Utility of (18)F-FDG PET-CT in staging and restaging of patients with malignant salivary gland tumours: a single-institutional experience

Mucoepidermoid carcinoma of the head and neck: CRTC1/3 MAML 2 translocation and its prognosticators

PURPOSE

Mucoepidermoid carcinoma (MEC) of the head and neck is a prevalent malignant salivary gland tumour with a reported good outcome. The aim of this study was to report the outcome in our centre.

METHODS

A retrospective chart analysis with survival analyses was performed combined with fluorescence in situ hybridization (FISH) analysis to assess CRTC1/3 MAML 2 fusion gene presence.

RESULTS

Sixty-four cases of MEC were identified. Median age at presentation was 51.4 years with a predominance for parotid gland involvement. Five, 10- and 20- year disease-free survival was 98%, 90% and 68%, respectively. Overall survival was 94%, 90% and 64%, respectively. Local recurrence was seen up to 14 years after primary diagnosis; distant metastases were diagnosed up to 17 years later. The overall recurrence rate was less than 20 per cent. CRTC1/3 MAML 2 fusion gene presence showed no survival benefit.

CONCLUSION

MEC of the head and neck has a favorable outcome with the exception of high-grade MEC. PNI and nodal involvement are not rare. CRTC1/3 MAML 2 fusion gene presence showed no survival benefit. The tendency for late onset of loco-regional and distant recurrence should not be underestimated.

Diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in sublingual and submandibular salivary gland tumors

The aim of the present study was to compare the diagnostic accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) with that of conventional imaging studies (CIS), such as CT or magnetic resonance imaging (MRI), in the clinical diagnosis and staging of submandibular and sublingual salivary gland tumors. In addition, the data obtained were used to evaluate the significance of maximum standardized uptake value (SUVmax) in diagnosing benign or malignant lesions. For the present study, 18 patients with submandibular or sublingual neoplasms underwent F-18 FDG PET/CT imaging with accompanying CT or MRI. The diagnostic values from 43 F-18 FDG PET/CT scans and 28 CIS of the 18 patients were compared to the gold standard histopathological and/or cytopathological diagnosis. The results demonstrated that the diagnostic accuracy for predicting primary tumors was similar between F-18 FDG PET/CT and CIS. By contrast, PET/CT imaging was more accurate in detecting lymph node metastasis compared with CT or MRI (95.4 vs. 66.7%). F-18 FDG PET/CT had a sensitivity of 88.9% and a specificity of 97.1%, whereas CT or MRI had a sensitivity of 54.5% and a specificity of 75.0%. F-18 FDG PET/CT also enabled screening for distant metastasis, as observed in 10 cases in the present study. Furthermore, there were no significant differences in SUVmax between benign or malignant salivary gland lesions, as high glucose metabolism was also observed in benign tumors. In conclusion, F-18 FDG PET/CT provides more accurate diagnostic information for the evaluation of submandibular and sublingual salivary gland tumors as compared with CIS in terms of lymph node and distant metastasis.

A nomogram to estimate the risk of developing distant metastases in parotid cancer

BACKGROUND

Parotid cancer (PC) is a heterogeneous group of malignant tumors whose management mainly focuses on locoregional control. However, distant metastases (DM) can represent the most common cause of treatment failure. We have defined the predictors and developed a model that can predict a single patient's risk to develop DM.

METHODS

We have analyzed our institutional database of 259 patients with PC and use it to develop a nomogram. C-index and calibration curves were used to assess performance of our model.

RESULTS

DM appeared in 18.9% of patients. Age, cT, pN, perineural invasion, and adenoid cystic carcinoma were significantly associated with distant failure.

CONCLUSIONS

We here present the first model to identify patients with PC at high risk of DM. Such tool can be of great value in managing these rare cancers in terms of a more precise prognosis and follow-up while waiting for better systemic therapies to come in the future.

Extensive Regional Metastasis of High-Grade Mucoepidermoid Carcinoma of an Unknown Primary Tumor

PURPOSE

Mucoepidermoid carcinoma (MEC) is the most common salivary carcinoma. It arises most frequently in the major salivary glands, but can also arise in minor glands or intraosseous sites. MEC of an unknown primary occurs very rarely. The present report documents only the third case reported in medical studies.

METHODS

A 66-year-old man with previous carcinoma in situ (CIS) of the left posterior oral tongue that had been excised in 2004 and again in 2010 presented with a hard lymph node, 3 × 2 cm at level II of the right neck in July 2015. Positron emission tomography-computed tomography (PET-CT) revealed multiple, bilateral cervical lymphadenopathy, with no primary site identified. Fine needle aspiration biopsy and cytologic examination from the right neck was positive for malignancy, suggestive of metastatic squamous cell carcinoma. Panendoscopy and biopsy revealed CIS at the tongue bases and tonsils bilaterally (p16-negative). The patient's case was presented to a tumor board, and definitive concurrent cispl.atin-based chemoradiation was recommended for TisN2cM0, stage IVA oropharyngeal CIS, which was completed in November 2015. PET-CT in January 2015 showed complex interval changes, with some areas demonstrating improvement (ie, no uptake in the left neck) and worsening in others (ie, increased metabolic activity in the right neck), suggestive of residual disease. Repeat PET-CT in March 2016 showed increased nodal involvement and increasing standardized uptake value. Bilateral modified radical neck dissection was undertaken, and histologic examination showed high-grade MEC in 51 of 61 lymph nodes with extracapsular spread and soft tissue involvement.

RESULTS

The patient died in May 2016 at 2 months after surgery.

CONCLUSIONS

Metastatic MEC of an unknown primary is a diagnostic challenge. PET-CT might not be the most reliable diagnostic investigation to identify the primary or metastatic foci, such as was demonstrated in the present case.

Is There a Role for PET/CT Parameters to Characterize Benign, Malignant, and Metastatic Parotid Tumors?

OBJECTIVE

Assessment of benign and malignant lesions of the parotid gland, including metastatic lesions, is challenging with current imaging methods. Fluorine-18 FDG PET/CT is a noninvasive imaging modality that provides both anatomic and metabolic information. Semiquantitative data obtained from PET/CT, also known as PET/CT parameters, are maximum, mean, or peak standardized uptake values (SUVs); metabolic tumor volume; total lesion glycolysis; standardized added metabolic activity; and normalized standardized added metabolic activity. Our aim was to determine whether FDG PET/CT parameters can differentiate benign, malignant, and metastatic parotid tumors.

MATERIALS AND METHODS

Thirty-four patients with parotid neoplasms underwent PET/CT before parotidectomy; maximum SUV, mean SUV, peak SUV, total lesion glycolysis, metabolic tumor volume, standardized added metabolic activity, and normalized standardized added metabolic activity were calculated on a dedicated workstation. Univariate analyses were performed. A ROC analysis was used to determine the ability of PET/CT parameters to predict pathologically proven benign, malignant, and metastatic parotid gland neoplasms.

RESULTS

Fourteen patients had a benign or malignant primary parotid tumor. Twenty had metastases to the parotid gland. When the specificity was set to at least 85% for each parameter to identify cut points, the corresponding sensitivities ranged from 15% to 40%. Assessment of benign versus malignant lesions of parotid tumors, as well as metastasis from squamous cell carcinoma versus other metastatic causes, revealed that none of the PET/CT parameters has enough power to differentiate among these groups.

CONCLUSION

PET/CT parameters, including total lesion glycolysis, metabolic tumor volume, standardized added metabolic activity, and normalized standardized added metabolic activity, are not able to differentiate benign from malignant parotid tumors, primary parotid tumors from metastasis, or metastasis from squamous cell carcinoma and nonsquamous cell carcinoma metastasis.

Facial Paralysis Secondary to Extensive Perineural Spread of Adenocarcinoma of the Parotid Gland Identified by PET/CT

Brain MRI in an 82-year-old man with presumed Bell's palsy revealed a clinically unsuspected right parotid gland mass but no other acute findings. Biopsy revealed poorly differentiated adenocarcinoma. Staging F-FDG PET/CT revealed an FDG-avid parotid mass, abnormal FDG uptake along the course of the facial nerve from mass to skull base, and multiple FDG-avid right level II neck lymph nodes and hepatic metastases. The PET/CT findings and prolonged clinical course suggest that diffuse perineural spread of tumor from a smoldering parotid neoplasm, and not idiopathic Bell's palsy, was responsible for the patient's facial paralysis.

Prognostic Factors and Treatment Outcomes of Parotid Gland Cancer

Objective

To investigate the treatment outcomes of parotid gland cancer at a single center over a 10-year period and to evaluate the prognostic significance of maximum standardized uptake value.

Study Design

Retrospective case series with chart review.

Setting

Academic care center.

Subjects and Methods

Ninety-eight patients with primary parotid gland cancer who were surgically treated at Yonsei University Head & Neck Cancer Clinic between January 1999 and December 2008 were analyzed. Patient data were collected retrospectively from medical charts. The investigators analyzed the association of clinicopathological factors and maximum standardized uptake value on 18F-fluorodeoxyglucose positron emission tomography–computed tomography scan with disease-specific survival.

Results

Mean patient age was 49.7 years. Mean follow-up was 48.8 months. Thirty-three, 40, 30, and 23 patients had stage I, II, III, and IVA disease, respectively. Mucoepidermoid carcinoma was the most common histologic type (34.7%), followed by acinic cell carcinoma (27.6%). Eighteen patients (18.4%) experienced recurrences (mean recurrence gap, 20.6 months; range, 2-87 months). Five- and 10-year disease-specific survival rates were 93.6% and 81.8%, respectively. In the univariate analysis, pathologic T stage, pathologic lymph node status, resection margin, external parenchymal extension, and maximum standardized uptake value were significantly associated with disease-specific survival. Pathologic lymph node status and maximum standardized uptake value were independent prognostic factors in the multivariate analysis.

Conclusion

Our single-center experience with parotid gland cancer treatment is consistent with the literature. Cervical lymph node metastasis and high maximum standardized uptake value are associated with poor survival in parotid gland cancer.

Prevalence and risk of malignancy of focal incidental uptake detected by fluorine-18-fluorodeoxyglucose positron emission tomography in the parotid gland: a meta-analysis

This study aimed at performing a meta-analysis on the prevalence and risk of malignancy of focal parotid incidental uptake (FPIU) detected by hybrid fluorine-18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) or (18)F-FDG PET alone. A comprehensive literature search of studies published up to July 2014 was performed. Records reporting at least 5 FPIUs were selected. Pooled prevalence and malignancy risk of FPIU were calculated including 95 % confidence intervals (95 % CI). Twelve records were selected for our meta-analysis. Pooled prevalence of FPIU detected by (18)F-FDG PET or PET/CT was 0.6 % (95 % CI 0.4-0.7 %), collecting data of 220 patients with FPIU. Overall, 181 FPIUs underwent further evaluation and 165 FPIUs were pathologically proven. Pooled risk of malignancy was 9.6 % (95 % CI 5.4-14.8 %), 10.9 % (95 % CI 5.8-17.3 %) and 20.4 % (95 % CI 12.3-30 %), considering all FPIUs detected, only those which underwent further evaluation and only those pathologically proven, respectively. Selection bias in the included studies, the heterogeneity among studies and the publication bias are limitations of our meta-analysis. Overall FPIUs are observed in about 1 % of (18)F-FDG PET or PET/CT scans and they are benign in most of the cases. Nevertheless, further evaluation is needed whenever FPIUs are detected by (18)F-FDG-PET or PET/CT to exclude malignant lesions or with possible malignant degeneration. Prospective studies are needed to confirm the findings reported by our meta-analysis.

Diagnostic accuracy of integrated (18)F-FDG PET/CT for restaging patients with malignant germ cell tumours

OBJECTIVE

Evaluation of utility of fluorine-18 fludeoxyglucose ((18)F-FDG) positron emission tomography/CT (PET/CT) for restaging patients with primary malignant germ cell tumours (GCTs).

METHODS

Data of 92 patients (age, 31.94 ± 10.1 years; male/female, 86/6) with histopathologically confirmed malignant GCTs (gonadal, 88; mediastinal, 4; seminomatous, 47 and non-seminomatous, 45) who underwent (18)F-FDG PET/CT for restaging (suspected recurrence/post-therapy evaluation) were retrospectively analysed. Two experienced nuclear medicine physicians reviewed the PET/CT images in consensus, qualitatively and semi-quantitatively [maximum standardized uptake value (SUVmax)]. Histopathology (if available) and clinical/imaging/biochemical follow-up (minimum of 6 months) were employed as the reference standard.

RESULTS

(18)F-FDG PET/CT was interpreted as positive in 59 and negative in 33 patients. Local disease was seen in 5, nodal disease in 50 and distant metastasis in 22 patients. PET/CT was true positive in 49, false positive in 10, true negative in 30 and false negative in 3 patients. (18)F-FDG PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 94.2%, 75.0%, 83.0%, 90.9% and 85.8% overall; 90.0%, 74.0%, 72.0%, 90.9% and 80.8% in seminomatous GCT; and 96.8%, 76.9%, 91.1%, 90.9% and 91.1% in non-seminomatous GCT, respectively. Difference in PET/CT accuracy for seminomatous and non-seminomatous GCTs was not significant (p = 0.263). PET/CT demonstrated disease in 13 patients with negative/equivocal conventional imaging findings and in 9 patients with normal tumour markers. No site- or histology-based difference was seen in SUVmax.

CONCLUSION

(18)F-FDG PET/CT demonstrates high diagnostic accuracy for restaging patients with malignant GCTs. It has comparable diagnostic performance in both seminomatous and non-seminomatous malignant GCTs.

ADVANCES IN KNOWLEDGE

The present article demonstrates high diagnostic accuracy of (18)F-FDG PET/CT for restaging both seminomatous and non-seminomatous malignant GCTs in a large patient population.

Salivary mucoepidermoid carcinoma revisited

Clinicopathological features, prognosis and therapeutic strategies for mucoepidermoid carcinoma originating in salivary and salivary-type glands of the head and neck are reviewed. We emphasise histopathological aspects, appraise the value of histochemistry, electron microscopy, immunohistochemistry and cytophotometry, and discuss histogenesis and characteristic gene translocations. We additionally consider possible diagnostic difficulties, problems related to histological grading and accuracy of existing literature, and areas of controversy or uncertainty which may benefit from further investigations.