Eur Arch Otorhinolaryngol (1991) 248 : 268-270
European Archives of
Oto-RhinoLaryngology © Springer-Verlag 1991
Papillary carcinoma in thyroglossal duct remnants L. Pacheco-Ojeda 1, C. Micheau 2, N. Stafford a, P. Marandas 2, B. Luboinski a, and A. L. Martinez 1 1Oncology and Endocrinology Services, Social Security Hospital, Av. America y Asuncion, Quito, Ecuador 2Pathology and Head and Neck Surgery Services, Institut Gustave Roussy, Villejuif, France Received August 17, 1990 / Accepted September 11, 1990
Summary. A b o u t 100 cases of carcinoma arising in thyroglossal r e m n a n t s have b e e n r e p o r t e d in the world literature. Five additional cases were discovered incidentally on histopathological examinations of specimens following Sistrunk's o p e r a t i o n for r e m o v a l of thyroglossal cysts and are n o w reported. T h e possibility of p r e o p e r a t i v e clinical diagnosis and the modalities of t r e a t m e n t are discussed. Key words: Thyroglossal duct - Papillary carcinoma Sistrunk o p e r a t i o n
Introduction Embryologically, the thyroid gland develops f r o m an invagination of tissue at the base of the t o n g u e ( f o r a m e n caecum) which occurs during the 3rd or 4th w e e k of fetal d e v e l o p m e n t . By the 7th w e e k this tissue has d e s c e n d e d t h r o u g h or b e h i n d the hyoid b o n e to its final, midline position at the r o o t of the neck, anterior to the trachea. If the resulting tract fails to b e c o m e obliterated, a thyroglossal cyst ( T G C ) m a y occur at any point along its p a t h of descent. Such lesions are m o r e c o m m o n l y seen during the first two decades of life. Carcinomas arising in thyroglossal duct ( T G D ) remnants are extremely rare. In a review of 338 cases of thyroglossal cysts f r o m the M a y o Clinic, D e a n e and T e l a n d e r [3] did not find a single case of malignancy. A p p r o x i m a t e l y 100 cases have b e e n r e p o r t e d in the literature to date. A l t h o u g h some of these reports are recent [1, 2, 6, 8, 11, 12, 15] extensive reviews were published by Jacques et al. [4] in 1970 (55 cases), Livolsi et al. [7] in 1974 (76 cases), and J o s e p h K o m o r o w s k i [5] in 1975 (52 cases) and T u r n e r et al. [13] in 1978 (95 cases). W e r e p o r t five additional cases. Offprint requests to: L. Pacheco-Ojeda
Case reports Case 1. A 33-year-old woman presented with an asymptomatic mass in the upper part of the midline of her neck. This lesion had been present for 3 months and appeared as a 3-cm, round cystic lump which was fixed to the upper part of the thyroid cartilage. The rest of her physical examination was unremarkable. A thyroid scan, thyroid hormone levels and laryngeal tomograms were normal. Sistrunk's operation was performed in July 1980 at the Social Security Hospital, Quito, Ecuador. The thyroid gland appeared normal at the time of surgery and frozen sections from the specimen were reported as negative for tumor. However, histological examination of the permanent (paraffin) sections showed a typical papillary carcinoma within the TGC. The histology was confirmed by pathologists at the Memorial Sloan-Kettering Cancer Center in New York. A further thyroid and whole body scan was performed postoperatively but was normal. The patient remains disease-free after 8 years, no further treatment having been necessary. Case 2. A 42-year-old woman presented with a 1-year history of an asymptomatic swelling located in the submental midline region of her neck. Physical examination revealed a 5-cm, ovoid, fluctuant, deeply fixed, slightly left-sided lump whose clinical diagnosis was a TGC. Preoperative thyroid function tests and thyroid scan were normal. A fine-needle aspiration cytology was reported as benign. A Sistrunk's operation was performed in July 1989 at the Social Security Hospital in Quito, Ecuador. Histological study of the lesion revealed a papillary carinoma extending to the thyroid bone. As a postoperative thyroid scan reported a low uptake area in the isthmus, re-exploration of the neck was performed. A nodule was found in the thyroid gland and a total thyroidectomy was performed. Histological study showed no tumor in the thyroid gland but papillary carcinoma was found in a lymph node located over the sternal notch and superficial to the strap muscles. Modified neck dissection was performed. Thyroid hormone substitutive therapy was given postoperatively. Case 3. A 32-year-old woman presented with a 4-year history of an upper midline asymptomatic neck mass. Clinical examination showed that this mass was 5 cm in size, ovoid, firm, and deeply fixed. The mass was diagnosed as a TGC. Thyroid function tests and thyroid scan were within normal limits. A C T scan showed a solid homogeneous mass, located inferiorly to the body of the hyoid bone, and a normal thyroid gland. A Sistrunk's operation was performed in December 1989 at the Social Security Hospital in Quito, Ecuador. Frozen section examination revealed a papillary
L. Pacheco-Ojeda et al.: Carcinoma in thyroglossai duct remnants
269
Fig. 1. Papillary adenocarcinoma in the wall of a thyroglossal cyst. Hematoxylin and eosin, × 40
carcinoma but as the thyroid gland appeared normal at palpation no further surgery was done. Definitive histological examination confirmed the previous diagnosis. Thyroid suppression therapy was given postoperatively. Case 4. A 36-year-old nun underwent resection of a TGC in community hospital in Paris, France, in April 1985. Histologically, a mulfi-focal papillary carcinoma within the tract was reported. The patient was then sent to the Institut Gustave-Roussy for consultation. At this time the patient appeared in good health and physical examination was unremarkable. She was admitted for an extended thyroid isthmectomy and bilateral paratracheal and supraclavicular node dissections, after which she made a good recovery. Histology revealed a microfocus of papillary and follicular carcinoma in the excised thyroid gland. Fourteen nodes were removed in the right neck dissection and 8 nodes in the left dissection, but all were negative for tumor. The patient remains alive and well 4 years after initial surgery. Case 5. A 27-year-old woman underwent Sistrunk's operation for a clinically diagnosed TGC in a local hospital in Paris, France, in April 1986. A preoperative thyroid scan had been normal. Histological examination of the operative specimen revealed a papillary carcinoma arising in the TGC. Additional surgery was not believed necessary at this time. One year later a cold nodule in the right thyroid lobe was found a routine thyroid scan. A total thyroidectomy was then performed and multiple foci of papillary and follicular carcinoma were found histologically in both lobes. The patient was referred to the Institut Gustave-Roussy where a further thyroid scan revealed insignificant uptake of radioiodine, in the neck. A whole body scan was negative and no further treatment was given. The patient has since remained disease-free, 3 years after initial presentation.
Discussion T G C walls are lined with n o r m a l ectopic thyroid tissue in 5 - 4 5 % of cases [3, 7]. H o w e v e r , such a situation should be distinguished f r o m an ectopic lingual thyroid. A n y lesion capable of affecting the thyroid gland (e.g. goiter, carcinoma, etc.) could therefore theoretically occur in any ectopic thyroid tissue. If a papillary
carcinoma is f o u n d along the course of the thyroglossal tract, it is m o s t likely that the f o r m e r has developed within the latter, although the possibility of a metastasis f r o m a p r i m a r y carcinoma of the thyroid gland must be excluded. C a r c i n o m a s arising in T G C s are m o s t c o m m o n in females b e t w e e n the third and sixth decades of life, as also reflected in our cases n o w reported. Clinically, they a p p e a r as slowly growing anterior neck swellings which are usually otherwise asymptomatic. A diagnosis of a T G C can usually be m a d e clinically and Sistrunk's procedure u n d e r t a k e n . P r e o p e r a t i v e d e m o n s t r a t i o n of a mass within the cyst can be suggested by ultrasound or C T scanning [12]. The distribution of the histological types of thyroid carcinoma in T G C s is: papillary (82%), mixed papillary and follicular (8%), squamous cell (6%) and others (5%) [4]. R e c e n t cases of pure follicular [14], post-radiation papillary [9] and anaplastic [10] carcinomas have b e e n reported. Papillary carcinomas arising in the thyroid gland per se as o p p o s e d to in a T G D are similar histologically w h e n e x a m i n e d with electron m i c r o s c o p y [11]. Initial clinical and scan evaluations of the thyroid gland were n o r m a l in all of our cases. In 13 out of 76 cases in the review of Livolsi et al. [7], total thyroidectomies were p e r f o r m e d , with microscopic loci for malign a n c y f o u n d in 27% of the glands. A g o o d result was obtained in 54 out of 78 patients described in the review of T u r n e r et al. [13]. All of these patients u n d e r w e n t excisions of their cysts and adjacent tissues. A f t e r a m e a n follow-up period of 5.2 years, there were only 3 recurrences, all of which were treated successfully. T h e n e e d for total thyroidectomies in patients with carcinomas in T G C s is a controversial issue. T h e possibility of the presence of additional microscopic loci tum o r associated with the lesion is similar to the p r o b l e m of thyroid gland carcinomas clinically limited to one lobe of the gland. In such cases the extent of thyroid gland ex-
270
L. Pacheco-Ojeda et al.: Carcinoma in thyroglossal duct remnants
cision remains unsettled at the present time. As it is now accepted that a carcinoma of the T G C can occur as an isolated, coincidental event [5, 11, 13], wide excision of the T G D t h r o u g h Sistrunk's p r o c e d u r e m a y be an adequate treatment. H o w e v e r , histological verification for complete r e m o v a l of the cyst (and t u m o r ) must be made. Five of 55 patients in the review of Jacques et al. [4] were f o u n d to have palpable l y m p h a d e n o p a t h i e s . N e c k dissections were carried out in 10 cases, of which half were f o u n d to have positive nodes histologically. A papillary carcinoma of the T G D is capable of producing neck n o d e metastases even in the absence of associated loci of carcinoma within the thyroid gland. This was seen in one of our cases. H o w e v e r , if palpable neck nodes are present clinically, a modified neck dissection is indicated. C o m p l e m e n t a r y t r e a t m e n t (e.g. thyroid suppression, radioactive I TM or telecobalt therapy) m a y be indicated, according to the individual case. T h e prognosis for patients with T G D neoplasia seems to be very good, as d e m o n s t r a t e d by o u r 5 patients n o w reported. T h e r e was no mortality in the review of Jacques et al. [4] and only 2 deaths o c c u r r e d in the series of Livolsi et al. [7]. Only 3 cases of recurrent or metastatic disease were described in either of these reports.
3. Deane SA, Telander RL (1978) Surgery for thyroglossal duct and branchial cleft anomalies. Am J Surg 136 : 348-353 4. Jacques DA, Chambers RG, Oertel JE (1970) Thyroglossal tract carcinoma. Am J Surg 120 : 439-445 5. Joseph TJ, Komorowski RA (1975) Thyroglossal duct carcinoma. Hum Pathol 6 : 717-728 6. Kchir N, Dellagi K, Boubaker S (1986) Carcinomes papillaires d6veloppds sur kystes du tractus thyr6oglosse. Ann Otolaryngol Chir Cervicofac 103 : 57-60 7. Livolsi VA, Perzin KH, Savetsky L (1974) Carcinoma arising in median ectopic thyroid (including thyroglossal duct tissue). Cancer 34 : 1303-1315 8. Lustmann J, Benoliel R, Zelster R (1989) Squamous cell carcinoma arising in a thyroglossal duct cyst in the tongue. J Oral Maxillofac Surg 47 : 81-85 9. McGuirt WF, Marshall RB (1980) Postirradiation carcinoma in a thyroglossal duct remnant: follicular variant of papillary thyroid carcinoma. Head Neck Surg 2 : 420-424 10. Nussbaum M, Buchwald RP, Ribner A, Mori K, Litwins J (1981) Anaplastic carcinoma arising from median ectopic thyroid (thyroglossal duct remnant). Cancer 48 : 2724-2728 11. Ronan SG, Deutsch E, Ghosh L (1986) Thyroglossal duct carcinomas: light and electron microsopic studies. Head Neck Surg 8 : 222-225 12. Silverman PM, Degesys GE, Ferguson B J, Bierre AR (1985) Papillary carcinoma in a thyroglossal duct cyst: CT findings. J Comput Assist Tomogr 9 : 806-809 13. Turner PL, Hill HF, Aberdeen JB (1978) Papillary adenocarcinoma arising in a thyroglossal cyst. Aust NZ Surg 48:426428 14. Van Zuiden LJ, Machin GA, Mydland WE (1979) Follicular carcinoma in a thyroglossal duct. Can J Surg 22 : 590-592 15. Vincent SD, Synhorst JB (1989) Adenocarcinoma arising in a thyroglossal duct cyst: report of a case and literature review. J Oral Maxillofac Surg 47 : 633-635
References 1. Berridge DC, Webb AJ (1986) Cervical thymus cyst and thyroglossal carcinoma. Br J Surg 73 : 44 2. Colloby PS, Sinha M, Holl-Allen R, Crocker J (1989) Squamous cell carcinoma is a thyroglossal cyst remnant: a case report and review of the literature. World J Surg 13 : 137-139
European Archives of
Oto-RhinoLaryngology © Springer-Verlag 1991
Papillary carcinoma in thyroglossal duct remnants L. Pacheco-Ojeda 1, C. Micheau 2, N. Stafford a, P. Marandas 2, B. Luboinski a, and A. L. Martinez 1 1Oncology and Endocrinology Services, Social Security Hospital, Av. America y Asuncion, Quito, Ecuador 2Pathology and Head and Neck Surgery Services, Institut Gustave Roussy, Villejuif, France Received August 17, 1990 / Accepted September 11, 1990
Summary. A b o u t 100 cases of carcinoma arising in thyroglossal r e m n a n t s have b e e n r e p o r t e d in the world literature. Five additional cases were discovered incidentally on histopathological examinations of specimens following Sistrunk's o p e r a t i o n for r e m o v a l of thyroglossal cysts and are n o w reported. T h e possibility of p r e o p e r a t i v e clinical diagnosis and the modalities of t r e a t m e n t are discussed. Key words: Thyroglossal duct - Papillary carcinoma Sistrunk o p e r a t i o n
Introduction Embryologically, the thyroid gland develops f r o m an invagination of tissue at the base of the t o n g u e ( f o r a m e n caecum) which occurs during the 3rd or 4th w e e k of fetal d e v e l o p m e n t . By the 7th w e e k this tissue has d e s c e n d e d t h r o u g h or b e h i n d the hyoid b o n e to its final, midline position at the r o o t of the neck, anterior to the trachea. If the resulting tract fails to b e c o m e obliterated, a thyroglossal cyst ( T G C ) m a y occur at any point along its p a t h of descent. Such lesions are m o r e c o m m o n l y seen during the first two decades of life. Carcinomas arising in thyroglossal duct ( T G D ) remnants are extremely rare. In a review of 338 cases of thyroglossal cysts f r o m the M a y o Clinic, D e a n e and T e l a n d e r [3] did not find a single case of malignancy. A p p r o x i m a t e l y 100 cases have b e e n r e p o r t e d in the literature to date. A l t h o u g h some of these reports are recent [1, 2, 6, 8, 11, 12, 15] extensive reviews were published by Jacques et al. [4] in 1970 (55 cases), Livolsi et al. [7] in 1974 (76 cases), and J o s e p h K o m o r o w s k i [5] in 1975 (52 cases) and T u r n e r et al. [13] in 1978 (95 cases). W e r e p o r t five additional cases. Offprint requests to: L. Pacheco-Ojeda
Case reports Case 1. A 33-year-old woman presented with an asymptomatic mass in the upper part of the midline of her neck. This lesion had been present for 3 months and appeared as a 3-cm, round cystic lump which was fixed to the upper part of the thyroid cartilage. The rest of her physical examination was unremarkable. A thyroid scan, thyroid hormone levels and laryngeal tomograms were normal. Sistrunk's operation was performed in July 1980 at the Social Security Hospital, Quito, Ecuador. The thyroid gland appeared normal at the time of surgery and frozen sections from the specimen were reported as negative for tumor. However, histological examination of the permanent (paraffin) sections showed a typical papillary carcinoma within the TGC. The histology was confirmed by pathologists at the Memorial Sloan-Kettering Cancer Center in New York. A further thyroid and whole body scan was performed postoperatively but was normal. The patient remains disease-free after 8 years, no further treatment having been necessary. Case 2. A 42-year-old woman presented with a 1-year history of an asymptomatic swelling located in the submental midline region of her neck. Physical examination revealed a 5-cm, ovoid, fluctuant, deeply fixed, slightly left-sided lump whose clinical diagnosis was a TGC. Preoperative thyroid function tests and thyroid scan were normal. A fine-needle aspiration cytology was reported as benign. A Sistrunk's operation was performed in July 1989 at the Social Security Hospital in Quito, Ecuador. Histological study of the lesion revealed a papillary carinoma extending to the thyroid bone. As a postoperative thyroid scan reported a low uptake area in the isthmus, re-exploration of the neck was performed. A nodule was found in the thyroid gland and a total thyroidectomy was performed. Histological study showed no tumor in the thyroid gland but papillary carcinoma was found in a lymph node located over the sternal notch and superficial to the strap muscles. Modified neck dissection was performed. Thyroid hormone substitutive therapy was given postoperatively. Case 3. A 32-year-old woman presented with a 4-year history of an upper midline asymptomatic neck mass. Clinical examination showed that this mass was 5 cm in size, ovoid, firm, and deeply fixed. The mass was diagnosed as a TGC. Thyroid function tests and thyroid scan were within normal limits. A C T scan showed a solid homogeneous mass, located inferiorly to the body of the hyoid bone, and a normal thyroid gland. A Sistrunk's operation was performed in December 1989 at the Social Security Hospital in Quito, Ecuador. Frozen section examination revealed a papillary
L. Pacheco-Ojeda et al.: Carcinoma in thyroglossai duct remnants
269
Fig. 1. Papillary adenocarcinoma in the wall of a thyroglossal cyst. Hematoxylin and eosin, × 40
carcinoma but as the thyroid gland appeared normal at palpation no further surgery was done. Definitive histological examination confirmed the previous diagnosis. Thyroid suppression therapy was given postoperatively. Case 4. A 36-year-old nun underwent resection of a TGC in community hospital in Paris, France, in April 1985. Histologically, a mulfi-focal papillary carcinoma within the tract was reported. The patient was then sent to the Institut Gustave-Roussy for consultation. At this time the patient appeared in good health and physical examination was unremarkable. She was admitted for an extended thyroid isthmectomy and bilateral paratracheal and supraclavicular node dissections, after which she made a good recovery. Histology revealed a microfocus of papillary and follicular carcinoma in the excised thyroid gland. Fourteen nodes were removed in the right neck dissection and 8 nodes in the left dissection, but all were negative for tumor. The patient remains alive and well 4 years after initial surgery. Case 5. A 27-year-old woman underwent Sistrunk's operation for a clinically diagnosed TGC in a local hospital in Paris, France, in April 1986. A preoperative thyroid scan had been normal. Histological examination of the operative specimen revealed a papillary carcinoma arising in the TGC. Additional surgery was not believed necessary at this time. One year later a cold nodule in the right thyroid lobe was found a routine thyroid scan. A total thyroidectomy was then performed and multiple foci of papillary and follicular carcinoma were found histologically in both lobes. The patient was referred to the Institut Gustave-Roussy where a further thyroid scan revealed insignificant uptake of radioiodine, in the neck. A whole body scan was negative and no further treatment was given. The patient has since remained disease-free, 3 years after initial presentation.
Discussion T G C walls are lined with n o r m a l ectopic thyroid tissue in 5 - 4 5 % of cases [3, 7]. H o w e v e r , such a situation should be distinguished f r o m an ectopic lingual thyroid. A n y lesion capable of affecting the thyroid gland (e.g. goiter, carcinoma, etc.) could therefore theoretically occur in any ectopic thyroid tissue. If a papillary
carcinoma is f o u n d along the course of the thyroglossal tract, it is m o s t likely that the f o r m e r has developed within the latter, although the possibility of a metastasis f r o m a p r i m a r y carcinoma of the thyroid gland must be excluded. C a r c i n o m a s arising in T G C s are m o s t c o m m o n in females b e t w e e n the third and sixth decades of life, as also reflected in our cases n o w reported. Clinically, they a p p e a r as slowly growing anterior neck swellings which are usually otherwise asymptomatic. A diagnosis of a T G C can usually be m a d e clinically and Sistrunk's procedure u n d e r t a k e n . P r e o p e r a t i v e d e m o n s t r a t i o n of a mass within the cyst can be suggested by ultrasound or C T scanning [12]. The distribution of the histological types of thyroid carcinoma in T G C s is: papillary (82%), mixed papillary and follicular (8%), squamous cell (6%) and others (5%) [4]. R e c e n t cases of pure follicular [14], post-radiation papillary [9] and anaplastic [10] carcinomas have b e e n reported. Papillary carcinomas arising in the thyroid gland per se as o p p o s e d to in a T G D are similar histologically w h e n e x a m i n e d with electron m i c r o s c o p y [11]. Initial clinical and scan evaluations of the thyroid gland were n o r m a l in all of our cases. In 13 out of 76 cases in the review of Livolsi et al. [7], total thyroidectomies were p e r f o r m e d , with microscopic loci for malign a n c y f o u n d in 27% of the glands. A g o o d result was obtained in 54 out of 78 patients described in the review of T u r n e r et al. [13]. All of these patients u n d e r w e n t excisions of their cysts and adjacent tissues. A f t e r a m e a n follow-up period of 5.2 years, there were only 3 recurrences, all of which were treated successfully. T h e n e e d for total thyroidectomies in patients with carcinomas in T G C s is a controversial issue. T h e possibility of the presence of additional microscopic loci tum o r associated with the lesion is similar to the p r o b l e m of thyroid gland carcinomas clinically limited to one lobe of the gland. In such cases the extent of thyroid gland ex-
270
L. Pacheco-Ojeda et al.: Carcinoma in thyroglossal duct remnants
cision remains unsettled at the present time. As it is now accepted that a carcinoma of the T G C can occur as an isolated, coincidental event [5, 11, 13], wide excision of the T G D t h r o u g h Sistrunk's p r o c e d u r e m a y be an adequate treatment. H o w e v e r , histological verification for complete r e m o v a l of the cyst (and t u m o r ) must be made. Five of 55 patients in the review of Jacques et al. [4] were f o u n d to have palpable l y m p h a d e n o p a t h i e s . N e c k dissections were carried out in 10 cases, of which half were f o u n d to have positive nodes histologically. A papillary carcinoma of the T G D is capable of producing neck n o d e metastases even in the absence of associated loci of carcinoma within the thyroid gland. This was seen in one of our cases. H o w e v e r , if palpable neck nodes are present clinically, a modified neck dissection is indicated. C o m p l e m e n t a r y t r e a t m e n t (e.g. thyroid suppression, radioactive I TM or telecobalt therapy) m a y be indicated, according to the individual case. T h e prognosis for patients with T G D neoplasia seems to be very good, as d e m o n s t r a t e d by o u r 5 patients n o w reported. T h e r e was no mortality in the review of Jacques et al. [4] and only 2 deaths o c c u r r e d in the series of Livolsi et al. [7]. Only 3 cases of recurrent or metastatic disease were described in either of these reports.
3. Deane SA, Telander RL (1978) Surgery for thyroglossal duct and branchial cleft anomalies. Am J Surg 136 : 348-353 4. Jacques DA, Chambers RG, Oertel JE (1970) Thyroglossal tract carcinoma. Am J Surg 120 : 439-445 5. Joseph TJ, Komorowski RA (1975) Thyroglossal duct carcinoma. Hum Pathol 6 : 717-728 6. Kchir N, Dellagi K, Boubaker S (1986) Carcinomes papillaires d6veloppds sur kystes du tractus thyr6oglosse. Ann Otolaryngol Chir Cervicofac 103 : 57-60 7. Livolsi VA, Perzin KH, Savetsky L (1974) Carcinoma arising in median ectopic thyroid (including thyroglossal duct tissue). Cancer 34 : 1303-1315 8. Lustmann J, Benoliel R, Zelster R (1989) Squamous cell carcinoma arising in a thyroglossal duct cyst in the tongue. J Oral Maxillofac Surg 47 : 81-85 9. McGuirt WF, Marshall RB (1980) Postirradiation carcinoma in a thyroglossal duct remnant: follicular variant of papillary thyroid carcinoma. Head Neck Surg 2 : 420-424 10. Nussbaum M, Buchwald RP, Ribner A, Mori K, Litwins J (1981) Anaplastic carcinoma arising from median ectopic thyroid (thyroglossal duct remnant). Cancer 48 : 2724-2728 11. Ronan SG, Deutsch E, Ghosh L (1986) Thyroglossal duct carcinomas: light and electron microsopic studies. Head Neck Surg 8 : 222-225 12. Silverman PM, Degesys GE, Ferguson B J, Bierre AR (1985) Papillary carcinoma in a thyroglossal duct cyst: CT findings. J Comput Assist Tomogr 9 : 806-809 13. Turner PL, Hill HF, Aberdeen JB (1978) Papillary adenocarcinoma arising in a thyroglossal cyst. Aust NZ Surg 48:426428 14. Van Zuiden LJ, Machin GA, Mydland WE (1979) Follicular carcinoma in a thyroglossal duct. Can J Surg 22 : 590-592 15. Vincent SD, Synhorst JB (1989) Adenocarcinoma arising in a thyroglossal duct cyst: report of a case and literature review. J Oral Maxillofac Surg 47 : 633-635
References 1. Berridge DC, Webb AJ (1986) Cervical thymus cyst and thyroglossal carcinoma. Br J Surg 73 : 44 2. Colloby PS, Sinha M, Holl-Allen R, Crocker J (1989) Squamous cell carcinoma is a thyroglossal cyst remnant: a case report and review of the literature. World J Surg 13 : 137-139
