Extensive incisive canal cyst

Extensive incisive canal cyst Report

of a case

LB.,

A. Saunders, A.B., D.D.X.,” Henry M’iswiewski, D.D.X.,“” and Simon Soumerai, M.D.,*“* Camden, N. J.

WEST

JERSEY

Lawrence

HOSPITAL

T

he median anterior maxillary cyst (incisive canal cyst), which lies in or near the incisive canal, is the most common type of maxillary developmental or fissural cyst. The majority of these cysts arise from proliferation of epithelial remnants of the nasopalatine duct which lies within the incisive canal of the maxilla, although a rare type of median alveolar cyst has been described arising anterior to the incisive canal from remnants of the dental lamina. The studies of Stafnel an co-workers concerning the incidence of median anterior maxillary cysts indicate that they may be found in no fewer than one in every 100 patients and thus cannot be considered rare lesions. Many median anterior maxillary cysts give little evidence of their presence. Occasionally they become infected, producing pain and swelling, and open via a small fistula on or near the palatine papilla. Burket2 found microscopic evidence of cyst formation in this region in approximately two thirds of a series of autopsies; therefore, it seems quite possible that a cyst of sufficient size to be seen in t,he roentgenogram can occur in this region. Cysts of the incisive canal are usually limited as to size. The bone cavity that such a cyst occupies is not closed but communicates directly with the oral cavity, and drainage of the cystic contents to the surface may take place to inhibit continuous growth. Occasionally, as in the case that follows, there is continued growth, and almost always the greatest expansion of the cyst takes place in an upward and posterior direction in the palate. Such an extensive cyst, because of its location, might be referred to as a median cyst; however, in the removal of such cysts as well as those of intermediate size, it will be found *Dental Intern, West Jersey Hospital. **Chief of Oral Surgery, West Jersey Hospital. ***Associate Pathologist, West Jersey Hospital; Jefferson Medical College, Philadelphia, Pa.

284

Assistant

Professor

of

Pathology,

Extehve

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that the incisive canal has been obliterated and that the contents of the canal are situated within the cystic cavity; therefore, it is plausible to infer that they arise in the incisive canal. Roentgenographic examination of the teeth would reveal a round, ovoid, or heart-shaped radiolucent area, sometimes bilateral and usually well outlined in the midline between or above the roots of the maxillary central incisors. It may cause separation or divergence of the roots. These are vital unless coincidently infected. The radiopaque line that follows the median line in the roentgenogram and gives one the impression that two cysts are present is produced by the base of the nasal septum. CASE REPORT On Oct. 25, 1965, a 13-year-old Negro boy was seen on an emergency basis at the West Jersey Hospital after he had been hit on the side of the face while playing football. There was swelling of the right side of the face, with infraorbital edema and ecchymosis. Intraoral and extraoral roentgenograms revealed no fractures of facial bones or teeth. These films showed soft-tissue swelling, with no maxillary sinus involvement. Oral examination disclosed a normal complement of teeth in good repair, with no soft-tissue injury. All teeth gave a positive response to vitalometer testing, and the patient experienced some slight pain upon palpation of tissue. There was evidence of malpositioning of some teeth. After examination had revealed that there were no fractures and that all teeth were intact and vital, the patient was dismissed and referred to a general dentist for further care. On March 7, 1966, the patient’s guardian aunt. called me at the dental clinic to report that she was worried about an enlargement and distortion of her nephew’s face. The boy was taken to an orthodontist, who thought that hospital attention was needed. Re-examination at this time disclosed an extremely large swelling of the anterior maxillary region involving the floor of the nasal fossa and hard palate (Fig. 1). An occlusal-plane intraoral film and periapieal films revealed a very large circumscribed area of radiolucency in the palate, with malpositioning and displacement of the maxillary incisors. All teeth were found to be vital of the mucolabial fold but showed some mobility and tenderness to percussion. Palpation caused discomfort (Figs. 3 and 4).

Fig. 1. Preoperative

photograph

of patient.

286

S’aumlers,

Wimiewski,

Pig. 8. Photograph

Fig.

3. Extraoral

O.S., O.M. & O.P. September,1968

and S’outtt J txi

taken at time of postop~~rat ive rc,-esarninxtion

lateral

skull film taken ou llatient’s

admission

in office.

to hospital.

The patient was admitted to the hospital on March 13, 1966, for evacuation of an extensive maxillary cyst. The medical history was negative except for a slight functional heart murmur. Medical clearance was granted, and routine preoperative screening tests were performed. Operation

The Partsch or marsupialization technique was the procedure of choice. Enucleation of such a cyst invites disaster, since it is virtually impossible to separate the cyst from either the membrane of the nose or the antrum without perforation or without leaving cystic tissue behind. In other words, the consequences of rnucleation are likely to be naso-oral or antro-oral fistulas or recurrence of the cyst. A “window” incision was made with a No. 15 Bard-Parker blade, x inch in diameter,

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Fig. 4. Occlusal-plane

film taken on initial

idsive

card

cyst

207

visit to hospital.

Fig. 5. Occlusal film taken 4 months postoperatively.

in the midline high up in the mucolabial fold. A soft area of previous fistulous tract could be palpated here. The scalpel was inserted through the thin eggshell-like labial plate directly into the cyst. At this point, a large quantity of dark brown crystalline fluid flowed from the site. A culture of the contents was taken and a piece of the oral mucosal fragments in the area of incision was removed. Interrupted sutures were used to attach the oral mucosa to the cystic membrane in an edge-to-edge relationship. The cystic cavity and its contents were thoroughly aspirated at this time; +!J inch gauze was inserted into the defect to act as an obturator and was sutured into place at the window. It was thought best to wait until the cystic cavity had shrunk enough to permit its enucleation without danger of perforating the sinus or nasal membranes. The patient left the operating room in good condition. The following day the vital signs were normal, and there was no pain or bleeding. There-

fore, the patient was discharged with instrucztions to use salt-water mouthwashc~s, lo rclfraio from biting down on hard food substanc(~s, and to r+$urn to tll(a oral surgeon’s ofiic~ within a few days for tJxamination and rrmoval of sulur15. Pathology

report

The specimen consisted of fibrous tissue with chronic nonspecific inflammation. Few bone spicules were present. No cyst lining could be definitely identified in the sections examined. Along one edge of the specimen, some hyalinized fibrous tissue was locally covered with flattened cuboidal cells. The culture report indicated a large> increase in beta hcmolytic streptococci sensitive to penicillin. Second

operative

procedure

On Oct. 13, 1966, the patient was admitted to t.he hospital for enucleation of the maxillary cyst. Roentgenograms of the maxilla, which included intraoral films, revealed a large radiolucent cystic lesion measuring 3 by 4 cm. with a sclerotic rib about the cyst, This lesion had caused the spreading of the central incisors. Nasotracheal general anesthesia was induced, and the patient was prepared and draped in the usual manner. An adequate surgical flap was made in the anterior mucolabial region of the maxilla, and a culture of the purulent material within the cyst was taken for a sensitivity test. Then the cyst was enucleated with curettes. Electrocautery waa used in the region of the nasopalatine foramen. The bony cavity was packed xvith Gelfoam soaked with aqueous penicillin, 400,000 units. The wound was closed with 4-O black silk interrupted sutures, and the patient left the operating room in good condition. He was again referred to the oral surgeon’s office for suture removal and follow-up care. At present the boy is doing well, and the postoperative course has been uneventful (Fig. 2). A postoperative roentgenogram shomcd excellent bone formation (Fig. 5). Pathology

report

The gross specimen consisted of a partially collapsed cyst measuring 3 by 2.5 by 1.5 em. It had a fibrous wall and a glistening trabeculated inner lining which varied in color from tan to brownish red. Histologically, the cyst lining consisted in part of a stratified squamous epithelium (Fig. 6) and in part of a pseudostrat,ified ciliated columnar epithelium (Fig. ‘7). The wall of the cyst showed a dense fibrous tissue with a subepithelial inflammatory infiltrate of round cells admixed with a few polymorphonuclear leukocytes; there were occasional cholesterol spaces surrounded by hemosiderin laden with histiocytes (Fig. 8). No mucous glands were noted.

DISCUSSION Incisive canal cysts are not rare lesions, and they do not usually expand at such a rapid rate. This patient’s lesion was discovered by coincidence following injury to the right side of the face. It was unnoticed at first because of apparent ‘ ‘ negative’ ’ radiographs and the attention given to facial fractures and the accidental injury. The patient had been seen previously by a general dentist, but roentgenograms were not taken. The lesion was noted upon examination of the patient at a later date when the cyst apparently became filled with hemorrhagic material and broke through the labial plate of bone, thus causing considerable facial swelling and distoration. Most reports state that nasopalatine cysts occupy the lower end of the canal, but proportional variability occurs and cysts have been reported originating in the vicinity of the nasal orifice. Although there is no absolute correlation between the cyst site and the type of epithelium found, squamous epithelium is seen almost consistently in cyst linings taken from the inferior portion of the

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Fig.

Fig.

Fig. 6. Section of cyst membrane showing pseudostratified respiratory epithelium and dense fibrous tissue mith subepithelial round-cell infiltrate. (Magnification, x100.) Fig. 7. Close-up of epithelial lining showing ciliated pseudostratified respiratory epithelium. (Magnification, x430.)

canal and respiratory epithelial tissue or a modification of it appears above that ‘level. Unexpected diversions from this descending pattern of epithelium may be due to metaplastic transformation.* The connective tissue capsule of the cyst may contain mucous gland tissue. Cartilage may be identified in the wall of the cyst, but it is surmised that sometimes juxtaposed cartilage tissue may be excised inadvertently from the bed of the cyst and incorporated as part of the specimen. Identification of cholesterol in nasopalatine cysts, however, is uncommon. The viscous fluid content may be pus or mucoid material.

290

Saudem,

Wisniewski,

and ,S’ozctn~ mi

O.S.,O.M. 8.50.1’. September, 1968

In the present case the specimen presented did not contain mucous gland tissue, but it did show a substantial amount of cholesterol, probably produced by the trauma and subsequent inflammation. SUMMARY A case report involving an extensive incisive canal cyst has been presented. The surgical procedure was performed in two steps: (1) the Partsch technique to expel the cyst’s contents and to reduce size of the cyst and (2) enucleation of the cyst sac. This report stresses the importance of thorough x-ray examination following any injury to the head, since there is always the possibility of an oral pathosis of a different nature being present at the time of injury.

1. Stafne, E. C.: Oral Roentgenographic Diagnosis, ed. 2, Philadelphia, 1963, W. B. Saunders Company, pp. 186-189. Duct Structures and Peculiar Bony Patterns Observed in 2. Burket, L. W.: Nasopalatine Anterior Maxillary Region, Arch. Path. 23: 793-800, 1937. 3. Waldron, C. A.: The Differential Diagnosis of Radiolucent Areas in the Jaws, D. Clin. North America, p. 299, July, 1964. 4. Shafer, W. G., Hine, M. K., and Levy, B. M.: Textbook of Oral Pathology, ed. 2, Philadelphia, 1963, W. B. Saunders Company, pp. 3-61. 5. Archer, W. H.: Textbook of Oral Surgery, ed. 2, Philadelphia, 1956, W. B. Saunders Company, pp. 282-331. 6. Thoma, Kurt H.: Oral Surgery, ed. 4, St. Louis, 1963! The C. V. Mosby Company, vol. 2. 7. Kruger, Gustav 0: Textbook of Oral Surgery, St LOUIS, 1959, The C. V. Mosby Company. 8. Killey, H. C., and Kay, L. W.: Benign Cystic Lesions of Jaws, Their Diagnosis and Treatment, Edinburgh, 1966, E. & 8. Livingstone, Ltd., pp. 68-85.