Patterns and pitfalls in fine needle aspiration of salivary gland

Nanoscale infrared probing of amyloid formation within the pleomorphic adenoma tissue

BACKGROUND

The process of malignant transformations of many tumour cases is still unclear and more specific experimental approaches are necessary. The detailed identification of the pathological changes may help in the therapy progression through the development of drugs with more selective action.

METHODS

In this study, the AFM-IR nanospectroscopy was applied for the first time to the pleomorphic adenoma (TM) and the marginal tissue characterizations. In order to verify the obtained spectral information, conventional FT-IR investigations were also performed.

RESULTS

The AFM-IR data (topographies, intensity maps, and spectra) show structural changes observed for the margin and TM samples. Additionally, within the tumour tissue the fibril-like areas, characteristic for amyloid diseases, were distinguished.

CONCLUSIONS

The application of AFM-IR allows to determine changes in the protein secondary structures between the fibrils and the regions outside them. It has been proved that, for the former areas, the α-helix/random coil/ β-sheet components dominate, while for the latter regions the α-helix/random coil indicate the main contribution to the protein composition.

GENERAL SIGNIFICANCE

The FT-IR results remain in good agreement with the AFM-IR data recorded for the areas outside the fibrils of the TM. This observation confirms that by means of the conventional FT-IR method the identification of the considered fibrils structure would be impossible. Only application of the AFM-IR nanospectroscopy allow for characterization and visualization of the fibrillization process occurring within the investigated tumour tissue.

Usefulness of ultrasound and fine needle aspiration cytology of major salivary gland lesions

PURPOSE

To assess the clinical value of ultrasound (US) and fine needle aspiration (FNA) of salivary gland lesions prior to surgery, for preoperative decision-making and long-term follow-up/outcome.

MATERIALS & METHODS

We retrospectively analyzed the medical charts of 98 consecutive patients with major salivary gland lesions who were treated in a single medical from 2008 to 2017. Preoperative US and FNA was performed in all patients. Cytology results were compared with histopathological diagnoses. The correlation between preoperative US findings, cytology and histopathological diagnoses was assessed.

RESULTS

Twenty-three specimens were histopathologically malignant, and 75 were diagnosed as benign. Three false-positive results diagnosed as malignant in cytology had a final histology of sialadenitis, pleomorphic adenoma and Warthin's tumor, respectively. In six cases, cytology yielded false-negative results. The overall accuracy of FNA in distinguishing benign from malignant lesions was 91%. Sensitivity was 70% and specificity 93%. There was no significant correlation between US features and final pathology, but larger size had some correlation with malignancy (p = 0.306). No complications were observed during or after performing FNA.

CONCLUSION

FNA from salivary gland lesions is safe and in many cases can help in preoperative decision making or surgical planning. Hence, the results of FNA cytology should have an integral role in clinical decision-making and management of major salivary gland lesions. False-negative results do occur and therefore should be used only as an adjunctive measure.

Label-free blood serum detection by using surface-enhanced Raman spectroscopy and support vector machine for the preoperative diagnosis of parotid gland tumors

BACKGROUND

It is difficult for the parotid gland neoplasms to make an accurate preoperative diagnosis due to the restriction of biopsy in the parotid gland neoplasms. The aim of this study is to apply the surface-enhanced Raman spectroscopy (SERS) method for the blood serum biochemical detection and use the support vector machine for the analysis in order to develop a simple but accurate blood serum detection for preoperative diagnosis of the parotid gland neoplasms.

METHODS

The blood serums were collected from four groups: the patients with pleomorphic adenoma, the patients with Warthin's tumor, the patients with mucoepidermoid carcinoma and the volunteers without parotid gland neoplasms. Au nanoparticles (Au NPs) were mixed with the blood serum as the SERS active nanosensor to enhance the Raman scattering signals produced by the various biochemical materials and high quality SERS spectrum were obtained by using the Raman microscope system. Then the support vector machine was utilized to analyze the differences of the SERS spectrum from the blood serum of different groups and established a diagnostic model to discriminate the different groups.

RESULTS

It was demonstrated that there were different intensities of SERS peaks assigned to various biochemical changes in the blood serum between the parotid gland tumor groups and normal control group. Compared with the SERS spectra of the normal serums, the intensities of peaks assigned to nucleic acids and proteins increased in the SERS spectra of the parotid gland tumor serums, which manifested the differences of the biochemical metabolites in the serum from the patients with parotid gland tumors. When the leave-one-sample-out method was used, support vector machine (SVM) played an outstanding performance in the classification of the SERS spectra with the high accuracy (84.1 % ~ 88.3 %), sensitivity (82.2 % ~ 97.4 %) and specificity (73.7 % ~ 86.7 %). Though the accuracy, sensitivity and specificity decreased in the leave-one-patient-out cross validation, the mucoepidermoid carcinoma was still easier to diagnose than other tumors.

DISCUSSION

The specific molecular differences of parotid gland tumors and normal serums were significantly demonstrated through the comparison between the various SERS spectra.But compared with the serum SERS spectra reported in the other studies, some differences exist between the spectra in this study and the ones reported in the lietratures. These differences may result from the various nano-particles, the different preparation of serum and equipment parameters, and we could need a further research to find an exact explanation.Based on the SERS spectra of the serum samples, SVM have shown a giant potential to diagnose the parotid gland tumors in our preliminary study. However, different cross validaiton methods could effect the accuracy and a further study involing a great number of samples should be needed.

CONCLUSIONS

This exploratory research demonstrated the great potential of SERS combined with SVM into a non-invasive clinical diagnostic method for preoperative diagnosis of parotid gland tumors. And the internal relation between the spectra and patients should be established in the further study.

Oncocytic carcinoma of the accessory lobe of the parotid gland

Oncocytic carcinoma is a rare tumor of the parotid gland. An additional case, characterized by an exceptional localization in the accessory lobe of the parotid gland, never reported to date in the literature, is described. The clinical and histologic difficulties in relationship to the diagnosis of a midcheek mass consisting of an unusual tumor are emphasized.

Discrimination of parotid neoplasms from the normal parotid gland by use of Raman spectroscopy and support vector machine

Preoperative diagnosis of neoplasms in the parotid gland is essential for successful surgical treatment. The purpose of this study is to apply Raman spectroscopy in order to distinguish the spectral differences between pleomorphic adenoma and Warthin tumor from that of normal parotid gland tissues. Furthermore we establish the diagnostic model of the Raman spectra of neoplasms in parotid gland by employing support vector machine (SVM) with Gaussian radial basis function. Firstly, Raman spectra from different histopathological tissues were obtained by near-infrared Raman microscope, SVM was then employed to analyze the different spectra and establish a discriminating model. As a result, the differences of peaks in the region 800-1800 cm(-1) demonstrated the biochemical molecular alterations between different histopathological tissues. Compared with normal parotid gland tissues, the content of proteins, lipids and DNA increased in pleomorphic adenoma. The content of DNA increased but proteins and lipids decreased in Warthin tumor. SVM displayed a powerful role in the classification of three different groups. The sensitivities and specificities of discrimination between different groups reached above 95% and 99%, respectively. Raman spectroscopy combined SVM algorithm could have great potential for providing a noninvasive, effective and accurate diagnostic technology for neoplasm diagnosis in the parotid gland.

Pleomorphic multicentric adenoma in the submandibular gland

Neoplasms of salivary glands represent a small group among the diseases involving the head and neck complex. In this group, the pleomorphic adenoma is the most frequent neoplasm, yet involves the submandibular gland in only 12.3% of cases. A patient presenting a swelling in the region of the submandibular gland was submitted to an incisional biopsy, where a fragment of the gland and one juxtaposed node were removed. Histologically they were defined as pleomorphic adenoma. Later, the patient was submitted to submandibulectomy and two other nodes were found close to the gland and removed. All specimens were histologically defined as pleomorphic adenoma. This multicentric finding is of great interest, perhaps explaining the recurrence rate of this neoplasm. The patient is in continuous follow-up and has not presented signs of recurrence.

The value of fine-needle aspiration cytology in salivary gland lesions, 1994-2004

OBJECTIVE

Fine-needle aspiration cytology (FNAC) of the salivary gland is a commonly accepted, sensitive and specific technique in the diagnosis of both neoplastic and nonneoplastic lesions of the salivary gland. The aim of this study was to investigate the efficacy of FNAC of salivary gland lesions and to decide whether the radiologist could perform it or not.

METHODS

We aspirated 162 salivary gland lesions of 56 patients undergoing biopsy and excision. A cytopathologist and a surgical pathologist made histopathological and cytological examinations in a blinded fashion.

RESULTS

In the present study, among the FNAC performed in 162 patients with salivary gland masses, 15 (9%) were inadequate, and the remaining 147 were diagnostic. Of the 162 cases, 56 (35%) were also checked histologically. With FNAC there were 89 (55%) nonneoplastic and 58 (36%) neoplastic lesions. With FNAC 45 of the neoplastic lesions were benign and 13 malignant tumors. When cytohistopathological correlation was performed, the overall accuracy in diagnosing benign and malignant lesions was 91 and 78%, respectively, except for 2 malignant lymphoma cases. The sensitivity and specificity for benign and malignant lesions were 72 and 100%, respectively. The diagnostic sensitivity for all neoplastic and nonneoplastic lesions was 84% and the specificity 92%. There was 1 false-positive result, in which a nonneoplastic lesion was misdiagnosed as a Warthin's tumor. Fifteen (26%) cases were false-negative, 12 of which were undefined.

CONCLUSION

FNAC is a useful and reliable tool in the diagnosis of salivary gland masses when performed by a radiologist or a clinician. There are no contraindications, and complications are minimal.