selected patients, partial nephrectomy—removing only the tumor while preserving the normal kidney—can be a key therapeutic strategy.

However, partial nephrectomy is not feasible for every tumor. The surgery becomes more complex as the tumor is:

·         Deeper,

·         Closer to the center, or

·         Nearer to major blood vessels or the collecting system.

Thus, the radiologist's role is not to decide, "You must perform a partial nephrectomy." Rather, it is to provide an anatomical map so the surgeon can make that determination.

5. I Rotated the Images Back to 3D

The tumor slowly rotated in the center of the screen. The patient stared at the display.

"Is that my kidney?"

"Yes."

"And that's the tumor?"

"That's correct."

In the 3D rendering, the tumor appeared distinct from the normal renal parenchyma. I explained the structures surrounding the tumor one by one.

"Here is the tumor."

"Here is the normal kidney."

"And the surrounding structures have been displaced like this."

On this patient's MRI, displacement of the microscopic normal renal structures surrounding the tumor was observed, and 3D tractography utilizing diffusion tensor imaging (DTI) clearly illustrated the displacement of structures adjacent to the mass.

He watched the screen and asked, "Can the kidney actually move like that?"

I paused for a moment.

"Strictly speaking, the surrounding structures were affected as the tumor grew."

He nodded slowly.

"So, is the surgery performed using this as a guide?"

"It is one of the important pieces of information you can reference before surgery."

I stopped for a second.

"However, this does not mean it is currently a standard surgical decision-making tool in every hospital."

Explaining that distinction was essential. The existence of a novel imaging technique does not instantly make it a clinical standard. Time is required to bridge the gap between promising research and established clinical practice. While DTI and tractography offer exciting potential for understanding the spatial relationship between a tumor and normal renal structures, they should not be interpreted as solely dictating the surgical method in this case.

6. "Do CT and MRI serve different purposes?"

His wife asked her first question.

"Yes." I nodded.

"They are not competing tests."

"They provide different information."

·         CT is fast and provides a broad overview. Using contrast enhancement, it evaluates the vascularity of the mass and its anatomical relationships, while simultaneously assessing the renal veins, inferior vena cava, perirenal fat, renal sinus, lymph nodes, liver, and potential distant metastasis.

·         MRI, on the other hand, offers superior soft tissue contrast. It evaluates microscopic fat using chemical-shift imaging, assesses diffusion characteristics via DWI and ADC, and helps analyze complex tumor-vessel relationships or ambiguous lesions in finer detail when necessary.

"So that's why you look at both CT and MRI."

"Exactly."

"You can't know everything from a single picture."

I smiled. "Medical imaging is a lot like a puzzle."

7. One Mass, Multiple Languages

·         CT speaks the language of density and contrast enhancement.

·         MRI speaks the language of tissue characterization and diffusion.

·         Chemical-shift MRI speaks of microscopic fat.

·         DCE-MRI speaks of blood flow and vascularity.

·         DWI speaks of water molecule movement.

·         ADC expresses it in numbers.

·         DTI speaks of tissue directionality.

·         And 3D imaging translates all of that information into spatial relationships.

I told the patient, "You can think of each test as speaking a different language."

"And the radiologist is the person who connects those languages into a single story."

He smiled faintly.

"Then what story is my kidney telling right now?"

I looked back at the screen. This question was different from before. At first, it had been: “Is it cancer?” Now, it was: “What story is my kidney telling?”

I answered a bit more slowly.

"Looking strictly at the current imaging..." I paused.

"...a solid mass in the kidney strongly suggests a malignant renal cell carcinoma—specifically, a clear cell phenotype—based on various imaging characteristics."

"However, what is important on the current imaging is..."

"...that we can map out where this mass is positioned within the kidney and how it relates to the surrounding structures."

He looked at the screen again.

8. Staging Is Not a Number, It Is Space

When discussing staging in kidney cancer, many patients think of numbers first: T1, T2, T3, T4. But to a radiologist, the T stage is not just a digit. That number is a compressed expression of how far the tumor has reached.

This patient's mass has a maximum diameter of approximately $6.6\text{ cm}$. Assuming it is confined to the kidney, it exceeds the size threshold for the T1b category. The provided imaging evaluation shows no clear renal vein or inferior vena cava invasion, nor obvious surrounding tissue invasion.

Yet staging doesn't end with a simple size calculation. The actual extent of tumor extension must be verified. This is why CT staging is essential.

[Insert Figure 2]

9. The Last Question of the Day

As the consultation was drawing to a close, the patient asked,

"Doctor."

"Yes."

"What do I need to do right now?"

I considered that the most vital question. Patients can find an overwhelming amount of information on the internet. Yet the more information they find, the harder it can be to know what actions to take. So, I laid out the sequence clearly:

"First, precise imaging evaluation and staging are required."

"Next, the Department of Urology will evaluate the feasibility and methods of surgery."

"If necessary, a biopsy for pathological diagnosis can be considered."

"Finally, we evaluate your renal function and general health status to determine the ultimate treatment strategy."

The treatment of a renal tumor is not decided by size alone. Stage, tumor location, renal function, status of the contralateral kidney, patient age, comorbidities, histological characteristics, and metastatic status are all considered together.

The patient listened quietly, then said, "So it's not over yet."

I nodded. "No. There are still many decisions to make."

10. And There Was One Thing I Didn't Tell Him

The tumor in the images was sending a loud, clear signal. But a patient's life is vastly more complex than any image.

A number like 6.6 cm does not dictate his entire future. The imaging phenotype of the tumor does not dictate his entire future either.

·         Pathological characteristics.

·         Stage.

·         Surgical feasibility.

·         Renal function.

·         Post-treatment follow-up.

·         And the life ahead of him.

All of these are bound together. That is why, every time I read an image, I pause to think one final question: Who is the next recipient of this image? Is it the patient? The surgeon? The medical oncologist? Or is it the family?

Images are delivered to doctors, but their true meaning ultimately returns to the patient's life.

[Medical Insight]

[Clinical Pearl]

[Patient Guide]

[Family Guide]

11. The Door Leading to the Epilogue

After the patient left the consultation room, I saved the images once more. The file name contained numbers. But those numbers were not the patient's name.

I closed the screen and had one final thought: Saving a kidney may not simply mean leaving behind renal tissue. It might mean preserving the time the patient has left to live.

Yet to make that decision, imaging alone, surgery alone, or pathology alone is never enough. Multiple disciplines must converge around a single patient. And at the center of it all, there is always a human being.

12. The Next Scene

A few days later, the patient was sitting in the urology clinic. CT and MRI scans were displayed side by side on the monitor. The doctor zoomed in on the images and said:

"Looking at the location of the tumor..."

A brief silence filled the room.

"...we can consider the possibility of a partial nephrectomy."

The patient held his breath. Was that word hope? Or the start of yet another long journey?

No one could know yet. Because the moment surgery is decided, an entirely new question begins:

“After the tumor is removed, how healthily will the remaining kidney function?”

In the next chapter, we follow that question. 

The above content is a web novel adapted from the article published on "https://leesangbock.blogspot.com/2026/09/renal-cell-carcinoma-mri-microscopic-fat-adc-fa.html"

Part II: Why What Looks Like Cancer Can Be More Than One Thing☜ Previous Chapter
Next Chapter ☞ Part IV: The Kidney Left Behind