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Concurrent duplication and azygos continuation of the inferior vena cava
CT: THE JOURNAL
OF COMPUTED
TOMOGRAPHY
1986;
10:287-290
287
(IICONCURRENT DUPLICATION AND AZYGOS CONTINUATION OF THE INFERIOR VENA CAVA WILLIAM MARSHALL
F.
COSCINA, C.
MINTZ,
MD,
PETER
MD,
AND
Duplication of the inferior vena cava and azygos continuation of the inferior vena cava arise from separate embryologic anlage. The former arises from persistence of both supracardinal veins and the latter from arrested development of the right subcardinal vein. Individually these entities are uncommon, but their occurrence together in one patient is exceedingly rare. A patient with both these anomalies of the venous system concurrently is described. This combination has been reported only once before in the radiologic literature. KEY WORDS:
Venous anomalies; Inferior vena cava; Azygos vein
Various anomalies of the major venous channels have been described and classified (l-5). The portion of the inferior vena cava from the level of the left renal vein to the right atrium is known to develop from the right subcardinal vein of the embryo. Azygos continuation of the inferior vena cava results from absence of the connection between the right subcardinal vein and the right atrium. This is termed hepatic interruption of the inferior vena cava. The inferior vena cava instead drains into the azygos vein, which continues cephalad to drain into the superior vena cava. The hepatic veins drain into the right atrium separate of the inferior vena cava. The embryologic explanation for duplication of
H.
52 Vanderbilt Avenue. New York, NY 10017 0149-936X/86/$3.50
MD, G.
COLEMAN,
MD
the inferior vena cava is that the left supracardinal vein persists as well as the normally persisting right supracardinal vein. The supracardinal venous system of the embryo contributes to the portion of the inferior vena(e) cava(e) inferior to the left renal vein. This is why the persistent left vena cava usually drains into the left renal vein. For the combined anomaly seen in the patient described here, both the subcardinal and the supracardinal venous systems of the embryo need to be anomalous in their development. Hence, the rarity of this combination is appreciated. With this combination of anomalies, blood from both inferior venae cavae drains into the azygos vein, which in turn drains into the superior vena cava. Only one similar case has been reported in the radiologic literature (6). To our knowledge, reports of only two other similar cases have been published, both autopsy studies from the World War II era without radiographic correlation (7, 8). However, both these cases differed from the present case in that they were associated with dextrocardia. One of these autopsy studies was marred by the fact that the thorax was opened first and part of the azygos system and its tributaries were removed before the subdiaphragmatic anomalies were realized (7). In the present case, the typical computed tomography (CT) features of this combination of anomalies are well demonstrated. CASE
From the Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Address reprint requests to: Peter H. Arger, MD, Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104. Received July 1985. 0 1986 by Elsevier Science Publishing Co., Inc.
ARGER,
BEVERLY
REPORT
A 59-year-old white woman presented with a Zmonth history of watery diarrhea. She had undergone subtotal adrenalectomy for Cushing’s disease 30 years earlier. Laboratory evaluation only revealed elevated serum gastrin values. An admitting chest radiograph was only remarkable for prominence of the azygos (Figure 1). A CT scan with con-
288
COSCINA
CT: THE JOURNAL OF COMPUTED
ET AL.
TOMOGRAPHY
VOL. 10 NO. 3
FIGURE 2. A CT scan obtained inferior to the left renal vein shows duplication of the inferior vena cava; Arrows = inferior vena cava; a = aorta.
FIGURE 1. Chest radiograph, posteroanterior view. Prominence of the azygos vein is identified [arrow).
3. A CT scan obtained at renal vein shows retroaortic crossing era1 inferior vena cava. a = aorta; renal vein; black arrow = vena cava
FIGURE
the level of the left to join the contralatwhite arrow = left confluence.
FIGURE 4. A CT scan obtained superior to the left renal vein shows an enlarged retrocrural azygos vein, which was continuous inferiorly with the inferior vena cava. (Hence, azygos continuation of the inferior vena cava.) The intrahepatic portion of the inferior vena cava is not present. (Hence hepatic interruption of the inferior vena cava.) Arrowhead = azygos vein; a = aorta.
1986
trast enhancement of a GE 9800 unit failed to demonstrate a pancreatic gastrinoma, but fortuitously did show duplication of the inferior vena cava associated with azygos continuation of the inferior vena cava (Figure 2). Incidentally, the left-sided inferior vena cava crossed retroaortic at the level of the left renal vein to join the right-sided inferior vena cava and form the azygos (Figs. 3, 4) DISCUSSION This case of azygos continuation of the inferior vena cava associated with duplication of the inferior vena cava is only the fourth to be reported in the world literature and only the second to be demonstrated roentgenographically. The first two cases, from the 194Os, were autopsies without radiographic correlation. Interestingly, these two early cases both differed from the present case in that they were associated with dextrocardia. Neither of these autopsy studies reported the position of the crossing of the left inferior vena cava to join the right, whether retroaortic or preaortic. Both the present case and the other more recent case are identical with levocardia and retroaortic crossing at the level of the left renal vein. A number of other combinations of anomalous venous structures have also been reported. Leftsided inferior vena cava has been reported with azygos continuation of the inferior vena cava in some cases (4, 9) and hemiazygos continuation in others (4, 10, ll), one of which emptied into the coronary sinus (11). Hence, a number of possible combinations of venous anomalies can exist. Although two cases of azygos continuation of the inferior vena cava with duplicated inferior vena cava have been reported with dextrocardia, to our knowledge there has been no report of association with or predisposition to more complex cardiac anomalies. The present case represents one of the rarest combinations of venous anomalies known. Any combination of venous anomalies that includes azygos or hemiazygos continuation of the inferior vena cava can be of great importance clinically. If right heart catheterization of pulmonary arteriography is attempted, unforeseen difficulties may be encountered. In patients undergoing upper abdominal or thoracic surgery, it is crucial that the surgeon be warned that the azygos vein cannot be clamped or sacrificed. Such patients usually do not have sufficient collaterals to acutely drain the venous return from the lower body if this occurs.
DUPLICATION-AZYGOUS
CONTINUATION
IVC
289
Therefore, it is important to recognize azygos continuation of the inferior vena cava radiologically. It is not certain whether the presence of duplicated inferior vena cava increases the risk of azygos continuation. At present, any patient noted to have one venous anomaly should carefully be examined for the presence of others. This approach will help safeguard against complications arising from procedures performed on patients harboring unrecognized venous anomalies.
REFERENCES 1. Mayo
vena
J, Robin
G, St. Louis
E, et al.: Anomalies
of the inferior
cava. AJR 1983;140:339-45.
2. Chuang VP, Mena CE, Haskins PA: Congenital the inferior vena cava. Review of embryogenesis tation of a simplified classification. Br J Radio1 13.
anomalies of and presen1974;47:206-
3. Royal SA, Callen PW: CT evaluation of anomalies of the inferior cava and left renal vein. AJR 1979;132:759--63. 4. Anderson RC, Adams P, Burke B: Anomalous inferior vena cava with azygos continuation (infrahepatic interruption of the inferior vena cava). J Pediatr 1961;59:370-83. 5. Milledge RD: Absence 1965;85:860-5. 6. Breckenridge inferior vena 1980;4:392-7.
of the inferior
vena
cava.
Radiology
JW, Kinlaw WB: Azygous continuation cava: CT appearance. J Comput Assist
of the Tomgr
7. Huseby RA, Boyden EA: Absence of the hepatic portion of the inferior vena cava with bilateral retention of the supracardinal system. Anat Ret 1941;81:537-44. a. Latimer inferior
HB, Virden HH: A case of complete absence vena cava. J Kansas Med Sot 1944;45:346.
of the
9. Floyd GD, Nelson WP: Developmental interruption of the inferior vena cava with azygos and hemiazygos substitution. 1976;119:55-7. Radiology DM, Berrigan TJ: Anomalous inferior 10. Haswell with accessory hemiazygos continuation. 1976;119:51-4. 11. Allen HA, Haney PJ: Left-sided iazygos continuation. J Comput
CONTINUING 1.
MEDICAL
inferior vena Assist Tomgr
EDUCATION
vena cava Radiology
cava with hem1981;5:917-20.
QUESTIONS
Azygos continuation of the inferior vena cava results from an anomaly of development of the: a. Vitelline vein. b. Supracardinal venous system. c. Subcardinal venous system. d. Umbilical vein.
2. Duplicated inferior vena cava arises from bilateral sistence of the: a. Vitelline vein. b. Supracardinal venous system. c. Subcardinal venous system. d. Umbilical vein.
per-
290
COSCINA
ET AL.
CT: THE JOURNAL OF COMPUTED
3. Knowledge of the presence of azygos continuation of the inferior vena cava can be especially ueful to the: a. Angiographer and neurosurgeon. b. Gastroenterologist and nephrologist. c. Angiographer and thoracic surgeon. d. Proctologist and dermatologist.
TOMOGRAPHY
VOL. 10 NO. 3
4. Concurrent duplication and azygos continuation inferior vena cava has been reported with: a. Dextrocardia. b. VSD. c. ASD. d. Coarctation of the aorta.
of the
OF COMPUTED
TOMOGRAPHY
1986;
10:287-290
287
(IICONCURRENT DUPLICATION AND AZYGOS CONTINUATION OF THE INFERIOR VENA CAVA WILLIAM MARSHALL
F.
COSCINA, C.
MINTZ,
MD,
PETER
MD,
AND
Duplication of the inferior vena cava and azygos continuation of the inferior vena cava arise from separate embryologic anlage. The former arises from persistence of both supracardinal veins and the latter from arrested development of the right subcardinal vein. Individually these entities are uncommon, but their occurrence together in one patient is exceedingly rare. A patient with both these anomalies of the venous system concurrently is described. This combination has been reported only once before in the radiologic literature. KEY WORDS:
Venous anomalies; Inferior vena cava; Azygos vein
Various anomalies of the major venous channels have been described and classified (l-5). The portion of the inferior vena cava from the level of the left renal vein to the right atrium is known to develop from the right subcardinal vein of the embryo. Azygos continuation of the inferior vena cava results from absence of the connection between the right subcardinal vein and the right atrium. This is termed hepatic interruption of the inferior vena cava. The inferior vena cava instead drains into the azygos vein, which continues cephalad to drain into the superior vena cava. The hepatic veins drain into the right atrium separate of the inferior vena cava. The embryologic explanation for duplication of
H.
52 Vanderbilt Avenue. New York, NY 10017 0149-936X/86/$3.50
MD, G.
COLEMAN,
MD
the inferior vena cava is that the left supracardinal vein persists as well as the normally persisting right supracardinal vein. The supracardinal venous system of the embryo contributes to the portion of the inferior vena(e) cava(e) inferior to the left renal vein. This is why the persistent left vena cava usually drains into the left renal vein. For the combined anomaly seen in the patient described here, both the subcardinal and the supracardinal venous systems of the embryo need to be anomalous in their development. Hence, the rarity of this combination is appreciated. With this combination of anomalies, blood from both inferior venae cavae drains into the azygos vein, which in turn drains into the superior vena cava. Only one similar case has been reported in the radiologic literature (6). To our knowledge, reports of only two other similar cases have been published, both autopsy studies from the World War II era without radiographic correlation (7, 8). However, both these cases differed from the present case in that they were associated with dextrocardia. One of these autopsy studies was marred by the fact that the thorax was opened first and part of the azygos system and its tributaries were removed before the subdiaphragmatic anomalies were realized (7). In the present case, the typical computed tomography (CT) features of this combination of anomalies are well demonstrated. CASE
From the Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Address reprint requests to: Peter H. Arger, MD, Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104. Received July 1985. 0 1986 by Elsevier Science Publishing Co., Inc.
ARGER,
BEVERLY
REPORT
A 59-year-old white woman presented with a Zmonth history of watery diarrhea. She had undergone subtotal adrenalectomy for Cushing’s disease 30 years earlier. Laboratory evaluation only revealed elevated serum gastrin values. An admitting chest radiograph was only remarkable for prominence of the azygos (Figure 1). A CT scan with con-
288
COSCINA
CT: THE JOURNAL OF COMPUTED
ET AL.
TOMOGRAPHY
VOL. 10 NO. 3
FIGURE 2. A CT scan obtained inferior to the left renal vein shows duplication of the inferior vena cava; Arrows = inferior vena cava; a = aorta.
FIGURE 1. Chest radiograph, posteroanterior view. Prominence of the azygos vein is identified [arrow).
3. A CT scan obtained at renal vein shows retroaortic crossing era1 inferior vena cava. a = aorta; renal vein; black arrow = vena cava
FIGURE
the level of the left to join the contralatwhite arrow = left confluence.
FIGURE 4. A CT scan obtained superior to the left renal vein shows an enlarged retrocrural azygos vein, which was continuous inferiorly with the inferior vena cava. (Hence, azygos continuation of the inferior vena cava.) The intrahepatic portion of the inferior vena cava is not present. (Hence hepatic interruption of the inferior vena cava.) Arrowhead = azygos vein; a = aorta.
1986
trast enhancement of a GE 9800 unit failed to demonstrate a pancreatic gastrinoma, but fortuitously did show duplication of the inferior vena cava associated with azygos continuation of the inferior vena cava (Figure 2). Incidentally, the left-sided inferior vena cava crossed retroaortic at the level of the left renal vein to join the right-sided inferior vena cava and form the azygos (Figs. 3, 4) DISCUSSION This case of azygos continuation of the inferior vena cava associated with duplication of the inferior vena cava is only the fourth to be reported in the world literature and only the second to be demonstrated roentgenographically. The first two cases, from the 194Os, were autopsies without radiographic correlation. Interestingly, these two early cases both differed from the present case in that they were associated with dextrocardia. Neither of these autopsy studies reported the position of the crossing of the left inferior vena cava to join the right, whether retroaortic or preaortic. Both the present case and the other more recent case are identical with levocardia and retroaortic crossing at the level of the left renal vein. A number of other combinations of anomalous venous structures have also been reported. Leftsided inferior vena cava has been reported with azygos continuation of the inferior vena cava in some cases (4, 9) and hemiazygos continuation in others (4, 10, ll), one of which emptied into the coronary sinus (11). Hence, a number of possible combinations of venous anomalies can exist. Although two cases of azygos continuation of the inferior vena cava with duplicated inferior vena cava have been reported with dextrocardia, to our knowledge there has been no report of association with or predisposition to more complex cardiac anomalies. The present case represents one of the rarest combinations of venous anomalies known. Any combination of venous anomalies that includes azygos or hemiazygos continuation of the inferior vena cava can be of great importance clinically. If right heart catheterization of pulmonary arteriography is attempted, unforeseen difficulties may be encountered. In patients undergoing upper abdominal or thoracic surgery, it is crucial that the surgeon be warned that the azygos vein cannot be clamped or sacrificed. Such patients usually do not have sufficient collaterals to acutely drain the venous return from the lower body if this occurs.
DUPLICATION-AZYGOUS
CONTINUATION
IVC
289
Therefore, it is important to recognize azygos continuation of the inferior vena cava radiologically. It is not certain whether the presence of duplicated inferior vena cava increases the risk of azygos continuation. At present, any patient noted to have one venous anomaly should carefully be examined for the presence of others. This approach will help safeguard against complications arising from procedures performed on patients harboring unrecognized venous anomalies.
REFERENCES 1. Mayo
vena
J, Robin
G, St. Louis
E, et al.: Anomalies
of the inferior
cava. AJR 1983;140:339-45.
2. Chuang VP, Mena CE, Haskins PA: Congenital the inferior vena cava. Review of embryogenesis tation of a simplified classification. Br J Radio1 13.
anomalies of and presen1974;47:206-
3. Royal SA, Callen PW: CT evaluation of anomalies of the inferior cava and left renal vein. AJR 1979;132:759--63. 4. Anderson RC, Adams P, Burke B: Anomalous inferior vena cava with azygos continuation (infrahepatic interruption of the inferior vena cava). J Pediatr 1961;59:370-83. 5. Milledge RD: Absence 1965;85:860-5. 6. Breckenridge inferior vena 1980;4:392-7.
of the inferior
vena
cava.
Radiology
JW, Kinlaw WB: Azygous continuation cava: CT appearance. J Comput Assist
of the Tomgr
7. Huseby RA, Boyden EA: Absence of the hepatic portion of the inferior vena cava with bilateral retention of the supracardinal system. Anat Ret 1941;81:537-44. a. Latimer inferior
HB, Virden HH: A case of complete absence vena cava. J Kansas Med Sot 1944;45:346.
of the
9. Floyd GD, Nelson WP: Developmental interruption of the inferior vena cava with azygos and hemiazygos substitution. 1976;119:55-7. Radiology DM, Berrigan TJ: Anomalous inferior 10. Haswell with accessory hemiazygos continuation. 1976;119:51-4. 11. Allen HA, Haney PJ: Left-sided iazygos continuation. J Comput
CONTINUING 1.
MEDICAL
inferior vena Assist Tomgr
EDUCATION
vena cava Radiology
cava with hem1981;5:917-20.
QUESTIONS
Azygos continuation of the inferior vena cava results from an anomaly of development of the: a. Vitelline vein. b. Supracardinal venous system. c. Subcardinal venous system. d. Umbilical vein.
2. Duplicated inferior vena cava arises from bilateral sistence of the: a. Vitelline vein. b. Supracardinal venous system. c. Subcardinal venous system. d. Umbilical vein.
per-
290
COSCINA
ET AL.
CT: THE JOURNAL OF COMPUTED
3. Knowledge of the presence of azygos continuation of the inferior vena cava can be especially ueful to the: a. Angiographer and neurosurgeon. b. Gastroenterologist and nephrologist. c. Angiographer and thoracic surgeon. d. Proctologist and dermatologist.
TOMOGRAPHY
VOL. 10 NO. 3
4. Concurrent duplication and azygos continuation inferior vena cava has been reported with: a. Dextrocardia. b. VSD. c. ASD. d. Coarctation of the aorta.
of the