[Value of duplex ultrasound in diagnosis of parotid tumors]

Potential of ultrasound diagnosis for parotid tumors: analysis of qualitative and quantitative parameters

OBJECTIVE

Histology of parotid tumors determines the extent of surgery. The aim was to test ultrasound (US) contrast enhancer-kinetics to identify histologic entities, possibly being superior to qualitative morphological parameters.

STUDY DESIGN

In a cross-sectional assessment of ultrasound diagnosis, the subjective US-classification was compared with contrast analysis with histology as gold standard.

SUBJECTS AND METHODS

A total of 64 male and 61 female patients with a mean age of 54 years were included, with 13 malignant tumors. These were classified with US morphology, then time-dependent contrast medium analysis.

RESULTS

A total of 92.8% of tumors were classified correctly as malignant or benign. The sensitivity, specificity, positive- and negative-predictive values were 66.7%, 86.3%, 60.6%, and 89.1% for differentiating Warthin tumors, but only 46.2%, 98.2%, 75%, and 94% for malignant lesions. Contrast parameters yielded significant parameters for benign tumors, not for malignant entities.

CONCLUSION

Although contrast medium analysis provided statistical criteria, these, however, do not possess the ability to improve the diagnostic prediction of tumor histology. Neither the morphologic classification nor contrast medium analysis was able to identify a malignant lesion sufficiently.

US of the major salivary glands: anatomy and spatial relationships, pathologic conditions, and pitfalls

Ultrasonography (US) is useful for differential diagnosis of diseases of the salivary glands. In acute inflammation, salivary glands are enlarged and hypoechoic with increased blood flow; they may contain multiple small, oval, hypoechoic areas. In chronic inflammation, salivary glands are normal sized or smaller, hypoechoic, and inhomogeneous. Sialolithiasis appears as markedly hyperechoic lines or points with distal acoustic shadowing. Sialosis appears as enlarged hyperechoic glands without focal lesions or increased blood flow. The US features of advanced Sjögren syndrome include inhomogeneous salivary glands with scattered small, oval, hypoechoic or anechoic areas, usually well defined, and increased parenchymal blood flow. Pleomorphic adenomas are usually hypoechoic, well-defined, lobulated lesions with posterior acoustic enhancement that may contain calcifications; Warthin tumors are usually oval, hypoechoic, well-defined lesions that often contain anechoic areas and are often hypervascularized. Malignant neoplasms of the salivary glands may have irregular shapes, irregular borders, blurred margins, and a hypoechoic inhomogeneous structure or may have a benign appearance. Salivary gland cysts have well-defined margins, anechoic contents, posterior acoustic enhancement, and no internal blood flow. However, US appearances of some diseases may overlap, thus producing diagnostic pitfalls.

Sonohistology for the computerized differentiation of parotid gland tumors

A system for the computerized differentiation of parotid gland tumors is proposed. The parotid gland is the largest of the salivary glands. It is found in the subcutaneous tissue of the face, overlying the mandibular ramus and anterior and inferior to the external ear. The classification system is based on a multifeature tissue characterization approach, using fuzzy inference systems as higher-order classifiers. Baseband ultrasonic echo data were acquired during conventional ultrasound imaging examinations using standard ultrasound equipment. Several tissue-describing parameters were calculated within numerous small regions of interest to evaluate spectral and textural tissue properties. The parameters were processed by an adaptive network-based fuzzy inference system, using the results of conventional histology after parotidectomy as the "gold standard." The results of the classification are presented as a numerical score indicating the probability of a certain tumor or alteration for each parotid gland. The score can be presented to the physician during examination of the patient to improve the differentiation between various types of parotid gland tumors. The system was evaluated on n = 23 cases of patients undergoing radical parotidectomy. The receiver operating characteristic curve area is A(ROC) = 0.95 +/- 0.07 when using fourfold cross-validation over cases and differentiating between various benign parotid gland tumors and monomorphic adenoma.

Utility and safety of ultrasound-guided fine-needle aspiration of salivary gland masses including a cytologist's review

OBJECTIVE

To evaluate the utility and safety of ultrasound-guided fine-needle aspiration of the salivary glands for diagnosis of focal masses in the salivary glands, including the prevalence of nondiagnostic sampling, the impact of the presence of a cytologist during the procedure, and the usefulness of flow cytometry.

METHODS

A retrospective analysis of 43 ultrasound-guided fine-needle aspirations of the salivary glands from 36 lesions in 33 patients was performed. Fine-needle aspirations were obtained under sonographic guidance, and 1 to 6 punctures were made with 20- to 25-gauge needles. Ultrasound-guided fine-needle aspirations obtained in the presence of a cytologist were compared with those performed without a cytologist regarding the adequacy of the specimen and the number of punctures performed. Postprocedural complications and the frequency with which flow cytometry was performed were noted. Cytopathologic diagnosis was correlated with clinical follow-up (n = 33) and surgical pathologic findings (n = 10).

RESULTS

Cytologic diagnosis was made in 31 (94%) of 33 patients, confirming a neoplastic process in 18 (50%) of 36 and a non-neoplastic process in 16 (44%) of 36. Although the presence of a cytologist at the bedside resulted in a higher prevalence of diagnostic sampling (P < .05), it did not alter the number of punctures performed (mean, 3 punctures). No complications were encountered except for pain in 2 patients. Flow cytometry was helpful in 8 (22%) of 36 patients.

CONCLUSIONS

Ultrasound-guided fine-needle aspiration of the salivary glands is a safe procedure with a low prevalence of nondiagnostic sampling. Approximately 44% of patients can be spared surgical intervention through diagnosis of a non-neoplastic process. The presence of a cytologist increases the likelihood of obtaining a diagnostic sample. Flow cytometry was helpful in 22% of patients.

Electrical impedance scanning used in addition to ultrasound for the verification of submandibular and parotid lesions: initial results

OBJECTIVES

Different dielectric properties of cancerous tissues are correlated with increased conductance potentially measurable using Electrical Impedance Scanning (EIS). Sonographically based differentiation of lesions in the salivary glands remains difficult. The clinical value of EIS used additionally to Ultrasound was investigated.

METHODS

Sonographically suspicious lesions of parotid (n = 25) and submandibular (n = 16) glands were examined using TransScan TS2000 (TransScan Medical, Israel; distributed by Siemens, Sweden). Bright focal spots representing areas of high conductance were read as positive; absence of a focal spot (ie, homogeneous gray) was read as negative. All lesions were histopathologically proved.

RESULTS

14/15 malignant (93.3%) and 13/26 benign lesions (50.0%) were correctly detected using EIS, NPV 93%, PPV 52%. All cases of squamous cell carcinoma were correctly identified. Lymph node relapse of T-cell lymphoma, lymph node relapse of malignant melanoma, malignant hemangioendothelioma and 2/3 adenocystic carcinoma (primary metastases) were correctly detected.

CONCLUSIONS

Our initial results suggest EIS to be of interest when used adjunctively to ultrasound for the identification of malignant lesions of the salivary glands. However, low specificity induced in part by current technical restrictions (bone interference, skin alterations, contact artifacts, prominence of the lesions) limit this clinical application.

Malignant non-Hodgkin's lymphoma mimicking a benign parotid tumor: sonographic findings

We report the case of an extranodal non-Hodgkin's lymphoma mimicking a benign tumor in the left parotid gland of a 71-year-old woman. The clinical presentation of the painless, mobile mass was suggestive of a benign parotid tumor such as an adenoma. The intraglandular tumor appeared sonographically as a well-circumscribed, hypoechoic, homogeneous, lobulated mass with mild distal sound enhancement. Power Doppler sonography showed marked intratumoral vascularization. The tumor was resected by lateral lobectomy of the parotid gland and was found histopathologically to be a diffuse large B-cell lymphoma.