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Surgical Correction of Complete Lingual Ectopia of the Thyroid Gland
Surgical Correction of Complete Lingual Ectopia of the Thyroid Gland OSMAR P. STEINWALD, JR., M.D.* ROBERT C. MUEHRCKE, M.D.** STEVEN G. ECONOMOU, M.D.***
Complete lingual ectopia of the thyroid gland occurs uncommonly. When it becomes necessary to correct this interesting condition a number of factors must be considered and several problems overcome if one is to realize a successful outcome. It is the purpose of this paper to present such an instance. A midline mass located at the base of the tongue should alert the observer of the possibility that this might be thyroid tissue. Often the mass is asymptomatic, but in some instances it may be sufficiently large or so placed as to interfere with deglutition or respiration. Dysarthria may also be attributable to this type of lesion. While diagnosis may be suspected by clinical observation, it should always be confirmed by scanning of the neck and tongue area after the ingestion of radioactive iodine (1 31 1). Such scanning determines whether there is functional thyroid tissue in the tongue mass as well as in the orthotopic thyroid site. If there is no thyroid tissue present in the neck on scanning, and the posterior tongue mass is shown to contain functional thyroid tissue, then the diagnosis of complete ectopia of the thyroid gland is confirmed.
THERAPY It would be a serious error ever to excise a mass in this location in the tongue without first excluding the possibility of its being thyroid From the Division of Surgery and the Division of Medicine, Rush Presbyterian-St. Luke's Medical Center, Chicago, Illinois, in affiliation with the University of Illinois College of Medicine '''Adjunct Surgeon, Rush Presbyterian-St. Luke's Medical Center; Clinical Instructor in Surgery, University of Illinois College of Medicine ''''Director of Medical Education, West Suburban Hospital, Oak Park, Illinois; Associate Professor of Medicine, University of Illinois College of Medicine ''"''''Attending Surgeon, Rush Presbyterian-St. Luke's Medical Center; Clinical Professor of Surgery, University of Illinois College of Medicine, Chicago, Illinois
Surgical Clinics of North America- Vol. 50, No. 5, October, 1970
1177
1178
OSMAR
P.
STEINWALD, JR., ROBERT C. MUEHRCKE, STEVEN
G.
EcoNOMOU
tissue. If there is thyroid tissue in both the lingual and orthotopic sites, there has been less concern about excising the symptomatic lingual mass. This attitude is not warranted in view of the availability of a successful method of preserving the lingual thyroid tissue. The exception would be the instance where the lingual mass is minute and its endocrine role inconsequential. Of course, it is unlikely that under such circumstances the mass would be symptomatic. Finally there is the rare instance when the lingual thyroid may be malignant.U The difficult problem is how best to treat the symptomatic lingual mass when it represents the only functional thyroid tissue in a patient. The lingual mass may be excised and the patient placed on oral thyroid medication; this is hardly satisfactory in the face of better alternatives. Likewise, the ectopic thyroid may be ablated with a therapeutic dose of 131 I, only for the patient to remain on thyroid hormone replacement therapy for life. With such therapy to the young female there is the added risk of ovarian damage. The lingual thyroid may be excised totally and heterotopically autotransplanted into other areas. There is a variable delay period between transplantation and function of the grafted thyroid tissue in addition to the considerable risk of nonviability or non-function of such completely transposed thyroid tissue. Heterotopic autotransplantation of the ectopic mass while maintaining continuity of the blood supply seems to be the most logical solution. This technique, combined with autografting of a section of the thyroid tissue into other areas, has been successfully employed once before on a 2 year old infant. 9 A similar approach to this problem is presented here in a 9 year old child.
CASE REPORT HISTORY AND PHYSICAL EXAMINATION. The patient, a 9 year old Caucasian girl, was admitted to the hospital with complaints of dysphagia and recurring sore throats. The parents reported stridor of increasing severity when the child was sleeping. The child was not aware of a mass in her throat or mouth. She was born of an uneventful pregnancy. Growth and development were normal, with no history suggestive of thyroid dysfunction. The patient denied frequent tonsillar infections. There was no family history of thyroid disease or abnormality. On physical examination the patient was alert and her vital signs were within normal limits. Her weight was 56 lb. (25.4 kg.) and height 50 inches (127 em.). On inspection of the oral cavity, a 2 em. dark red mass was seen arising from the midline of the tongue in the area of the foramen cecum (Fig. 1). The mass deviated slightly to the right and had an epithelial covering which appeared identical to that of the tongue. It was rubbery in consistency. The throat was not inflamed. There was no lymphoid hyperplasia; the tonsils were of normal size and appearance. The thyroid gland was not palpable in the usual position. The remainder of the physical examination was within normal limits. The results of the laboratory tests were as follows: protein-bound iodine, 4.7 micrograms, calcium, 9.7 mg., phosphorous, 4.3 mg. and
COMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1179
Figure 1. Photograph showing ectopic lingual thyroid in the vicinity of the foramen cecum.
cholesterol, 178 mg. per 100 ml. Lipid partition values were within limits of normal. Posteroanterior and lateral x-ray films of the neck and chest revealed no abnormalities. The patient was given the calculated tracer dose of 131 1 for scanning, which was 29.9 me. The anteroposterior and lateral isotope scans are shown (Fig. 2). The scans revealed functional thyroid tissue to be located only in the area of the lingual mass. No orthotopic functional thyroid tissue was noted. The conclusion was that the patient had complete ectopia of the thyroid gland. OPERATION. The patient was taken to the operating room; under general anesthesia with nasotracheal intubation the neck was extended. The skin of the neck and all of the torso was prepared and the areas draped. A 6-cm. transverse suprahyoid incision was made through the skin and platysma muscle (Fig. 3). The anterior bellies of the digastric muscles were retracted laterally. Most of the fibers of the mylohyoid and geniohyoid muscles were divided, and the lingual arteries were retracted laterally. Hemostasis was maintained with particular care so as to have an especially clear operative field by digital pressure from within the patient's mouth. The middle half of the mass was excised longitudinally with the overlying tongue epithelium-the oral cavity being entered with this incision. The excised mass appeared cystic in one area, was pink-tan in color, and was somewhat friable. A representative section was sent for microscopic study of a frozen section, and it was shown to be colloid goiter. The excised tissue, which grossly appeared to be thyroid, was sliced into sections 1 to 2 mm. thick and immediately placed as free autologous grafts into previously prepared
1180 OsMAR P.
STEINWALD,
]R., RoBERT C. MuEHRCKE, STEVEN G. EcoNOMOU
~L~~~\ Y)
~
)
L~.~j
Figure 2. Preoperative lateral and anteroposterior isotope scans of the pharynx following oral administration of 131 1. The scan is superimposed on line drawings of the patient's head. There is obvious uptake of '"I over the area of the lingual mass.
sites in pectoralis major and supra-umbilical rectus abdominis muscles bilaterally. The grafts were placed within the muscles by using blunt retraction of the fibers, as described by others. A few drops of a solution containing 500 mg. tetracycline in 250 cc. physiological saline were placed over the graft areas on the left side prior to closure of the wounds. No such solution was used on the right side. In addition a portion of the tissue was placed in the subcutaneous fat in the left inguinal area with the intention of excising a portion of it at a later date_ Approximately 3 minutes elapsed between excision of a portion of the lingual mass and the placement of the free grafts. The graft incisions were closed in layers and attention was returned to the neck incision. Using sharp dissection, each of the remaining lateral thyroid masses was separated from the overlying tongue epithelium, taking special care to maintain contiguous attachment of the thyroid to the lateral tissues. The masses were then rotated laterally and inferiorly from the oral cavity and secured in their new submandibular positions_ The H-shaped tongue opening was closed with interrupted 4-0 chromic catgut. A small soft rubber drain was exteriorized through the left lateral aspect of the incision and the neck wound closed in layers. Because of the manipulation of the base of the tongue and the possible obstructive edema or impairment of the patient's ability to expel mucus, a prophylactic tracheostomy was performed. The trachea came into view immediately and only fibrous tissue could be seen in the area normally occupied by the isthmus and the ventral portions of the thyroid lobes. The patient
COMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1181
Figure 3. Operative steps in developing pedicle grafts which contain lingual thyroid (insert). A, Transverse suprahyoid invasion with or without splitting of hyoid bone. B, Anterior bellies of digastric muscle retracted laterally and most of fibers of mylohyoid and geniohyoid muscles divided. The fibers of the genioglossous muscle are divided until the lingual mass is reached. C, The oral cavity is entered anterior to the mass. D, It is next bisected longitudinally and followed by completion of the H-shaped incision (dotted line). E, The pedicles have been developed. F, Separation of tongue epithelium from underlying closely adherent thyroid. G, Closure of H-shaped incision; lingual pedicles with associated thyroid tissue swung laterally to submandibular positions.
1182
OSMAR
P.
STEINWALD, JR., ROBERT C. MUEHRCKE, STEVEN
G.
ECONOMOU
tolerated the procedure well. Photomicrographs show various portions of the excised tissue (Fig. 4). There were no postoperative complications or unusual occurrences. The patient received penicillin and streptomycin postoperatively. The tracheostomy tube was removed on the third postoperative day and intravenous infusions were stopped on the fourth day after surgery. The patient was discharged from the hospital on the eighth day with all wounds healing well. Speech, swallowing, taste, and respiration were normal, as was tongue strength and sensation. No lingual mass was noted on oral inspection. There were no signs of symptoms of hypothyroidism, and accordingly the patient was discharged without medication. Three months later the patient retumed for re-evaluation. She was asymptomatic and clinically euthyroid. A second radioactive iodine scan was performed following a tracer dose of 131 !. The thyroid tissue placed in the submandibular areas on pedicles and three of the five free grafts were shown to be functional (Figs. 5 and 6). Seven months later a biopsy was performed of the free graft in the left lower quadrant (Fig. 7). At this time the posterior tongue appeared normal (Fig. 8). A tonsillectomy had been performed several years previously. Five years following the original operation the patient was clinically asymptomatic.
Figure 4. A, Photomicrograph of biopsy specimen of lingual thyroid. One surface (top) is covered by stratified squamous epithelium. In the underlying stroma there are several mucus glands and numerous irregular acini that vary in size and shape and are filled with eosinophilic colloid. B, The follicles are lined by a single layer of flattened cuboidal epithelium. There is no partition between the colloid filled acini and the adjacent striated muscle.
COMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1183
Figure 5. Anteroposterior and lateral isotope scans of the neck, performed approximately three months postoperatively and superimposed on line drawings of the patient's head. Thyroid tissue is now in both submandibular areas.
Figure 6. This composite illustration shows the uptake of a tracer dose of "''I by three of the five free grafts. The grafts placed in the pectoral areas do not show evidence of thyroid activity.
1184
OSMAR
P.
STEINWALD, JR., ROBERT
C.
MUEHRCKE, STEVEN
G.
EcONOMOU
Figure 7. (Left) Photomicrograph of the thyroid tissue biopsy which was transplanted subcutaneously in the left lower quadrant seven months previously. (Right) Electron microphotograph of same biopsy. Villi (VI) are seen projecting into lumen (L), containing colloid material. The cell contains numerous mitochondria, dark secretory granules (G), and vacuoles (VA). These cellular changes indicate metabolic and secretory activity. (Uranyl acetate X21,585)
Figure 8. Photograph taken seven months postoperatively showing the posterior tongue at the previous site of the ectopic thyroid to be normal in appearance. The tonsils are somewhat enlarged.
CoMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1185
DISCUSSION The procedure described is a satisfactory approach to the problem of complete or even incomplete lingual ectopia of the thyroid gland. By maintaining a blood supply to functional tissue the chance of losing the only available thyroid tissue is minimized. There should also be less difficulty with the usual waiting period for free autologous thyroid grafts to function. Apparently, in free grafting, thyroid tissue may not function for a varying period of time. 2· 10 The method of free implantation of thin strips of thyroid tissue into muscle has achieved the best functional result in experimental animals and in man. 3 • 4 • 5 • 6 This method has been a satisfactory adjuvant in this patient. Multiple sites were chosen for graft placement to increase the probability of achieving functional thyroid tissue. Reportedly exogenous thyroid medication should not be given preoperatively or postoperatively for fear of suppressing endogenous thyrotropic hormone production by the pituitary which may, in turn, impair the "take" and function of the free autografts.2· 11 A direct analogy, however, to Halsted's original investigation regarding increased acceptance of parathyroid grafts in patients not receiving parathormone 1 has not been established. The value of instilling a saline solution containing an antibiotic (tetracycline) into half the graft sites is unknown, because no site became infected and there was no obvious relationship to successful function of the grafts. Such use of antibiotics is somewhat arbitrary, but is justified by the fact that in securing the specimen for grafting, the oral cavity was opened and the grafts potentially contaminated. The hyoid bone may be divided in the midline to achieve better exposure without fear of untoward sequelae. Division was not necessary in this patient. Entering the oral cavity with the H-shaped incision allows for displacement into the wound of pedicles of tongue with attached thyroid. This allows for accurate and simple dissection of the closely adherent epithelium from the underlying thyroid tissue. Certainly, an inadequate dissection at this point which left behind any sizable amount of thyroid tissue might result in hyperplasia of this remnant. Such hyperplasia of residual tissue might be more likely if there was only free heterotopic autografting and these grafts did not function. Despite these considerations and the fact that our patient who was so treated did exceptionally well postoperatively, it is still probably best to use a technique not involving entry into the oral cavity. This can be achieved by using the intraoral finger as a guide to the depth of the tongue incision from the inside. Once a beginning has been made the dissection becomes easier. Although at the conclusion of such a dissection only thin epithelium separates the oral cavity from the operative field, it is preferable to having to close an H-shaped incision in this precarious tissue. Continued maintenance of hemostasis cannot be overemphasized in this highly vascular area. Care must also be used in handling the thyroid tissue itself because it is quite friable and liable to irreversible damage with rather minimal trauma.
1186
OSMAR
P.
STEINWALD, JR., ROBERT
C.
MUEHRCKE, STEVEN
G.
ECONOMOU
Tracheostomy was performed as a prophylactic measure with concern for postoperative edema and consequent airway obstruction. Although the prophylactic tracheostomy was probably not required in this patient, the procedure should be considered. In the immediate postoperative period, a clear airway should be of primary concern. The patient should be watched postoperatively and at regular intervals for some period thereafter for signs and symptoms of hypothyroidism. Whether the transplanted tissue in this patient will be capable of meeting the increased demands of thyroid hormone during adulthood and possible pregnancy remains to be seen. Parathyroid tetany as a complication is not to be expected because of different embryological anlage and migratory patterns of the parathyroid glands.
CONCLUSION The case of a symptomatic lingual mass representing complete lingual ectopia of the thyroid gland is presented. Free autologous thyroid grafts into muscle, and transposition of functional thyroid tissue in continuity with the blood supply as pedicle grafts bilaterally, has been successful in treating this condition in a 9 year old child. The patient continued to remain asymptomatic and euthyroid 5 years after the operation. The uncommon occurrence of symptomatic complete lingual ectopia of the thyroid gland and the simplicity and apparent success of the operation used to correct it, prompted the report of this unusual case.
REFERENCES 1. Halsted, W. S.: Auto- and isotransplantation, in dogs, of the parathyroid glandules. J. Exper. Med., 11:175, 1909. 2. Jones, P.: Autotransplantation in lingual ectopia of the thyroid gland. Arch. Dis. Child., 36:164, 1961. 3. Knake, E.: Studies on autografts of rabbit thyroid: their possible applicability to man. Transplant Bull., 4:136, 1957. 4. Lawson, R. S.: Case of lingual thyroid with successful grafting after operative removal. Aust. -New Zealand J. Surg., 26:241, 1957. 5. Liddle, E. B., Wittenstein, G. J., and Swan, H.: Studies on autotransplantation of thyroid and adrenal gland in dogs. S. Forum, 4:701, 1953. 6. Low, H. B. C., and Helmus, C.: Thyroid grafts. Arch. Surg., 83:767, 1961. 7. Montgomery, M. L.: Lingual thyroid: A comprehensive review. West. J. Surg., 43:661, 1935. 8. Nachman, H., Crawford, V., and Bigger, I. A.: Radioactive iodine in the diagnosis of lingual thyroid, J.A.M.A., 140:1154, 1949. 9. Skolnick, E. M., Newell, K. C., Rosenthal, I. M., and Webb, R. S.: Autotransplantation in lingual ectopia of the thyroid gland. Arch. Otolaryngol., 78:187, 1963. 10. Swan, H., Jenkins, D., and MacGregor, C.: Autotransplantation of the lingual thyroid. Arch. Surg., 76:458, 1958. 11. Swan, H., Harper, F., and Christensen, S. P.: Autotransplantation of thyroid tissue in treatment of lingual thyroid. Surg., 32:298, 1952. 12. Ward, G. E., Cantrell, J. R., Allan, W. B.: The surgical treatment of lingual thyroid, Ann. Surg., 139:536, 1954. Rush Presbyterian-St. Luke's Medical Center 1753 West Congress Parkway Chicago, Illinois 60612
Complete lingual ectopia of the thyroid gland occurs uncommonly. When it becomes necessary to correct this interesting condition a number of factors must be considered and several problems overcome if one is to realize a successful outcome. It is the purpose of this paper to present such an instance. A midline mass located at the base of the tongue should alert the observer of the possibility that this might be thyroid tissue. Often the mass is asymptomatic, but in some instances it may be sufficiently large or so placed as to interfere with deglutition or respiration. Dysarthria may also be attributable to this type of lesion. While diagnosis may be suspected by clinical observation, it should always be confirmed by scanning of the neck and tongue area after the ingestion of radioactive iodine (1 31 1). Such scanning determines whether there is functional thyroid tissue in the tongue mass as well as in the orthotopic thyroid site. If there is no thyroid tissue present in the neck on scanning, and the posterior tongue mass is shown to contain functional thyroid tissue, then the diagnosis of complete ectopia of the thyroid gland is confirmed.
THERAPY It would be a serious error ever to excise a mass in this location in the tongue without first excluding the possibility of its being thyroid From the Division of Surgery and the Division of Medicine, Rush Presbyterian-St. Luke's Medical Center, Chicago, Illinois, in affiliation with the University of Illinois College of Medicine '''Adjunct Surgeon, Rush Presbyterian-St. Luke's Medical Center; Clinical Instructor in Surgery, University of Illinois College of Medicine ''''Director of Medical Education, West Suburban Hospital, Oak Park, Illinois; Associate Professor of Medicine, University of Illinois College of Medicine ''"''''Attending Surgeon, Rush Presbyterian-St. Luke's Medical Center; Clinical Professor of Surgery, University of Illinois College of Medicine, Chicago, Illinois
Surgical Clinics of North America- Vol. 50, No. 5, October, 1970
1177
1178
OSMAR
P.
STEINWALD, JR., ROBERT C. MUEHRCKE, STEVEN
G.
EcoNOMOU
tissue. If there is thyroid tissue in both the lingual and orthotopic sites, there has been less concern about excising the symptomatic lingual mass. This attitude is not warranted in view of the availability of a successful method of preserving the lingual thyroid tissue. The exception would be the instance where the lingual mass is minute and its endocrine role inconsequential. Of course, it is unlikely that under such circumstances the mass would be symptomatic. Finally there is the rare instance when the lingual thyroid may be malignant.U The difficult problem is how best to treat the symptomatic lingual mass when it represents the only functional thyroid tissue in a patient. The lingual mass may be excised and the patient placed on oral thyroid medication; this is hardly satisfactory in the face of better alternatives. Likewise, the ectopic thyroid may be ablated with a therapeutic dose of 131 I, only for the patient to remain on thyroid hormone replacement therapy for life. With such therapy to the young female there is the added risk of ovarian damage. The lingual thyroid may be excised totally and heterotopically autotransplanted into other areas. There is a variable delay period between transplantation and function of the grafted thyroid tissue in addition to the considerable risk of nonviability or non-function of such completely transposed thyroid tissue. Heterotopic autotransplantation of the ectopic mass while maintaining continuity of the blood supply seems to be the most logical solution. This technique, combined with autografting of a section of the thyroid tissue into other areas, has been successfully employed once before on a 2 year old infant. 9 A similar approach to this problem is presented here in a 9 year old child.
CASE REPORT HISTORY AND PHYSICAL EXAMINATION. The patient, a 9 year old Caucasian girl, was admitted to the hospital with complaints of dysphagia and recurring sore throats. The parents reported stridor of increasing severity when the child was sleeping. The child was not aware of a mass in her throat or mouth. She was born of an uneventful pregnancy. Growth and development were normal, with no history suggestive of thyroid dysfunction. The patient denied frequent tonsillar infections. There was no family history of thyroid disease or abnormality. On physical examination the patient was alert and her vital signs were within normal limits. Her weight was 56 lb. (25.4 kg.) and height 50 inches (127 em.). On inspection of the oral cavity, a 2 em. dark red mass was seen arising from the midline of the tongue in the area of the foramen cecum (Fig. 1). The mass deviated slightly to the right and had an epithelial covering which appeared identical to that of the tongue. It was rubbery in consistency. The throat was not inflamed. There was no lymphoid hyperplasia; the tonsils were of normal size and appearance. The thyroid gland was not palpable in the usual position. The remainder of the physical examination was within normal limits. The results of the laboratory tests were as follows: protein-bound iodine, 4.7 micrograms, calcium, 9.7 mg., phosphorous, 4.3 mg. and
COMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1179
Figure 1. Photograph showing ectopic lingual thyroid in the vicinity of the foramen cecum.
cholesterol, 178 mg. per 100 ml. Lipid partition values were within limits of normal. Posteroanterior and lateral x-ray films of the neck and chest revealed no abnormalities. The patient was given the calculated tracer dose of 131 1 for scanning, which was 29.9 me. The anteroposterior and lateral isotope scans are shown (Fig. 2). The scans revealed functional thyroid tissue to be located only in the area of the lingual mass. No orthotopic functional thyroid tissue was noted. The conclusion was that the patient had complete ectopia of the thyroid gland. OPERATION. The patient was taken to the operating room; under general anesthesia with nasotracheal intubation the neck was extended. The skin of the neck and all of the torso was prepared and the areas draped. A 6-cm. transverse suprahyoid incision was made through the skin and platysma muscle (Fig. 3). The anterior bellies of the digastric muscles were retracted laterally. Most of the fibers of the mylohyoid and geniohyoid muscles were divided, and the lingual arteries were retracted laterally. Hemostasis was maintained with particular care so as to have an especially clear operative field by digital pressure from within the patient's mouth. The middle half of the mass was excised longitudinally with the overlying tongue epithelium-the oral cavity being entered with this incision. The excised mass appeared cystic in one area, was pink-tan in color, and was somewhat friable. A representative section was sent for microscopic study of a frozen section, and it was shown to be colloid goiter. The excised tissue, which grossly appeared to be thyroid, was sliced into sections 1 to 2 mm. thick and immediately placed as free autologous grafts into previously prepared
1180 OsMAR P.
STEINWALD,
]R., RoBERT C. MuEHRCKE, STEVEN G. EcoNOMOU
~L~~~\ Y)
~
)
L~.~j
Figure 2. Preoperative lateral and anteroposterior isotope scans of the pharynx following oral administration of 131 1. The scan is superimposed on line drawings of the patient's head. There is obvious uptake of '"I over the area of the lingual mass.
sites in pectoralis major and supra-umbilical rectus abdominis muscles bilaterally. The grafts were placed within the muscles by using blunt retraction of the fibers, as described by others. A few drops of a solution containing 500 mg. tetracycline in 250 cc. physiological saline were placed over the graft areas on the left side prior to closure of the wounds. No such solution was used on the right side. In addition a portion of the tissue was placed in the subcutaneous fat in the left inguinal area with the intention of excising a portion of it at a later date_ Approximately 3 minutes elapsed between excision of a portion of the lingual mass and the placement of the free grafts. The graft incisions were closed in layers and attention was returned to the neck incision. Using sharp dissection, each of the remaining lateral thyroid masses was separated from the overlying tongue epithelium, taking special care to maintain contiguous attachment of the thyroid to the lateral tissues. The masses were then rotated laterally and inferiorly from the oral cavity and secured in their new submandibular positions_ The H-shaped tongue opening was closed with interrupted 4-0 chromic catgut. A small soft rubber drain was exteriorized through the left lateral aspect of the incision and the neck wound closed in layers. Because of the manipulation of the base of the tongue and the possible obstructive edema or impairment of the patient's ability to expel mucus, a prophylactic tracheostomy was performed. The trachea came into view immediately and only fibrous tissue could be seen in the area normally occupied by the isthmus and the ventral portions of the thyroid lobes. The patient
COMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1181
Figure 3. Operative steps in developing pedicle grafts which contain lingual thyroid (insert). A, Transverse suprahyoid invasion with or without splitting of hyoid bone. B, Anterior bellies of digastric muscle retracted laterally and most of fibers of mylohyoid and geniohyoid muscles divided. The fibers of the genioglossous muscle are divided until the lingual mass is reached. C, The oral cavity is entered anterior to the mass. D, It is next bisected longitudinally and followed by completion of the H-shaped incision (dotted line). E, The pedicles have been developed. F, Separation of tongue epithelium from underlying closely adherent thyroid. G, Closure of H-shaped incision; lingual pedicles with associated thyroid tissue swung laterally to submandibular positions.
1182
OSMAR
P.
STEINWALD, JR., ROBERT C. MUEHRCKE, STEVEN
G.
ECONOMOU
tolerated the procedure well. Photomicrographs show various portions of the excised tissue (Fig. 4). There were no postoperative complications or unusual occurrences. The patient received penicillin and streptomycin postoperatively. The tracheostomy tube was removed on the third postoperative day and intravenous infusions were stopped on the fourth day after surgery. The patient was discharged from the hospital on the eighth day with all wounds healing well. Speech, swallowing, taste, and respiration were normal, as was tongue strength and sensation. No lingual mass was noted on oral inspection. There were no signs of symptoms of hypothyroidism, and accordingly the patient was discharged without medication. Three months later the patient retumed for re-evaluation. She was asymptomatic and clinically euthyroid. A second radioactive iodine scan was performed following a tracer dose of 131 !. The thyroid tissue placed in the submandibular areas on pedicles and three of the five free grafts were shown to be functional (Figs. 5 and 6). Seven months later a biopsy was performed of the free graft in the left lower quadrant (Fig. 7). At this time the posterior tongue appeared normal (Fig. 8). A tonsillectomy had been performed several years previously. Five years following the original operation the patient was clinically asymptomatic.
Figure 4. A, Photomicrograph of biopsy specimen of lingual thyroid. One surface (top) is covered by stratified squamous epithelium. In the underlying stroma there are several mucus glands and numerous irregular acini that vary in size and shape and are filled with eosinophilic colloid. B, The follicles are lined by a single layer of flattened cuboidal epithelium. There is no partition between the colloid filled acini and the adjacent striated muscle.
COMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1183
Figure 5. Anteroposterior and lateral isotope scans of the neck, performed approximately three months postoperatively and superimposed on line drawings of the patient's head. Thyroid tissue is now in both submandibular areas.
Figure 6. This composite illustration shows the uptake of a tracer dose of "''I by three of the five free grafts. The grafts placed in the pectoral areas do not show evidence of thyroid activity.
1184
OSMAR
P.
STEINWALD, JR., ROBERT
C.
MUEHRCKE, STEVEN
G.
EcONOMOU
Figure 7. (Left) Photomicrograph of the thyroid tissue biopsy which was transplanted subcutaneously in the left lower quadrant seven months previously. (Right) Electron microphotograph of same biopsy. Villi (VI) are seen projecting into lumen (L), containing colloid material. The cell contains numerous mitochondria, dark secretory granules (G), and vacuoles (VA). These cellular changes indicate metabolic and secretory activity. (Uranyl acetate X21,585)
Figure 8. Photograph taken seven months postoperatively showing the posterior tongue at the previous site of the ectopic thyroid to be normal in appearance. The tonsils are somewhat enlarged.
CoMPLETE LINGUAL ECTOPIA OF THE THYROID GLAND
1185
DISCUSSION The procedure described is a satisfactory approach to the problem of complete or even incomplete lingual ectopia of the thyroid gland. By maintaining a blood supply to functional tissue the chance of losing the only available thyroid tissue is minimized. There should also be less difficulty with the usual waiting period for free autologous thyroid grafts to function. Apparently, in free grafting, thyroid tissue may not function for a varying period of time. 2· 10 The method of free implantation of thin strips of thyroid tissue into muscle has achieved the best functional result in experimental animals and in man. 3 • 4 • 5 • 6 This method has been a satisfactory adjuvant in this patient. Multiple sites were chosen for graft placement to increase the probability of achieving functional thyroid tissue. Reportedly exogenous thyroid medication should not be given preoperatively or postoperatively for fear of suppressing endogenous thyrotropic hormone production by the pituitary which may, in turn, impair the "take" and function of the free autografts.2· 11 A direct analogy, however, to Halsted's original investigation regarding increased acceptance of parathyroid grafts in patients not receiving parathormone 1 has not been established. The value of instilling a saline solution containing an antibiotic (tetracycline) into half the graft sites is unknown, because no site became infected and there was no obvious relationship to successful function of the grafts. Such use of antibiotics is somewhat arbitrary, but is justified by the fact that in securing the specimen for grafting, the oral cavity was opened and the grafts potentially contaminated. The hyoid bone may be divided in the midline to achieve better exposure without fear of untoward sequelae. Division was not necessary in this patient. Entering the oral cavity with the H-shaped incision allows for displacement into the wound of pedicles of tongue with attached thyroid. This allows for accurate and simple dissection of the closely adherent epithelium from the underlying thyroid tissue. Certainly, an inadequate dissection at this point which left behind any sizable amount of thyroid tissue might result in hyperplasia of this remnant. Such hyperplasia of residual tissue might be more likely if there was only free heterotopic autografting and these grafts did not function. Despite these considerations and the fact that our patient who was so treated did exceptionally well postoperatively, it is still probably best to use a technique not involving entry into the oral cavity. This can be achieved by using the intraoral finger as a guide to the depth of the tongue incision from the inside. Once a beginning has been made the dissection becomes easier. Although at the conclusion of such a dissection only thin epithelium separates the oral cavity from the operative field, it is preferable to having to close an H-shaped incision in this precarious tissue. Continued maintenance of hemostasis cannot be overemphasized in this highly vascular area. Care must also be used in handling the thyroid tissue itself because it is quite friable and liable to irreversible damage with rather minimal trauma.
1186
OSMAR
P.
STEINWALD, JR., ROBERT
C.
MUEHRCKE, STEVEN
G.
ECONOMOU
Tracheostomy was performed as a prophylactic measure with concern for postoperative edema and consequent airway obstruction. Although the prophylactic tracheostomy was probably not required in this patient, the procedure should be considered. In the immediate postoperative period, a clear airway should be of primary concern. The patient should be watched postoperatively and at regular intervals for some period thereafter for signs and symptoms of hypothyroidism. Whether the transplanted tissue in this patient will be capable of meeting the increased demands of thyroid hormone during adulthood and possible pregnancy remains to be seen. Parathyroid tetany as a complication is not to be expected because of different embryological anlage and migratory patterns of the parathyroid glands.
CONCLUSION The case of a symptomatic lingual mass representing complete lingual ectopia of the thyroid gland is presented. Free autologous thyroid grafts into muscle, and transposition of functional thyroid tissue in continuity with the blood supply as pedicle grafts bilaterally, has been successful in treating this condition in a 9 year old child. The patient continued to remain asymptomatic and euthyroid 5 years after the operation. The uncommon occurrence of symptomatic complete lingual ectopia of the thyroid gland and the simplicity and apparent success of the operation used to correct it, prompted the report of this unusual case.
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