It is important to exclude a tumor which is directly extending into the ear canal from the parotid salivary gland, especially when dealing with an adenoid cystic or mucoepidermoid carcinoma. This can be eliminated by clinical or imaging studies. Otherwise, the histologic differential diagnosis includes a ceruminous adenoma (a benign ceruminous gland tumor) or a neuroendocrine adenoma of the middle ear (middle ear adenoma).

They generally have a good prognosis. In one larger study, the 5-year and 10-year survival were over 90% and 80% respectively.

Generally, there is a good prognosis for low-grade tumors, and a poor prognosis for high-grade tumors.

There are many diagnostic methods that can be used to determine the type of salivary gland tumour and if it is benign or malignant. Examples of diagnostic methods include:

Physical exam and history: An exam of the body to check general signs of health. The head, neck, mouth, and throat will be checked for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.

Endoscopy: A procedure to look at organs and tissues inside the body to check for abnormal areas. For salivary gland cancer, an endoscope is inserted into the mouth to look at the mouth, throat, and larynx. An endoscope is a thin, tube-like instrument with a light and a lens for viewing.

MRI

Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer.

Fine needle aspiration (FNA) biopsy: The removal of tissue or fluid using a thin needle. An FNA is the most common type of biopsy used for salivary gland cancer, and has been shown to produce accurate results when differentiating between benign and malignant tumours.

Radiographs: An OPG (orthopantomogram) can be taken to rule out mandibular involvement. A chest radiograph may also be taken to rule out any secondary tumours.

Ultrasound: Ultrasound can be used to initially assess a tumour that is located superficially in either the submandibular or parotid gland. It can distinguish an intrinsic from an extrinsic neoplasm. Ultrasonic images of malignant tumours include ill defined margins.

Benign myoepithelioma are treated with simple excision. They are less prone to recurrence than pleomorphic adenoma.

The diagnosis of salivary gland tumors utilize both tissue sampling and radiographic studies. Tissue sampling procedures include fine needle aspiration (FNA) and core needle biopsy (bigger needle comparing to FNA). Both of these procedures can be done in an outpatient setting. Diagnostic imaging techniques for salivary gland tumors include ultrasound, computer tomography (CT) and magnetic resonance imaging (MRI).

Fine needle aspiration biopsy (FNA), operated in experienced hands, can determine whether the tumor is malignant in nature with sensitivity around 90%. FNA can also distinguish primary salivary tumor from metastatic disease.

Core needle biopsy can also be done in outpatient setting. It is more invasive but is more accurate compared to FNA with diagnostic accuracy greater than 97%. Furthermore, core needle biopsy allows more accurate histological typing of the tumor.

In terms of imaging studies, ultrasound can determine and characterize superficial parotid tumors. Certain types of salivary gland tumors have certain sonographic characteristics on ultrasound. Ultrasound is also frequently used to guide FNA or core needle biopsy.

CT allows direct, bilateral visualization of the salivary gland tumor and provides information about overall dimension and tissue invasion. CT is excellent for demonstrating bony invasion. MRI provides superior soft tissue delineation such as perineural invasion when compared to CT only.

Wide, radical, complete surgical excision is the treatment of choice, with free surgical margins to achieve the best outcome and lowest chance of recurrence. Radiation is only used for palliation. In general, there is a good prognosis, although approximately 50% of patients die from disease within 3–10 years of presentation.

EMCas are diagnosed by examination of tissue, e.g. a biopsy.

Its appearance is very similar to adenomyoepithelioma of the breast, which may be the same tumour at a different anatomical site.

The histologic differential diagnosis includes adenoid cystic carcinoma and pleomorphic adenoma.

The prognosis of EMECL is relatively good, and considerably better than most other forms of NSCLC. The skull and dura are possible sites for metastasis from pulmonary EMC. The MIB-1 index is a predictive marker of malignant potential.

Carcinomas can be definitively diagnosed through biopsy, including fine-needle aspiration (FNA), core biopsy, or subtotal removal of single node. Microscopic examination by a pathologist is then necessary to identify molecular, cellular, or tissue architectural characteristics of epithelial cells.

Staging of carcinoma refers to the process of combining physical/clinical examination, pathological review of cells and tissues, surgical techniques, laboratory tests, and imaging studies in a logical fashion to obtain information about the size of the neoplasm and the extent of its invasion and metastasis.

Carcinomas are usually staged with Roman numerals. In most classifications, Stage I and Stage II carcinomas are confirmed when the tumor has been found to be small and/or to have spread to local structures only. Stage III carcinomas typically have been found to have spread to regional lymph nodes, tissues, and/or organ structures, while Stage IV tumors have already metastasized through the blood to distant sites, tissues, or organs.

In some types of carcinomas, Stage 0 carcinoma has been used to describe carcinoma "in situ", and occult carcinomas detectable only via examination of sputum for malignant cells (in lung carcinomas).

In more recent staging systems, substages (a, b, c) are becoming more commonly used to better define groups of patients with similar prognosis or treatment options.

Carcinoma stage is the variable that has been most consistently and tightly linked to the prognosis of the malignancy.

The criteria for staging can differ dramatically based upon the organ system in which the tumor arises. For example, the colon and bladder cancer staging system relies on depth of invasion, staging of breast carcinoma is more dependent on the size of the tumor, and in renal carcinoma, staging is based on both the size of the tumor and the depth of the tumor invasion into the renal sinus. Carcinoma of the lung has a more complicated staging system, taking into account a number of size and anatomic variables.

The UICC/AJCC TNM systems are most often used. For some common tumors, however, classical staging methods (such as the Dukes classification for colon cancer) are still used.

EMECL is staged in the same manner as other non-small cell lung carcinomas, based on the TNM (Tumor-Node-Metastasis) staging system.

Most of these tumors are treated with surgical removal. It is non recurrent.

Myoepitheliomas are diagnosed from an examination of the tissue by a pathologist.

Patients with thyroid oncocytomas present with a thyroid nodule, usually with normal thyroid function. If the tumor is big or invasive, there may be other symptoms such as difficulty swallowing or talking.

"FLCN" mutations are detected by sequencing in 88% of probands with Birt–Hogg–Dubé syndrome. This means that some people with the clinical diagnosis have mutations that are not detectable by current technology, or that mutations in another currently unknown gene could be responsible for a minority of cases. In addition, amplifications and deletions in exonic regions are also tested. Genetic testing can be useful to confirm the clinical diagnosis of and to provide a means of determining other at-risk individuals in a family even if they have not yet developed BHD symptoms.

Occurs in adults, with peak incidence from 20–40 years of age. A causal link with cytomegalovirus (CMV) has been strongly implicated in a 2011 research.

Treatment may include the following:

- Surgery with or without radiation

- Radiotherapy

Fast neutron therapy has been used successfully to treat salivary gland tumors, and has shown to be significantly more effective than photons in studies treating unresectable salivary gland tumors.

- Chemotherapy

Thyroid oncocytomas can be benign (adenomas) or malignant (carcinomas). Grossly, oncocytic adenomas are encapsulated, solid nodules with a characteristic brown cut surface. The gross appearance of a minimally invasive oncocytic carcinoma is indistinguishable to that of an adenoma, while widely invasive oncocytic carcinomas are obviously invasive macroscopically and display pervasive vascular invasion with multifocal involvement of the thyroid gland. There are no reliable cytologic features which distinguish oncocytic adenomas from carcinomas and the only criterion for a diagnosis of malignancy is the identification of transcapsular or vascular invasion.

Birt–Hogg–Dubé can be difficult to diagnose from symptoms alone, because hereditary renal cancers, pneumothorax, and cutaneous tumors occur with other syndromes. Hereditary bilateral, multifocal kidney tumors similar to those seen in BHDcan occur with von Hippel–Lindau disease (clear cell renal cell carcinoma), hereditary papillary renal cancer (papillary renal cell carcinoma), and hereditary leiomyomatosis and renal cell cancer syndrome. They are differentiated with examination of the tumors' histology.

Hereditary recurrent pneumothorax or pulmonary cysts are associated with Marfan syndrome, Ehlers–Danlos syndrome, Tuberous Sclerosis Complex (TSC), alpha1-antitrypsin deficiency, and cystic fibrosis. Non-hereditary recurrent pneumothorax and/or pulmonary cysts can occur with Langerhans cell histiocytosis and lymphangioleiomyomatosis. These conditions are differentiated from Birt–Hogg–Dubé through examining the patient history and performing a physical examination. In women suspected to have the disease, ruling out pulmonary or thoracic endometriosis may be necessary.

Though fibrofolliculomas are unique to Birt–Hogg–Dubé, they may present with an ambiguous appearance and must be confirmed histologically. Other diseases can mimic the dermatologic manifestations of BHD, including tuberous sclerosis complex, Cowden syndrome, familial trichoepitheliomas, and multiple endocrine neoplasia type 1. Tuberous sclerosis must be distinguished because both disorders can present with angiofibromas on the face, though they are more common in tuberous sclerosis.

Primary treatment for this cancer, regardless of body site, is surgical removal with clean margins. This surgery can prove challenging in the head and neck region due to this tumour's tendency to spread along nerve tracts. Adjuvant or palliative radiotherapy is commonly given following surgery. For advanced major and minor salivary gland tumors that are inoperable, recurrent, or exhibit gross residual disease after surgery, fast neutron therapy is widely regarded as the most effective form of treatment.

Chemotherapy is used for metastatic disease. Chemotherapy is considered on a case by case basis, as there is limited trial data on the positive effects of chemotherapy. Clinical studies are ongoing, however.

MCACL has a much more favorable prognosis than most other forms of adenocarcinoma and most other NSCLC's. Cases have been documented of continued growth of these lesions over a period of 10 years without symptoms or metastasis. The overall mortality rate appears to be somewhere in the vicinity of 18% to 27%, depending on the criteria that are used to define this entity.

Carcinoma ex pleomorphic adenoma is diagnosed by examining it under the microscope with consideration of the individual history.

In approximately 75% of cases ca ex PAs arise in a pleomorphic adenoma that is apparent when the tumour is excised. In the other approximately 25% of cases the individual had a pleomorphic adenoma excised previously and the diagnosis is made based on (1) the presence of a carcinoma, and (2) the history of a pleomorphic adenoma at that location.

Prognosis and treatment is the same as for the most common type of ovarian cancer, which is epithelial ovarian cancer.

The median survival of primary peritoneal carcinomas is usually shorter by 2–6 months time when compared with serous ovarian cancer. Studies show median survival varies between 11.3–17.8 months. One study reported 19-40 month median survival (95% CI) with a 5-year survival of 26.5%.

Elevated albumin levels have been associated with a more favorable prognosis.

The treatment is simple excision and exclusion of a malignant neoplasm.