Fine needle aspiration of the salivary glands: A review

The Evaluation and Management of Carcinoma of the Minor Salivary Glands

There are several hundred minor salivary glands throughout the upper aerodigestive tract, aiding in lubrication and protection of the system. Compared with all tumors of the head and neck and those of the six major glands, neoplasms of the minor glands are rare. However, more than half are found to be malignant, prompting a low threshold for further work-up. This review discusses the evaluation of patients who present with masses of the minor salivary glands, including strategies for tissue diagnosis and staging. Management options for and long-term survival outcomes of the most common malignancies affecting these glands are also discussed.

Major and minor salivary gland tumours

Salivary glands carcinomas are very rare epithelial malignant tumors. In 2013 in Europe, 7800 new diagnoses were estimated, 8.5 % of all head and neck cancer. The last WHO classification (2017) counts more than 20 malignant histotypes, this variety as well as the rarity of some of them needs a skilled pathologist for diagnosis. Surgery remains the mainstay of management followed by radiation in high-grade and high-risk pathological features cases. The intensity modulated radiotherapy (IMRT) should be preferred over conformational radiotherapy techniques as adjuvant and exclusive treatment in advanced cases. Particle radiotherapy (i.e. protons, carbon ions) can have a role in advanced/unresectable disease since it was proved to have better results over photons in loco-regional control both in adenoid cystic carcinoma and in other histotypes. Although chemotherapy is still the most frequent treatment for metastatic patients, several new compounds (i.e. anti-angiogenic agents, tailored agents, checkpoint inhibitors) are under investigation.

The diagnostic value of fine needle aspiration in parotid lumps

INTRODUCTION

Fine needle aspiration (FNA) is a safe and quick method of diagnosing superficial lumps, which aids preoperative planning. However, FNA of the parotid gland has not gained the widespread acceptance noted in other head and neck lumps. The aim of this study was to determine the ability of FNA of the parotid gland to differentiate benign and malignant disease, and to determine the impact on surgical outcome.

METHODS

A retrospective analysis of 201 consecutive parotid operations with preoperative FNA in a large district hospital in the UK was performed. The diagnostic characteristics were calculated for benign and malignant disease, and the impact on surgical procedure was determined.

RESULTS

In identifying benign disease, FNA has a sensitivity of 85% and a specificity of 76%. In detecting malignant disease, FNA has a sensitivity and specificity of 52% and 92% respectively. A false positive on FNA was associated with a higher incidence of neck dissection.

CONCLUSIONS

FNA is a useful diagnostic test. However, owing to low sensitivity, it is necessary to interpret it in the context of all other clinical information.

Fine-needle aspiration cytology of salivary gland tumours: a 10-year retrospective analysis

INTRODUCTION

The aim of this study was to evaluate the sensitivity, specificity, diagnostic accuracy, positive predictive value (PPV) and negative predictive value (NPV) of fine-needle aspiration cytology (FNAC) of salivary gland tumours performed at a tertiary cancer hospital over a time period of 10 years.

MATERIALS AND METHODS

A retrospective analysis was carried out between 1995 and 2004 to review the cases of patients with salivary gland tumours who had undergone pre-operative FNA and for whom definite histology was either by tru-cut biopsy or by histopathological examination of the operative specimen.

RESULTS

A total of 107 cases of salivary gland tumours were treated during that period, but only 82 cases diagnosed by FNAC could be correlated with histological and clinical data and were considered for this study. The sensitivity, specificity, diagnostic accuracy, PPV and NPV were estimated considering 54 benign and 28 malignant cases. Sensitivity was 90% (28/31), specificity was 98% (54/55), diagnostic accuracy was 95.1% (82/86), PPV was 96% and NPV was 94%.

DISCUSSION

This study confirms that FNA cytology is a technique that offers high sensitivity, specificity and diagnostic accuracy in salivary gland tumour diagnosis.

Major and minor salivary gland tumors

Malignant salivary gland tumors are rare. The most common tumor site is the parotid. Aetiologic factors are not clear. Nutrition may be a risk factor, as well as irradiation or a long-standing histologically benign tumor that occurs at youth. Painless swelling of a salivary gland should always be considered as suspicious, especially if no sign of inflammation is present. Signs and symptoms related to major salivary gland tumors differ from those concerning minor salivary gland tumors, as they depend on the different location of the salivary gland. Surgical excision represents the standard option in the treatment of resectable tumors of both major and minor salivary glands. Neutron, heavy ions or proton radiotherapy may be a treatment option for inoperable locoregional disease. Surgery, irradiation or re-irradiation are treatment options for local relapse, whereas radical neck dissection is indicated for regional relapses. Metastatic disease may be either treated with radiotherapy or palliative chemotherapy, depending on the site of metastases. For highly selected patients the employment of anti-androgen therapy is indicated.