Caso Clínico

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Presentation of a dermoid cyst case with an unusual location

Presentación de un caso de quiste dermoide con ubicación poco frecuente

 

A. Ostrosky¹, R. Luberti⁴, E. Mareso², J. Klurfan Federico³

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Abstract: The Dermoid Cyst is a benign pathology of embrionary origin and its localization in the floor of the mouth is not very frequent. With no preference for sex, it appears especially between the second and third decades of life. Computed scans and magnetic nuclear resonances are useful for its diagnosis. The treatment is surgical and recurrences, as well as malignant transformation, are exceptional. Key words: Dermoid cyst; Teratogenic cyst; Epidermoid cyst.

Resumen: El quiste dermoide es una patología benigna de origen embrionario y su localización en el piso de la boca es poco frecuente. No presenta predilección por sexo y aparece, especialmente, entre la segunda y la tercera década de vida. Para su diagnóstico son útiles las tomografías computadas y las resonancias nucleares magnéticas. El tratamiento es quirúrgico. Tanto las recidivas como la transformación maligna son excepcionales. Palabras clave: Quiste dermoide; Quiste teratogénico; Quiste epidermoide.

Recibido: 08-01-2003

Aceptado: 06-10-2004

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1 Jefe del Servicio de Cirugía Maxilofacial
2 Jefe del Servicio de Anatomía Patológica
3 Residente del Servicio de Cirugía Maxilofacial
Hospital Mariano y Luciano de la Vega, Moreno, Provincia de Buenos Aires, Argentina
4 Profesor Titular de la Cátedra de Radiología de la Facultad de Odontología,
Universidad de Buenos Aires, Buenos Aires, Argentina

Correspondencia:
Dr. Federico Juan Klurfan
Av. Santa Fe 1203 2° Piso
C1059ABG Buenos Aires, Argentina
Email: fklurfan@hotmail.com

 

Introduction

The dermoid cyst is a pathology that originates in the epithelial cells that become trapped during the closure or fusion of the embryonic processes that form the floor of the mouth.^1,2

According to Baker's suggestion put forward in 1883, it is classified as a medial dermoid cyst or of the midline, and lateral dermoid cyst, when it affects one or exceptionally both sides.³

Other authors have divided it according to the geniohyoid muscle; those found under it (in the submental region) and those found above it (in the sublingual region).³

The dermoid cyst shows no sex predilection. With regard to age, it appears particularly during the second and third decades of life.⁴ Shafer and col.⁵ claim that, unlike dermoid cysts observed in other parts of the body, those found on the floor of the mouth at birth are reported very sporadically. Nevertheless there are interesting cases registered in neonatal infants.^6,7

Various authors claim that the lesion when related to the mouth appears to exist at birth, but that generally it is clinically identified in young people.

Clinically it appears as a movable mass on palpation, with fluctuating characteristics and occasionally with a pasty consistency. Generally it grows slowly and it is painless. When located above the geniohyoid muscle it tends to raise the tongue leading to difficulties in phonation, swallowing and even respiratory problems.

Unlike the thyroglossal cyst, the dermoid cyst does not move when the tongue is extended.^8,9 The mucosa, skin and salivary fluid of the adjoining glands are nearly always normal, showing no adenopathies.

As this is a soft tissue entity, conventional radiographic examination is not very demonstrative. Before the advent of computed tomography and magnetic resonance imaging, the liquid content of the cyst was eliminated and a contrast medium was administered in order to determine radiographically the shape, edges, size and relationship with neighboring anatomical structures. ¹⁰

Its pathological anatomy is fundamental for the final diagnosis. The surface of the dermoid cyst consists of a keratinized stratified squamous epithelium, which contains one or various skin appendages such as hair follicles, sudoriparous and sebaceous glands. If these elements are not present, diagnosis is more difficult. Other histological variations of the cyst described are of the epidermoid and teratoid type.¹¹

Treatment is by means of surgery and, once removed, it does not recur bar a few exceptions.

Clinical case

In March 2002 a 26 year-old female patient was presented to our service with a solid tumor-like [mass], which was painless and had not extended into the deeper layers. It had been evolving for two years and was creating a bulge in the submental area as well as in the floor of the mouth (Fig. 1). The patient had no personal or family history of relevance.

In order to complete the study of the patient, fine needle aspiration (FNA) was carried out, and a sample was sent to the service of Pathological Anatomy. The computed tomography also requested showed the location of the lesion in the floor of the mouth, its considerable size and its well-defined margins (Fig. 2).

With the diagnosis confirmed by the Service of Pathological Anatomy, surgical excision of the lesion was recommended. Under general anesthesia the lesion was accessed by means of a horizontal incision in the anterior region of the neck at the same level of the crease in the skin (Fig. 3). The sample removed had a well-defined cystic formation with a diameter of 3 cm which, following incision, contained a yellowy white pasty material (Fig. 4).

On microscopic examination a cystic wall was observed, which had a keratinized stratified squamous epithelium with sebaceous glands. It had a break in continuity and was covered with a granuloma that consisted of lymphocytes, plasmocytes, histiocytes and giant cells of a strange body type (Fig. 5).

The postoperative recuperation of the patient was very satisfactory and during the following year no recurrence was detected (Fig. 6).

Discussion

The area of the head and neck is not a preferential location of the entity described, as is demonstrated by one of the largest reviews carried out by New and Erich.¹² Of 1495 dermoid cysts studied during 25 years in the Mayo clinic they observed that only 6.9% (103 cases) were located in this area, and that 1.6% (24 cases) of all dermoid cysts were located in the floor of the mouth.

Cases have been described in the region of the nose, sinuses, orbits, scalp, rectum, ovaries, abdomen, testicles, salivary glands, spinal cord, brain etc.^13-17

Exceptionally cases have been reported in the maxillary region. Worth¹⁸ recounts the case of a dermoid cyst located in the lower maxilla of a 40-year-old man that appeared radiologically to be a cyst of odontogenic origin.

In a statistical revue carried out in our service, a ratio of 1:1 was corroborated with regard to the sex predilection of this lesion that appears in young individuals between the ages of 15 and 45.

The malignant transformation of the lesion is exceptional, and few cases have been described.^19,20 According to Meyer³ the differential diagnosis from the clinical point of view should be carried out with the following entities.1) ranula; 2) cyst of the thyroglossal duct; 3) cystic hygroma; 4) branchial cleft cysts; 5) acute infections and cellulitis of the floor of the mouth; 6) infections of the submaxillary and sublingual glands; 7) benign and malignant tumors of the floor of the mouth; 8) adipose masses in the submental area.

The sialadenography of the submaxillary grand has been used for making the differential diagnosis between intraglandular lesions and cysts in the surrounding area. Seward¹⁰ presents a contrasted study with an obvious elevation of Wharton's duct, as a result of a dermoid cyst located in the floor of the mouth. Ultrasound and fine needle aspiration (FNA) have also been used for diagnostic purposes. In our case, the FNA was particularly useful in the differential diagnosis, although the exact diagnosis was obtained by means of a postoperative biopsy.

Computed tomography has practically replaced conventional radiography and it tends to be used in the investigation of the dermoid cyst.^21,22 Hypodense images are depicted (around -35 to -84 HU) corresponding with the fat content. This substance, which is produced by sebaceous glands, differentiates dermoid cysts from other masses with similar densities. When this is not clear, establishing the diagnosis is usually difficult on the basis of this procedure. Other investigators use NMR, especially in cerebral and orbital localizations. ^23,24 This procedure is an excellent way of displaying the internal structures, edges, size, shape and relationship with the anatomical structures of the dermoid cyst.

We have not observed any recurrence of the dermoid cysts operated on in our service. Bleninsopp and Rowe,²⁵ however present a case of recurrence in a 31 year old with a dermoid cyst of the floor of the mouth that had been operated on 13 years previously.

Conclusions

In our experience, we always carry out a FNA as a first step in order to obtain diagnostic confirmation and, with regard to imaging studies, we request a CT scan. We have also used nuclear magnetic resonance with very good results.

We agree with the authors consulted in the low incidence of the lesion in the floor of the mouth, and that following surgical treatment recurrence is not observed.

References

1. Eversole L. Patología Bucal. 1ª ed. Editorial Panamericana. Buenos Aires 1983;112.        [ Links ]

2. Zegarelli E, Kutscher A, Hyman G. Diagnóstico en Patología Oral. 2ª ed. Editorial Salvat. Barcelona 1982;238.        [ Links ]

3. Meyer I. Dermoid Cysts (dermoids) of the floor of the mouth. Oral Surg 1955;8:1149.        [ Links ]

4. Som P, Bergeron R. Radiología de Cabeza y Cuello. 2ª ed. Editorial Mosby-Year Book. Madrid 1993;544.        [ Links ]

5. Shafer W, Hine M, Levy B. Tratado de Patología Bucal. Editorial Interamericana. 3ª ed. México 1977;76.        [ Links ]

6. Bloom D, Carvalho D, Edmonds J, Magit A. Neonatal dermoid cyst of the floor of the mouth extendinsg to the midline neck. Arch Otolaryngol Head Neck Surg 2002;128:68.        [ Links ]

7. Gibson W, Fenton N. Congenital sublingual dermoid cyst. Arch Otolaryngol 1982;108:745.        [ Links ]

8. Fitzpatrick T, Eisen A, Wolff K, Fredberg I, Austen K. Dermatology in General Medicine. Vol I Editorial Mc Graw-Hill. Fourth ed. New York 1993;869.        [ Links ]

9. Brown J, Morokoff A, Mitchell P, González M. Unusual imaging appearance of an intracranial dermoid cyst. AJNR 2001;22:1970.        [ Links ]

10. Seward H. Dermoid cysts of the floor of the mouth. Br J Oral Surg 1965;3:36.        [ Links ]

11. Brown J, Morokoff A, Mitchell P, González M. Unusual imaging appearance of an intracranial dermoid cyst. AJNR 2001;22:1970.        [ Links ]

12. New G, Erich J. Dermoid cyst of the head and neck. Surg Gynecol Obstet 1937;65:48.        [ Links ]

13. Loke D, Woolford T. Open septorhinoplasty approach for the excisión of a dermoid cyst and sinus with primary dorsal reconstruction. J Laringol Otol 2001;115:657.        [ Links ]

14. Amir R, Dunham M. Bilateral choanal atresia associated with nasal dermoid cyst and sinus. Int J Pediatr Otorhinolaryngol 2001;58:81.        [ Links ]