Intraoral adenoid cystic carcinoma: prognostic factors and outcome

Treatment Outcomes of Adenoid Cystic Carcinomas of the Head and Neck Region-A Single-Institution Experience

Malu RafiObjectives  This study was undertaken to evaluate the characteristics and treatment outcomes of patients with adenoid cystic carcinomas of the head and neck region treated at a tertiary cancer center in south India. Materials and Methods  This was a retrospective study done on patients treated at the institute between 2004 and 2011. Clinicopathological details and treatment outcomes were captured from the treatment records to estimate the treatment outcomes and factors affecting them. Results  There were a total of 140 patients with mean age of presentation of 46 years and a median follow-up of 65 months. The most common single site of presentation was the oral cavity. One-hundred eighteen patients (84.3%) underwent primary surgical resection in which 38% had negative surgical margins. Ninety-nine patients were given adjuvant radiotherapy and 18 patients received radical radiotherapy, mostly for surgically inaccessible and inoperable tumors. Median time to recurrence and distant metastasis was 37 and 34 months, respectively. The overall survival and disease-free survival estimate using the Kaplan-Meier method were 92.3 and 71.9%, respectively, at 5 years. Surgical removal of the primary tumor and the nodal stage had the most significant impact on the overall survival outcomes of these patients. Conclusion  Surgery remains the most impactful treatment modality in the management of these rare epithelial tumors. The use of adjuvant radiotherapy may help to tackle the issues of perineural spread and inadequate surgical margins in technically difficult sites. Radical radiotherapy also has impressive response rates.

A Case of Primary Intraosseous Adenoid Cystic Carcinoma of the Mandible

Primary intraosseous adenoid cystic carcinoma (PIACC) of the jaw is rare. To our knowledge, only 51 cases have been reported in the English literature. We present a rare case of PIACC arising in the mandible with multiple bone metastases and review the previous articles. A 70-year-old woman presented with paresthesia of the right chin and lower gingiva for 4 months. Radiography revealed an irregular radiolucent region on the right side of the ramus, infiltrating to the mandibular canal. Biopsy revealed a pathological diagnosis of adenoid cystic carcinoma. Multiple bone metastases were present in the sternum, scapula, and thighs. The treatment effect was progressive disease for chemotherapy; therefore, best supportive care was provided for 3 years.

Treatment of Adenoid Cystic Carcinoma of the Palate and Reconstruction of Defect With Nasoseptal Flap: A Clinical Case and Review of Literature

Adenoid cystic carcinoma (ACC) is a malignant tumor arising from the salivary glands. While surgery is the mainstay of treatment for ACC of the palate, adjuvant radiotherapy and/or chemotherapy should be considered in high-risk cases. Oronasal fistula, a complication of palatal surgery, may cause speech disturbance and food regurgitation; the nasoseptal flap is a potential option to repair this defect as it is readily available and reliable. Here, we present a case of locally advanced ACC of the palate in a patient who underwent endoscopic-assisted transoral tumor excision with nasoseptal flap reconstruction postoperative chemoradiotherapy.

Occult Neck Metastases in Head and Neck Adenoid Cystic Carcinoma: A Systematic Review and Meta-Analysis

Introduction: Adenoid cystic carcinoma (AdCC) is a rare tumor whose clinical course is burdened by local recurrence and distant dissemination. Lymph node metastasis is not believed to be common and its clinical impact is controversial. The aim of this study was to determine: (1) the prevalence of occult metastasis at diagnosis in cN0 head and neck AdCC, (2) its prognostic role, and (3) the consequent need to perform elective neck dissection (END). Material and Methods: A systematic review and meta-analyses following PRISMA guidelines was performed. PubMed, Embase, and Central databases were questioned up to July 2021 to identify studies reporting on the prevalence of occult neck metastases in head and neck AdCC. A single-arm meta-analysis was then performed to determine the pooled prevalence of occult lymph node metastases among the retained studies. Results: Of the initial 6317 studies identified, 16 fulfilled the inclusion criteria, and they were included in the meta-analysis. Of a population of 7534 patients, 2530 cN0 patients were treated with END, which revealed 290/2530 cases of occult metastases (pN+/cN0). Meta-analysis of the results of END in the 16 studies estimated an overall prevalence of occult metastases at diagnosis of 17%. No further subgroup analysis was possible to identify factors influencing lymph node involvement and the prognostic role of END. Conclusions: Taking 20% as an historically proposed cut off, a 17% prevalence of occult metastases represents a borderline percentage to get a definitive conclusion about the indication to END for head and neck AdCC. A more advanced UICC stage, an oropharyngeal minor salivary glands origin, and a high-grade transformation are factors to be considered in a comprehensive patient’s tailored therapeutic strategy. Multicenter prospective studies are the key to finding stronger recommendations on this topic.

Impact of tumor site on the prognosis of salivary gland neoplasms: A systematic review and meta-analysis

In numerous types of cancer, the primary tumor site can show a correlation with disease behavior and survival outcomes. In salivary gland tumors (SGTs) this association remains controversial. This study assessed the association between primary sites of SGTs and prognosis. Studies from five databases were assessed and a meta-analysis was performed using studies that presented 95 % confidence interval (95 % CI), hazard ratio (HR) and survival analysis. Gathered information from 46,361 patients showed that site had a prognostic impact on SGTs. Tumors involving minor salivary glands showed worse overall survival (HR = 1.60; 95 % CI = 1.17-2.19; p = 0.003), disease-specific survival (HR=1.63; 95 % CI = 1.12-2.37; p = 0.01), and cause-specific survival (HR=2.10; 95 % CI = 1.72-2.55; p = 0.00001). Tumors from major salivary glands showed better recurrence-free survival (HR=2.31; 95 % CI = 1.77-3.02; p = 0.00001), and locoregional control of disease (HR=2.66; 95 % CI = 1.20-5.91; p = 0.02). Our results showed that the primary site of SGTs has an impact on patient prognosis.

Concurrent chemoradiotherapy for locally advanced unresectable adenoid cystic carcinoma of head and neck: experience from a single institute

PURPOSE

To analyze the outcome of locally advanced unresectable adenoid cystic carcinoma (ACC) of head and neck treated with radical concurrent chemoradiotherapy (CRT) at a single tertiary care centre.

METHODS

Between 2011 and 2018, 23 patients with locally advanced unresectable ACC of head and neck treated with non-surgical radical treatment with concurrent chemoradiotherapy were evaluated for outcome and toxicity. All but one patient received cisplatin-based concurrent chemotherapy and 74% of patients were treated with intensity-modulated radiotherapy.

RESULTS

Median follow-up was 53 months (range 3-115 months). Following treatment, 11 patients achieved complete response (47.8%) and of the 12 patients with residual disease, 7 patients additionally had disease stabilization without local progression. Overall 15 patients had disease progression. Median time to progression was 28 months (range 6-67 months). The 3-year and 5-year overall survival, local progression-free survival (LPFS) and distant progression-free survival (DPFS) were 78%, 79.7%, 67.4% and 63%, 50.9%, 48.6%, respectively. Acute grade 3 mucositis was observed in three patients, and one patient additionally developed grade 4 neutropenia with subsequent complete recovery. No grade 3 or higher late toxicity was observed.

CONCLUSION

Radical concurrent chemoradiotherapy is a promising treatment option in locally advanced unresectable ACC with acceptable toxicity.

Elective neck dissection in adenoid cystic carcinoma of head and neck: yes or no? A systematic review

PURPOSE

Adenoid cystic carcinoma of head and neck (AdCCHN) is salivary gland malignancy known for its slow progression accompanied with perineural invasion, rare lymphatic spread to the neck, high rate of local recurrence and delayed onset of distant metastases. While local recurrence and distant metastases are most common patterns of relapse and cause of death in AdCCHN, it has been debated whether lymph node involvement affects the course of the disease. The aim of this systematic review was to address this important issue and to recommend guidelines on clinically node-negative neck management in patients with AdCCHN.

METHODS

A systematic review of the published literature on cases of elective neck dissection (END) among patients with AdCCHN was performed.

RESULTS

This analysis included a total of 5767 AdCCHN patients with 2450 ENDs, ranging from 10 to 1190. Elective lymphadenectomy was employed in 42.5% of patients with AdCCHN (range 9.2-100%). The overall rate of occult neck metastases in patients with AdCCHN was reported to range between 0 and 43.7%, the average being 13.9%.

CONCLUSIONS

If performed, END should be limited to levels I-III of the ipsilateral neck since occult metastases are exclusively located within these neck regions. Although END is associated with a prolonged regional recurrence-free period, it influence on final outcome or survival is still controversial. This review strongly supports conduction of prospective trials on indications, prognostic significance and extent of END in AdCCHN.

Mass spectrometry-based proteome profile may be useful to differentiate adenoid cystic carcinoma from polymorphous adenocarcinoma of salivary glands

OBJECTIVE

The aim of this study was to determine the proteome of adenoid cystic carcinoma (AdCC) and polymorphous adenocarcinoma (PAc) and to identify a protein signature useful in distinguishing these two neoplasms.

STUDY DESIGN

Ten cases of AdCC and 10 cases of PAc were microdissected for enrichment of neoplastic tissue. The samples were submitted to liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the proteomics data were analyzed by using the MaxQuant software. LC-MS/MS spectra were searched against the Human UniProt database, and statistical analyses were performed with Perseus software. Bioinformatic analyses were performed by using discovery-based proteomic data on both tumors.

RESULTS

LC-MS/MS analysis identified 1957 proteins. The tumors shared 1590 proteins, and 261 were exclusively identified in AdCC and 106 in PAc. Clustering analysis of the statistically significant proteins clearly separated AdCC from PAc. Protein expression 10 times higher in one group than in the other led to a signature of 16 proteins-6 upregulated in AdCC and 10 in PAc. A new clustering analysis showed reverse regulation and also differentiated both tumors.

CONCLUSIONS

Global proteomics may be useful in discriminating these two malignant salivary neoplasms that frequently show clinical and microscopic overlaps, but additional validation studies are still necessary to determine the diagnostic potential of the protein signature obtained.

Multicenter study of carbon-ion radiation therapy for nonsquamous cell carcinomas of the oral cavity

Background

The aim of this study was to evaluate the efficacy and safety of carbon‐ion radiation therapy for nonsquamous cell carcinomas of the oral cavity in a multicenter study.

Methods

Retrospective analysis of the clinicopathological features and outcomes of 76 patients with oral nonsquamous cell carcinomas with N0‐1 M0 status and were treated with carbon‐ion radiation therapy at four institutions in Japan between November 2003 and December 2014 was performed.

Results

Salivary gland carcinoma, mucosal melanoma, and three other carcinomas were found in 46, 27, and 3 patients, respectively. T1‐3, T4a, and T4b disease was diagnosed in 27, 18, and 31 patients, respectively. Median follow‐up period was 31.1 months (range, 3‐118 months). Three‐year local control, progression‐free survival, and overall survival of all patients were 86.8%, 63.1%, and 78.4%, respectively. Multivariate analysis showed T classification (T4) to be a significant independent poor prognostic factor for local control. Acute grade 3 mucositis was observed in 38 patients. Grades 3 and 4 late morbidities were observed in 9 and 4 patients, respectively. No grade 5 late toxicity was observed.

Conclusions

Oral nonsquamous cell carcinomas could be treated effectively, with acceptable toxicity, by carbon‐ion radiation therapy.

Feasibility of carbon-ion radiotherapy for oral non-squamous cell carcinomas

Background

This study evaluated carbon‐ion radiotherapy (C‐ion RT) for oral non‐squamous cell carcinomas (non‐SCC).

Methods

We retrospectively obtained data from 74 patients who underwent C‐ion RT for oral malignancies between April 1997 and March 2016. The C‐ion RT was administered in 16 fractions at a total dose of 57.6 or 64.0 Gy (relative biological effectiveness).

Results

Forty‐three patients had salivary gland carcinomas, 29 patients had mucosal melanoma, and 2 patients had other types of pathologies. The tumors were classified as T1‐T3 (24 cases), T4a (21 cases), or T4b (29 cases). The median follow‐up was 49 months. The 5‐year rates were 78.8% for local control, 36.2% for progression‐free survival, and 58.3% for overall survival. Although 10 patients developed grade 3 osteoradionecrosis after C‐ion RT, all patients maintained their mastication and deglutition functions after sequestrectomy and prosthesis placement.

Conclusion

C‐ion RT was effective for oral non‐SCC and had acceptable toxicities.

Oropharyngeal adenoid cystic carcinoma invading the mandibular bone through the mandibular foramen

Adenoid cystic carcinoma (ACC) is a rare epithelial tumor of the head and neck region, and one of the most common malignant tumors of the salivary glands. ACC is a slow-growing tumor characterized by perineural invasion and often has a high-recurrence rate. We describe a case of oropharyngeal ACC invading the mandibular bone through the mandibular foramen that showed a rare pattern of origin and invasion. A 70-year-old woman complained of noise and pain around the right temporomandibular joint. Osteomyelitis was suspected on the initial imaging examinations, although the findings were slightly atypical. However, a mass was observed in the right oropharyngeal wall on subsequent imaging examinations, and mandibular bone invasion, rather than osteomyelitis, was additionally suspected. The mass in the right oropharyngeal wall and right mandible was surgically excised. On postoperative histopathological examination, the mass was finally diagnosed as ACC. As tumor cells were also observed around the inferior alveolar nerve, mandibular bone invasion through the mandibular foramen was suspected. An oropharyngeal ACC invading the mandibular bone through the mandibular foramen is extremely rare. The present case suggests that bone invasion should be considered carefully with several imaging examinations when a malignant tumor such as ACC is observed around the jaw bone.

Adenoid cystic carcinoma of alveolar mucosa: A rare case report

Adenoid cystic carcinomas are rare epithelial malignancies of salivary glands that show slow growth and local invasion with recurrences seen many years after diagnosis. Upto 50% of tumors occur in intraoral minor salivary glands usually in the hard palate. Tumors on the alveolar mucosa are extremely rare. We present a case of adenoid cystic carcinoma on the right alveolar mucosa in a 35 year old female. The case is been presented for its rarity.

Relationship between autophagy and perineural invasion, clinicopathological features, and prognosis in pancreatic cancer

AIM

To investigate the relationship between autophagy and perineural invasion (PNI), clinical features, and prognosis in patients with pancreatic cancer.

METHODS

Clinical and pathological data were retrospectively collected from 109 patients with pancreatic ductal adenocarcinoma who underwent radical resection at the First Affiliated Hospital of Zhengzhou University from January 2011 to August 2016. Expression levels of the autophagy-related protein microtubule-associated protein 1A/1B-light chain 3 (LC3) and PNI marker ubiquitin carboxy-terminal hydrolase (UCH) in pancreatic cancer tissues were detected by immunohistochemistry. The correlations among LC3 expression, PNI, and clinical pathological features in pancreatic cancer were analyzed. The patients were followed for further survival analysis.

RESULTS

In 109 cases of pancreatic cancer, 68.8% (75/109) had evidence of PNI and 61.5% (67/109) had high LC3 expression. PNI was associated with lymph node metastasis, pancreatitis, and CA19-9 levels (P < 0.05). LC3 expression was related to lymph node metastasis (P < 0.05) and was positively correlated with neural invasion (P < 0.05, r = 0.227). Multivariate logistic regression analysis indicated that LC3 expression, lymph node metastasis, pancreatitis, and CA19-9 level were factors that influenced neural invasion, whereas only neural invasion itself was an independent factor for high LC3 expression. Univariate analysis showed that LC3 expression, neural invasion, and CA19-9 level were related to the overall survival of pancreatic cancer patients (P < 0.05). Multivariate COX regression analysis indicated that PNI and LC3 expression were independent risk factors for poor prognosis in pancreatic cancer (P < 0.05).

CONCLUSION

PNI in patients with pancreatic cancer is positively related to autophagy. Neural invasion and LC3 expression are independent risk factors for pancreatic cancer with a poor prognosis.

Adenoid cystic carcinoma of the base of tongue: A population-based study

BACKGROUND

The objective was to assess demographic and survival patterns in patients with adenoid cystic carcinoma of the base of tongue.

METHODS

Patients were extracted from the Surveillance, Epidemiology and End Results (SEER) database from 1973 through 2012 and were categorized by age, gender, race, historical stage A, and treatment. Incidence and survival were compared with Kaplan Meier curves and mortality hazard ratios.

RESULTS

A total of 216 patients were included. After adjusting for age, gender, race and tumor-directed treatment, patients over the age of 70years had a significantly increased mortality [HR=2.847, 95% CI (1.499, 5.404) p=0.0014]. Furthermore mortality among patients with distant disease was significantly increased [HR=2.474 95% CI (1.459, 4.195) p=0.00008].

CONCLUSION

By examining the largest collection of patients we have demonstrated that there is a significant difference in mortality based on both the age at diagnosis and in the setting of distant disease.

Perineural Spread in Noncutaneous Head and Neck Cancer: New Insights into an Old Problem

Head and neck malignancies have the propensity to invade nerves. Perineural tumor invasion is common, with some series reporting rates of 30 to 100%. Squamous cell carcinoma and adenoid cystic carcinoma are the most commonly involved tumors. The most commonly involved nerves are the trigeminal (cranial nerve [CN] V) and facial (CN VII) and their branches. Neural spread away from a tumor is encountered less often and usually causes specific symptoms such as pain, muscle weakness, and atrophy, depending on the involved nerves. While clinical symptoms and physical examination may suggest the presence of neural invasion, specific imaging modalities such as fat-suppressed T1-weighted magnetic resonance images, should be utilized to identify perineural tumor spread in its early phases. Perineural tumor spread should be considered and addressed in the treatment planning of patients with head and neck or skull base cancers as it can influence the extent of surgery, and the dosage and fields of radiation therapy. In the current review, we discuss the clinical course of perineural tumor spread and its therapeutic implications.

Cervical lymph node metastasis in adenoid cystic carcinoma of oral cavity and oropharynx: A collective international review

The purpose of this study was to suggest general guidelines in the management of the N0 neck of oral cavity and oropharyngeal adenoid cystic carcinoma (AdCC) in order to improve the survival of these patients and/or reduce the risk of neck recurrences. The incidence of cervical node metastasis at diagnosis of head and neck AdCC is variable, and ranges between 3% and 16%. Metastasis to the cervical lymph nodes of intraoral and oropharyngeal AdCC varies from 2% to 43%, with the lower rates pertaining to palatal AdCC and the higher rates to base of the tongue. Neck node recurrence may happen after treatment in 0-14% of AdCC, is highly dependent on the extent of the treatment and is very rare in patients who have been treated with therapeutic or elective neck dissections, or elective neck irradiation. Lymph node involvement with or without extracapsular extension in AdCC has been shown in most reports to be independently associated with decreased overall and cause-specific survival, probably because lymph node involvement is a risk factor for subsequent distant metastasis. The overall rate of occult neck metastasis in patients with head and neck AdCC ranges from 15% to 44%, but occult neck metastasis from oral cavity and/or oropharynx seems to occur more frequently than from other locations, such as the sinonasal tract and major salivary glands. Nevertheless, the benefit of elective neck dissection (END) in AdCC is not comparable to that of squamous cell carcinoma, because the main cause of failure is not related to neck or local recurrence, but rather, to distant failure. Therefore, END should be considered in patients with a cN0 neck with AdCC in some high risk oral and oropharyngeal locations when postoperative RT is not planned, or the rare AdCC-high grade transformation.

Nerve Growth Factor Signals as Possible Pathogenic Biomarkers for Perineural Invasion in Adenoid Cystic Carcinoma

OBJECTIVE

The molecular mechanisms underlying perineural invasion (PNI)-a characteristic pathological feature of adenoid cystic carcinoma (ACC)-remain largely unclear. Recently, nerve growth factor (NGF) has been implicated in perineural invasion in certain malignancies. Overexpression of Myb related to the MYB-NFIB fusion gene in ACC has also been correlated with perineural invasion and survival. However, this concept is controversial. The aim of this study was to examine the expression of NGF together with its receptors, tropomyosin receptor kinase A (TrkA) and p75NRT, and Myb in ACC and assess their relationship with perineural invasion and survival.

STUDY DESIGN

Case series with chart review.

SETTING

The University of Tokyo Hospital.

SUBJECTS AND METHODS

We retrospectively analyzed 37 patients with ACC surgically treated from 1991 to 2011. We examined expression levels of NGF, TrkA, p75NRT, and Myb in the ACC specimens and their correlations with PNI and prognosis.

RESULTS

NGF, TrkA, p75NRT, and Myb overexpression rates were 65%, 65%, 30%, and 62%, respectively. Pearson product-moment correlation coefficient revealed a strong correlation between NGF/TrkA immunostaining and PNI (NGF: r = 0.68, P < .0001; TrkA: r = 0.53, P = .0007). Moreover, NGF overexpression was significantly associated with worse 8-year local control rate (27% vs 80%, P = .005). However, p75NRT and Myb expression was related to neither perineural invasion nor survival.

CONCLUSION

Our findings demonstrated that NGF and TrkA overexpression, but not Myb and p75NRT overexpression, may contribute to PNI and thus cause local recurrence in patients with ACC.

FZD2 inhibits the cell growth and migration of salivary adenoid cystic carcinomas

Several studies have reported that FZD2 regulates tumor biology in a complex manner. The aim of the present study was to identify the role of FZD2 in the cell growth and metastasis of salivary adenoid cystic carcinomas (SACCs). The expression of FZD2 in ACC-83 and ACC-LM cells were measured with real-time PCR. Immunohistochemical staining was used to detect the expression of FZD2 in clinical SACC samples with or without metastasis. Cell proliferation and Transwell assays were performed to explore the effects of FZD2 on cell growth and migration following the silencing of FZD2 with small interference RNAs and the overexpression of FZD2 with plasmid. Our data showed that FZD2 was downregulated in ACC-LM cells, which are an adenoid cystic carcinoma cell line with high metastatic potential, compared to ACC-83 cells, which have low metastatic potential. Additionally, the expression of FZD2 was lower in SACC tissues with metastasis compared to SACC tissues without metastasis (P<0.05). Cell proliferation and migration of ACC-83 cells were increased after the knockdown of FZD2 and decreased following overexpression of FZD2. Knockdown of FZD2 downregulated the expression of PAI-1. Our results suggest that FZD2 may be a tumor suppressor gene in SACCs that inhibits cell growth and migration.

MCM3 as a novel diagnostic marker in benign and malignant salivary gland tumors

BACKGROUND

Proliferation markers widely have been used to diagnose and determine the behaviour and prognosis of benign and malignant tumours. Minichromosome maintenance 3 (MCM3) is a novel proliferation marker. The aim of this study was to evaluate and compare MCM3 with Ki-67 in diagnosis of salivary gland tumours.

MATERIALS AND METHODS

In this retrospective study, immunohistochemical expression of MCM3 and Ki-67 was evaluated in 15 pleomorphic adenomas (PA), 17 mucoepidermoid carcinomas (MEC) and 18 adenoid cystic carcinomas (ADCC) . Labeling indices (LIs) for the two markers were calculated and compared.

RESULTS

MCM3 and Ki-67 LIs were significantly higher in MEC and ADCC compared to PA. The LI of MCM3 was significantly higher than that of Ki-67 in MEC and PA. There was no significant difference between the two markers in ADCC. A cut-off point of 8% with 74.3% sensitivity and 93.3% specificity for MCM3 was obtained to discern between benign and malignant tumors.

CONCLUSIONS

These results suggest that MCM3 might be a useful proliferation marker for differential diagnosis and recognition of clinical behavior of salivary gland tumors.

Prosthetic rehabilitation of a patient with adenoid cystic carcinoma with continuous orbital-maxillary defect

Extensive head and neck surgical procedures severely affect vital functions, physical appearance and lead to huge psychological trauma in the patients. Well-constructed maxillofacial prosthesis will help them lead a normal social life for the remaining precious time. This case report explains the prosthetic rehabilitation of continuous orbital-maxillary surgical defect in a patient with adenoid cystic carcinoma with restricted mouth opening. Maxillofacial prosthesis needs individual modification to a treatment plan according to the defect and existing clinical conditions. In this case, magnetically retained three-piece prosthesis was designed because of high recurrence rate of the adenoid cystic carcinoma, lack of adequate bone for implants and limited mouth opening in the patient. The prosthesis restored the phonetics, aesthetics and deglutition of the patient by re-establishing the separation of oral-nasal-orbital cavities.

Prognostic value of expression of molecular markers in adenoid cystic cancer of the salivary glands compared with lymph node metastasis: a retrospective study

BACKGROUND

Adenoid cystic cancer arising in the salivary glands has distinctive features such as perineural invasion, distant metastasis, and a variable prognosis. In salivary gland cancer, c-kit, EGFR, and VEGF are representative molecular markers that may predict remnant and recurrent tumors. In this study, the expression of c-kit, EGFR, and VEGF in adenoid cystic cancer was evaluated, and the relationships between the expression of these markers and the clinical findings were investigated.

METHODS

The medical records of 48 patients who were treated for parotid adenoid cystic cancer from January 1990 to January 2006 were reviewed. The tumor location, size, histological subtypes, perineural invasion, the resected margin status, and lymph node metastasis were assessed. Immunohistochemical staining and semiquantitative analysis of c-kit, EGFR and VEGF were performed. The relationship between the expression of each marker and the clinicopathological factors were analyzed.

RESULTS

Positive c-kit immunostaining was present in 45 patients (94%), with weak positivity (+1) in 23, moderate positivity (+2) in 19 and strong positivity (+3) in three. Positive EGFR immunostaining was observed in 27 (56%), with weak positivity (+1) in 19 and moderate positivity (+2) in eight with no strong positive staining. Positive VEGF immunostaining was present in 42 patients (88%) with weak positivity (+1) in 12, moderate positivity (+2) in 17, and strong positivity (+3) in 13. Only the expression of VEGF was significantly higher in parotid gland tumors than in any other gland (P = 0.032). Marginal involvement was associated with strong VEGF expression (P = 0.02). No marker was significantly correlated with recurrence or the survival rate. Lymph node status was related to the survival rate.

CONCLUSIONS

The expression of c-kit, EGRF, and VEGF had no predictive value for recurrence or the prognosis of adenoid cystic cancer. Only the lymph node status was related to the prognosis.

Invasion of the hypoglossal nerve by adenoid cystic carcinoma of the tongue: case report and review of the literature

Adenoid cystic carcinoma (ACC) is a rare but highly aggressive malignancy mainly originating from the salivary glands. ACC is well known for its propensity toward neural invasion (NI). NI is the process of neoplastic invasion in and along nerves. It is a distinct and well-documented phenomenon in ACC; however, it is an underestimated route of metastatic spread. Multiple distant metastases can be established through NI route, and NI is believed to portend a poor prognosis. Despite increasing recognition of NI in many malignancies, the molecular mechanism behind NI is not well established. We present a unique case of hypoglossal nerve invasion by ACC arising from the minor salivary glands in the tongue of a 34-year-old man. We also review and discuss current theories on the pathogenesis and mechanism of NI.