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| Carcinoma Ex Benign Pleomorphic Adenoma of the Parotid Gland
S. A. Reza Nouraer M.A.(Cantab.), M.B.B.Chir., Kirsten L. Hope, M.B.B.S., Charles G. Kelly, M.R.C.P., F.R.C.R., Neil R. McLean, F.R.C.S., and James V. Soames, B.D.S., Ph.D., F.D.S.R.C.P.S. Presented at the British Association of Plastic Surgeons Winter Scientific Meeting, in London, England, December of 2003, and at the Royal Australasian College of Surgeons Scientific Meeting, in Melbourne, Australia, May of 2004. Awarded Best Presentation Prize at the British Association of Head & Neck Oncologists Annual Scientific Meeting, in London, England, May of 2004.
London, Liverpool and Newcastle upon Tyne, United Kingdom; and Adelaide, Adelaid, Australia
Background: Carcinoma in pleomorphic salivary adenoma is a common histologic subtype of primary parotid malignancy.
Methods: In this study, 28 patients (predominantly male) with histologically diagnosed carcinoma in pleomorphic salivary adenoma presenting over 10 years were retrospectively reviewed.
Results: Only 25 percent of patients had a previously treated pleomorphic salivary adenoma. Although the presenting features suggested malignancy in some cases, over all they were nonspecific, overlapping with the presentation of benign disease. Preoperative investigations included fine needle aspiration cytology, which was only 29-per cent sensitive, and computed tomography and/or magnetic resonance imaging. There were 14 superficial and 12 total or radical parotidectomies. The facial nerve was resected en bloc with the tumor in nine cases and immediately reconstructed with good reanimation results in patients with recent-onset facial paresis. Only 44 percent of patients had a complete histologic tumor clearance, and this was the most significant determinant of survival (p <0.01, log-rank analysis). The locoregional control rate was 66 percent at 5 years, but recurrent disease proved invariably fatal. Five-year disease specific survival was 44 percent with a high rate of disease specific mortality (87 per cent).
Conclusions: Carcinoma in pleomorphic salivary adenoma is very difficult to diagnose preoperatively. Fine needle aspiration cytology had a disappointingly low sensitivity for this tumor, potentially misdirecting surgical management. While good locoregional disease control could be achieved with surgery and radiotherapy, carcinoma in pleomorphic salivary adenoma was shown to be aggressive with a high disease-specific rate of mortality. Given that incomplete tumor resection was the most important prognostic factor, a high index of clinical suspicion, radical ablative surgery, and immediate soft-tissue and nerve reconstruction for proven cases are advocated. (Plast. Reconstr. Surg. 116: 1206, 2005.)
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Carcinoma Ex Benign Pleomorphic Adenoma of the Parotid Gland
S. A. Reza Nouraer M.A.(Cantab.), M.B.B.Chir., Kirsten L. Hope, M.B.B.S., Charles G. Kelly, M.R.C.P., F.R.C.R., Neil R. McLean, F.R.C.S., and James V. Soames, B.D.S., Ph.D., F.D.S.R.C.P.S.
Presented at the British Association of Plastic Surgeons Winter Scientific Meeting, in London, England, December of 2003, and at the Royal Australasian College of Surgeons Scientific Meeting, in Melbourne, Australia, May of 2004. Awarded Best Presentation Prize at the British Association of Head & Neck Oncologists Annual Scientific Meeting, in London, England, May of 2004.
London, Liverpool and Newcastle upon Tyne, United Kingdom; and Adelaide, Adelaid, Australia
Background: Carcinoma in pleomorphic salivary adenoma is a common histologic subtype of primary parotid malignancy.
Methods: In this study, 28 patients (predominantly male) with histologically diagnosed carcinoma in pleomorphic salivary adenoma presenting over 10 years were retrospectively reviewed.
Results: Only 25 percent of patients had a previously treated pleomorphic salivary adenoma. Although the presenting features suggested malignancy in some cases, over all they were nonspecific, overlapping with the presentation of benign disease. Preoperative investigations included fine needle aspiration cytology, which was only 29-per cent sensitive, and computed tomography and/or magnetic resonance imaging. There were 14 superficial and 12 total or radical parotidectomies. The facial nerve was resected en bloc with the tumor in nine cases and immediately reconstructed with good reanimation results in patients with recent-onset facial paresis. Only 44 percent of patients had a complete histologic tumor clearance, and this was the most significant determinant of survival (p <0.01, log-rank analysis). The locoregional control rate was 66 percent at 5 years, but recurrent disease proved invariably fatal. Five-year disease specific survival was 44 percent with a high rate of disease specific mortality (87 per cent).
Conclusions: Carcinoma in pleomorphic salivary adenoma is very difficult to diagnose preoperatively. Fine needle aspiration cytology had a disappointingly low sensitivity for this tumor, potentially misdirecting surgical management. While good locoregional disease control could be achieved with surgery and radiotherapy, carcinoma in pleomorphic salivary adenoma was shown to be aggressive with a high disease-specific rate of mortality. Given that incomplete tumor resection was the most important prognostic factor, a high index of clinical suspicion, radical ablative surgery, and immediate soft-tissue and nerve reconstruction for proven cases are advocated. (Plast. Reconstr. Surg. 116: 1206, 2005.)
The prognosis for patients with primary parotid malignancy is highly dependent on tumor histology. (1-3) Carcinoma arising from pleomorphic salivary adenoma is a common tumor subtype; its diagnosis requires histologic demonstration of both invasive adenocarcinoma, which is most commonly of the poorly differentiated, "not-otherwise-specified" variety, juxtaposed with regions of benign mixed tumor (Fig.1). (3-6) Not uncommonly, however, by the time the patient presents, the invasive adenocarcinoma will have fully replaced the benign element. In these cases, the diagnosis is inferred from the presence of hyaline scarring, Nhich is highly characteristic of degenerated benign pleomorphic adenomas. (3) There are yet to-be-explained geographical differences in the incidence of this tumor type. In the United Kingdom, carcinoma-ex-pleomorphic salivary idenoma is the most common subtype of primary parotid malignancy (25 percent) (4) and the second most common primary submandibular carcinoma (26 percent), (7) whereas, in the United States, it is less prevalent than mucoepidermoid carcinoma and adenocarcinoma, accounting for around 12 percent of primary parotid malignancies. (8)
Even though this diagnosis, by definition, requires histologic evidence of a preceding plemorphic adenoma, (3,9,10) the temporal association between the pleomorphic salivary adenoma and this malignancy is unclear. Malignant degeneration accounts for 5 to 7 percent of recurrent pleomorphic adenomas, (9-12) and this possibility must to be considered in evaluating patients with recurrent "benign" pleomorphic adenomas. Very little is known, however, about the epidemiology of de novo carcinoma in pleomorphic salivary adenoma presentations, (i.e., malignancies presenting for the first time, having arisen in previously undetected, benign pleomorphic adenomas).
There also is controversy regarding the optimal surgical management of these tumors, and, in particular, the treatment of the facial nerve. Radical parotidectomy and facial-nerve sacrifice with neck dissection have been advocated for carcinoma-ex-pleomorphic salivary adenoma (3) ; however, many surgeons remain divided in their approach to the management of the facial nerve. Some preserve a functioning nerve close to the tumor margin, on the grounds that good postoperative disease control is achieved with planned radiotherapy, while others sacrifice and reconstruct these nerves on the premise that despite good locoregional disease control with postoperative radiotherapy, compromising resection margins could be oncologically unsafe. (13,14)
As malignant parotid disease accounts for less than 0.6 percent of head and neck neoplasms, (15-17) most published reports have, by necessity, presented pooled data from different malignant tumors, and, consequently, many of these controversies remain unresolved for individual tumor types. We, therefore, undertook a review of cases of carcinoma-ex pleomorphic salivary adenoma presenting in North East England over a 10-year period. |
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Fig.1. Histologic appearance of carcinoma-ex-pleomorphic salivary adenom. Myxochondroid stroma, pathognomonic of benign pleomorphic adenoma, A. Poorly differentiated adenocarcinojma, B. Remnants of normal parotid tissue, C.
PATIENTS AND METHODS
Demographic details of all patients treated at the multidisciplinary Head and Neck Oncology Service at the Northern Centre for Cancer treatment between 1989 and 1998 with the histologic diagnosis of carcinoma in pleomorphic salivary adenoma of the parotid gland, based on the World Health Organization Inter ational Classification, (17) were reviewed retrospectively. Information about the source of referral, clinical presentation, diagnostic workup, surgical and adjuvant therapies, morbidity, and outcome was obtained from the clinical notes and operating records, the Northern Centre for Cancer Treatment's database, and pathology databases.
Data were presented either as means with SD or as percentages, when appropriate. Diseasefree interval and survival times were calculated using the Kaplan-Meier's method with log-rank statistics. The impact of the different variables on survival was assessed using Cox Regression analyses. Data were analyzed and displayed using Minitab release 13.2 for Windows (Minitab Inc., State College, Pa.).
RESULTS
General
In the 10-year study period, 28 patients were treated with a diagnosis of carcinoma in pleomorphic salivary adenoma. There were 19 men and 9 women (ratio, 2.1:1) and the average age of presentation was 61 14 years (Mean SD; range, 32 to 86), with no significant sex difference in the age of presentation. Five patients (18 percent) were referred for surgical management to our center following a biopsy procedure that demonstrated parotid malignancy, and the remainder underwent parotid surgery as their first operative intervention. There were 13 left- and 15 right-sided tumors.
History of Previous Benign Pleomorphic Adenoma
Only seven patients (25 percent) had a history of a previously treated benign pleomorphic adenoma before presenting with carcinoma in pleomorphic salivary adenoma. Of those, four patients had carcinoma in pleomorphic salivary adenoma as their first recurrence, occurring on average 14 years (range, 5 to 25 years) following superficial parotidectomy. Three patients had at least one benign recurrence before malignancy, having all been initially treated by parotid excision.
Clinical Presentation
The median duration of symptoms was 6 months (interquartile range of 4 to 12 months) and the most frequently reported symptom was the presence of a parotid mass (96 percent). The nature and frequency of the presenting features are given in Table I.
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Table 1 : Presenting Features of Carcinoma in Pleomorphic Salivary Adenoma
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| Feature* |
No. (percent) |
| Parotid mass |
|
| Present |
24 (96) |
| Not present |
1 (4) |
History of recent growth |
|
| <6 months |
13 (52) |
| <12 months |
19 (76) |
| 18 months |
20 (80) |
| long-standing (>18 months) |
2 (8) |
| Patient did not know |
3(12) |
| Fixation (skin or deep) |
4 (16) |
| Palpable lymphadenopathy Pain |
5 (20) |
| Tumor fungation |
3 (12) |
| Facial nerve patsy |
|
| No involvement |
19 (76) |
| Long-standing involvement (previous surgery) |
2 (8) |
| Recent-onset involvement |
4 (16) |
| Dentures not fitting |
1 (4) |
| Multiple presenting features (cumulative) |
|
| Mass as the sole presenting feature |
6 (24) |
| Mass with one associated feattire |
15 (60) |
| Mass with Iwo associated features |
22 (88) |
| Mass with >two associated features |
25 (100) |
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Preoperative Evaluation
Fourteen patients (50 percent) had fine needle aspiration cytology. Twelve of these patients had no previous history of parotid disease, one had a superficial parotidectomy for benign pleomorphic adenoma 24 years previously, and the other had undergone two previous parotid excisions and radiotherapy dating back over 55 years. Malignant cells were only identified in four cases: fine needle aspiration cytology was unsuccessful in one patient, and the remaining nine cases were reported as benign pleomorphic adenoma. This gave a sensitivity of 29 percent for diagnosing malignancy in this series. Of the remaining 14 patients, three had an incisional biopsy, one a trucut biopsy, and another patient presented with a palpable lymph node that was biopsied. All were diagnostic of malignancy. Five patients with 'recurrent' disease underwent surgery without prior histologic evaluation and four patients with first presentation also had operation without preoperative cytology or histology (Table II). |
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Table II : Preoperative Histological Evaluation
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| Mode of Investiagation |
No. |
| Fine needle aspiration cytology |
14 (50% of total) |
| Unsuccessful |
1 (7%) |
| Diagnotic of ueoplasm |
13 (93%) |
| Diagnostic of malignant neoplasm |
4 (29%) |
| Biopsy (all diagnostic of malignancy) |
5 (18% of total) |
| Incisional biopsy |
3 |
| Trucut biopsy |
1 |
| Lymph node biopsy |
1 |
| No pre-operative histological evaluation |
9 (32% of total) |
| Presenting as ‘recurrent pleomorphic adenoma |
5 |
| First presentation with parotid disease |
4 |
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Fifteen patients (53 percent) had preoperative imaging. Twelve had computed tomography alone or computed tomography in combination with magnetic resonance imaging and three patients had preoperative magnetic resonance imaging only. Magnetic resonance imaging was believed to be superior to computed tomography in terms of better delineation of tissue planes. Two patients underwent postoperative computed tomography scanning, which demonstrated advanced local disease in one patient, and disseminated malignancy in an other.
Operative Treatment
Two patients presented with metastatic disease and were treated with primary palliative radiotherapy. Fourteen patients underwent a superficial parotidectomy. Twelve underwent more radical surgery and the facial nerve was sacrificed in nine cases. Six patients underwent concomitant neck dissection for clinical or radiological neck disease, all in conjunction with a radical parotidectomy. There was one functional, one modified, and four radical neck dissections. Malignant infiltration of the cervicai lymph nodes was histologically confirmed in all patients undergoing neck dissection.
Immediate reconstructive surgery was per formed for facial re-animation and soft-tissue coverage. Six patients had sural nerve grafting, and the radial forearm free flap was the flap most frequently used to reconstruct the soft tissue defect (Table III) |
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Table III : Details of Surgery Performed
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| Type of Surgery |
No. |
| Ablative surgery |
|
| Parotidectomy |
|
| No operation performed (palliative radiotherapy) |
2 |
| Superficial parotidectomy |
14 |
| Total parotidectomy |
3 |
| Radical parotidectomy |
9 |
| Neck dissection surgery |
|
| No neck dissection |
19 |
| Functional neck dissection |
1 |
| Modified neck dissection |
1 |
| Radical neck dissection |
4 |
| Not specified |
1 |
| Reconstructive surgery |
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| Facial re-animation surgery |
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| Immediate aural nerve grafting |
6 |
| Soft—tissue reconstruction |
|
| Radial forearm free flap |
5 |
| Sternornastoid flap |
1 |
| Cervical rotation flap |
1 |
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Pathologic Findings
The tumor extended to the margins of resection in 56 percent of cases and lymph nodes with metastatic tumor deposits were identified in 32 percent of specimens, either in the neck dissections or within the surgical excision specimens. The type of operative procedure performed did not influence the likelihood of achieving histologic tumor clearance (likelihood ratio, 1.12; p > 0.4, Fisher's Exact Test).
Radiotherapy
All patients received adjuvant external beam irradiation of 63 Gy in 30 fractionated sessions commencing within 6 to 8 weeks of surgery. For two patients with disseminated malignancy at presentation, this was the only form of therapy, performed with palliative intent.
Morbidity
Two patients developed infections postoperativelyone had pneumonia and the other a wound infectionboth settled with antibiotics. A third patient developed a frozen shoulder following radical neck dissection, which improved with physiotherapy. There was one flap failure; a cervical rotation flap was dbrided and replaced with a split thickness skin graft.
There were two cases of longstanding preoperative facial nerve palsy. The nerve was sacrificed in both cases with no reconstruction. Of the remaining seven cases, where the facial nerve was sacrificed intraoperatively, six were immediately reconstructed with sural nerve grafting and of those six patients, five had very good recovery at 1-year follow-up. There was one case of lip weakness in a patient with superficial parotidectomy and nerve preservation, which recovered spontaneously. two patients developed mild Frey's syndrome that did not require treatment.
Disease Recurrence and Survival
No patient died perioperatively, and at the end of the follow-up period 12 patients were alive and 16 were dead, 14 of whom succumbed to disseminated malignancy within an average of 29 months (range, 3 to 64). The mean follow-up for patients who died was 29 5 months. Patients who were alive at the time of the study had been followed up for an average of 80 9 months.
Six patients developed locoregional recurrence. The average time to recurrence was 25.5 months (range, 2 to 50 months) and all but one of these patients died of the disease within an average of 13 months (range, 2 to 29 months). Significantly, there was no adverse relationship between flap coverage of the parotidectomy defect and local recurrence or survival (p> 0.4 in both cases, log-rank analysis). The 5-year locoregional disease control rate was 66 percent (log-rank analysis) and this is illustrated in Figure 2 using the Kaplan-Meier method. |
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Fig.2. Locoregional disease control with time (Kaplan Meier's method). The sample size is 26,
consisting of all patients who had a surgical procedure.
The 5-year disease-specific survival rate was 44 percent, which was significantly worse than for primary parotid malignancies as a whole in the same catchment area as reported by Malata et al. (4) (p < 0.02, Chi-square test). Nodal status, incomplete resection margins, and whether or not neck dissection was undertaken were identified by univariate log rank analysis and multivariate Cox regression as significant prognostic factors (p< 0.005). Among these, completeness of resection margins was the most significant determinant of prognosis (p < 0.01; Fig. 3). Importantly, the type of operation (superficial versus total parotidectomy) did not influence survival (p > 0.1; log-rank analysis). Overall disease-specific survival is illustrated in Figure 4 (Kaplan-Meier's analysis). |
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Fig. 3. R0 resection margins clear; R1/2, resectIon margins involved. Disease-specific
survival as a function of the completeness of surgical resection in patients with
carcinoma in pleomorphic salivary adennoma (Kaplan-Meier's method).
DISCUSSION
This study reviewed retrospectively all cases of carcinoma in pleomorphic salivary adenoma of the parotid gland seen in a multidisciplinary head and neck clinic over a 10-year period. While there are limitations to this study arising from the rarity of the condition and, therefore, the relatively small sample size, it was still possible to make important inferences about the presentation, tumor behavior, and outcome of patients presenting with this subtype of primary parotid malignancy. (4,7,18)
Almost all patients presented with a parotid mass, which is a nonspecific finding in the majority of parotid neoplasms. The duration of symptoms was more helpful, as 76 percent of patients had symptoms for less than 12 months. Other associated features were pain (20 per cent), tumor fungation (12 percent), fixation to adjacent structures (16 percent), and recent onset facial nerve paresis (16 percent). The nature and distribution of the presenting fea tures in this series correspond well with those found by other researchers. (2,19,20) It is crucial to point out that the majority of the presenting symptoms in our patients can also occur with
benign disease,8'2' stressing the importance of maintaining a high index of clinical suspicion, particularly in patients with recent onset of symptoms and in the presence of several presenting features (Table I). |
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Fig. 4. Disease-specific survival for patients with carci noma in pleomorphic salivary adenoma (Kaplari-Meier anal ysis).
Although carcinoma in pleomorphic salivary adenoma by definition arises from benign pleomorphic adenoma, the relationship between this malignancy and its preceding lesion appears complex. It is significant that only 25 percent of patients in this series had a previously treated benign pleomorphic adenoma and, furthermore, men were more than twice as likely to develop the disease than women. The causes for male preponderance are unknown, as both primary and recurrent pleomorphic adenomas predominantly occur in women. (12,21,22) It is possible that women seek advice for a parotid swelling earlier than men, who may neglect to seek advice for long periods and, thus, are more likely to present with malignant transformation. Further research is needed to better elucidate the pathological processes responsible for the development of carcinoma in pleomorphic salivary adenoma.
Computed tomography was the most commonly used imaging modality, but the authors now favor magnetic resonance imaging as the modality of choice, given its superior sensitivity in detecting malignancy and delineating tissue planes, as has been previously reported. (4, 23)
The diagnostic yield of fine needle aspiration cytology was particularly disappointing and potentially misleading in this series. While it was very sensitive in diagnosing neoplasia (sensitivity, 93 percent), comparing well with other published work, (24) it only identified four cases of malignancy (sensitivity, 29 percent). This discrepancy (24.25) potentially has significant clinical implications, in that a "positive" cyto logical diagnosis of benign pleomorphic adenoma could misdirect the initial management toward treating benign rather than malignant parotid disease.
Surgery was planned largely on the basis of tumor anatomy. It is clear that a combination of low clinical suspicion and fine needle aspiration cytology diagnosis of benign pleomorphic adenoma directed the initial operative management toward treating "benign" disease in a significant number of cases, resulting in incomplete histologic tumor clearance in 56 percent of patients. This compared unfavorably with the results of Malata and Camilleri (40 percent) whose large study looked at all histologic types of parotid tumors from the same catchment area. (4) This is also reflected in the fact that formal tumor-node-metastasis staging was not performed and relevant data were not recorded in a sizeable proportion of patients in this series, making it impossible for us to perform a survival-by-disease-stage analysis in this report.
Six patients had immediate facial nerve reconstruction of whom five had excellent facial reanimation at 1 year. Twenty-five percent of patients had soft-tissue reconstruction and the radial forearm free flap was the most common reconstructive option chosen. Flap coverage did not negatively impact disease recurrence and survival, and allowed postoperative radio therapy to be given sooner than would other wise have been the case. Our practice of routine adjuvant radiotherapy is based on large studies that demonstrate a clear benefit for radiotherapy in controlling locoregional recurrence. (25-27)
Good locoregional disease control was achieved in this series, with only six patients (25 percent) developing recurrences despite incomplete tumor clearance in more than half of patients. This compares favorably with the published literature and can be attributed largely to postoperative radiotherapy. (25-27) The only significant risk factor for locoregional recurrence was the presence of nodal disease; incomplete resection margins and flap cover age did not increase recurrence significantly (log-rank analysis; p > 0.2). However, recurrent disease was fatal within an average of 13 months in the majority of patients.
Disease-specfic 5-year survival was 44 percent and no deaths occurred after 63 months. Longer follow-up studies may be required to determine the metastasizing behavior of this tumor with greater certainty. The prognosis of carcinoma-ex-pleomorphic salivary adenoma is significantly worse than for parotid malignancies as a group, as reported by Malata et al. (4) on pooled sample from the same geographic area (p < 0.02; chi-square test). Factors negatively influencing survival were incomplete resection margins, presence of neck disease, and whether or not neck-dissection surgery was performed. These prognostic variables were simiar to those found by others. (28)
This study has important implications for the management of patients with suspected parotid neoplasm. It is clear that this malignancy cannot be reliably distinguished from benign pleomorphic adenoma on the basis clinical and fine needle aspiration biopsy findings alone. We believe that primary parotid malignancies (including carcinoma-ex-pleomorphic salivary adenoma), occur with sufficient frequency amidst "benign" presentations to warrant active exclusion in the workup of patients with a suspected parotid neoplasm, (6,21) Magnetic resonance imaging has emerged as the investigation of choice in distinguishing between benign and malignant parotid disease and for surgical planning. (23) We now favor magnetic resonance imaging as the first-line investigation of choice in suspected parotid neoplasm, followed by guided core biopsy to secure a definitive histologic diagnosis in cases of suspected malignancy, once a pleomorphic salivary adenoma has been excluded on magnetic resonance imaging.
The surgical treatment of these patients presents a formidable management challenge both with respect to the optimal extent of pacenchymal resection and the treatment of facial nerve. Universal radical parotidectomy has been advocated for the management of these patients. (3,21) In our retrospective series, surgery was planned on the basis of tumor anatomy and not histology and the facial nerve was only resected when in close proximity of, or involving, the tumor. Cautiously bearing in mind the limitations imposed by the relatively small sample size, we found no significant relationship between the type of operation and the likelihood of achieving histologic tumor clearance (p> 0.4; Fisher's Exact Test) or survival (p> 0.1; log-rank analysis). Radical parotidectomy
is associated with significant morbidity and our data appear to suggest that it may not be nec ssary in all cases of carcinoma-ex-pleomorphic salivary adenoma. We have retained superficial parotidectomy in the armamentarium of extirpative options for the management of carcino ma-ex-pleomorphic salivary adenoma and, furthermore, do not undertake universal facial nerve resection. This approach is set within the context of the overwhelming requirement to achieve complete histologic clearance and radical surgery with facial nerve resection and immediate nerve and soft-tissue reconstruction is undertaken for more extensive tumors. Furthermore, we would undertake completion surgery in cases when the primary operation has failed to achieve complete tumor clearance.
Neck dissection was identified as an independent predictor of survival and we would now undertake routine neck dissection surgery, although the data do not allow the optimal type of neck dissection to be identified from this series. Further larger studies are needed to answer this question.
A satisfactory locoregional disease control rate was achieved despite the high incidence of resection margin positivity and this can be largely attributed to postoperative radiotherapy We therefore continue to employ postoperative radiotherapy in all patients with carcinoma-ex pleomorphic salivary adenoma of the parotid gland.
CONCLUSIONS
Carcinoma-ex-pleomorphic salivary adenoma of the parotid gland is an aggressive tumor with a high disease-specific mortality rate but no apparent tendency for late metastasis. It presents a diagnostic challenge, and its detection requires a high index of suspicion and clinical vigilance and is a prerequisite to appropriate management. Fine needle aspiration cytology is unhelpful in distinguishing between pleomorphic salivary adenoma and carcinoma in pleomorphic salivary adenoma in some cases, and could misdirect surgical management toward treating "benign" disease. An incomplete histologic resection margin significantly reduces survival and while more limited surgery may be adequate for selected cases, a radical surgical approach to ensure complete histologic clearance with universal postoperative radiotherapy should be undertaken. |
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