Hi, this is Elliot Fishman, and welcome to Part 2 of our review of recurrent renal cell carcinoma: patterns of tumor recurrence.

We spoke a bit about the importance, or we spoke at length of the importance of doing arterial phase imaging, because mets, particularly from clear cell, which is 80 plus percent of tumors, are very vascular. And then we spoke about recurrence.

Here's a good example: left nephrectomy, recurrence near the renal bed involving bowel. So, it's direct extension into bowel, with bowel involvement, also involvement of the left psoas muscle, very nicely seen as you look at these images.

And as you scan down, you can see the extent. There's an IVC filter in place. Contralateral right kidney looks good.

Here it is on the coronal view. The left adrenal gland is here. Patient had a nephrectomy, but they've recurred, and it's involving small bowel, and it's involving the psoas muscle very nicely seen there. And again, it's somewhat vascular, which is good because the primary was a clear cell renal cell carcinoma.

Now, what about the pancreas? I showed you on the first part of the talk some lesions that became isodense on venous phase imaging, but were clearly seen on arterial phase. The most common tumor to go to pancreas is renal cell. It looks identical at times to a neuroendocrine tumor, particularly when it's solitary. But you will have known the patient had a renal cell, either with a partial or a total nephrectomy.

Here's an example of multiple metastasis to the pancreas. Now, the average met to the pancreas occurs about 10 years after initial diagnosis, so the patient... again, the importance of follow-up. Patients will get partial... partial resections of tumors, but if the tumor is extensive like this, they may get a total pancreatectomy, but patients with aggressive pancreatic surgery for metastatic renal cell often do very well. You can see the multiple lesions in the head of the pancreas and the body and tail. Pancreatic duct is usually not dilated, but here, because of this met, it is going to be dilated.

And then you could follow it on the MIP imaging as well, a very nice example of multifocal metastatic renal cell carcinoma to the pancreas. Again, the MIP and the volume rendering all show the metastasis very nicely. And here's a few more images with volume rendering also showing you the true extent, the pancreatic duct, the multiple tumors. And again, you look very carefully, make sure there's nothing going on in the liver, that's a cyst. You look at the bowel, you'll be looking everywhere for the possibility.

Here's the same patient on the cinematic. You can see the patient's dilated pancreatic duct, you also can see many of the metastasis that go to the patient's pancreas, and again simply changing the rendering, we can see that even a little bit better.

What you also will see in this patient, and I'll show you a few others, after you got looking at the pancreas, again the satisfaction of search, there's an enhancing lesion in the left lower quadrant, that's going to end up being in small bowel. You can see it very nicely here as well, you see the SMA, there's the branches of the SMA, that's the metastasis. So again, look very carefully. You see one set of lesions, you should be even more suspicious for additional lesions. Here again, the left nephrectomy and the patient's tumor involving bowel in the pelvis, measuring about all of 12 millimeters, but again, when lesions are vascular, when you do good technique, good injection, you are going to pick up these lesions.

You can see the lesion is fairly easy to see here on arterial phase, but as you go to venous phase, okay, there it is, but you might have thought this was some food in bowel or whatever, you may not have called that, and I don't blame you. But there's the lesion, and again a good example why the arterial phase is so much more valuable, because the lesions are very obvious, you're not making what I would call a difficult call. Now, yes, you should be suspicious, but it's surely a lot easier on those arterial phase imaging.

Now, another example: we were restaging a patient with renal cell. Well, guess what, liver metastasis, guess what, pancreatic metastasis, the patient has had surgery by the left kidney. And then as you scan down, more metastasis to the pancreas, and then you'll also see in addition to the pancreas and liver, the patient has metastasis to a duodenum, pancreas, duodenum, you see a node right here adjacent to the duodenum which is vascular, which is also metastatic disease. So again, now we're dealing with multiple sites of disease in the pancreas, multiple sites of disease to nodes and to small bowel as well. And this is the typical pattern: when patients get metastasis, it's often multiple and multiple organs. There's some new chemotherapies, there's some immunotherapy with chemotherapy. Patients with multiple sites of disease obviously are typically not going to benefit from additional surgery, you need to have other therapies at hand, and you can see very nicely in this example, the patient's extent of disease.

What else? Same patient: duodenum and liver and pancreas. Again, I'm trying to show you the importance of looking very carefully at the full set of images. And as you go from arterial to venous, the lesions wash out and become more difficult to see. But again, targeting and looking carefully: bowel, pancreas, bowel, nodes, pancreas again, and then here's another lesion in the patient's bowel. Patient's lesions in bowel are often subtle, renal cell can present with GI bleeding, so that's something else to think about. And in the venous phase, you can see how the lesions, including here, are difficult to see, that's the lesion, but it's washed out. The lesions in the head of the pancreas, the nodal lesion, the lesion's in duodenum, all wash out substantially by the venous phase imaging, and that indeed can be a challenge. Again, I rather be reading this image: one, two, one, two, right? Much easier to see on the arterial imaging. So again, the importance, we look at all the images. Every once in a while things will show better on the venous, but that's typically more likely going to be with a papillary renal cell carcinoma and not a clear cell renal cell carcinoma. So again, the importance of looking carefully.

Here's another case, which I just showed you about the pancreas, the liver, and again, what you need to know.

In this second case, there's a metastasis to the tail of the pancreas. Again, if you didn't notice the kidney was missing, and you said that was a neuroendocrine tumor, you would be right, but in this case you're going to be wrong, very nicely showing you that on the MIP imaging as well, as well as the cystic lesion in the left kidney.

So again, nodal disease, patient with a met to the pancreatic head, and nodes in the left para-aortic region. Again, adenopathy is often going to be vascular with clear cell, with papillary, it's not going to be vascular, but again, you should be able to recognize the presence of adenopathy.

And here as we scan downward, the patient's right nephrectomy, the para-aortic adenopathy very nicely shown in this example.

Or another patient: again, multiple lesions in the pancreas, there's a 5 millimeter, and maybe a 15 millimeter, right nephrectomy, right adrenalectomy, but again you have the pancreas, and then as we scan downward, we're going to look for any other potential lesions. And again, this patient had metastasis to small bowel here and here, similar to the last case. As I mentioned, small bowel metastasis, what else could this be? Could be a carcinoid tumor, could be a GIST tumor. But again, in the presence of a history of renal cell carcinoma, a renal cell metastatic to bowel is going to be the most common. And as I mentioned, it is one of the causes of GI bleeding, very nicely seen on the coronal, there's that 1 centimeter lesion going to the patient's jejunum, a very nice example. And here it is again with the volume rendering and with the MIP imaging, you can see some of the feeding vessels, the jejunal branches off the patient's SMA, very nicely shown in this example. And again, once I see that, again it's harder to see, looks a little bit like the first case I showed you, again the lesion washes out, but it's in the lumen. But then you say, well, is this a lesion? What's going on? I think you really need to see the enhancement to definitely call a lesion and not overcall things. Surgeons will typically, when they're solitary or even a couple lesions, will go in and do a resection, and they'll follow the bowel, look very carefully for the presence of any other lesions. The small bowel metastasis can occasionally intussuscept, it's not very common, but it can occur. Intussusceptions, we think about metastatic melanoma, we think about benign tumors like lipomas, we think about lymphoma. Metastasis often don't intussuscept because they're relatively small and fixed. But again, the importance of arterial versus venous phase imaging, and how it's important to be able to pick up even these subtle lesions, which again is shown very nicely in this case on the cinematic rendering. As we've spoken before, we do a lot of cinematic rendering, and I am trying to automate the cinematic rendering with AI, or using some AI, to help us pick up these smaller lesions. Again, the ability to change the parameters and look carefully become very, very important, but can be very challenging when you're very busy in clinical practice, but look how nicely that lesion is shown, just a really, really nice example. And then when I accentuate it a bit more, look how obvious it is. So, one of the key things is how can we make these lesions obvious on cinematic without overcalling or without undercalling? And that's going to be our challenge.

Now, what else can we look at? Well, we can look at the adrenal gland. The adrenal, this patient has nodes in the mediastinum, so we know the patient has recurrence, and we're scanning downward, there's something going on in the patient's liver, there's something going on in the left adrenal gland. So, now we have mediastinal disease, I think we may have pancreatic disease, we have liver disease, and we have adrenal. Now, this is venous phase, so the lesions are not very bright, but the left adrenal is a classic metastasis in a patient who's had a left nephrectomy, and the liver lesions are not very vascular on venous phase, but again we have multiple sites of disease, from the mediastinum to the pancreas, to the liver, to the left adrenal gland.

Here's another example: a patient with recurrent renal cell, left adrenal. You can see the metastasis are vascular, very classic if you're going to deal with a clear cell renal cell carcinoma. You can see it is pushing on the patient's left kidney. This patient had a right nephrectomy, but a very classic metastasis. Obviously, if you didn't know about a renal cell, you can go through differential, but the kidney's obviously missing, this is classic metastatic renal cell to the patient's contralateral adrenal gland.

Or in this case, here's another adrenal metastasis, very nicely shown there. The patient also has adenopathy. Again, the point I'm making about multiple sites of disease. There's also an implant by the patient's spleen, the para-aortic nodes, the adrenal gland. And again, the nodes, as well as the adrenal, are going to be vascular in this patient who had a left nephrectomy for a clear cell renal cell carcinoma. Multiple organs are involved. And again, the lesions do wash out a bit, but the adrenal, as well as the liver, are all going to be seen on arterial and late phase imaging, but better seen on arterial.

Patients with adenopathy, I showed you nodes in the last case. Here's nodes in the posterior mediastinum. You can have nodes in the posterior mediastinum, I showed you an example before in the anterior mediastinum, and the paratracheal space. As we scan down on this patient, look how bulky the nodes are. It almost looks like a patient with lymphoma, the nodes are so bulky, but the patient had renal cell, had a left nephrectomy. These nodes were biopsied just to confirm, and this was metastatic renal cell with bulky para-aortic adenopathy. You can see it very nicely here with the left nephrectomy and the left renal artery resected, and the really bulky disease that's present. Very, very nicely shown.

Now, other sites of disease: you can have disease in the contralateral kidney. Now, it could be the patient had synchronous tumors and maybe you didn't see the second one, that happens, or the primary tumor can metastasize to contralateral kidney, which is maybe a bit more common.

So, let's do this: let's take a short break, I want to come back with Part 3. Part 3 is going to be our final part, we're going to look at a few more sites of metastasis, we're going to discuss a little bit about how we strategize on these patients, and then we'll call it a day.

So, let's take a five minute break and come back, and I'll see you soon.