PÁGINA DEL RESIDENTE

What’s your diagnosis?

¿Cuál es su diagnóstico?

A 29-year-old woman without any known drug allergies or medical history of interest was seen in the emergency room for hemifacial inflammation that had begun one week earlier. The patient referred chronic left mandibular pain, moderate difficulties opening her mouth (trismus), and mild dysphagia.

In the physical examination, severe trismus and evident signs of inflammation at the level of the left mandibular angle were observed. A painful mass of firm consistency was palpated. No abnormal tooth mobility or pain was noted when her teeth were tapped.

In the orthopantomography, a radiolucent image with well defined edges and multilocular aspect was identified that occupied the body, angle, ramus, and condyle of the left mandible and included the roots of tooth 37. An impacted tooth 38 was found adjacent to the cystic image (Fig. 1).

Cervicofacial CAT with contrast identified a highly aggressive lesion in the left mandible with bone expansion, cortical thinning, and rupture of the medial cortical of the ascending ramus. A soft-tissue lesion measuring 2 x 0.8 x 0.5 cm was located adjacent to the ascending ramus (Fig. 2).

Antibiotic therapy was begun with a presumptive diagnosis of infected mandibular cyst and adjacent inflammatory accumulation.

Mandibular odontogenic keratocyst. Presentation as gradually developing trismus

Queratoquiste odontogénico mandibular. Presentación como trismus de larga evolución

R. Sánchez Burgos¹, J.L. Del Castillo Pardo de Vera², M.J. Morán Soto², L. Pingarrón Martín¹, M. Burgueño García³

¹ Médico Residente.
² Médico Adjunto.
³ Jefe de Servicio.
Servicio de Cirugía Oral y Maxilofacial. Hospital Universitario La Paz, Madrid. España

Correspondence

The patient underwent surgery with general anesthesia to resect the lesion. An intraoral approach via a crest incision was used. Teeth 37 and 38 were extracted and the cyst in the area of the mandibular body and condyle was resected and fixed with Carnoy solution. The lingual nerve included in the tumoral tissue was sectioned and resutured.

Two specimens were obtained in the intervention and studied histologically. The first specimen of adjacent soft tissue showed no tumoral infiltration. The second specimen was identified as a keratocyst with granulomatous reaction to keratin.

Postoperative follow-up orthopantomography showed that the cyst had been eliminated and mandibular fractures were absent (Fig. 3).

The patient’s trismus improved during hospitalization and up until the intervention. Throughout the hospital admission, the patient was fed enterally by nasogastric tube. She had mild trismus and adequate tolerance of feeding at discharge. Follow-up with regular outpatient visits disclosed a favorable evolution without recurrence.

Discussion

Odontogenic keratocyst, also known as primordial cyst, is defined as a developmental cyst of odontogenic origin. Its interest lies in the high recurrence rate, which is estimated at 20-30%. Odontogenic keratocysts represent 3-11% of mandibular cysts. They occur most frequently in the second, third, and fourth decades of life and there was a higher incidence in men than in women (1:1.4) and predilection for the mandibular angle and ramus (65-80%).

According to the histologic origin, keratocysts can be divided into two types: keratocysts of primordial origin (60% of cases), which develop from the remains of the dental lamina without any association with the teeth, and keratocysts of dentigerous origin (40%), which arise from the reduced enamel organ and are associated with impacted teeth.

Histologic study revealed a thin wall of stratified squamous- cell epithelium with cuboid or columnar cells in palisade, but no inflammatory infiltrate. These cells usually present parakeratosis (80%), but orthokeratosis has been described in a minority of cases that behave less aggressively and have a lower rate of recurrence. The cyst is filled with a creamy, dirty whitecolored material of characteristic odor, constituted by keratin.

Keratocysts are characterized by high cellular proliferation potential that is regulated by proteins related to cellular apoptosis, like p53, bcl-2, ki67, and PCNA, which are increased in this type of cysts. Keratocysts also produce IL-1, IL-6, TNF, and intraluminal prostaglandins, which explains their recurrent behavior and high growth rate with respect to other odontogenic cysts.

Despite their high proliferative rate, they rarely affect the bone cortex, so that they may remain asymptomatic for a long time. In many cases they are a radiologic finding. Symptoms may begin as a result of cyst infection, debutingwith signs of localinflammation and, in advanced cases, abscess, fistula, or trismus. Cortical perforation may occur in up to 25% of cases, given the growth potential of keratocysts. In this case the condition may debut as a pathologic fracture.

Radiographically, they may present as radiolucent unilocular or multilocular lesions with sharp edges. An unemerged tooth is associated in up to 40% of cases. Adjacent tooth roots may be displaced, but root resorption phenomena have not been described. In the case of multilocular lesions, it is necessary to rule out the association with Gorlin syndrome, an ectomesodermal dysplasia of autosomal dominant hereditary origin that is characterized by multiple basal-cell nevi, skeletal malformations, and keratocysts.

Radiologically, the differential diagnosis must be made with mandibular lesions that course with radiolucency, such as ameloblastoma, a benign tumor that presents in the majority of cases as radiolucent multilocular cysts that can cause erosion of adjacent dental roots and cortical expansion. Ameloblastoma sometimes is associated with impacted teeth. Likewise, keratocysts have to be differentiated from other odontogenic cysts with the same radiologic characteristics, such as follicular cysts directly related to the crown of impacted teeth, in contrast with keratocysts.

The treatment of keratocysts consists of tumor enucleation and curettage of the bed. The most important aim is to reduce the high recurrence rates, as keratocysts can recur up to ten years after surgery.

The therapeutic possibilities include simple enucleation (not recommended due to high recurrence rates, 17-56%). Coadjuvant techniques can be used, such as the application of Carnoy solution after enucleation (absolute alcohol, chloroform, 98% acetic acid, and ferric chloride) or cryocautery, which diminishes the recurrence rate (1-8.7%). Likewise, decompressive techniques derived from marsupialization can be used before surgery to reduce the cyst size and intraluminal pressure, allowing less aggressive surgery and reducing the recurrence rate. In aggressive cases, mandibular block resection may be performed.

The patient has to be followed up postoperatively to detect possible recurrences, which can be attributed to incomplete enucleation or curettage due to the weakness of the cyst wall, the invasion of adjacent soft tissues, or the presence of satellite cysts, given the high mitotic activity of the entity, which was not detected at the time of surgery.

Correspondence:
Rocío Sánchez Burgos
Servicio de Cirugía Oral y Maxilofacial
Hospital Universitario La Paz
Pº Castellana 261. 28046 Madrid. España
Email: ro_sb@hotmail.com

References

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