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Surgery - Salivary Gland Tumours
Introduction
tumors with a variety of histological subgroups that originate in either the major (parotid, submandibular, sublingual) or small salivary glands. 15% arise in the submandibular glands (30–50% malignant); 20% arise in the parotid glands (20% malignant); and 15% arise in the small salivary glands (>60% malignant). Less than 0.3 percent of sublingual gland tumors are malignant.
Etiology
Unknown Causes
Risk Factors
The following environmental factors have been identified: Epstein-Barr virus with lymphoepithelial tumors; smoking (Warthin's); radiation (Warthin's and mucoepidermoid carcinomama).
Epidemiology
comparatively uncommon; most affect adults. Pleomorphic adenoma has an average age of 42 years, Warthin's tumor has an average age of 60 years (male > female), acinic cell carcinoma affects women in their 50s, and squamous carcinomas attack men in their 70s.
History
A swelling that normally grows slowly and without pain. A malignant tumor increases the likelihood of pain.
Examination
Examining the edema and looking for indications of fixation is important. induration or ulceration of the mucosa or skin underlying it in locally advanced instances. One should use both hands to palpate the submandibular gland. examination of the mouth cavity because parapharyngeal space might become inflamed by deep lobe parotid tumors. facial nerve function in parotid lesions and signs of regional lymphadenopathy; weakness in this area should increase the possibility of malignancy.
Investigations
Imaging: To define the mass and its position in relation to adjacent structures and staging, ultrasound, CT, or MRI scans are utilized.
Tissue biopsy: FNA is a useful tool, however it is not a 100% reliable method for histological diagnosis.
Because of the possibility of tumor spilling, incisional or excisional biopsy of tumors in large glands should be avoided.
Histopathology:
& benign tumors About 80–85% of parotid gland tumors are pleomorphic adenomas. lack of a real capsule in epithelium or myoepithelial cells, which explains their propensity to regrow following excision.
Once called as adenolymphoma, Warthin's tumor (papillary cystadenoma lymphomatosum) accounts for 15% of parotid neoplasms and 10% of bilateral or multicentric tumors with glandular, cystic, and eosinophilic epithelium.
& Malignant carcinomas: Parotid cancer is the most common type of acinic cell carcinoma. broad histological spectrum accompanied with lymphocyte infiltrations.
The most prevalent malignant tumor of the parotid gland, mucoepidermoid carcinoma can range in malignancy from low grade to severe.
& Adenoid cystic carcinoma: aggressive with a perineural spread into the brain and the potential for late metastases; it is the sixth most common malignant carcinoma of the submandibular region.
& Aggressive forms of adenocarcinoma, squamous, and undifferentiated carcinomas.
& Non-epithelial tumors (such as lymphomas and haemangiomas): Very uncommon.
Management
Medical: Saved for infectious tumors or lymphomas.
Surgical: Both benign and malignant tumors can be removed.
Superficial or whole parotidectomy, with careful preservation of the facial nerve and its branches that pass between the deep and superficial lobes, is the treatment for parotid-related benign or low-grade cancers. Should the nerve be affected, it is possible to undertake sacrifice and prompt reconstruction using a nerve graft.
Submandibular: An incision in the submandibular triangle is used to address tumors.
Resection may be required if malignant tumors involve the lingual or hypoglossal nerves. This causes a partial loss of sensation and tongue movement; the patient should be informed of this. Additionally, there's a chance of harming the facial nerve's mandibular branch, which could cause asymmetry in the mouth and lower lip. If there is involvement of lymph nodes, neck dissection is done.
Palate cancers: Usually require a large excision and intricate repair.
Therapy: If the tumor is malignant, adjuvant post-operative radiotherapy ought to be administered.
Chemotherapy: Usually used for palliation, although not very effective.
Complications
Following a parotidectomy, there may be facial nerve damage, bleeding, necrosis of the skin flap, salivary fistula, and Frey's syndrome (10–50%), which is characterized by abnormal regeneration of postganglionic parasympathetic nerve fibers that typically innervate the parotid to sympathetic nerves of the sweat glands, causing gustatory sweating. Pleomorphic adenomas, because they feature pseudopod-like extensions extending from the tumor, are prone to recurrence even with simple enucleation.
Prognosis
If left untreated, pleuromorphic adenomas gradually increase and carry a 5% risk of developing into malignant transformation. Five-year survival for mucoepidermoid carcinoma is 70%; higher-grade types have a worse survival rate. Because perineural invasion is difficult to eliminate and has a tendency for late recurrence, adenoid cystic carcinoma has a poor prognosis. Only 25–50% of high grade tumors have a 10-year survival rate, compared to 80–95% for low grade tumors.
Introduction
tumors with a variety of histological subgroups that originate in either the major (parotid, submandibular, sublingual) or small salivary glands. 15% arise in the submandibular glands (30–50% malignant); 20% arise in the parotid glands (20% malignant); and 15% arise in the small salivary glands (>60% malignant). Less than 0.3 percent of sublingual gland tumors are malignant.
Etiology
Unknown Causes
Risk Factors
The following environmental factors have been identified: Epstein-Barr virus with lymphoepithelial tumors; smoking (Warthin's); radiation (Warthin's and mucoepidermoid carcinomama).
Epidemiology
comparatively uncommon; most affect adults. Pleomorphic adenoma has an average age of 42 years, Warthin's tumor has an average age of 60 years (male > female), acinic cell carcinoma affects women in their 50s, and squamous carcinomas attack men in their 70s.
History
A swelling that normally grows slowly and without pain. A malignant tumor increases the likelihood of pain.
Examination
Examining the edema and looking for indications of fixation is important. induration or ulceration of the mucosa or skin underlying it in locally advanced instances. One should use both hands to palpate the submandibular gland. examination of the mouth cavity because parapharyngeal space might become inflamed by deep lobe parotid tumors. facial nerve function in parotid lesions and signs of regional lymphadenopathy; weakness in this area should increase the possibility of malignancy.
Investigations
Imaging: To define the mass and its position in relation to adjacent structures and staging, ultrasound, CT, or MRI scans are utilized.
Tissue biopsy: FNA is a useful tool, however it is not a 100% reliable method for histological diagnosis.
Because of the possibility of tumor spilling, incisional or excisional biopsy of tumors in large glands should be avoided.
Histopathology:
& benign tumors About 80–85% of parotid gland tumors are pleomorphic adenomas. lack of a real capsule in epithelium or myoepithelial cells, which explains their propensity to regrow following excision.
Once called as adenolymphoma, Warthin's tumor (papillary cystadenoma lymphomatosum) accounts for 15% of parotid neoplasms and 10% of bilateral or multicentric tumors with glandular, cystic, and eosinophilic epithelium.
& Malignant carcinomas: Parotid cancer is the most common type of acinic cell carcinoma. broad histological spectrum accompanied with lymphocyte infiltrations.
The most prevalent malignant tumor of the parotid gland, mucoepidermoid carcinoma can range in malignancy from low grade to severe.
& Adenoid cystic carcinoma: aggressive with a perineural spread into the brain and the potential for late metastases; it is the sixth most common malignant carcinoma of the submandibular region.
& Aggressive forms of adenocarcinoma, squamous, and undifferentiated carcinomas.
& Non-epithelial tumors (such as lymphomas and haemangiomas): Very uncommon.
Management
Medical: Saved for infectious tumors or lymphomas.
Surgical: Both benign and malignant tumors can be removed.
Superficial or whole parotidectomy, with careful preservation of the facial nerve and its branches that pass between the deep and superficial lobes, is the treatment for parotid-related benign or low-grade cancers. Should the nerve be affected, it is possible to undertake sacrifice and prompt reconstruction using a nerve graft.
Submandibular: An incision in the submandibular triangle is used to address tumors.
Resection may be required if malignant tumors involve the lingual or hypoglossal nerves. This causes a partial loss of sensation and tongue movement; the patient should be informed of this. Additionally, there's a chance of harming the facial nerve's mandibular branch, which could cause asymmetry in the mouth and lower lip. If there is involvement of lymph nodes, neck dissection is done.
Palate cancers: Usually require a large excision and intricate repair.
Therapy: If the tumor is malignant, adjuvant post-operative radiotherapy ought to be administered.
Chemotherapy: Usually used for palliation, although not very effective.
Complications
Following a parotidectomy, there may be facial nerve damage, bleeding, necrosis of the skin flap, salivary fistula, and Frey's syndrome (10–50%), which is characterized by abnormal regeneration of postganglionic parasympathetic nerve fibers that typically innervate the parotid to sympathetic nerves of the sweat glands, causing gustatory sweating. Pleomorphic adenomas, because they feature pseudopod-like extensions extending from the tumor, are prone to recurrence even with simple enucleation.
Prognosis
If left untreated, pleuromorphic adenomas gradually increase and carry a 5% risk of developing into malignant transformation. Five-year survival for mucoepidermoid carcinoma is 70%; higher-grade types have a worse survival rate. Because perineural invasion is difficult to eliminate and has a tendency for late recurrence, adenoid cystic carcinoma has a poor prognosis. Only 25–50% of high grade tumors have a 10-year survival rate, compared to 80–95% for low grade tumors.
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