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Ectopic Thyroid Tissue Causing Bronchial Obstruction
CASE REPORTS Ectopic Thyroid Tissue Causing Bronchial Obstruction Irene 0. Gleason, M.D., Timothy T. Tildon, M.D.,
and Victor J. Kosen, M.D.
E
ctopic thyroid tissue may develop in various positions from the base of the tongue to the porta hepatis. T h e sites have been lingual, suprahyoid, infrahyoid, laryngeal, intratracheal, intraesophageal, mediastinal, aortic, pericardial, cardiac, and hepatic. In the following unusual case normal thyroid tissue was found obstructing the lumen of the right upper lobe bronchus. A 33-year-old man was admitted for schizophrenia in 1961. Review of a thoracic roentgenogram taken two years before revealed nodular calcifications in the right peritracheal region and right hilum. Physical examination and laboratory tests were unremarkable. Skin tests for histoplasmosis and tuberculosis were positive. He had several episodes of pneumonitis of the right upper lobe beginning in 1962 and later developed lobar atelectasis. In 1965 an intraluminal mass was seen in a bronchogram of the right upper lobe (Fig. 1). A thoracotomy was performed. Calcified, hard lymph nodes were noted in the hilus of the lung and the subcarinal area. Atelectasis of the right upper lobe was thought to be due to a broncholith. The right upper lobe was resected. Three millimeters from the line of resection, attached to the inferior wall of the bronchus and occluding the lumen, was a pink-white pedunculated nodule measuring 1 cm. in diameter. The mucosal surface was smooth. On section, the tumor was sharply circumscribed and encapsulated. Microscopically, it was composed of normal-appearing thyroid follicles (Fig. 2) containing abundant eosinophilic colloid. Cuboidal to low columnar cells lined the follicles. The lung parenchyma revealed focal chronic pneumonitis, patchy pulmonary fibrosis, and emphysema. The hilar lymph nodes were focally caseous and partially calcified. A Grocott stain of the granulomata revealed Histoplasma capsulatum. No thyroid tissue was seen in these lymph nodes. From the Departments of Pathology and Thoracic Surgery, Wadsworth Hospital, Veterans Administration Center, L o s Angeles, and the Department of Surgery, The University of California at Los Angeles School of Medicine, Los Angeles, Calif. Accepted for publication Aug. 25, 1966.
VOL.
3,
NO. 2, FEB.,
1967
151
GLEASON, TILDON, AND ROSEN
FIG. 1. Bronchogram showing a mass obstructing the right upper lobe bronchus.
Six months after bronchogram and lobectomy a scan of the neck and chest was done with observation of I131 uptake. T h e thyroid gland appeared normal in size and configuration. No extrathyroidal uptake of I131 was observed, and n o functioning aberrant tissue was identified. DISCUSSION
Misplaced thyroid tissue in the mediastinum, wall of aorta, pericardium, heart, and porta hepatis is thought to be due to the closeness of the thyroid anlage to the developing heart and great vessels as the
F I G . 2. Photomicrograph showing bronchial lumen reduted to a cleft by ectopic thyroid tissue. x80.
152
THE ANNALS OF THORACIC SURGERY
CASE REPORT:
Bronchial Obstruction by Thyroid Tissue
thyroid descends from the pharynx into the neck. T h e thyroid is incorporated into these structures if they fail to separate as they descend into the mediastinum. Early embryonic scattering of thyroid epithelium, before the division of the common body cavity by formation of the diaphragm, is thought to produce accessory thyroid in the porta hepatis [ 11. Still another theory for abnormal positions of the thyroid beyond the neck is overmigration. Since ectopic thyroid tissue has not been found in the bronchus before, it is difficult to know how it got there. Perhaps one or more of the above theories are applicable. SUMMARY
An unusual and perhaps the first case of ectopic thyroid tissue obstructing a bronchus is reported. Pneumonia and atelectasis resulted, and right upper lobectomy was performed. REFERENCE 1. Von Schubert, W. Uber eine Akzessorische Schilddruse in der Leberforte. Zbl. Allg. Path. 96~339,1957.
VOL.
3,
NO. 2, FEB.,
1967
153
and Victor J. Kosen, M.D.
E
ctopic thyroid tissue may develop in various positions from the base of the tongue to the porta hepatis. T h e sites have been lingual, suprahyoid, infrahyoid, laryngeal, intratracheal, intraesophageal, mediastinal, aortic, pericardial, cardiac, and hepatic. In the following unusual case normal thyroid tissue was found obstructing the lumen of the right upper lobe bronchus. A 33-year-old man was admitted for schizophrenia in 1961. Review of a thoracic roentgenogram taken two years before revealed nodular calcifications in the right peritracheal region and right hilum. Physical examination and laboratory tests were unremarkable. Skin tests for histoplasmosis and tuberculosis were positive. He had several episodes of pneumonitis of the right upper lobe beginning in 1962 and later developed lobar atelectasis. In 1965 an intraluminal mass was seen in a bronchogram of the right upper lobe (Fig. 1). A thoracotomy was performed. Calcified, hard lymph nodes were noted in the hilus of the lung and the subcarinal area. Atelectasis of the right upper lobe was thought to be due to a broncholith. The right upper lobe was resected. Three millimeters from the line of resection, attached to the inferior wall of the bronchus and occluding the lumen, was a pink-white pedunculated nodule measuring 1 cm. in diameter. The mucosal surface was smooth. On section, the tumor was sharply circumscribed and encapsulated. Microscopically, it was composed of normal-appearing thyroid follicles (Fig. 2) containing abundant eosinophilic colloid. Cuboidal to low columnar cells lined the follicles. The lung parenchyma revealed focal chronic pneumonitis, patchy pulmonary fibrosis, and emphysema. The hilar lymph nodes were focally caseous and partially calcified. A Grocott stain of the granulomata revealed Histoplasma capsulatum. No thyroid tissue was seen in these lymph nodes. From the Departments of Pathology and Thoracic Surgery, Wadsworth Hospital, Veterans Administration Center, L o s Angeles, and the Department of Surgery, The University of California at Los Angeles School of Medicine, Los Angeles, Calif. Accepted for publication Aug. 25, 1966.
VOL.
3,
NO. 2, FEB.,
1967
151
GLEASON, TILDON, AND ROSEN
FIG. 1. Bronchogram showing a mass obstructing the right upper lobe bronchus.
Six months after bronchogram and lobectomy a scan of the neck and chest was done with observation of I131 uptake. T h e thyroid gland appeared normal in size and configuration. No extrathyroidal uptake of I131 was observed, and n o functioning aberrant tissue was identified. DISCUSSION
Misplaced thyroid tissue in the mediastinum, wall of aorta, pericardium, heart, and porta hepatis is thought to be due to the closeness of the thyroid anlage to the developing heart and great vessels as the
F I G . 2. Photomicrograph showing bronchial lumen reduted to a cleft by ectopic thyroid tissue. x80.
152
THE ANNALS OF THORACIC SURGERY
CASE REPORT:
Bronchial Obstruction by Thyroid Tissue
thyroid descends from the pharynx into the neck. T h e thyroid is incorporated into these structures if they fail to separate as they descend into the mediastinum. Early embryonic scattering of thyroid epithelium, before the division of the common body cavity by formation of the diaphragm, is thought to produce accessory thyroid in the porta hepatis [ 11. Still another theory for abnormal positions of the thyroid beyond the neck is overmigration. Since ectopic thyroid tissue has not been found in the bronchus before, it is difficult to know how it got there. Perhaps one or more of the above theories are applicable. SUMMARY
An unusual and perhaps the first case of ectopic thyroid tissue obstructing a bronchus is reported. Pneumonia and atelectasis resulted, and right upper lobectomy was performed. REFERENCE 1. Von Schubert, W. Uber eine Akzessorische Schilddruse in der Leberforte. Zbl. Allg. Path. 96~339,1957.
VOL.
3,
NO. 2, FEB.,
1967
153