Unusual Periapical Pathosis - Adenoid Cystic Carcinoma

Clinical ZJpdateAnd Case Report By Dr Paul V. Abbott, BDSc, MDS. FRACDS(Endo), FPFA. FADI. FICD, Endodontist, 5 Westley Avenue, Ivanhoe, Victoria, 3079.

Unusual Periapical Pathosis Adenoid Cystic Carcinoma Introduction The vast majority of periapical radiolucenciesrepresent periapical pathosis due to diseases of the dental pulp. However, there are many other pathological entities that present as radiolucencies of the jaws and at times they may be positioned near the apex of a tooth root. Hence, these diseases can masquerade as periapical pathosis of endodontic origin which may lead to diagnostic difficulties and challenges for the clinician. In such cases, the diagnosis can usually only be confirmed by histological examination of a tissue +sy specimen that has been obtained surgically. Then, once the disease has been identified, appropriate treatment can be provided which will lead to more favourable treatment outcomes with lower morbidity and greater patient survival. No studies have been reported in the literature to indicate whether dental practitioners routinely submit surgically-obtained periradicular tissue specimens for histological examination even though it is recommended by professional associations and teaching authorities. However, it is likely that very few general dentists submit such tissue samples whereas some endodontists and most oral and maxillofacial surgeons do so routinely. In an internationaljournal editorial recently, Walton questioned whether routine histopathologic examination of endodontic periradicular surgical specimens was warranted and he concluded by saying that it could not be justified (I). Walton stated that the presumed intention to identify non-endodontic lesions was reasonable, but he questioned whether such identification did ever in fact occur. Walton claimed that there were not enough meaningful occurrences where a more invasive or dangerous lesion had been discovered as a result of such a biopsy (I). Some of Walton's other reasons included: The benefit does not outweigh the risks or justify the expense to the patient and to the insurance carrier. It is little more than an exercise that may be of academic interest but is of no value to the patient. Careful, systematic clinical diagnosis will (and should) ddferentiate endodontic pathosis from non-endodontic pathosis. During endodontic surgery, very little of the pathologic tissue is recovered and is often crushed so it may only be by chance that an entity other than inflammatorytissue is identified. These reasons can be readily invalidated by common sense and clinical experience. Firstly, it is difficult to imagine what risk there could be to the patient or to the insurance carrier by placinga tissue specimen into a biopsy jar and sending it to a pathology service for examination. Secondly, the expense is only minimal in Australia as most of the costs of the pathological examination will be covered by Medicare. Thirdly, patients generally prefer to be informed of the diagnosis and natureof their disease, particularly if they perceive that it was serious enough to justify surgical treatment. Fourthly, the value of an accurate diagnosis lies in the ability to provide adequate. appropriate and timely treatment. Fdhly, clinical diagnosis is not always reliable (see below) and fi~lly.experienced oral pathologists AUSTRALIAN ENDODONTIC JOURNAL VOLUME 27 No. 2 AUGUST 200 I

are usually able to diagnose sinister diseases even with less than optimal tissue specimens. The publication of Walton's controversial editorial statements was followed by numerous "Letten to the Editor" in the same journal (2-7). all of which strongly disagreed with him and it was notable that there has not been a single letter written in support of Walton's point of view. The letters came from the President of the American Association of Endodontists (2) and the President of the American Academy of Oral and Maxillo-Facial Pathologists (3), as well as from independent oral pathologists, oral surgeons and endodontists (4-7). The authors of all of these letters disputed the rationale of Walton's arguments and provided examples of various lesions that had been identified by routine biopsies of periradicular surgical specimens. The list of diseases identified in this way included: myeloma, leukaemia, antral carcinoma, osteogenic sarcoma, malignant lymphomas, odontogenic keratocysts. Langerhans cell granulomatosis. metastatic renal adenocarcinoma. central cemento-ossifying fibroma, adenoid cystic carcinoma of the mandible, and primary central squamous cell carcinoma (2-7). It is not known how often these diseases mimic periapical pathosis because not enough cases are reported in the literature. They probably occur quite rarely but all of the authors of these letters agreed that the serious nature and potential consequences of these diseases are sufficient to just@ the routine histological examination of all surgically removed tissues. Walton's premise was based on havinga correct clinical diagnosis (I). However, it must be recognised that clinical diagnosis is not infallible and even competent practitioners cannot always be correct. Diagnosis can be affected by many factors and is somewhat subjective at times because clinicians rely to a large extent on the history and description of symptoms provided by the patient. Clinical tests and radiographs are essential tools which can be very helpful but they are not always reliable. Central malignancies of the jaws often destroy adjacent nerves (5) and hence pulp sensibility tests can be midleading. This problem can be overcome to some extent by always assessing the aetiology of any suspected pulp disease before endodontic treatment is commenced because pulp diseases will always be caused by some irritant (for example, caries, cracks, leaking restoration, trauma, etc.). The absence of the common aetidogical factors should be considered as a "warning sign" to suggest that the differentialdiagnosis needs to be extended to include diseases other than those of endodontic origin. Diagnosis may be even more complicated in many cases - such as when the patient is referred to a specialist after some treatment (usually endodontic) has been provided unsuccessfully (7). It may then be impossible for the specialist to make a retrospective diagnosis as to whether there was indeed periapical pathosis of endodontic origin present originally. The situation may be even further complicated if the endodontic treatment had not been performed to an acceptable technical standard or with aseptic techniques. 73

The following case report emphasises the need to submit all tissue samples removed during periapical surgery for histological examination.

Case Report A 5 I-year-old male was referred to the author in February I999 with a two-year history of pain and numbness of the right half of his palate. A detailed history was obtained and this indicated that endodontic treatment of tooth I.5 had been commenced in I99 I by a general dentist. The patient stated that he had pain prior to this treatment but he could not recall the details of his symptoms. The treatment was not completed as the patient went overseas for the next five years. He recalled having an occasional dull ache during this time and then the buccal cusp fractured off the tooth in I997 so he returned to his dentist. The numbness of the palate was noted at that time and his dentist re-commenced the endodontic treatment of tooth I.5.The symptoms did not change but the root canal filling was completed anyway. A temporary restoration was placed within the endodontic access cavlty but the tooth was not restored any further. The aching and numbness continued and so the patient consulted with his general medical practitioner who advised him to take antibiotics for a "tooth abscess" but this did not change the situation. He subsequently consulted with two other dentists. another general medical practitioner. two Oral & Maxillo-Facial Surgeons, one Ear, Nose and Throat Surgeon, and one Neurologist. Various diagnostic tests were performed, including periapical and panoramic radiographs, CT scans of the jaws and brain. and blood tests. No definitive diagnosis was offered and the medical practitioners kept saying that it was "just an infected tooth". The patient became quite disillusioned with the situation and refused to have a k p s y that was suggested by one of the oral surgeons. The patient then saw a new dentist who referred him for an endodontic assessment. The history and symptoms (especially the numb palate) suggested a "non-endodontic" disease but diagnosis was complicated by having had previous endodontic treatment of tooth I.5. It was not possible to retrospectivelydetermine whether this endodontic treatment had been required in I99 I. In addition, there were several complicating factors which indicated that the root canal system was very likely to be infected again (with an associated chronic apical periodontitis in addition to the original pathosis) - these complicating factors included: incomplete endodontic treatment in 1991; a technically unsatidactory root canal filling with gross over-extension of the root filling materials through the wide open apical foramen; the tooth had not been adequately restored; and the temporary restoration was defective (Fig. I). The patient was advised of the above findings and of the endodontist's concerns about the nature of the radiducency and the cause of the numbness of his palate. The differential diagnosis included the above endodontic problems and some form of "nonendodontic pathosis". The patient was advised that it was possible that the "periapical lesion" may have been placing pressure on the greater palatine nerve to cause the numbness, but the author was not aware of any previous case reports of this happening in the palate. However, there are reports of periapical abscesses causing anaesthesia and paraesthesia of the lower lip due to pressure being place on the mental nerve (8.9). A consultation was arranged M h an Oral and Maxillo-Facial Surgeon to further assess the lesion with a view to curettage and biopsy of the maxillary lesion. The mesially-impacted 4.8 and the very carious 4.7 also required extraction and therefore a general 74

Fgure I :Penapical radiogroph taken on presentation in I 999 to the endodonost. Note the unrestored crown. the technicolly unsoos$actory root canal filling wth gross apical aver-extenwon of filling materials. and the large radiolucency extending throughout the entire maxilla ond moxillary antrum

Figure 2: Penopicol radiogroph taken immediately after placing the new root canol filling and prior co surgery

anaesthetic was arranged. The treatment plan also included endodontic re-treatment of the I .5 prior to surgery as this tooth was deemed to be restorable and desirable to retain for occlusal and functional reasons. Endodontic re-treatment was required due to the infected root canal system. The previous root canal filling was removed and the canal was cleaned and medicated with a mixture of a corticosteroid/antibiotic paste and calcium hydroxide. A temporary restoration was placed using a stainless steel band and glass ionomer cement. The patient did not have any relief of his symptoms over the following three weeks which provided further evidence that the lesion was not likely to be endodontic in origin. A new root canal filling was then placed one day prior to surgery (Fig. 2) when the large lesion was curetted. The oral surgeon noted that the lesion extended into the maxillary antrum and the tissue was sent for histological examination. The histopathology report indicated that the lesion was an infiltrative glandular tumour which had not been completely removed. There were nests of epithelial cells within a myxomatous matrix. The epithelium was forming both small and large ducts, and there were areas of cystic-like spaces scattered throughout a chronically-inflamedfibrous connective tissue stroma. There was respiratory epithelium. presumably from the lining of the maxillary antrum, along one border but the rest of the lesion was not AUSTRALIAN ENDODONTICJOURNALVOLUME 27 No. 2 AUGUST 2001

encapsulated. The dtfferential diagnosis included a polymorphous adenocarcinoma or an adenoid cystic carcinoma with the latter being the most likely diagnosis. Subsequently, the patient had a hemi-maxillectomyand radiotherapy. A prosthesis/obturator was constructed and after two years, he is alive and well. Annual review appointments have been recommended and the patient is expected to have at least a I0-year prognosis but this is difficult to estimate.

Conclusion This case demonstrates that sinister lesions can masquerade as periapical pathosis due to pulpal disease and it emphasises that ALL surgically removed tissue specimens should be examined histologically. If all periapical tissues were discarded then such lesions would not be diagnosed until a later stage of the disease which may have an adverse effect on morbidtty and survival. Finally, when considering the question "To biopsy or not to biopsy?",remember the old adage: ''If it's worth toking out then it's worth c k k i n g out!".

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Acknowledgements Thanks to Dr Anna Talacko and Prof. Michael Aldred of Dorevitch Pathology in Melbourne for their assistance and histological diagnosis, and to Assoc. Prof. Andrew Smith for his advice and surgical management of this patient.

References I . Walton R.E. Routine histopathologic examination of endodontic periradicular surgical specimens - is it warranted?Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998; 86: 505. 2. Newton C.W To biopsy or not? Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999; 87: 642. 3. Ulrs G.L.To biopsy or not?Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999; 87: 642-3. 4. Ramer M. To biopsy or not?Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999; 87: 643-4. 5. Boughman R.A. To biopsy or not?Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999: 87: 644-5. Periapical biopsy or not. Oral Surg Oral Med 6. Summerlin 0.). Oral Pathol Oral Radiol Endod 1999; 88: 645-6. 7. Talacko A.. Aldred M.)., Smith A.. Abbott PK, Nerwich A. Periapical biopsy?Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000; 89: 532-3. 8. Abbott PV Lower lip paraesthesia following restoration of a second premolar tooth. Case report. Aust Dent J 1997; 42: 297-30 I. 9. 0ntavrk D.. BrodIn P, Aas E. Paraesthesia following endodontic treatment: survey of the literature and case report. Int Endod J 1983: 16: 167-72.

From The Journals Pulpal Responses To Cooling Tooth Temperatures Goodis H.E.. Winthrop K. White).M. Endod 2000; 26: 263-7 This investigation presented a unique method of lowering tooth temperatures to study the interactions that might occur between pulpal microvasculature and pulpal sensory nerve thresholds. The study measured pulpal blood flow and sensitivtty to electrical stimulation as tooth temperatures were lowered. Dark rubber dams were placed on test teeth before placement of the cooling device in an attempt to shield gingival microcirculation. Laser Doppler flowmetry was used to measure pulp blood flow, while sensory thresholds were recorded simultaneously using an electric pulp tester. As tooth temperatures were lowered, the teeth became less responsive. Pulp blood flow also slowed. but did not completely stop. Results indicated that sensory thresholds were altered. and in some subjects, abolished, without total cessation of pulpal blood flow. Continuous blood flow is necessary so that noxious substances may be prevented from accumulating in the pulp. This IS especially true due to the low compliance nature of the pulp, which has no collateral circulation. It has been shown that injection of local anaesthetic solutions completely blocks pulp blood flow. Therefore, AUSTRALlAN ENDODONTICJOURNALVOLUME 27 No. 2 AUGUST 2001

cooling the tooth before and during operative procedures may be a better method of controlling adverse responses to restorative procedures than the use of local anaesthetics. because the pulp blood flow, while reduced, still occurred throughout cooling. The results suggest that nerves are affected by cooling more than the pulp blood flow. Furthermore. cooled nerves should release fewer neuropeptides when the pulp is stimulated, as in tooth restoration procedures. This may occur due to tooth cooling desensitising pulpal receptors, preventingrelease of neuropeptides.Cooling may cause a fall in metabolic rate of pulpal tissue. so that the consequences of ischaemia may be less than when the pulp tissues are at normal body temperatures. This study presents a non-invasive method of evaluating sensory thresholds and pulp blood flow in response to lowered tooth temperatures. Tooth cooling. as a clinical method of reducing adverse pulpal reactions, awaits evaluation. A consideration in such an evaluation is the length of time requiredto produce the observer effects. If that time IS shortened without discomfort to the patient. consideration of tooth cooling as a replacement for injectable anaesthetics may become useful. 75