The Blood Supply of Mediastinal Parathyroid Adenomas JOHN L. DOPPMAN, M.D.,* STEVEN J. MARX, M.D.,t MURRAY F. BRENNAN, M.D.,4 ROBERT M. BEAZLEY, M.D.,§ GLENN GEELHOED, M.D.,§ G. D. AURBACH, M.D.t
Arteriography for parathyroid localization following unsuccess- From the National Institutes of Health, Bethesda, Maryland ful neck surgery should include selective catheterization of the and The George Washington University Hospital, inferior thyroid and internal mammary arteries bilaterally. When Washington, D.C. the arterial supply to a mediastinal adenoma arises from the internal mammary artery, recovery from the neck may not be possible and an open mediastinal exploration (or embolization) is generally derived from one of two sources, the should be considered.
N OUR EXPERIENCE ,4'5'8 most enlarged parathyroid glands undetected at the initial operation will be found in the neck. In a previous series of 16 such patients reported from this institution,4'8 only one ectopic gland was found and this was posterior cervical. However, when parathyroid tissue is aberrant in location the
anterior superior mediastinum, particularly the substance of the thymus gland, is a frequent site. The majority of such glands can be removed through a cervical incision by pulling up the thymic fat pad. We agree with Scholz et al.7 that less than 2% of parathyroid adenomas will require a sternal splitting procedure although a much higher percentage (21% in the MGH series)6 may lie within the strict anatomic boundaries of the superior mediastinum. Recent experience suggests that arteriography can provide useful information to the surgeon planning a second operation that may require a mediastinal exploration. The arterial supply to mediastinal parathyroid glands
inferior thyroid artery or the internal mammary artery. Single arterial feeders are the rule although we have seen one exception (Fig. 1). Most commonly, the feeding artery arises as a branch from the caudal loop of the inferior thyroid artery and descends into the anterior mediastinum (Figs. 2a and b). Care must be taken in children not to misinterpret a normal thymic artery and stain (Fig. 3). It seems reasonable that when an adenoma hangs at the end of such a vascular pedicle, it should be pulled out of the anterior mediastinum with the fat pad provided it is not too deep and that previous surgery had not produced extensive scarring.
Submitted for publication December 29, 1975. Reprint requests: John L. Doppman, M.D., Bldg. 10, Rm. 6S211, National Institutes of Health, Bethesda, Maryland 20014. * Diagnostic Radiology Department, The Clinical Center. t Metabolic Diseases Branch, NIAMDD. t Department of Surgery, National Cancer Institute. National Institutes of Health, Bethesda, Maryland 20014. § Department of Surgery, George Washington University Hospital, Washington, D.C. Current address of Dr. Beazley: Louisiana State University, New Orleans, Louisiana.
488
FIG. 1. Cervico-mediastinal para-
thyroid adenoma with feeding arteries from both the inferior thyroid (large arrow) and intemal mammary (small arrows) arteries. Such a dual blood supply is unique in our experience.
Vol. 185
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BLOOD SUPPLY OF PARATHYROID ADENOMAS
489
FIGS. 2a and b. (left) Typical descending arterial supply (arrows) from inferior thyroid arteries to mediastinal parathyroid adenomas (arrowheads). (right) Patient on right had right thyroidectomy at first operation.
FIG. 3. A hyperplastic gland (large arrows) lying just below the left thyroid lobe was overlooked at initial exploration in this 11 year old girl with familial hyperparathyroidism. Note its blood supply arising from the caudal loop of the inferior thyroid artery. A large thymic branch (small arrows) from the inferior thyroid artery descends into the mediastinum to stain normal thymus (arrowheads) and could be confused with a mediastinal adenoma. This branch is never seen in adults.
However, in a significant percentage of cases the arterial supply originates from the internal mammary artery. We have not attempted to compute this incidence since our clinical series is so heavily biased towards repeat explorations. There is normally a thymic branch arising from the proximal internal mammary artery; it may in addition provide ascending branches to the thyroid isthmus (Fig. 4). We believe that when this vessel sup-
ua~~~~ ~~~~~~~~~... X
FIG. 4. Selective catheterization of thymic branch of internal mammary artery (small arrows) with thymic
staining
(lower
arrow
heads) and early venous drainage (large arrows). Note branch to thyroid isthmus (upper heads).
arrow
_
w
~~~~~~~~~~~~~~~~~~~
..,, ,W=...,W,~~~~~~~~
Ann. Surg. * April 1977
DOPPMAN AND OTHERS
490
FIG
a
a
.
a
a
i
e
s
wl lS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~f
iS/#EaL
w ,
s
4 E i sia':
e
t
h
b
h
h
e
m
A
FIGS. 5a to c. Mediastinal parathyroid adenoma supplied by the thymic branch of the internal mammary arteries.
plies a mediastinal gland it could exert a tethering effect which would resist extraction from above: in fact, attempts at such extraction might be hazardous. Probably more significant in accounting for the failure of extraction from above, however, is the absence of an ascending vascular pedicle. All three patients illustrated in Figs. 5a to c had undergone previous neck exploration with attempts to pull up as much thymic fat pad as possible. In all instances, the adenoma was left behind. The relatively high incidence of mediastinal adenomas with internal mammary4 as compared to the more common inferior thyroidal2 blood supply in our series of patients with previously unsuccessful parathyroid exploration suggests that the latter are being successfully retrieved at the initial cervical exploration. Therefore, when prior surgery has failed and an internal mammary blood supply has been identified, the surgeon should be alerted to the probable need for a direct mediastinal approach through the sternum, especially if the internal mammary branch is short. Another approach to this problem is transcatheter embolization which in our hands is proving to be effective treatment for mediastinal adenomas but long term analysis of results is still required.3
ADDENDUM: All patients illustrated in fig. 5 were treated by embolization through the catheter and all are euparathyroid up to 2 years postembolization.
References 1. Cope, 0. L.: Surgery of Hyperparathyroidism: The occurrence of Parathyroid in the Anterior Mediastinum and the Division of the Operation into two Stages. Ann. Surg., 114:4:706, 1941. 2. Doppman, J. L., Mallette, L. E., Marx, S. J., et al.: The Localization of Abnormal Mediastinal Parathyroid Glands. Radiology, 115:31, 1975. 3. Doppman, J. L., Marx, S. J., Spiegel, A. M., et al.: Treatment of Hyperparathyroidism by Percutaneous Embolization of a Mediastinal Adenoma. Radiology, 115:37, 1975. 4. Doppman, J. L., Wells, S. A., Shimkin, P. M., et al.: Parathyroid Localization by Angiographic Techniques in Patients with Previous Neck Surgery. Br. J. Radiol., 46:403, 1973. 5. Mallette, L. E., Bilezikian, J. P., Heath, D. A. and Aurbach, G. D.: Primary Hyperparathyroidism: Clinical and Biochemical Features. Medicine, 53:127, 1974. 6. Nathaniels, E. K., Nathaniels, A. M. and Wang, C. A.: Mediastinal Parathyroid Tumors: A Clinical and Pathological Study of 84 Cases. Ann. Surg. 171:2:165, 1970. 7. Scholz, D. A., Purnell, D. C., Woolner, L. B. and Clagett, 0. T.: Mediastinal Hyperfunctioning Parathyroid Tumors. Review of 14 cases. Ann. Surg., 178:2:173, 1973. 8. Wells, S. A., Doppman, J. L., Bilezikian, J. P., et al.: Repeated Neck Exploration in Primary Hyperparathyroidism: Localization of Abnormal Glands by Selective Thyroid Arteriography, Selective Venous Sampling and Radioimmunoassay. Surgery, 74:678, 1973.
Arteriography for parathyroid localization following unsuccess- From the National Institutes of Health, Bethesda, Maryland ful neck surgery should include selective catheterization of the and The George Washington University Hospital, inferior thyroid and internal mammary arteries bilaterally. When Washington, D.C. the arterial supply to a mediastinal adenoma arises from the internal mammary artery, recovery from the neck may not be possible and an open mediastinal exploration (or embolization) is generally derived from one of two sources, the should be considered.
N OUR EXPERIENCE ,4'5'8 most enlarged parathyroid glands undetected at the initial operation will be found in the neck. In a previous series of 16 such patients reported from this institution,4'8 only one ectopic gland was found and this was posterior cervical. However, when parathyroid tissue is aberrant in location the
anterior superior mediastinum, particularly the substance of the thymus gland, is a frequent site. The majority of such glands can be removed through a cervical incision by pulling up the thymic fat pad. We agree with Scholz et al.7 that less than 2% of parathyroid adenomas will require a sternal splitting procedure although a much higher percentage (21% in the MGH series)6 may lie within the strict anatomic boundaries of the superior mediastinum. Recent experience suggests that arteriography can provide useful information to the surgeon planning a second operation that may require a mediastinal exploration. The arterial supply to mediastinal parathyroid glands
inferior thyroid artery or the internal mammary artery. Single arterial feeders are the rule although we have seen one exception (Fig. 1). Most commonly, the feeding artery arises as a branch from the caudal loop of the inferior thyroid artery and descends into the anterior mediastinum (Figs. 2a and b). Care must be taken in children not to misinterpret a normal thymic artery and stain (Fig. 3). It seems reasonable that when an adenoma hangs at the end of such a vascular pedicle, it should be pulled out of the anterior mediastinum with the fat pad provided it is not too deep and that previous surgery had not produced extensive scarring.
Submitted for publication December 29, 1975. Reprint requests: John L. Doppman, M.D., Bldg. 10, Rm. 6S211, National Institutes of Health, Bethesda, Maryland 20014. * Diagnostic Radiology Department, The Clinical Center. t Metabolic Diseases Branch, NIAMDD. t Department of Surgery, National Cancer Institute. National Institutes of Health, Bethesda, Maryland 20014. § Department of Surgery, George Washington University Hospital, Washington, D.C. Current address of Dr. Beazley: Louisiana State University, New Orleans, Louisiana.
488
FIG. 1. Cervico-mediastinal para-
thyroid adenoma with feeding arteries from both the inferior thyroid (large arrow) and intemal mammary (small arrows) arteries. Such a dual blood supply is unique in our experience.
Vol. 185
. No.
4
BLOOD SUPPLY OF PARATHYROID ADENOMAS
489
FIGS. 2a and b. (left) Typical descending arterial supply (arrows) from inferior thyroid arteries to mediastinal parathyroid adenomas (arrowheads). (right) Patient on right had right thyroidectomy at first operation.
FIG. 3. A hyperplastic gland (large arrows) lying just below the left thyroid lobe was overlooked at initial exploration in this 11 year old girl with familial hyperparathyroidism. Note its blood supply arising from the caudal loop of the inferior thyroid artery. A large thymic branch (small arrows) from the inferior thyroid artery descends into the mediastinum to stain normal thymus (arrowheads) and could be confused with a mediastinal adenoma. This branch is never seen in adults.
However, in a significant percentage of cases the arterial supply originates from the internal mammary artery. We have not attempted to compute this incidence since our clinical series is so heavily biased towards repeat explorations. There is normally a thymic branch arising from the proximal internal mammary artery; it may in addition provide ascending branches to the thyroid isthmus (Fig. 4). We believe that when this vessel sup-
ua~~~~ ~~~~~~~~~... X
FIG. 4. Selective catheterization of thymic branch of internal mammary artery (small arrows) with thymic
staining
(lower
arrow
heads) and early venous drainage (large arrows). Note branch to thyroid isthmus (upper heads).
arrow
_
w
~~~~~~~~~~~~~~~~~~~
..,, ,W=...,W,~~~~~~~~
Ann. Surg. * April 1977
DOPPMAN AND OTHERS
490
FIG
a
a
.
a
a
i
e
s
wl lS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~f
iS/#EaL
w ,
s
4 E i sia':
e
t
h
b
h
h
e
m
A
FIGS. 5a to c. Mediastinal parathyroid adenoma supplied by the thymic branch of the internal mammary arteries.
plies a mediastinal gland it could exert a tethering effect which would resist extraction from above: in fact, attempts at such extraction might be hazardous. Probably more significant in accounting for the failure of extraction from above, however, is the absence of an ascending vascular pedicle. All three patients illustrated in Figs. 5a to c had undergone previous neck exploration with attempts to pull up as much thymic fat pad as possible. In all instances, the adenoma was left behind. The relatively high incidence of mediastinal adenomas with internal mammary4 as compared to the more common inferior thyroidal2 blood supply in our series of patients with previously unsuccessful parathyroid exploration suggests that the latter are being successfully retrieved at the initial cervical exploration. Therefore, when prior surgery has failed and an internal mammary blood supply has been identified, the surgeon should be alerted to the probable need for a direct mediastinal approach through the sternum, especially if the internal mammary branch is short. Another approach to this problem is transcatheter embolization which in our hands is proving to be effective treatment for mediastinal adenomas but long term analysis of results is still required.3
ADDENDUM: All patients illustrated in fig. 5 were treated by embolization through the catheter and all are euparathyroid up to 2 years postembolization.
References 1. Cope, 0. L.: Surgery of Hyperparathyroidism: The occurrence of Parathyroid in the Anterior Mediastinum and the Division of the Operation into two Stages. Ann. Surg., 114:4:706, 1941. 2. Doppman, J. L., Mallette, L. E., Marx, S. J., et al.: The Localization of Abnormal Mediastinal Parathyroid Glands. Radiology, 115:31, 1975. 3. Doppman, J. L., Marx, S. J., Spiegel, A. M., et al.: Treatment of Hyperparathyroidism by Percutaneous Embolization of a Mediastinal Adenoma. Radiology, 115:37, 1975. 4. Doppman, J. L., Wells, S. A., Shimkin, P. M., et al.: Parathyroid Localization by Angiographic Techniques in Patients with Previous Neck Surgery. Br. J. Radiol., 46:403, 1973. 5. Mallette, L. E., Bilezikian, J. P., Heath, D. A. and Aurbach, G. D.: Primary Hyperparathyroidism: Clinical and Biochemical Features. Medicine, 53:127, 1974. 6. Nathaniels, E. K., Nathaniels, A. M. and Wang, C. A.: Mediastinal Parathyroid Tumors: A Clinical and Pathological Study of 84 Cases. Ann. Surg. 171:2:165, 1970. 7. Scholz, D. A., Purnell, D. C., Woolner, L. B. and Clagett, 0. T.: Mediastinal Hyperfunctioning Parathyroid Tumors. Review of 14 cases. Ann. Surg., 178:2:173, 1973. 8. Wells, S. A., Doppman, J. L., Bilezikian, J. P., et al.: Repeated Neck Exploration in Primary Hyperparathyroidism: Localization of Abnormal Glands by Selective Thyroid Arteriography, Selective Venous Sampling and Radioimmunoassay. Surgery, 74:678, 1973.
