Familial
Occurrence
of Thyroglossal
Duct Cyst
By Muta M. lssa and Pieter deVries
Santa Clara, California and Stanford, California p Persistence and dilation of the embryologic thyroglossal tract gives rise to the condition of thyroglossal duct cyst. Although these cysts have an embryologic origin, there is rarely a history of inheritance. A search of the literature shows only two family reports, which includes a total of nine patients. We report on a third family with thyroglossel duct cyst in two members. The patients were female siblings aged 2 and 6 years, both of whom underwent successful surgical excision of their thyroglossal duct cysts by modified Sistrunk’s technique. 1991 by Saunders Company INDEX WORDS: Thyroglossal
duct cyst.
S
WELLINGS in the neck are common in childhood and are predominantly of a benign nature. Lymphadenopathy constitutes the largest portion of these benign neck lesion, followed by thyroglossal duct cyst.’ The latter is a benign cyst that originates from an abnormally persisting thyroglossal tract. Due to their frequent occurrence, there has been an abundance of literature on various clinical aspects; nevertheless, there is little knowledge about the underlying mechanism of thyroglossal duct persistence. Therefore, the familial occurrence of this condition, although rare, is of interest. CASE
REPORTS
Case 1 A healthy asymptomatic 6-year-old girl was noted by her mother to have a neck lump. Physical examination showed a 2-cm neck mass situated at the midline in the thyrohyoid region. It was soft and fluctuant and moved up with swallowing and protrusion of the tongue. The clinical impression was of thyroglossal duct cyst. The thyroglossal duct together with its cyst were totally excised by a modified Sistrunk technique: in which the hyoid bone and the musculature were not reapproximated. Histopathologic examination showed a cyst lined by both columnar and squamous epithelium consistent with thyroglossal duct origin and no evidence of thyroid tissue. The patient had an uneventful recovery. Case
2
A younger sibling was brought to the surgical clinic after discovery of a similar neck lump. The patient, a 2-year-old girl, had From the Department of Surgery, Kaiser Permanente Hospital, Santa Clara, CA, and the Department of Surgery, Stanford University Medical Center, Stanford, CA. Date accepted: August 31, 1989. Address reprint requests to Muta M. Issa, MD, Department of Surgery, SO67, Stanford University Medical Center, 300 Pasteur Dr, Stanford, CA 94305. Copyright Q 1991 by W.B. Saunders Company 0022-3468191 I2601 -0007$03.00/0
30
a 3-cm nontender, fluctuant swelling situated to the right of the midline at the thyrohyoid region. Surgical excision (Fig 1) and pathological examination of the excised cyst and duct showed “fibrous connective tissue lined by respiratory type mucosa with focal areas of thyroid tissue and fragments of minor salivary gland.” The patient had an uneventful recovery. The patients’ parents showed no signs of thyroglossal duct cyst and detailed search of the family history failed to show other members with the same condition. However, there was a significant family history, on the maternal side, of other thyroid disease. The sisters’ maternal grandmother had autoimmune hypothyroidism (Hashimoto’s disease) and the maternal grandfather died of anaplastic carcinoma of the thyroid gland.
DISCUSSION
The thyroglossal duct, the track of embryologic descent of the thyroid primordia, originates from a diverticulum of the pharyngeal mucosa in the midventral line between the first and the second pharyngeal pouches. This diverticulum between the tuberculum impar (the primordium of the ventral two thirds of the tongue) and the second pharyngeal pouch at first has a well marked lumen. It subsequently becomes a solid strand, still definitely connected with the endodermal pharyngeal floor, in the 5-mm embryo. It has been generally believed that this connection is lost in the 6- to 7-mm embryo as the now bilobed primordia becomes associated with the third arterial arches. Fraze? has stated: It does not seem certain that there is actual disappearance of the cellular track connecting the bilobed bud with the entoderm [thyroglossal duct]. It is probably ruptured, though it may be only stretched, but it certainly loses its special staining powers and cannot be found in sections. The frequency of its reappearance, however, in whole or part, at later stages suggests that the track may usually or frequently remain in whole or part, and temporarily resume some of its biological attributes later.
The normal disappearance or the abnormal persistence of the thyroglossal track remains speculative and requires further investigation. However, it should be noted that the foramen cecum, usually referred to as the origin of the thyroglossal duct, in fact, does not evolve until a later stage of development. Reports of familial occurrence are rare and we were only able to find two prior reports in the literature. With the addition of this report there are now a total of three families (11 patients). In the family in this report, the condition involved two
Journal ofPediatric Surgery,
Vol26, No 1 (January),
1991: pp 30-31
FAMILIAL OCCURRENCE OF THYROGLOSSAL
Fig 1. The intraoperative appearance case 2. Arrow points to the hyoid bone,
31
DUCT CYST
of thyroglossal
duct cyst in
family members of the same generation, whereas in the previously reported two families, the condition occurred in three and four generations. Ashworth reported the disease in three consecutive generations-a grandmother, mother, and daughter. Millikan et al5 reported the condition in a mother, two daughters, one granddaughter, and two great-granddaughters. In the latter report, two family branches were involved. In the first one it was the mother, daughter, and granddaughter. In the second branch of the family it was the same mother, a second
daughter, then an uninvolved third-generation followed by two great-granddaughters. There were also other associated thyroid diseases of hypothyroidism and thyroid cancer, which is similar to the family in this report. The presence of ectopic thyroid glandular tissue in the excised specimen has been reported to occur in 10% of patients with thyroglossal duct cysts.” Thyroid tissue was present in the specimen of one of the two patients. In the previously reported familial cases, the subject of ectopic thyroid tissue was only addressed in one patient, in whom thyroid tissue was not present.5 Therefore, it is unknown whether or not an etiological link exists between ectopic thyroid tissue and the persistence of thyroglossal tract. All three families reported were of different geographical location: Virginia, Colorado, and Northern California. We are unaware of any environmental, nutritional, or endocrine factors common to these patients. All the 11 familial patients were female, in contrast to the male preponderance reported in other series of thyroglossal duct cysts of 56%’ and _59%.* This difference can not currently be explained. Finally, we think that familial pattern of thyroglossal duct cyst occurs more often than the literature reflects. An awareness of the occurrence of a familial pattern is needed in hope for further future reports that may add to the understanding of the etiologic factors and inherited patterns of this condition.
REFERENCES 1. Jaffe BF: Neck masses and malignant tumors of the head and neck, in Fergusen CF, Kendig EL Jr (eds): Disorders of the Respiratory Tract in Children, ~012: Pediatric Otolaryngology (ed 2). Philadelphia. PA, Saunders, 1972, pp 1125-1157 2. &trunk WE: The surgical treatment of cysts and sinuses of the thyroglossal tract. Ann Surg 71:121-122,192O 3. Frazer JE: A Manual of Embryology. London, England, Bailliere, 1931, p 233 4. Ashworth JT: Three generations of thyroglossal remnant in one family. J Family Pratt 8:524-525, 1979
5. Millikan JS, Murr P, Moore EE, et al: A familial thyroglossal duct cysts. JAMA 244:1714, 1980
pattern
of
6. Telander RL. Deane SA: Thyroglossal and branchial cysts and sinuses. Surg Clin North Am .57:779-791, 1977
cleft
7. Guimaraes SB, Uceda JE. Lynn HB: Thyroglossal remnant in infants and children. Mayo Clin Proc 47:117-120,
duct 1972
8. Pollock WF: Cysts and sinuses of the thyroglossal Surg 112:225-232,1966
duct. Am J
Occurrence
of Thyroglossal
Duct Cyst
By Muta M. lssa and Pieter deVries
Santa Clara, California and Stanford, California p Persistence and dilation of the embryologic thyroglossal tract gives rise to the condition of thyroglossal duct cyst. Although these cysts have an embryologic origin, there is rarely a history of inheritance. A search of the literature shows only two family reports, which includes a total of nine patients. We report on a third family with thyroglossel duct cyst in two members. The patients were female siblings aged 2 and 6 years, both of whom underwent successful surgical excision of their thyroglossal duct cysts by modified Sistrunk’s technique. 1991 by Saunders Company INDEX WORDS: Thyroglossal
duct cyst.
S
WELLINGS in the neck are common in childhood and are predominantly of a benign nature. Lymphadenopathy constitutes the largest portion of these benign neck lesion, followed by thyroglossal duct cyst.’ The latter is a benign cyst that originates from an abnormally persisting thyroglossal tract. Due to their frequent occurrence, there has been an abundance of literature on various clinical aspects; nevertheless, there is little knowledge about the underlying mechanism of thyroglossal duct persistence. Therefore, the familial occurrence of this condition, although rare, is of interest. CASE
REPORTS
Case 1 A healthy asymptomatic 6-year-old girl was noted by her mother to have a neck lump. Physical examination showed a 2-cm neck mass situated at the midline in the thyrohyoid region. It was soft and fluctuant and moved up with swallowing and protrusion of the tongue. The clinical impression was of thyroglossal duct cyst. The thyroglossal duct together with its cyst were totally excised by a modified Sistrunk technique: in which the hyoid bone and the musculature were not reapproximated. Histopathologic examination showed a cyst lined by both columnar and squamous epithelium consistent with thyroglossal duct origin and no evidence of thyroid tissue. The patient had an uneventful recovery. Case
2
A younger sibling was brought to the surgical clinic after discovery of a similar neck lump. The patient, a 2-year-old girl, had From the Department of Surgery, Kaiser Permanente Hospital, Santa Clara, CA, and the Department of Surgery, Stanford University Medical Center, Stanford, CA. Date accepted: August 31, 1989. Address reprint requests to Muta M. Issa, MD, Department of Surgery, SO67, Stanford University Medical Center, 300 Pasteur Dr, Stanford, CA 94305. Copyright Q 1991 by W.B. Saunders Company 0022-3468191 I2601 -0007$03.00/0
30
a 3-cm nontender, fluctuant swelling situated to the right of the midline at the thyrohyoid region. Surgical excision (Fig 1) and pathological examination of the excised cyst and duct showed “fibrous connective tissue lined by respiratory type mucosa with focal areas of thyroid tissue and fragments of minor salivary gland.” The patient had an uneventful recovery. The patients’ parents showed no signs of thyroglossal duct cyst and detailed search of the family history failed to show other members with the same condition. However, there was a significant family history, on the maternal side, of other thyroid disease. The sisters’ maternal grandmother had autoimmune hypothyroidism (Hashimoto’s disease) and the maternal grandfather died of anaplastic carcinoma of the thyroid gland.
DISCUSSION
The thyroglossal duct, the track of embryologic descent of the thyroid primordia, originates from a diverticulum of the pharyngeal mucosa in the midventral line between the first and the second pharyngeal pouches. This diverticulum between the tuberculum impar (the primordium of the ventral two thirds of the tongue) and the second pharyngeal pouch at first has a well marked lumen. It subsequently becomes a solid strand, still definitely connected with the endodermal pharyngeal floor, in the 5-mm embryo. It has been generally believed that this connection is lost in the 6- to 7-mm embryo as the now bilobed primordia becomes associated with the third arterial arches. Fraze? has stated: It does not seem certain that there is actual disappearance of the cellular track connecting the bilobed bud with the entoderm [thyroglossal duct]. It is probably ruptured, though it may be only stretched, but it certainly loses its special staining powers and cannot be found in sections. The frequency of its reappearance, however, in whole or part, at later stages suggests that the track may usually or frequently remain in whole or part, and temporarily resume some of its biological attributes later.
The normal disappearance or the abnormal persistence of the thyroglossal track remains speculative and requires further investigation. However, it should be noted that the foramen cecum, usually referred to as the origin of the thyroglossal duct, in fact, does not evolve until a later stage of development. Reports of familial occurrence are rare and we were only able to find two prior reports in the literature. With the addition of this report there are now a total of three families (11 patients). In the family in this report, the condition involved two
Journal ofPediatric Surgery,
Vol26, No 1 (January),
1991: pp 30-31
FAMILIAL OCCURRENCE OF THYROGLOSSAL
Fig 1. The intraoperative appearance case 2. Arrow points to the hyoid bone,
31
DUCT CYST
of thyroglossal
duct cyst in
family members of the same generation, whereas in the previously reported two families, the condition occurred in three and four generations. Ashworth reported the disease in three consecutive generations-a grandmother, mother, and daughter. Millikan et al5 reported the condition in a mother, two daughters, one granddaughter, and two great-granddaughters. In the latter report, two family branches were involved. In the first one it was the mother, daughter, and granddaughter. In the second branch of the family it was the same mother, a second
daughter, then an uninvolved third-generation followed by two great-granddaughters. There were also other associated thyroid diseases of hypothyroidism and thyroid cancer, which is similar to the family in this report. The presence of ectopic thyroid glandular tissue in the excised specimen has been reported to occur in 10% of patients with thyroglossal duct cysts.” Thyroid tissue was present in the specimen of one of the two patients. In the previously reported familial cases, the subject of ectopic thyroid tissue was only addressed in one patient, in whom thyroid tissue was not present.5 Therefore, it is unknown whether or not an etiological link exists between ectopic thyroid tissue and the persistence of thyroglossal tract. All three families reported were of different geographical location: Virginia, Colorado, and Northern California. We are unaware of any environmental, nutritional, or endocrine factors common to these patients. All the 11 familial patients were female, in contrast to the male preponderance reported in other series of thyroglossal duct cysts of 56%’ and _59%.* This difference can not currently be explained. Finally, we think that familial pattern of thyroglossal duct cyst occurs more often than the literature reflects. An awareness of the occurrence of a familial pattern is needed in hope for further future reports that may add to the understanding of the etiologic factors and inherited patterns of this condition.
REFERENCES 1. Jaffe BF: Neck masses and malignant tumors of the head and neck, in Fergusen CF, Kendig EL Jr (eds): Disorders of the Respiratory Tract in Children, ~012: Pediatric Otolaryngology (ed 2). Philadelphia. PA, Saunders, 1972, pp 1125-1157 2. &trunk WE: The surgical treatment of cysts and sinuses of the thyroglossal tract. Ann Surg 71:121-122,192O 3. Frazer JE: A Manual of Embryology. London, England, Bailliere, 1931, p 233 4. Ashworth JT: Three generations of thyroglossal remnant in one family. J Family Pratt 8:524-525, 1979
5. Millikan JS, Murr P, Moore EE, et al: A familial thyroglossal duct cysts. JAMA 244:1714, 1980
pattern
of
6. Telander RL. Deane SA: Thyroglossal and branchial cysts and sinuses. Surg Clin North Am .57:779-791, 1977
cleft
7. Guimaraes SB, Uceda JE. Lynn HB: Thyroglossal remnant in infants and children. Mayo Clin Proc 47:117-120,
duct 1972
8. Pollock WF: Cysts and sinuses of the thyroglossal Surg 112:225-232,1966
duct. Am J
