Case Presentation And Discussion on
Mandibular Mass

Oliver S. Leyson, M.D.

OMMC – Department of Surgery

August 31, 2004

CASE OF  18 y/o female

Chief complaint: Mandibular mass on the left

History of Present Illness

History of the present illness strated 2 years PTA when the patient noted slow growing non tender mass on the left  submandibular area.  Patient had no history of dental carries nor tooth infection.  Patient sought consult to a private clinician and requested a Panoramic View of mandible, which later revealed a expansile mass 6x6cm with crown convergence root divergence with multiple areas of rare fraction and sclerotic border. Intact cortical bone and multilocular radioluscencies. Primary impression was an Ameloblastoma of the mandible. Patient opted to sought consult in our institution prompted consult hence admission.

PHYSICAL EXAMINATION:

Gen survey:      conscious,coherent

Vital Signs: BP:120/80  CR:104  RR:21

HEENT:  anicteric sclerae pink palpebral conjunctivae.

3x3 cm mass noted below the erupted tooth of the  left canine of the mandible, smooth, well delineated, hard, lymphadenopathies (-).Mass noted below the erupted tooth of the  left canine of the mandible, fixed, well delineated, hard, non tender, no ulceration on the gingiva.

Chest:  symmetrical chest expansion no retraction clear breath sound

Cardiac:  normal rate, regular rhythm

Abdomen:  flat, normo-active bowel sound, no guarding no tenderness

Extremities:   good pulses, no  cyanosis of the nailbeds  on the extremities.

SALIENT FEATURES

18 y/o female

2 years hx slow growing mandibular mass

Solid, hard, non-tender,

No history of tooth infection/carries

Panoramic x-ray: Sclerotic border intact cortical bone, multilocular radioluscencies

Clinical Diagnosis

Clinical diagnosis based on the pattern recognition and prevalence presented by the patient we can arrived to a Primary clinical diagnosis of Odontogenic and non-odontogenic  type of mandibular mass.

PARACLINICAL DIAGNOSTIC PROCEDURE

We need a paraclinical diagnostic procedure to increase the degree of certainty of my primary clinical diagnosis.

Goal of Paraclinical Diagnostic Procedure

Adequate tissue for diagnosis

PARACLINICAL DIAGNOSTIC PROCEDURE

•         Punch Biopsy was requested and revealed mature connective tissue in stroma  palisading columnar (nuclei are polarized) epithelial cells in the periphery of ameloblastic layer.  

•         no capsule  loosely arranged stellate reticulum inside islands

•         Impression: Ameloblastoma Plexiform pattern

PRE-TREATMENT DIAGNOSIS

TREATMENT

Pre-treatment Diagnosis:

            Benign Ameloblastoma, Mandible, Left

Goals of Treatment :

•         Resolution of tumor

•         Restoration of mandibular continuity

–        Bilateral harmonious masticatory function

–        Restore symmetry of the face

•         No recurrence

TREATMENT OPTION

TREATMENT OPTION

PREOPERATIVE PREPARATION

•         Informed consent

•         Psychosocial support

•         Screen for any condition that will interfere with treatment

•         Prepare materials for operation

OPERATIVE TECHNIQUE

•         operative field prepped and draped aseptically

•         asepsis and antisepsis done

•         skin markings following the natural skin crease is made 3-4 cm below the lower border of the horizontal portion of the mandible  from the angle of the mandible to the mentum.

•         Lidocaine 2% with Adrenaline of 1/100,000 was injected following  the skin markings

•         Using a blade#15, skin incision was made thru the markings, carried down to the platysma muscle and its fascial envelope,but not extending deep to the cervical fascia.

•         skin flap is developed carefully.

•         Identification and preservation of the mandibular branch of the facial nerve was secured.

•         Stay sutures were placed thru the platysma to retract the flaps.

•         Incisor tooth was removed and gigli saw was inserted through the floor of the mouth.

•         The mandible is sectioned through the midportion of the socket of the removed tooth

•         The cheek flap is reflected laterally to at least the level of masseter muscles.

•         Gingivobucal incision from the incisor to the last molar done

•         Muscle attachments to the mandible are released.

•         Wound is closed in 3 layers with the floor of mouth attached to buccal mucosa

•         Lip is approximated and closed in layers.

•         Penrose drain was placed below the inferior border of the mandible.

•         Mandible recontructed using Stainless steel.

•         Cortical screws on the edged of the remaining mandible.

•         A oblique incision done on the left

•         Bone graft harvested on the ipsilateral side of the iliac bone

•         Closure of soft tissue done with careful repair of  the platysma muscle

•         Hemostasis checked

•         OS and Instrument Count

•         Skin closed with nylon 4.0 simple interrupted sutures

INTRAOPERATIVE FINDINGS

•         Solid mass measures 3 x 3 cm involving the 1/3 of the anterior mandible on the left.

•         On section showed a pearly-white mass inside the bone honey combed appearance.

POST-OPERATIVE MANAGEMENT

•         Maintained NPO until fully awake

•         Adequate antibiotics and analgesia given

•         Intravenous fluid continued

•         Daily wound cleaning and dressing

OPERATION DONE

PARTIAL MANDIBULECTOMY, LEFT

WITH RECONSTRUCTION OF THE MANDIBLE WITH METALLIC PLATES (STAINLESS) WITH CANCELLOUS BONE (ILIAC)

POST-OPERATIVE MANAGEMENT

•         Discharged after 1 week

•         Adequate antibiotic coverage

•         Betadine gargle three times a day

•         Follow up after one week

FOLLOW UP PLAN

•         Patient was discharged after 1 week

•         Adviced weekly close follow-up.

•         Daily wound care

•         For removal of drain after 1 week

AFTERMATH OF THE PATIENT

•         Resolution of the mandibular ameloblastoma

•         Alive patient

•         Happy and contented with the outcome.

•         No medico-legal suit

PREVENTION AND HEALTH PROMOTION    

•         Advised on proper post-op care

–        Wound cleaning and dressing

•         Schedule and frequency of follow-up

FINAL DIAGNOSIS:

MULTICYSTIC AMELOBLASTOMA MANDIBLE LEFT

S/P PARTIAL MANDIBULECTOMY, LEFT

WITH RECONSTRUCTION OF THE MANDIBLE WITH METALLIC PLATES (STAINLESS) AND PLACEMENT OF CANCELLOUS BONE (ILIAC)

DISCUSSION

Ameloblastoma

Ameloblastoma is an entirely epithelial tumor arising from the dental lamina, Hertwig sheath, the enamel organ, or the lining of dental follicles/dentigerous cysts.

Ameloblastoma is the most common epithelial odontogenic tumor. Ameloblastomas usually occur in individuals aged 20-40 years; however, the unicystic variant most often occurs in adolescents.

This lesion occurs in both the maxilla and mandible, but the posterior mandible is the most common location; only 20% of lesions are found in the maxilla. The lesion is distributed equally between males and females.

Although ameloblastoma generally is not classified as a malignant lesion (a rare malignant variant exists), it is extremely aggressive and infiltrative. Many have suggested that this lesion should be considered a low-grade or indolent malignancy, similar to basal cell carcinoma.

Many histologic and behavioral similarities are found between the 2 lesions  It generally does not metastasize but is slow growing, persistent, and hard to eradicate. If ameloblastoma is not noticed as an incidental finding on radiographs taken for other purposes, the first symptom is usually painless bony expansion.

Radiographic findings

Ameloblastomas typically appear as an expansile multilocular radiolucency in the area of the lower third molar, but they may be found anywhere in the jaws.These lesions may be unilocular when small, and they often resorb the teeth they contact. These lesions are never radiopaque.

Histologic characteristics

Ameloblastoma does not have a capsule. The neoplastic component is purely epithelial and resembles the cap stage of odontogenesis (ie, polarized tall columnar cells on the outer aspect of the lesion with SR on the inner aspect, which may form a cyst). The lesion may have a reactive connective tissue component that is not neoplastic. This is a nonfunctional tumor, ie, it does not induce the surrounding connective tissue, which in turn is unable to induce enamel formation. In effect, these tumors represent arrested odontogenesis. Multiple histologic varieties exist, eg, the acanthomatous type in which the SR is replaced by squamous cells and pearls, the granular cell type in which the SR is replaced by granular cells, and the plexiform type in which the SR is reduced or absent.

Treatment

The treatment of ameloblastoma is surgical excision with wide free margins (see “Surgical considerations”). Appropriate reconstruction may be performed at the same time. All patients with ameloblastoma, regardless of surgical treatment method or histologic type, must be monitored radiographically throughout their lifetime. If excision is inadequate, recurrence is common.

Surgical considerations

• The maxillary ameloblastoma is not confined by the strong cortical plate found in the mandible. In addition, the posterior maxilla lies in close relationship to many vital structures. These factors make strong arguments for aggressive and definitive surgical treatment of the maxillary ameloblastoma.
• In the mandible, 1-cm clear margins are considered the standard. This may be accomplished with block or segmental resection, depending on the relationship of the lesion to the inferior cortical border.
• The single exception to this may be the unicystic ameloblastoma. This variant most commonly appears in late adolescence and, as the name suggests, is characterized by a unicystic radiolucency that most commonly is found in the area of the mandibular third molars. Unlike other types of ameloblastomas, it is believed that this lesion is encapsulated and can be removed with enucleation/curettage procedures alone. These lesions may recur, and recurrences may require more aggressive treatment. Most authors believe that if left untreated, this lesion becomes an ameloblastoma of one of the classic varieties, leading to the corollary conclusion that these lesions simply represent an early stage in the development of ameloblastoma.
• For peripheral ameloblastoma, a more conservative excision with close clinical follow-up is the standard of care.

Relationship to other lesions

• Basal cell carcinoma: Basal cell carcinoma is another infiltrative, essentially nonmetastasizing adnexal neoplasm. Basal cell carcinomas and ameloblastomas are slow growing but persistent, and they may cause death via local extension into vital structures. If one considers that the tooth is an oral adnexal structure, then it is easy to understand why ameloblastoma may be seen as an analogue to basal cell carcinoma.
• Tibial adamantinoma: This lesion is histologically similar to the plexiform variety of ameloblastoma. It is considered a low-grade malignancy and, as the name suggests, is found in the tibia.
• Craniopharyngioma: This pituitary tumor arises from Rathke pouch, part of the oral stomadeum that histologically appears somewhat like ameloblastoma. However, it is actually more like the Gorlin cyst.
• Peripheral ameloblastoma: This lesion is histologically identical to the central ameloblastoma, but it does not involve bone and is confined entirely to the gingiva. It has a lower potential for growth and invasion than the central ameloblastoma, and, quite possibly, it is responsible for reported cases of basal cell carcinoma in the gingiva.
• Malignant ameloblastoma: Approximately 2% of ameloblastomas metastasize, usually to the lungs. It is thought that these lesions actually may be the result of aspiration of material from fungating lesions in the oral cavity and, therefore, do not represent true metastases.
• Ameloblastic carcinoma: These are cytologically malignant lesions with hyperchromatism, pleomorphism, and high mitotic activity. Real metastases occur with ameloblastic carcinoma.

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