Patterns Of Tumor Spread

The presence of lymphatic or vascular invasion documented on histologic examination is an important prognostic indicator of primary testicular tumors because these are the pathways of metastatic spread.

Lymphatic invasion leads to tumor spread along four to eight efferent lymphatic channels that accompany the spermatic cord. These channels pass through the internal inguinal ring, where they join together to form major lymphatic channels accompanying the tes-ticular vessels. These major vessels cross the ureter at the pelvic brim and then fan out into several branches to enter the retroperitoneal lymph nodes (Figure 6-2).

Right-sided testicular tumors spread to the right paracaval and retrocaval nodes as well as to the pre-caval nodes and interaorticocaval lymph nodes (Figure 6-3, A).

Left-sided tumors also spread to lymph nodes around the great vessels. Those nodes that are first involved are usually the lymph nodes in the left para-aortic region below the left renal vein (see Figure 6-3, B). In general, lymph nodes involved in right-sided tumors tend to be lower in the retroperi-toneum than those involved in left-sided tumors. This simply reflects the anatomic arrangement of normal retroperitoneal lymph node chains. Crossover of lymph node involvement will occa sionally be seen, but this is relatively uncommon (see Figure 6-3, C).

Further spread of disease extends above the renal vessels in the retroperitoneal and retrocrural spaces. Lymphatic spread may also extend to nodes lateral to the paracaval and para-aortic groups; these nodes are are sometimes referred to as "echelon nodes." The so-called echelon node on the right was first described by the anatomist Rouviere, in his elegant description of anatomic dissection.10 An echelon node on the left has also been described. With the knowledge derived from CT, it is now clear that these echelon nodes lie on the anterior surface of the iliopsoas and, although an unusual site of disease, may be a first site of relapse (Figure 6-4).11

The pattern of tumor spread in testicular tumors is characteristic and is usually contiguous below the diaphragm; thus, the consistency with which right-sided tumors spread to the right-sided retroperi-toneal nodes and left-sided tumors spread to left-sided nodes is extremely high.12 If a single node that is deemed to be enlarged is demonstrated on the contralateral side to the primary tumor, then histo-logic verification of metastatic disease is recommended prior to therapy. However, direct spread of tumor from one side to the other, via communicating lymphatics, is common particularly if several nodes are involved or if there is a large coalescent nodal

Diagram Retrocrural Lymph Node

Figure 6-2. Schematic representation of lymphatic drainage of the testes to the retroperitoneum: axial representation of nodal distribution just below the level of the renal vessels. A plane drawn down the center of the aorta separates left-sided from right-sided nodes. Right-sided nodal groups include the aortocaval nodes. "Echelon" nodes lie more laterally. On the left, lymphatic drainage is initially to the node groups immediately below the left renal vessels. On the right, the lymphatics fan out more, and there tends to be more variability in the initial site of metastatic nodes from right-sided tumors. (Reproduced with permission from Husband JE, Reznek RH, editors. Imaging in oncology. UK: ISIS Medical Media; 1998.)

Figure 6-2. Schematic representation of lymphatic drainage of the testes to the retroperitoneum: axial representation of nodal distribution just below the level of the renal vessels. A plane drawn down the center of the aorta separates left-sided from right-sided nodes. Right-sided nodal groups include the aortocaval nodes. "Echelon" nodes lie more laterally. On the left, lymphatic drainage is initially to the node groups immediately below the left renal vessels. On the right, the lymphatics fan out more, and there tends to be more variability in the initial site of metastatic nodes from right-sided tumors. (Reproduced with permission from Husband JE, Reznek RH, editors. Imaging in oncology. UK: ISIS Medical Media; 1998.)

Aortocaval Lymph NodeParacaval Lymph Nodes Onct

Figure 6-3. Retroperitoneal nodal disease demonstrated on CT. A, Left-sided testicular tumors typically spread to left para-aortic lymph nodes just below the level of the left renal vein (arrow). B, Right-sided tumors usually spread to the retrocaval (arrow), paracaval, precaval, or aortocaval lymph nodes. C, The presence of crossover lymphatic trunks can result in dissemination of disease from a right-sided testicular tumor to nodes on the left. Note the enlarged right-sided aortocaval and left-sided para-aortic nodes (arrow).

Figure 6-3. Retroperitoneal nodal disease demonstrated on CT. A, Left-sided testicular tumors typically spread to left para-aortic lymph nodes just below the level of the left renal vein (arrow). B, Right-sided tumors usually spread to the retrocaval (arrow), paracaval, precaval, or aortocaval lymph nodes. C, The presence of crossover lymphatic trunks can result in dissemination of disease from a right-sided testicular tumor to nodes on the left. Note the enlarged right-sided aortocaval and left-sided para-aortic nodes (arrow).

mass.12 Crossover occurs more commonly from right to left than from left to right. This may be due to the fact that lymph nodes on the right are situated lower in the retroperitoneum and that lymphatic flow is generally in a cranial direction (see Figure 6-3, C).

Pelvic nodal disease is uncommon but may occur in certain specific situations. In patients with large retroperitoneal masses, retrograde flow of tumor cells through the lymphatics may result in nodal disease. Cryptorchidism and previous scrotal surgery are also risk factors for nodal disease in the pelvis (Figure 6-5).13

Mediastinal nodal disease usually occurs by direct contiguous spread of tumor via the thoracic duct into the posterior mediastinum through the diaphragmatic hiatus in seminoma (Figure 6-6), but with an NSGCT, tumor spread is more random.14 Not infrequently, however, nodal disease is seen in the anterior mediastinum, aortopulmonary window, or hilar regions, without any evidence of posterior mediastinal or subcarinal involvement. This is more commonly seen in cases of NSGCT than in cases of seminoma. Tumor spread of disease to the supra-clavicular fossae and to lymph nodes in the neck is also more common in cases of NSGCT. Pleural masses and effusions are well-recognized features of seminoma15 and are usually accompanied by other manifestations of metastatic spread.

Vascular invasion of the primary tumor results in hematogenous spread predominantly to the lungs.

Seminoma Vascular Invasion
Figure 6-4. An "echelon" node on CT. In this man with relapsed seminoma, there was an enlarged echelon node (arrow) lying anterior to the left psoas muscle. (Reproduced with permission from Husband JE, Reznek RH, editors. Imaging in oncology. UK: ISIS Medical Media; 1998.)
Medical Penoctomy Photos
Figure 6-5. Pelvic disease. This 47-year-old man with a history of right orchiectomy for undescended testes developed a large semi-nomatous mass within the right pelvis. The mass appears to be of near uniform density on this computed tomography (CT) scan.

Hematogenous spread is more common in cases of NSGCT than in cases of seminoma. It should also be remembered that nodal masses may contribute to hematogenous spread as tumor cells may also invade the blood vessels that supply lymph node deposits. This is more likely to occur in large nodal masses that have spread beyond the lymph node capsule.

Other sites of bloodborne metastases include the brain, the liver, and bone. Metastases in unusual sites may be identified in patients with both seminomas and NSGCTs. Unusual sites of disease are most commonly seen in relapsed patients who have undergone previous treatment for metastatic disease. It is therefore important that the radiologist be aware of the patient's previous history and current clinical symptoms. Unusual sites include the kidneys, adrenal glands, muscles, spleen, prostate, pericardium, pleura, and peritoneum (Figure 6-7).16

Was this article helpful?

0 0
10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Responses

  • saare
    Can testicular tumor on right spread to lymph node on left?
    7 years ago
  • john
    Where are retrocrural lymph node?
    7 years ago
  • demi
    Where is aortocaval lymph nodes located?
    6 years ago
  • cairn
    Where are retrocrural lymph nodes?
    6 years ago
  • aleksander
    What is multiple enlarged para aortic and aortocaval lymph nodes?
    6 years ago

Post a comment