Auris' Nasus ' Larynx (Tokyo) 18, 87-92 (1991)
BRANCHIAL CLEFT (POUCH) ANOMALIES: A REVIEW OF 42 CASES Toru TAKIMOTO, M.D., Makoto ITOH, M.D ., Mitsuru FURUKAWA, M.D ., Kenzou SAKANO, M.D.,* Hideo SAKASHlTA, M.D .,** lunichi IWAWAKI, M .D. ,** and Toru VIE, M.D .*** Department of Otolaryngology, School of M edicine, Kanazawa University, Kanazawa, Japan *Department of Otolaryngology, Kurobe City Hospital, Toyama, Japan ** Department of Otolaryngology, Hillli City Hospital, Himi, Japan ** *Department of Otolaryngology, Fukui Saiseikai Hospital, Fukui, Japan
A r etrospective review was made of the medical records of 42 patients, who had had branchial cyst, sinus, or fistula, and who had been seen and treated at our hospitals. Three of these lesions were considered to have originated from the first branchial cleft, 36 from the second branchial cleft and/or pouch, and 3 from the fourth branchial pouch. There were no sex and side of presentation differences in the second branchial anomalies. However, the first branchial anomalies occurred predominantly in females , and the fourth branchial anomalies were predominantly left-sided. Pathological findings were of squamous epithelium and subepithelial lymphoid follicles in most branchial remnants . Skin, adenexa, and cartilage were observed in two first branchial cleft sinuses (Work's classification Type II) . Columnar epithelium (respiratory type) was observed in a second branchial pouch cyst and a second branchial fistula. All the p atients with first or fourth branchial anomalies had previous infections with incision and drainage procedures, whereas only two out of 36 patients with second branchial anomalies had had previous incision procedures. All patients after complete removal of branchial anomalies have no recurrence. Branchial apparatus becomes evident during the third and fourth weeks of fetal development, and it has disappeared at the end of 6 weeks (PROCTOR and PROCTOR, 1970). The branchial apparatus consists of six paired mesodermal arches, separated by invaginations of endoderm on the inside, and ectoderm on Received for publication
June 18, 1990 87
T. TAKIMOTO et al.
88
the outside, known respectively as the pharyngeal pouches and branchial clefts (CHANDLER and MITCHELL, /981). Branchial anomalies may arise from incomplete resolution of the branchial cleft (pouch) remnants. A branchial sinus refers to a tract which communic.ates with either the gut or the skin while a branchial fistula connects the gut to the skin. A branchial cyst is formed from entrapped remnants of either a branchial cleft or pouch without a complete sinus tract. This report reviews the medical records of 42 patients, who had either first branchial cleft fistulae, or second branchial anomalies (cyst or fistula), or fourth branchial pouch sinuses during a 15-year period from 1975 to 1990. Follow-up information was obtained from clinic and office records. MATERIALS AND METHOD
The patients were seen and treated in Kanazawa University Medical School Hospital, Fukui Saiseikai Hospital, Kurobe City Hospital, Himi City Hospital, Japan, between 1975 and 1990. The medical records of these patients were analyzed. The clinical observations recorded included: age, sex, clinical features, familial history, type of surgery (excision or drainage), the type of branchial remnant, and the pathological findings. RESULTS
From 2 to 6 cases were seen and treated each year. The age and sex distributions of the cases are shown in Table 1. The youngest patient was 5 and the oldest 72 years old. There were 22 males and 20 females. Nineteen lesions were on the right side, and 23 on the left. All were unilateral. There are no significant differences with regard to sex and side of presentation in the second branchial Table 1.
Branchial cleft (pouch) anomaly: age and sex distribution.
- - - - -
Age distribution
0- 5 5-10 11-20 21-30 31-40 41-50 51-60 61-70 71 Total
~
Male
I (1)"
---------
Female
Total
0
I
I (l)a
6(1)" 8 3
9 (1)" 7 (2)b 2
0
0 0 0
0
22
20
42
• First branchial cleft anomaly,
b
fourth branchial pouch anomaly.
2 15 15 5 2
BRANCHIAL CLEFT ANOMALY
89
cysts. However, all three cases of first branchial cleft anomalies occurred in females, and all three cases of fourth branchial pouch anomalies were on the left side. There was no familial history of branchial cleft anomalies among these cases . Three branchial anomalies were considered to have originated in the first branchial cleft; using WORK'S classification (1972) one was of type I and two were type II (Fig. 1). Twenty-six were derived from the second branchial cleft (pouch). Using BAILEY'S classification (1922), the majority of branchial cysts were of types I to III. Only one case was of type IV. There was also one complete branchial
F ig. 1. Fistulography, showing a first branchial cleft anomaly (arrow) extending from the upper neck to the external auditory canal.
Fig. 2. Fistulography, showing a second branchial fistula (arrow) from the lower neck to the upper part of the palatopharyngeal fold.
Fig. 3. Radioopaque meal roentgenogram demonstrating an internal fistula (arrow) originating from the apex of the left piriform sinus.
90
T. TAKIMOTO et al.
fistula (Fig. 2). Three branchial anomalies were considered to have been derived from the fourth branchial pouch (Fig. 3). Branchial cysts most commonly presented as cystic masses anterior to the sternocleidomastoid muscle in the upper third of the neck. Five patients with branchial cyst presented with a painful and tender swelling because of infection. Only two patients with second branchial anomalies had had previous incision procedures, but all the patients with first branchial cleft and fourth branchial pouch anomalies had had previous episodes of infection with incision and drainage procedures. All patients after surgical removal of branchial anomaly had no recurrence. Histopathological studies revealed squamous epithelium and sUbepithelial lymphoid follicles in the fourth branchial pouch sinuses and second branchial cysts (Bailey's classification type I ot type III). Columnar epithelium (respiratory type) was observed in the type IV second branchial cyst. Both squamous and columnar epithelium were observed in the second branchial fistula. Among the cases of the first branchial cleft anomaly, skin, adenexa, and cartilage were observed in the two cases of WORK (1970) classification type II, whereas only squamous epithelium was observed in the one case of type 1. There were no post-operative complications and recurrences. DISCUSSION
Although branchial cleft and pouch anomalies are rare, their true incidence is not known. First branchial cleft anomalies probably constitute less than I % of all branchial anomalies (ARONSOHN, BATSAKIS, RICE, and WORK, 1976). First branchial cleft anomalies have been classified into two types: type I, of ectodermal origin, involving only the membranous part of the canal; type II, involving both the ectoderm and mesoderm (WORK, 1972). Second branchial cysts or fistulas are the most common type of all branchial anomalies. BAILEY (1922) classified second branchial cysts into four different types. Most second branchial cysts are type I, II, or III. Type IV are extremely rare (DILKES, CHAPMAN, and STAFFORD, 1990). Third and fourth branchial anomalies are extremely rare. Previously, fourth branchial anomalies had been thought to be more a theoretical possibility than a reality. The only one possible remnant of fourth branchial pouch was described by TUKER and SKOLNICK (1973). However, TAKAI, MIYAUCHI, MATSUZAKA, and KUMA (1979) popularized the concept of a fourth branchial pouch anomaly originating from the piriform sinus and linked to recurrent episodes of acute suppurative thyroiditis and perithyroid space abscess. Since then, approximately 50 cases of fourth branchial pouch anomaly have been reported (NAGANO, KAWABORI, IMQ:rO, TAKAHASHI, SHIRATO, and UNNO, 1987; GODIN, KEARNS, PRANSKY, SEID, and WILSON, 1990). Even, we have seen 4 cases of piriform sinus fistula including a previously reported case (UMEDA, WATANABE, OSHIRO, and HAOKA, 1971). These
BRANCHIAL CLEFT ANOMALY
91
results suggest that fourth branchial pouch remnants may be more frequent than previously believed. In the literature, first branchial cleft anomalies occurred predominantly in females (WORK, 1972; BELENKY and MEDINA, 1980), and fourth branchial anomalies virtually always occur on the left side (GODIN et at., 1990), but there are no significant differences with regard to sex or presented side in second branchial anomalies (MARAN and BUCHANAN, 1978). Our series reflects these trends. Histological findings of all removed branchial cysts (Bailey's classification of type I to type III) excluding one case of pharyngeal cyst (type IV) revealed nonkeratinized stratified squamous epithelium and subepithelial lymphoid tissue including one case with metaplastic :columnar epithelium . Columnar (respiratory type) and squamous epithelium were observed in one case of second branchial fistula of our series. The hypothesis of the origin of second branchial cysts has not been agreed upon. Recently, an electron microscopic and enzyme histochemical studies showed that the appearance of the branchial cyst lining is similar to that of the epithelium lining the crypts of the palatine tonsils. The squamous epithelium derived from the palatine tonsil spreads I'ia the lymphatic system to the regionallymph nodes . Subsequent growth of this epithelium and cystic degeneration of the nodes form the cyst (HoWIE and CROCKER, 1981; WILD, MISCHKE, LOBECK, and KASTENBAUER, 1987). In cases with a mass in the lateral neck, one must consider branchial cyst in the differential diagnosis to Iymphoadenitis, thymic cyst, dermoid cyst, and parathyroid cyst, to name some of the possibilities. The distinguishing gross features of branchial cysts are that first branchial cleft fistulas or cysts are located above the neck in association with the parotid gland and external ear canal and that the other branchial cleft or pouch anomalies present as fistulas or cysts which are located anterior to the sternocleidomastoid muscle. The patients with either first or fourth branchial anomalies in this study had had previous infections with incision and drainage procedures. Some patients must be operated upon only during a remission from infection . There should not be repeated improper surgery of the neck because it makes increasingly difficult to excise branchial cysts, sinus, and fistulas. Therefore, one must be aware of the existence of branchial fistulas, cysts or sinuses and obtain the diagnosis pre-operatively. REFERENCES ARONSOHN, R. S., BATSAKIS, J. G., RICE, G. H ., and WORK , W. P. : Anomalies of first branchial cleft. Arch . Dlolaryngol. 102 : 737-740, 1976. BAILEY, H.: The clinical aspects of branchial cysts. Br. J . SlIrg 10 : 565- 572,1922. BELENKY, W. M., and MEDINA, J. E.: First branchial cleft anomalies. Laryngoscope 90: 28-39, 1980. CHANDLER, J. R., and MITCHELL, B.: Branchial cleft cysts, sinuses, and fistulas. Dlolaryngol. Clin. North Alii. 14: 175-186, 1981.
T. TAKIMOTO et al.
92
DILKES, M. G., CHAPMAN, J., and STAFFORD, N. D.: Per-oral excision of a branchial cyst. J. Laryngol. Otol. 104: 143-144, 1990. GODIN, M. S., KEARNS, D. B., PRANSKY, S. M., SEID, A. B., and WILSON, D. B.: Fourth branchial pouch sinus: Principles of diagnosis and management. Laryngoscope 100: 174-178, 1990. HOWIE, A. J., and CROCKER, J.: The lining of branchial cysts studied by electron microscopy and enzyme histochemistry. Pathology 135: 189-197, 1981. MARAN, A. G. D., and BUCHANAN, D. R.: Branchial cysts, sinuses and fistulae. Clin. Otolaryngol. 3: 77-92, 1978. NAGANO, E., KAWABORI, S., iMOTO, S., TAKAHASHI, M., SHIRATO, M., and UNNO, T.: Piriform sinus fistula-Relation to acute thyroiditis- . Pract. Otol. (Kyoto) (in Japanese) Supp\. 15: 154-159, 1987. PROCTOR, B., and PROCTOR, c.: Congenital lesions of the head and neck. Otolaryngol. Clin. North Am. 221-248, 1970. TAKAI, S., MIYAUCHI, A., MATSUZAKA, F., and KUMA, K.: Internal fistula as a route of infection in acute suppurative thyroiditis. Lancet 1: 751-752, 1979. TUKER, H. M., and SKOLNICK, M. L.: Fourth branchial cleft (pharyngeal pouch) remnant. Trans. Am. A cad. Ophthalmol. Otolaryngol. 77: 368-371, 1973. UMEDA, R., WATANABE, Y., OSHIRO, K., and HAOKA, N.: A case of congenital lateral cervical fistula. Pract. Otol. (Kyoto) (in Japanese) 64: 1341-1344, 1971. WILD, G., MISCHKE, D., LOBECK, H., and KASTENBAUER, E.: The lateral cyst of the neckCongenital or acquired? Acta Otolaryngol. 103: 546-550, 1987. WORK, W. P.: New concepts of first branchial cleft defects. Laryngoscope 82: 1581-1593, 1972.
Request reprints to:
Dr. T. Takimoto, Department of Otolaryngology, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa 920, Japan
BRANCHIAL CLEFT (POUCH) ANOMALIES: A REVIEW OF 42 CASES Toru TAKIMOTO, M.D., Makoto ITOH, M.D ., Mitsuru FURUKAWA, M.D ., Kenzou SAKANO, M.D.,* Hideo SAKASHlTA, M.D .,** lunichi IWAWAKI, M .D. ,** and Toru VIE, M.D .*** Department of Otolaryngology, School of M edicine, Kanazawa University, Kanazawa, Japan *Department of Otolaryngology, Kurobe City Hospital, Toyama, Japan ** Department of Otolaryngology, Hillli City Hospital, Himi, Japan ** *Department of Otolaryngology, Fukui Saiseikai Hospital, Fukui, Japan
A r etrospective review was made of the medical records of 42 patients, who had had branchial cyst, sinus, or fistula, and who had been seen and treated at our hospitals. Three of these lesions were considered to have originated from the first branchial cleft, 36 from the second branchial cleft and/or pouch, and 3 from the fourth branchial pouch. There were no sex and side of presentation differences in the second branchial anomalies. However, the first branchial anomalies occurred predominantly in females , and the fourth branchial anomalies were predominantly left-sided. Pathological findings were of squamous epithelium and subepithelial lymphoid follicles in most branchial remnants . Skin, adenexa, and cartilage were observed in two first branchial cleft sinuses (Work's classification Type II) . Columnar epithelium (respiratory type) was observed in a second branchial pouch cyst and a second branchial fistula. All the p atients with first or fourth branchial anomalies had previous infections with incision and drainage procedures, whereas only two out of 36 patients with second branchial anomalies had had previous incision procedures. All patients after complete removal of branchial anomalies have no recurrence. Branchial apparatus becomes evident during the third and fourth weeks of fetal development, and it has disappeared at the end of 6 weeks (PROCTOR and PROCTOR, 1970). The branchial apparatus consists of six paired mesodermal arches, separated by invaginations of endoderm on the inside, and ectoderm on Received for publication
June 18, 1990 87
T. TAKIMOTO et al.
88
the outside, known respectively as the pharyngeal pouches and branchial clefts (CHANDLER and MITCHELL, /981). Branchial anomalies may arise from incomplete resolution of the branchial cleft (pouch) remnants. A branchial sinus refers to a tract which communic.ates with either the gut or the skin while a branchial fistula connects the gut to the skin. A branchial cyst is formed from entrapped remnants of either a branchial cleft or pouch without a complete sinus tract. This report reviews the medical records of 42 patients, who had either first branchial cleft fistulae, or second branchial anomalies (cyst or fistula), or fourth branchial pouch sinuses during a 15-year period from 1975 to 1990. Follow-up information was obtained from clinic and office records. MATERIALS AND METHOD
The patients were seen and treated in Kanazawa University Medical School Hospital, Fukui Saiseikai Hospital, Kurobe City Hospital, Himi City Hospital, Japan, between 1975 and 1990. The medical records of these patients were analyzed. The clinical observations recorded included: age, sex, clinical features, familial history, type of surgery (excision or drainage), the type of branchial remnant, and the pathological findings. RESULTS
From 2 to 6 cases were seen and treated each year. The age and sex distributions of the cases are shown in Table 1. The youngest patient was 5 and the oldest 72 years old. There were 22 males and 20 females. Nineteen lesions were on the right side, and 23 on the left. All were unilateral. There are no significant differences with regard to sex and side of presentation in the second branchial Table 1.
Branchial cleft (pouch) anomaly: age and sex distribution.
- - - - -
Age distribution
0- 5 5-10 11-20 21-30 31-40 41-50 51-60 61-70 71 Total
~
Male
I (1)"
---------
Female
Total
0
I
I (l)a
6(1)" 8 3
9 (1)" 7 (2)b 2
0
0 0 0
0
22
20
42
• First branchial cleft anomaly,
b
fourth branchial pouch anomaly.
2 15 15 5 2
BRANCHIAL CLEFT ANOMALY
89
cysts. However, all three cases of first branchial cleft anomalies occurred in females, and all three cases of fourth branchial pouch anomalies were on the left side. There was no familial history of branchial cleft anomalies among these cases . Three branchial anomalies were considered to have originated in the first branchial cleft; using WORK'S classification (1972) one was of type I and two were type II (Fig. 1). Twenty-six were derived from the second branchial cleft (pouch). Using BAILEY'S classification (1922), the majority of branchial cysts were of types I to III. Only one case was of type IV. There was also one complete branchial
F ig. 1. Fistulography, showing a first branchial cleft anomaly (arrow) extending from the upper neck to the external auditory canal.
Fig. 2. Fistulography, showing a second branchial fistula (arrow) from the lower neck to the upper part of the palatopharyngeal fold.
Fig. 3. Radioopaque meal roentgenogram demonstrating an internal fistula (arrow) originating from the apex of the left piriform sinus.
90
T. TAKIMOTO et al.
fistula (Fig. 2). Three branchial anomalies were considered to have been derived from the fourth branchial pouch (Fig. 3). Branchial cysts most commonly presented as cystic masses anterior to the sternocleidomastoid muscle in the upper third of the neck. Five patients with branchial cyst presented with a painful and tender swelling because of infection. Only two patients with second branchial anomalies had had previous incision procedures, but all the patients with first branchial cleft and fourth branchial pouch anomalies had had previous episodes of infection with incision and drainage procedures. All patients after surgical removal of branchial anomaly had no recurrence. Histopathological studies revealed squamous epithelium and sUbepithelial lymphoid follicles in the fourth branchial pouch sinuses and second branchial cysts (Bailey's classification type I ot type III). Columnar epithelium (respiratory type) was observed in the type IV second branchial cyst. Both squamous and columnar epithelium were observed in the second branchial fistula. Among the cases of the first branchial cleft anomaly, skin, adenexa, and cartilage were observed in the two cases of WORK (1970) classification type II, whereas only squamous epithelium was observed in the one case of type 1. There were no post-operative complications and recurrences. DISCUSSION
Although branchial cleft and pouch anomalies are rare, their true incidence is not known. First branchial cleft anomalies probably constitute less than I % of all branchial anomalies (ARONSOHN, BATSAKIS, RICE, and WORK, 1976). First branchial cleft anomalies have been classified into two types: type I, of ectodermal origin, involving only the membranous part of the canal; type II, involving both the ectoderm and mesoderm (WORK, 1972). Second branchial cysts or fistulas are the most common type of all branchial anomalies. BAILEY (1922) classified second branchial cysts into four different types. Most second branchial cysts are type I, II, or III. Type IV are extremely rare (DILKES, CHAPMAN, and STAFFORD, 1990). Third and fourth branchial anomalies are extremely rare. Previously, fourth branchial anomalies had been thought to be more a theoretical possibility than a reality. The only one possible remnant of fourth branchial pouch was described by TUKER and SKOLNICK (1973). However, TAKAI, MIYAUCHI, MATSUZAKA, and KUMA (1979) popularized the concept of a fourth branchial pouch anomaly originating from the piriform sinus and linked to recurrent episodes of acute suppurative thyroiditis and perithyroid space abscess. Since then, approximately 50 cases of fourth branchial pouch anomaly have been reported (NAGANO, KAWABORI, IMQ:rO, TAKAHASHI, SHIRATO, and UNNO, 1987; GODIN, KEARNS, PRANSKY, SEID, and WILSON, 1990). Even, we have seen 4 cases of piriform sinus fistula including a previously reported case (UMEDA, WATANABE, OSHIRO, and HAOKA, 1971). These
BRANCHIAL CLEFT ANOMALY
91
results suggest that fourth branchial pouch remnants may be more frequent than previously believed. In the literature, first branchial cleft anomalies occurred predominantly in females (WORK, 1972; BELENKY and MEDINA, 1980), and fourth branchial anomalies virtually always occur on the left side (GODIN et at., 1990), but there are no significant differences with regard to sex or presented side in second branchial anomalies (MARAN and BUCHANAN, 1978). Our series reflects these trends. Histological findings of all removed branchial cysts (Bailey's classification of type I to type III) excluding one case of pharyngeal cyst (type IV) revealed nonkeratinized stratified squamous epithelium and subepithelial lymphoid tissue including one case with metaplastic :columnar epithelium . Columnar (respiratory type) and squamous epithelium were observed in one case of second branchial fistula of our series. The hypothesis of the origin of second branchial cysts has not been agreed upon. Recently, an electron microscopic and enzyme histochemical studies showed that the appearance of the branchial cyst lining is similar to that of the epithelium lining the crypts of the palatine tonsils. The squamous epithelium derived from the palatine tonsil spreads I'ia the lymphatic system to the regionallymph nodes . Subsequent growth of this epithelium and cystic degeneration of the nodes form the cyst (HoWIE and CROCKER, 1981; WILD, MISCHKE, LOBECK, and KASTENBAUER, 1987). In cases with a mass in the lateral neck, one must consider branchial cyst in the differential diagnosis to Iymphoadenitis, thymic cyst, dermoid cyst, and parathyroid cyst, to name some of the possibilities. The distinguishing gross features of branchial cysts are that first branchial cleft fistulas or cysts are located above the neck in association with the parotid gland and external ear canal and that the other branchial cleft or pouch anomalies present as fistulas or cysts which are located anterior to the sternocleidomastoid muscle. The patients with either first or fourth branchial anomalies in this study had had previous infections with incision and drainage procedures. Some patients must be operated upon only during a remission from infection . There should not be repeated improper surgery of the neck because it makes increasingly difficult to excise branchial cysts, sinus, and fistulas. Therefore, one must be aware of the existence of branchial fistulas, cysts or sinuses and obtain the diagnosis pre-operatively. REFERENCES ARONSOHN, R. S., BATSAKIS, J. G., RICE, G. H ., and WORK , W. P. : Anomalies of first branchial cleft. Arch . Dlolaryngol. 102 : 737-740, 1976. BAILEY, H.: The clinical aspects of branchial cysts. Br. J . SlIrg 10 : 565- 572,1922. BELENKY, W. M., and MEDINA, J. E.: First branchial cleft anomalies. Laryngoscope 90: 28-39, 1980. CHANDLER, J. R., and MITCHELL, B.: Branchial cleft cysts, sinuses, and fistulas. Dlolaryngol. Clin. North Alii. 14: 175-186, 1981.
T. TAKIMOTO et al.
92
DILKES, M. G., CHAPMAN, J., and STAFFORD, N. D.: Per-oral excision of a branchial cyst. J. Laryngol. Otol. 104: 143-144, 1990. GODIN, M. S., KEARNS, D. B., PRANSKY, S. M., SEID, A. B., and WILSON, D. B.: Fourth branchial pouch sinus: Principles of diagnosis and management. Laryngoscope 100: 174-178, 1990. HOWIE, A. J., and CROCKER, J.: The lining of branchial cysts studied by electron microscopy and enzyme histochemistry. Pathology 135: 189-197, 1981. MARAN, A. G. D., and BUCHANAN, D. R.: Branchial cysts, sinuses and fistulae. Clin. Otolaryngol. 3: 77-92, 1978. NAGANO, E., KAWABORI, S., iMOTO, S., TAKAHASHI, M., SHIRATO, M., and UNNO, T.: Piriform sinus fistula-Relation to acute thyroiditis- . Pract. Otol. (Kyoto) (in Japanese) Supp\. 15: 154-159, 1987. PROCTOR, B., and PROCTOR, c.: Congenital lesions of the head and neck. Otolaryngol. Clin. North Am. 221-248, 1970. TAKAI, S., MIYAUCHI, A., MATSUZAKA, F., and KUMA, K.: Internal fistula as a route of infection in acute suppurative thyroiditis. Lancet 1: 751-752, 1979. TUKER, H. M., and SKOLNICK, M. L.: Fourth branchial cleft (pharyngeal pouch) remnant. Trans. Am. A cad. Ophthalmol. Otolaryngol. 77: 368-371, 1973. UMEDA, R., WATANABE, Y., OSHIRO, K., and HAOKA, N.: A case of congenital lateral cervical fistula. Pract. Otol. (Kyoto) (in Japanese) 64: 1341-1344, 1971. WILD, G., MISCHKE, D., LOBECK, H., and KASTENBAUER, E.: The lateral cyst of the neckCongenital or acquired? Acta Otolaryngol. 103: 546-550, 1987. WORK, W. P.: New concepts of first branchial cleft defects. Laryngoscope 82: 1581-1593, 1972.
Request reprints to:
Dr. T. Takimoto, Department of Otolaryngology, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa 920, Japan
