Cervical cysts, sinuses, and fistul˦ of branchial, pharyngothymic duct, and thyroglossal duct origin

CERVICAL CYSTS, SINUSES, A N D FISTUL2ZE OF BRANCHIAL, PHARYNGOTHYMIC DUCT, AND THYROGLOSSAL DUCT ORIGIN

By M. AMR, M.S. Students' Hospital, Cairo ALTHOUGH much has been written about the various cysts, sinuses, and fistula: o f the neck, there is still a good deal of uncertainty about many aspects of the subject from development to treatment. In this review of eighty-two cases, an attempt has been made to correlate the clinical and histological findings with the more recent embryological explanations. Apart from the analysis of the whole group, examples have been chosen for more detailed description. Some of the reported cases are typical o f the sort of lesion, others show unusual features. These cases were 1.9 per cent. of a larger group of 4,230 general surgical cases operated upon at the Students' Hospital, Cairo. Most of them were done by the writer, or under his supervision. Lesions of thyroglossal duct origin were I'O6 per cent., those of branchial origin o.59 per cent., whilst those of thymic duct origin were only 0"044 per cent. of the whole. Terminology.--Based on observations made by Rathke in 1825, a systemic clinical correlation between malformations of the branchial system and cysts and sinuses of the lateral neck was first made by Ascherson in 1832 ; Housinger introduced the term "branchial fistula" in 1864 (Gore, I959) , but Frazer (194 o) objected to this term, as he felt that the development of the branchial apparatus and structures derived from it are quite different in the human from gill-bearing animals of lower vertebrates. However, as the term is still widely used in the literature and everyday practice, it will be kept in this paper, to avoid more confusion.

The D e v e l o p m e n t of the Primitive P h a r y n x . - - T h e primitive pharynx has its floor made of the pericardium, its roof made of the mesoderm containing the notocord, and its sides by sheets of mesoderm. It is lined by entoderm and covered from outside by ectoderm. Visceral or branchial arches are already visible in the 5 mm. embryo, as prominent bars, both from outside and inside. There are six arches, the last two being rudimentary. Caudal to each bar is a groove. T h e internal grooves are called pharyngeal pouches, and are lined by entoderm ; the external grooves are called branchial (visceral) clefts, and are lined by ectoderm. On the ventro-lateral aspect of the primitive pharynx, the ectoderm comes very close to the entoderm forming a thin membrane, with practically no intervening mesoderm but the pouches never communicate with the clefts. This membrane, the " cleft or closing membrane," always remains intact (Fig. I), while in gill-bearing animals the clefts are complete (Lewis, 1942). The Branchial Apparatus.--This is composed of the branchial arches and clefts. Each arch has its vascular aortic arch, its nerve, its muscle plate, and its skeletal bar (see table). The nerves are marked by ectodermal thickenings, " epibranchial placodes " (Frazer, 1926) : that of the seventh nerve is above the second arch, that of the ninth above the third arch, and that of the tenth on the 148

CERVICAL

CYSTS,

SINUSES,

AND

FISTUL2~

149

fourth arch. T h e ectodermal placodes sink in, and become cystic ; as they move from the surface they draw in a tube of ectoderm, the" ductus pharyngobranchiahs " (Hamilton et al., 1952); later they disappear. Placodal vesicles IX and X correspond to the glosso-pharyngeal and vagus nerves respectively. dorsal aorta ~ giving 4th aortic arch

~ .

~

~

,

( ~ cleff

.... ,

/~k3rd cleft

| ectoderm ~ , ~ '

~'"

membrane~ e n t o d o r m ~

~.~,~i

~ 3 r d

j ~ ) ~ [ ~ . ~ ~ ~ ~ ~ ( m a n d , b u l

branch,a,arch

first arch a

r

)

1, ]|, 1]I ph~yn~eal pouches

Mandibular (1st)

• a~ch__.______t ~ ~ / ~ ~,o,~~2~;2-----_____J ~ ~

! ~//~ "

~

3rd arch

B

FIG. I Diagrammatic representation of the early stages of development of the pharynx in the human embryo. A, 2 mm. stage (transverse section). B, 6 ram. stage.

The precervical sinus of His (Fig. I) develops by an overgrowth of the second arch externally, and the third arch internally. It disappears by the 15 mm. stage, about the seventh week. The mode of disappearance as described in most textbooks is by fusion of the edges of the sinus (Lewis, I942 ; McGregor, 1946), but Frazer (194 o) and later Garrett (I948) showed that the sinus disappears by

150

BRITISH

JOURNAL

OF

PLASTIC

SURGERY

obliteration from its floor• The third cleft, they believe, takes part in the formation of the skin of the neck and is not covered in ; it only becomes flattened down. TABLE

Structures Derived from Branchial Arches ] Skeleton

First Arch

Second Arch

Artery .

Stapes

:Malleus

Stylo-hyoid ligament Small cornu of

Nerve

Internal maxillary

cornu of hyoid Lower part of body of hyoid

Thyroid cartilage ...

hyoid Upper part of body! I of hyoid Stapedial

Fifth

.

Fourth Arch

Great

Incus

Spheno-mandibular ligament Lower jaw

Third Arch

Common and in- I Subclavian or arch ternal carotid of aorta

Seventh

Ninth

Tenth

Mandibular division Facial Muscles

•

Glosso-pharyngeal Superior laryngeal branch Digastric, expres- Stylo-pharyngeus Inferior constricsion of face i tion and cricothyroid

Mastication

The Pharyngeal Pouches.--The tonsil develops at the pharyngeal end of the second pouch (Fig. 2). The third pharyngeal pouch is observed as early as the

2 t

~

~

1:

--Tonsil

parathyroid~ ' ~ J III & I V ~ _ ~

thymus - lateral thyroid rudiment

I v

~ . ]IF tld\

I, |I, llI, IV pharyngeal pouches

,ultimobranchial body

FIG. 2 Normal epithelial structures derived from pharyngeal pouches.

Io-somite stage of the embryo. It leaves the primitive pharynx between the third and fourth arches, i.e., between the hyoid bone and the upper border of the thyroid cartilage. This is an important landmark in tracing the structures derived from the third pouch. By the fifth week the thymus gland develops from the ventral end of the third pouch; the parathyroid III develops from the dorsal end of the same pouch (Fig. 2). As the thymus gland is carried down by the descending pericardium, it draws a stalk, which at first has a lumen; this later

CERVICAL

CYSTS,

SINUSES~

AND

FISTUL~L

IgI

becomes obliterated by growth of the lining entoderm and elongation of the duct. The stalk gives way near the pharynx, separating the thymus from parathyroid III. At no stage in development has the thymic duct any connection with the ectoderm. This point is of great importance in differentiation between vestigial structures of thymic duct origin and those of branchial origin. The fourth pouch comes through the inferior constrictor muscle, either behind the thyroid cartilage or piercing it, to give rise to the thyroid and parathyroid IV which is fixed in place higher than parathyroid III by its attachment to the thyroid gland (Frazer, I94o). The Thyroglossal Duct.--The thyroid gland is developed from a median diverticulum of the ventral wall of the pharynx and two lateral ones from the fourth pharyngeal pouch (Fig. 2). The median divertiant. Post. culum appears about the fourth week between the --~ hyoid first and second branchial arches (Norris, I918; bone Stahl and Lyall, r954) , and grows downwards thyroglossal and backwards to come into contact with the tPact epithelial growth from the lateral pharynx, effecting some fusion with this. This fixes the gland which does not follow the pericardium farther down. The hyoid bone (a structure of the second arch) appears in the embryo following the FIG. 3 descent of the gland, still connected to the pharynx Relation of the thyroglossal duct by the thyroglossal tract, and so gains its close to the hyoid bone (Frazer's relationship to the future duct. Frazer described conception). the tract as folding against the lower border of the hyoid, passing up behind it for a short distance, then turning down to reach the lower border again (Fig. 3). Other observers describe the tract as passing anterior, posterior, or through the bone. This only shows that the tract is intimately related to the bone. The tract is at first a solid column but later becomes canalised, acquiring a lining of cuboidal epithelium, its upper part forming the lingual duct, while from the hyoid bone to thyroid isthmus it forms the thyroid duct (Marshall and Becker, I949). At no stage of its development is the thyroglossal duct connected to the surface ectoderm. The tract disappears between the fifth and eighth weeks.

~

Classifieation.--For descriptive purposes cervical cysts, sinuses, and fistulre are usually classified into two large clinical groups. The details are shown in the following table together with their possible embryological origin :-Lesion.

Origin.

A. Lateral Cervical Cysts, Sinuses, and Fistulm-I. Complete lateral cervical fistula Branchial apparatus and pharyngeal pouches. 2. External lateral cervical sinus . First or second branchial clefts. Branchial apparatus and pharyngeal 3. Branchial cysts pouches. 4-Deep cysts and sinuses and Pharyngeal pouches and thymic duct. some pharyngeal diverticula First branchial deft. 5. Pre-auricular sinuses

152

BRITISH

JOURNAL

OF

PLASTIC

Lesion.

SURGERY Origin.

B. Median Cervical Cysts, Sinuses, and Fistula:-6. Medial cervical cleft 7. Thyroglossal cysts and fistulm

Branchial apparatus. Thyroglossal duct.

CASE REPORTS

I. C o m p l e t e Lateral Cervical Fistulm. Case I.--Hosp. No. 492. A boy of 12, with bilateral symmetrical fistula: of the lower neck, present since birth. On examination two tiny openings were seen about { in. above the sterno-clavicular joints, along the anterior border of the sterno-mastoid muscles. The left opening was slightly wider and on the summit of a small soft reducible

FIG. 4

FIG. 5

Fig. 4.--X-ray of a complete branchial fistula in Case I after lipiodol injection. Dye is seen trickling down the pharynx. Fig. 5.--Specimen removed from Case I.

cyst ; it discharged a mucoid material on pressure. Lipiodol injected in the left fistula showed it to communicate with the pharynx on X-ray (Fig. 4). At operation the tract formed a small cyst under the platysma, then passed along the anterior border of the sterno-mastoid muscle, superficial to the infra-hyoid muscle plane• Its relationship to the carotid vessels was remote. It then passed under the lower border of the posterior belly of the digastric muscle, superficial to the hypoglossal nerve, and joined the lateral wall of the pharynx, where it was ligated and severed. The excised tract is shown in Figure 5. Microscopically the lining epithelium is ciliated columnar at the pharyngeal end,

CERVICAL

CYSTS~

SINUSES~

AND

FISTUL2~

FIG. 6 Photomicrograph of specimen shown in Figure 5.

FIG. 7

FIG. 8

Fig. 7.--Photomicrograph of branchial cyst showing both stratified and columnar epithelium (Case 3). Fig. 8.--Photomicrograph of branchial cyst lined by stratified epithelium (Case 4).

I53

I54

BRITISH

JOURNAL

OF

PLASTIC

SURGERY

and stratified squamous at the cutaneous end. The transition between them is shown in Figure 6. There is no evidence of a membrane between the two parts of the fistula.

2. External Lateral Cervical Sinus. Case 2.--Hosp. No. 467/59. A female, aged I I , with a small sinus in the lateral lower neck. On operation it was found to be a very short tract of a few millimetres in length, ending in a fibro-muscular band extending upwards to the lateral pharynx, and having the same direction and anatomical relations as a branchial fistula. 3. Branchial Cysts. Case 3.--Hosp. No. 1 I/6I. A girl of 15, with a cyst in the lateral neck in the position of a branchial cyst. This was removed and by pathological examination proved to be lined by both ciliated columnar and squamous epithelium (Fig. 7). Case 4.--Hosp. No. 42/57. A typical example of a branchial cyst: a boy, presenting with a cystic swelling below the right angle of the mandible. The scar o f a previous incision was seen in the overlying skin. Operation and pathological examination proved the case to be a branchial cyst lined by squamous epithelinm (Fig. 8). 4. T h y m i c Duct Remnants. Case 5.--Hosp. No. 718/6o. A male, aged i8 years, presenting with a painless, slowly growing swelling in the right side of the neck noticed two years before. A rounded firm swelling could be seen and felt under the lower third of the right sterne-mastoid muscle. It could be moved freely from side to side, but not in the vertical plane. : Operation.--A skin crease oblique incision was used. The deep fascia was incised anterior to the sterno-mastoid. The swelling was found lateral to the thyroid lobe and in close relationship to the carotid sheath. It was ovoid, tapering at its upper and lower poles in twa white cords ; the upper passed below the anterior belly of omo-hyoid to join the lateral wall of the pharynx below the posterior belly of digastric muscle ; the lower cord passed downwards and medially deep to the infra-hyoid muscles, where it passed behind the right sterno-davicular joint. Pathological Examination: Macroscopical.--The excised specimen is shown in Figure 9. The cut surface showed a honeycombed appearance with greyish semitranslucent septa. The contents were hyaline or ha:morrhagic. Microscopical (Fig. Io, A).--The main mass shows the cystic spaces to be lined by flat epithelium with some lymphoid infiltration. The cords (Fig. IO, B) are seen to be mainly composed of an outer layer of well-developed skeletal muscle and lined by flat epithelium. Case 6.--Hosp. No. 752. A boy of 18 who, at the age of 6, was noticed to have a swelling in the left side of the neck which varied in size until the age of I2, when a sinus developed, discharging intermittently. On examination the sinus was about I cm. medial to the anterior border of the sterno-mastoid, opposite the cricoid cartilage (Fig. I I). A probe passed easily in a caudal direction. The surrounding skin was scarred. Lipiodol was injected and the X-ray showed the tract to pass downwards and then upwards to about 2 cm. short of the hyoid bone (Fig. I2, A). Exploration was done through a transverse incision including the opening of the sinus. The granulating sinus passed deep to the sterno-mastoid, then between the anterior belly of the omo-hyoid and the sterno-thyroid muscles forming a cul-de-sac and then tapering upwards (Fig. I2, B) lateraf'to the left lobe of the thyroid to end in the thyro-hyoid membrane. The operation was difficult and tedious because of the prolonged inflammatory process and fibrosis.

CERVICAL

CYSTS~

SINUSES~

AND

FISTUL2~

FIG. 9 Cyst and tract of thymic duct origin (Case 5).

A FIG. IO Photomicrograph of specimen shown in Figure 9.

B A, Cyst.

B, Cords.

IS ~

I56

BRITISH

FIG. I I

JOURNAL

OF

PLASTIC

SURGERY

FIG. I2A

Fig. I I . - - S e c o n d a r y cervical sinus from a persistent thymic duct (Case 6). Fig. I2.--A, X-ray after lipiodol injection of sinus shown in Figure II. B, T h e excised primary thymic tract and secondary fistula (Case 6).

FIG. IBB Fig. I 3 . - - A , Pre-auricular sinus in a young boy. B, Photomicrograph of pre-auricular sinus (Case 7).

CERVICAL CYSTS, SINUSES, AND FISTUL/E

157

5. Pre-aurieular Sinus. Case 7.--Hosp. No. 435/61. A girl of 9 years, presenting with a long-standing ulcer in front of the left ear. On closer examination a pin-point pit occluded by a comedo-like material was seen at the root of the helix of the left auricle. The pit admitted ,a fine probe for a few millimetres. The ulcer responded to dressings and to cleaning the primary sinus of dried secretions. The tract and ulcer were then excised as one mass, with primary repair. Healing was uneventful. Pathological examination showed a ramified, squamous-lined tract (Fig. 13, B). 6. Median Cervical Cleft. Case 8.--Hosp. No. 855/58. A boy of 8 years presented with a median web in the skin of the neck, which hampered full extension (Fig. 14, A), and which had been present since birth. On examination a pinkish, slightly depressed median strip extended from about the level of the hyoid to shortly above the suprasternal notch, of about o. 5 cm. width. The upper and lower limits were overhanging, but could not be probed for more than 2 ram. The strip resembled dry mucous membrane. Operation was a simple plastic procedure : excision of the strip, followed by repair by multiple Z-plastics, resulting in a zig-zag line (Fig. 14, B). Full extension was achieved and no secondary contracture occurred later. 7- Thyroglossal Cysts and Fistulae. Case 9.--Hosp. No. 515/6o. A boy of II years, presenting with a discharging median sinus of the neck which was operated upon four times previously. On examination, the opening was found to occupy a position midway between the hyoid bone and suprasternal notch. There was excessive scarring round the sinus with adherent skin and limitation of full neck extension. It moved on swallowing and on protrusion of the tongue. Operation.--An ellipse of skin was separated around the opening and the skin above and below was extensively undermined. The tract was followed to the hyoid bone which was found to be intact. From the hyoid, a fibro-muscular band was found to pass downwards and was followed to behind the left sterno-clavicular joint. The levator thyroidem muscle was also present and attached to the hyoid, separate from the tract. T h e operation was completed by resection of the body of the hyoid with these structures attached to it (Fig. 15). DISCUSSION As Frazer (1926) has stated, vestigial remnants may arise as a result of: ..... I. Abnormal persistence o f normal embryological states. 2. Abnormal process of development. Examples of the first are the thyroglossal duct and thymic duct remnants ; ,examples of the latter are the median cervical cleft, the pre-auricular sinuses, and t h e branchial fistula: and cysts. A. LATERAL CERVICAL CYSTS, SINUSES, AND FISTUL2E

O f the twenty-one cases in this series, nineteen were of branchial origin and ~only two o f thymic duct origin. Ages varied from 8 to 22 years. O f the nineteen branchial lesions, eight were cysts, six in male patients, and two in females. Eleven were sinuses and fistula:, six males, and five females. O f the fistula:, two were ~bilateral, one in a male, and one in a female. One fistula proved to communicate 2D

158

BRITISH

JOURNAL

OF

PLASTIC

SURGERY

A Median cervical sinus (Case 8).

B FIG. I4 A, Before operation.

B, After operation.

FIG. 15 Excised thyroglossal fistula shown with ellipse of skin. From the hyoid bone extends a long tract passing behind the sterno-clavicular joint, and a short pyramidal lobe (Case 9).

CERVICAL

CYSTS,

SINUSES~

AND

FISTUL~

159

with the pharynx (Case I, Fig. 4), another was a short external sinus (Case 2). All sinuses and fistula: were noticed at birth or shortly after, whilst cysts were first noticed at a later age ; none of the patients had any previous significant history. I. C o m p l e t e Lateral Cervieal Fistulm.--These are also called branchial fistula: their lower part is of branchial origin, while the upper part is derived from the second pharyngeal pouch. This is shown by the clinical findings, anatomical relations, and histological picture. Clinically.--All cases had the external skin opening a short distance (about I in.) above the sterno-clavicular joint, along the line from this joint to the angle of the mandible. Lipiodol injection, when used, showed the extent of the tract. Cystic dilatations were observed in some tracts, at the upper or lower end, or in between (Figs. 4 and 16). The tract, being attached to the skin, may cause a tiny fold, which may be exaggerated on swallowing because of contraction of the muscle sheath. Anatomy.--The anatomical features described in Case I were the same in all the cases. In no case did the carotid vessels form an intimate relation to the tract, as usually stressed. Sometimes these vessels were encountered only when purposely searched for and cleared. McGregor (1946 ) describes the fistula as passing deep to the hypoglossal nerve. In this series the nerve was always found crossing deep to the fistula. This is also the experience of other writers. Throughout its course, the tract was always ensheathed FIG. 16 by a definite and complete muscle sheath Branchial fistula--X-rayafterlipiodol injection showing a small cystic extending from the platysma up to the pharyndilatation near the pharynx. geal wall. All fistula were superficial to the plane of the infra-hyoid muscles and ended above the level of the hyoid bone. Wilson (1955) reported the pharyngeal opening to be in the posterior faucial pillar. Histology (Case I and Figs. 6 and 17, A, B, and c).---Sections taken at the point of attachment to skin show the stratified epithelium of skin to be continuous with that of the fistula (Fig. 17, A). As the tract is followed up by serial sections the squamous epithelium is replaced by one layer of the adult columnar respiratory type of epithelium and not an embryological one (Case i and Figs. 6 and 17, B); mucous glands may be found. Subepithelial lymphoid infiltration is not constant. At the pharyngeal end of the tract, minor salivary gland tissue was observed in one of the sections (Fig. 17, c). Skeletal muscle fibres are seen to ensheath the epithelial tube. Infiltration with inflammatory cells denoted the presence of infection. Treatment and Results.--Two transverse incisions were used: the lower one surrounded the opening, and the higher was located at the highest limit of dissection reached, using a skin crease parallel to the first in a stepladder fashion. The dissected tract was then withdrawn in the upper incision and dissection completed. Injection of coloured solutions or probing was thought to be harmful and was not

I60

BRITISH

A

JOURNAL

OF

PLASTIC

SURGERY

B

C

D FIG. 17 Photomicrograph of a branchial fistula at different levels (A, B, and C). D, Specimen.

See Text.

CERVICAL

CYSTS,

SINUSES~

AND

FISTULAL

I6I

tried. The skeletal muscle sheath was the guide to the tract. No operative complications occurred and the cosmetic results were good. Recurrences were not experienced in this series. Development.mSuch a fistulous communication has never been described in the course of normal development of the embryo. Therefore, it should result from an abnormal process of development. As the internal opening is in the posterior faucial pillar, the upper part of the tract is derived from the second pharyngeal pouch which forms the upper part lined by a single layer of epithelium (Wilson, I955). The branchial apparatus shares to a variable extent in the formation of the rest of the tract, i.e., the lower part which is lined by stratified epithelium. As the pharyngeal pouches and branchial clefts are normally separated by a closing membrane, this membrane is expected to persist and to separate the two parts of the fistula. There was no operative or histological indication of such a membrane, and it was not encountered by other workers. Completely patent tracts are the rule, and it is probable that the septum may have disappeared in some way or other. It was the belief of His that the membrane is broken by probing during operation (McGregor, 1946) ; in this series probing was not used before or during operations. As regards the mode of formation of the lower part of the tract, there is still some difference of opinions. It was thought to be the result of incomplete closure of the cervical sinus, but Frazer (I926) has shown that the sinus disappears by obliteration from its floor and not by fusion of its margins and that another source could be the origin of these fistula=, probably the second branchial cleft (also Wilson, I955 ; Lyall and Stahl, I956). It is certain that the thymic duct has nothing to do with this type of fistula:. A case of congenital bilateral and symmetrical salivary fistula: above the sterno-clavicular joints has been described by Klinko and Heranyi (I959), but with completely different anatomical relations. Fistula: derived totally from the first branchial cleft were also described; they pass from below the lower border of the mandible to the external meatus and are lined by stratified epithelium (cervico-aural fistula:) (Wilson, I955). Gore and Masson (I959) collected thirteen such cases, and Weissman and Horiotz reported the eighteenth case in 1963. There is no example of these in this series.

2. External Lateral Cervical Sinuses.---External sinuses represent the lower part of a complete fistula and are lined by squamous epithelium denoting their origin from ectoderm (Case 2). Blind internal sinuses have also been described to open in the pharynx, in the posterior faucial pillar, and represent the upper part of the tract (ventral part of second pharyngeal pouch). They are lined by entoderm. 3. Lateral Cervical Cysts of Branchial Origin (Branchial Cysts).---The usual presentation was a cystic slowly growing and painless swelling behind the angle of the mandible (Fig. I8), overlapped by the anterior border of the sterno-mastoid and frequently mixed with tuberculous glands. Aspiration of contents may show cholesterol crystals and injection of lipiodol may outline the contour and extent of the cyst (Fig. 19). Their relations are similar to the upper part of the complete fistula. No recurrences or recurrent cases were encountered. Histologically most of the cysts were lined by squamous epithelium, sometimes

I62

BRITISH

JOURNAL

OF PLASTIC

SURGERY

with marked subepithelial lymphoid aggregations (see Fig. 8). Case 3 (Fig. 7) showed both squamous and columnar epithelium. This type of cyst probably represents the closed variant of the complete fistula, having lost its connection with the surface epithelium and their origin is probably similar, i.e., from both pharyngeal pouches and branchial clefts as shown by the presence of both types of epithelium. What causes the cyst to migrate upwards is the elongation of the neck, with lack of skin fixation low down, as in the case of a fistula. Cysts supposed to arise from placodal nodes X should be closely related to the vagus nerve and lined by squamous epithelium.

FIG. 18

FIG. 19

Fig. I 8 . - - T h e characteristic site of a branchial cyst. Fig. I9.--X-ray of branchial cyst after aspiration and injection of lipiodol.

4. Cysts and Fistulae of Thymic Duct and Pharyngeal Pouch Origin.Cases 5 and 6 are believed to be examples of persistent tracts of thymic duct origin, the latter with secondary eruption on the skin of the neck. Both tracts were located at a deeper plane than the branchial ; lying deep to the infra-hyoid muscles, they followed a different anatomical course. They joined the pharynx at a lower level than branchial fistula: ; they passed downwards on the inferior constrictor muscle, behind the lateral lobe of the thyroid, crossing the inferior thyroid artery superficially, to pass behind the corresponding sterno-clavicular joint. The left recurrent laryngeal nerve formed a medial relation to the tract in Case 6. Excision was more difficult than excision of branchial fistula: ; a longitudinal incision along the anterior border of the sterno-mastoid would have given better access. Meyer (I937) believed that all lateral cervical fistula: below the hyoid bone are of thymic duct origin with secondary eruption on the skin. This was based on the assumption that the branchial apparatus belonged to the head and not to the neck. Meyer therefore concluded that all vestigial structures below the level of the hyoid bone are of thymic duct origin. This could apply to Case 6, but not to the eleven other cases described as typical branchial fistula:. Evidently there are many differences. The anatomical relations of the branchial fistula: described here and by other workers do not conform with the course of the thymic duct in the embryo while the relations of the tracts of Cases 5 and 6 coincide with what is expected to be the position of the persistent thymic duct, especially their relationship to the

CERVICAL CYSTS, SINUSES, AND EISTUL.m~

163

infra-hyoid muscle plane which was shown by Wilson (1955) to separate structures derived from ectoderm, vestigial or otherwise, from those derived from entoderm. The skin opening of a branchial fistula is dearly a congenital opening, since it is present from birth and there is no evidence of scarring as in secondary eruptions (Case 6). In addition the stratified epithelium of the skin is continued without interruption into the lower part of the branchial fistula:, unlike the finding in Case 6 where the main tract was connected to the surface through a granulation-lined secondary tract. The developmental differences have already been discussed. The case Meyer reported in 1937 could be interpreted now as one of first branchial fistula while that reported in 1932 is typical of what we know as a complete branchial fistula. Histological Differences.--All branchial fistula: examined have, as a constant feature, a variable extent of stratified squamous lining which is difficult to explain in a purely entodermal structure such as the thymic duct. Lastly, there is no need for other considerations if lesions representing a persistent thymic duct are present. 5. Pre-aurieular Sinuses and Cysts.--These rather uncommon lesions are small pits a few millimetres deep, usually situated at the root of the helix of the auricle. Aird (1957) described seven types. The pre-auricular and anterior (marginal) helicine are those commonly encountered. They are supposed to be the result of failure of complete fusion between the six tubercles of His at the dorsal end of the first branchial cleft. Probably the other types described by Aird such as the post-auricular, are examples of first arch fistula: (cervico-aural fistulae). Each of the five cases in this series presented with a discharging septic granulating area in front of the ear, defying all sorts of conservative management. Healing, if taking place, was only temporary. Wide excision of the sinus, its ramifications and any ulcer or scar left was done when sepsis was under control by the usual methods of which an important procedure was the regular probing of the primary sinus and cleaning it of inspissated contents. Repair was by wide undermining and advancement of local flaps ; grafts were not needed and there were no incidents of breaking down of suture lines. Injection of coloured material was thought to be more confusing and was not tried, but the use of a probe was sometimes helpful to show the direction of the sinus. No recurrences were encountered in this series. Histologically the ramified crypts were lined by squamous epithelium (see Fig. 13, B). Biopsy is essential in the elderly and recurrent cases, as diagnosis is sometimes confused with rodent ulcer when the primary sinus is inconspicuous or missed (Kadri, 1961 ). B. MEDIAN CERVICAL CYSTS, SINUSES, AND FISTULT~.

M e d i a n Cervical Sinus (Cleft).--This probably results from failure of the branchial arches to fuse completely at the midline. Failure of circulation during development was suggested (Wynn Williams, 1952). It is a rare condition and may cause some confusion in diagnosis. The lesion is excised for cosmetic reasons and to improve the extension of the neck. Linear suture results in recurrence of the contracture. Alternatively, the flaps of a big " Z " are rotated, having the

16 4

BRITISH

JOURNAL

OF

PLASTIC

SURGERY

original incision as the diagonal of the " Z " (Wynn Williams, 1952). The writer used multiple " Z ' s " with smaller flaps and obtained a very satisfactory result (see Fig. 14). Thyroglossal Duet R e m n a n t s . - - O f the fifty-five cases, twenty-two were cysts, thirty fistula:, two bands, and one was an abscess. Thyroglossal Cysts.--These are retention cysts of the thyroglossal duct and may occur anywhere along its line from the foramen cmcum, down between the genio-glossi, above the hyoid, or below it, down as far as the thyroid isthmus (Pemberton and Stalker, 194o). Most of the cases operated upon were located just below the hyoid bone (Fig. 2o), a few were at the level of the thyroid isthmus, but none was below that level. Other workers describe the lowest level as low as the suprasternal notch (Stahl and Lyall, 1954). Of the twenty-two cysts three were recurrent, i.e., 13"6 per cent. ; one was in a patient of this series, and in the form of a cyst three months after the first operation. The case of the abscess was an infected cyst which was drained. The cysts are superficially situated, those below the hyoid bone were separated from the skin by the infra-hyoid muscle raphe. They are thin-walled and contain mucoid material (Fig. 21). One cyst in this series contained pultaceous sebaceous material ; this was not examined histologically. ThyroglossalFistulce.--All were in the midline and discharged mucoid material, Except for one suprahyoid fistula, all the rest were below the bone. The fistula in Case 9 was situated midway between the hyoid bone and the suprasternal notch ; the rest were just below the bone. Bailey (1933) attributed the low position o f some fistula: to their long duration and fixation to the skin while the neck is elongating. Of the thirty fistula:, ten were recurrent, i.e., 3° per cent., which is a high proportion. One of them was from this same series, and was within three months from the first operation. Akhough females are more prone to thyroid gland disease, congenital malformations of the thyroglossal duct were more common in the males of this series. Fistula: were more common in males and cysts more common in females, probably because females present before bursting of the cyst on the skin. The tract has no natural communication with the skin. The low proportion of recurrent cysts is probably due to the fact that cysts are converted into fistula: on operative interference of any kind short of radical excision. Of the recurrent fistula:, one recurred twice and another four times (Case 9)- Thyroglossal cysts and fistula: are lined by cuboidal epithelium in one layer (Fig. 21); occasionally mucous glands or stratified epithelium may be present. Treatment.--The treatment of cysts and fistula: follows the same principle. In all reported recurrent cases and in the two cases recurring in this series, the hyoid bone was found intact. Radical excision as described by Sistrunk (192o) was used. Through a transverse incision the tract was dissected to the hyoid bone, and I cm. of the hyoid was resected in continuity ; the dissection carried on upwards and backwards in a direction 45 degrees from the line of the lower border of the hyoid without stripping off the periosteum of the resected part. This last procedure used to be recommended to avoid entering the larynx. This hazard is remote, as the hyoid is separated from the lumen of the larynx by a good amount of areolar tissue, and by the epiglottis posteriorly (Fig. 22). Fear from this potential hazard used to lead to inadequate excisions. Above the hyoid the

CERVICAL

CYSTS~ SINUSES~ AND

FISTUL2~

FIG. 20 Thyroglossal cyst ; excised wkh part of hyoid bone and cored muscle of tongue.

FIG. 21 Photomicrograph of thyroglossal cyst.

163

166

BRITISH

JOURNAL

OF PLASTIC

SURGERY

tract is too delicate and coring of the muscles in this direction is the safest procedure. Sistrunk resected the mucous membrane round the foramen caecum ; this was not attempted in this series. Fallon (I95I) used a special corer. Injection of the tract with sclerosing solutions, and the use of X-rays are not without danger ; they are unreliable and add difficulty to later operation. Kinsella (I939) tried to make a compromise and was satisfied with the less radical operation of ligation of the tract below the hyoid bone, recurrences being treated with X-rays.

hyoid fatty areolar ti iglottis

thyrohyoid mem~

thyroid cartil

cartilage

FIG. 22 Diagrammatic representation of a longitudinal section through the larynx.

CONCLUSIONS There is a distinct difference between cysts and fistulae of thymic duct origin and those of branchial cleft origin. The differentiation between these two entities can be made on clinical and radiological grounds before operation. Operations on thymic duct remnants are more difficult and may be hazardous after prolonged suppuration and secondary eruption on the skin. Meyer's assumption that the origin of all the cysts and fistulae below the hyoid bone is from the thymic duct is no more acceptable. Primary complete lateral cervical fistulae opening below the level of the hyoid bone are of double origin; the second pharyngeal pouch and a branchial cleft (probably the second) or the cervical sinus. Some branchial cysts show evidence o f this double origin. Thymic duct sinuses in the neck are always of secondary eruption. The problem of thyroglossal duct remnants is recurrence, the close relationship

CERVICAL

CYSTS,

SINUSES,

AND

FISTULiE

167

.of the tract to the hyoid bone being responsible, and the bone should be resected in continuity without stripping of periosteum. Late presentation is the underlying cause of the greater proportion of fistula: in relation to cysts of thyroglossal duct origin in this series. REFERENCES AIRD, I. A. (1957). " Companion in Surgical Studies," p. 431. Edinburgh and London : E. & S. Livingstone. ASCHERSON, F. M. (I832). " D e Fistulis Colli Congenitis." Berolini. BAILEY, H. (1933). Brit. J. Surg., 2I, 173. FALLON, J. (i95I). Surg. Gynec. Obstet., 93, lO7. FRAZER, J. E. (1926). J . Anat., 61, 132. - - - - (194o). " A Manual of Embryology," 2nd ed. London : Bailli6re, Tindall & Cox. GARRETT, F. D. (1948). Anat. Rec., IOO, IOI. GORE, DON, and MASSON, A. (1959)- Ann. Surg., 15o , 309. HAMILTON, W. J., BOYD, J. D., and MOSSMAN, H. W. (1952). " H u m a n Embryology," 2nd ed. Cambridge : W. Heifer. KADRI, SH. (1961). Personal Communication. KINSELLA, V. J. (1939). Brit. J. Surg., 26, 714 . KLINKO, D., and HERANYI, J. (1959). Excerpta Med., 14. LEWIS, W. H. (Ed.) (1942). " Gray's Anatomy of the H u m a n Body," 24th ed. Philadelphia : Lea & Febiger. LYALL, D., and STAHL, W. M., jun. (1956). Int. Abstr. Surg., IO2, 417. MARSHALL, S. F., and BECKER, W. F. (1949). Ann. Surg., 129, 642. McGREGOR, A. L. A. (1946). " Synopsis of Surgical Anatomy." Bristol : John Wright & Sons Ltd. MEYER, H. W. (1932). Ann. Surg., 95, 226. -(1937). Arch. Surg., 35, 766. NORRIS, E. H. (1918). Amer. ft. Anat., 24, 443. PEMBERTON, J. DE J., and STALKER, L. K. (194o). Ann. Surg., I I I , 95 o. RATHKE (1825). Quoted by Meyer (1932). SISTRUNK, W. E. (192o). Ann. Surg., 71, 12I. STAHL, W. H., and LYALL,D. (1954). Ann. Surg., 139, 123. WEISSMAN, F., and HORIOTZ, F. (1963). Plast. reconstr. Surg., 16, 79. WILSON, C. P. (1955). Ann. R. Coll. Surg. Engl., 17, I. WYNN-WILLIAMS,D. (I952). Brit. J. plast. Surg., 5, 87.

Submitted for publication, April 1963.