The patient is a 64-year-old woman with a nonhealing oral ulcer.
Karen T. Pitman, MD: We will be discussing the case of a 64-year-old woman who was referred to the Department of Otolaryngology, University of Pittsburgh Medical Center, with the chief complaint of a nonhealing ulcer in the oral cavity that had been present for 2 months. Upon further questioning, the patient noted the recent onset of right otalgia and a 10-pound weight loss. She denied experiencing trismus or odynophagia.
The patient's social history was remarkable for alcohol(Drug information on alcohol) and tobacco abuse. Her past medical and surgical history was remarkable only for periodontal disease and the subsequent loss of all dentition 10 years ago. An otolaryngologist in the community had seen her 2 weeks prior to referral, and a biopsy of the oral ulcer disclosed squamous cell carcinoma.
On physical examination, the patient appeared to be adequately nourished and to be her stated age. Inspection of the oral cavity revealed that the patient was edentulous and had an ulcerative lesion of the right retromolar trigone, which extended into the soft palate, buccal mucosa, and base of the tongue. Leukoplakia was noted along the floor of the mouth and the right ventral surface of the tongue. Figure 1 depicts the location of the lesion, which had its epicenter on the alveolar process of the ascending ramus of the mandible.
Flexible fiberoptic examination of the nasopharynx, hypopharynx, and larynx was normal. There was no palpable cervical adenopathy.
Our pathologists reviewed the biopsy specimens obtained at the outside institution and confirmed the diagnosis of moderately differentiated squamous cell carcinoma.
Dr. Pitman: What specific concerns would you have about the extent of the primary lesion?
Carl H. Snyderman, MD: Tumors in the retromolar trigone typically present at an advanced stage. Tumors in this area raise several concerns. First, the close proximity of the retromolar trigone to the mandible poses a high risk of invasion of the mandible, either by direct invasion through the alveolar surface or along the inferior alveolar nerve. Another concern is the deep infiltration into the pterygoid musculature, making it more difficult to obtain clear surgical margins. With involvement of the tongue base and soft palate, there is downgrading of oral function following surgery, which should be considered the therapy of choice. There is also the risk of a second primary tumor.
Dr. Pitman: How do you clinically assess the patient for bone invasion?
Dr. Snyderman: One historical clue is the presence of hypesthesia or paresthesia of the inferior alveolar nerve. In my experience, however, I have found these symptoms to be rare, and I tend to rely on radiographs to determine bony invasion. In the edentulous patient, there may be irregularities on the mandibular surface due to prior dental extractions, which can mimic erosion by cancer. I usually start with a CT scan to evaluate the mandible for cortical erosion. If perineural infiltration is a concern, MRI is probably a better imaging study to look for extension of the tumor along the marrow space.
Dr. Pitman: Both CT and MRI were obtained before the patient was referred to our institution. Dr. Weissman, from a practical standpoint, when one encounters a patient with a tumor approximating bone who has not undergone imaging studies, what is your recommendation about the sequence of imaging studies to obtain?
Jane L. Weissman, MD: The questions you ask will determine which studies you recommend. If you want to determine whether the mandible exhibits cortical erosion, a CT scan is the study of choice. Ideally, images should be obtained perpendicular to the tumor mass so that you could optimally look for enhancement along the course of the nerve within the bone. The inferior alveolar nerve will enhance long before the CT scan shows erosion or enlargement of the osseous canal.
Dr. Pitman: Dr. Weissman will now review the radiographic studies obtained for this patient.
Dr. Weissman: A contrast-enhanced CT scan demonstrated the extensions of the soft-tissue mass (Figure 2). On the side of the tumor, the fat is effaced, and the tumor is inseparable from the ascending ramus of the mandible and from the posterior aspect of the maxilla. The tumor is also inseparable from the pterygoid muscles. The tumor extends into the lateral aspect of the soft palate and uvula. At the base of the tonsillar pillar, there is a suggestion that the tumor is extending submucosally around the glossopharyngeal sulcus and into the base of the tongue.
It is difficult to assess bone involvement from this study. Gross involvement would be apparent; you would see frank erosion of the mandible. Gross perineural involvement might be apparent with replacement of the normal marrow.
The axial T1-weighted MR images before contrast demonstrate that the tumor does abut the signal void of the cortex of the ascending ramus; this is seen better after gadolinium enhancement and with fat suppression (Figure 3). The MRI shows that the tumor is inseparable from the mandible, but the subtle irregularity of the cortex is imperceptible. You can see the tumor infiltrating into the confluent pillar, again probably submucosally, and extending downward.
The images of the neck show some suspicious lymph nodes. By size criteria, these nodes are normal, but the inhomogeneous enhancement suggests the possibility of tumor involvement.
In summary, the radiographic studies reveal a tumor in the retromolar trigone, extending to the lateral aspect of the soft palate and along the glossopharyngeal sulcus to the tongue base. There is no other tumor involvement of the mandible, but subtle cortical erosion cannot be assessed by these studies. Examination of the neck shows a suspicious mass in the right neck (level II), and the left neck looks normal.
Dr. Pitman: Are there any other studies that could be obtained to help assess for mandibular invasion?
Dr. Weissman: A software package for the CT scanner called the DentaScan is used in our institution to evaluate the thickness of the alveolus in edentulous patients in whom the dentist is planning to do dental implants. What makes it useful for the dentist and for our purposes is that this program allows you to obtain extremely thin slices through the alveolar process. Typically, 1.0-mm intervals are utilized, and they are scanned without an interslice gap. This is usually done without contrast for the purpose of looking for obvious bony involvement, rather than the extent of the soft-tissue component of the tumor.
The DentaScan software reformats direct coronal and axial images. I think that perhaps the axial images and the 1.0-mm thin slices are the most helpful part of this study for evaluating both the maxillary buttress and the ascending ramus of the mandible.
Jonas T. Johnson, MD: I would argue that further imaging of this patient is unnecessary, because it is inconceivable that you would surgically manage a T3 lesion of the retromolar trigone without a segmental mandibulectomy. The only exception would be if you were considering the possibility of irradiating the patient, in which case, further imaging might be needed to convince yourself that irradiation would be a bad choice. The retromolar trigone comprises the soft tissue overlying the mandible, and less than a segmented resection would be an inadequate oncologic operation. Conceptually, what you need to ask yourself is how extensive a resection is needed. In this case, I think a segmental mandibulectomy is a foregone conclusion.
Dr. Pitman: Before proceeding with the formulation of the treatment plan for this lesion, the presence of a second primary carcinoma or distant metastasis must be ruled out. What further studies should be obtained for this purpose?
Jennifer R. Grandis, MD: The lung and esophagus are among the most common sites of second primary tumors in patients with upper aerodigestive tract squamous cell carcinoma. These tumors would be discovered by radiographic studies, such as a barium swallow and chest radiograph. Examination under anesthesia and direct laryngoscopy are also performed. I do not routinely do bronchoscopy to rule out endobronchial primaries. Distant metastases are relatively uncommon, and the most likely location is the chest.
Dr. Pitman: Do you think that flexible fiberoptic laryngoscopy performed in the office is satisfactory for an endoscopic examination, or do you need to repeat the examination in the operating room?
David E. Eibling, MD: The answer to that question, I think, depends on the patient. I occasionally perform flexible fiberoptic laryngoscopy in the office. However, I routinely repeat it in the operating room, although the question of whether this is necessary is valid. In some cases, you really are less able to examine certain areas, such as the post-cricoid area and pyriform sinus, in the office; these are best seen in the operating room.
Dr. Johnson: I would still repeat laryngoscopy, in part, because I agree that you probably see some areas, such as the pyriform sinus, better directly than indirectly. I also do esophagoscopy in the operating room. Since I am doing endoscopy, it seems appropriate to look both places, but I have wondered if that is necessary because we have already done flexible endoscopy in the office and billed for it.
Eugene N. Myers, MD: I think that the two examinations are complementary, and I do not exclude either one. The only way to evaluate vocal cord movement is in the office when the patient is awake. Often, because of a tumor that is either bulky or exophytic and hangs over the glottis or into the pyriform sinus where there is a lot of edema, you really do not obtain an accurate view of the extent of the tumor on an office examination.