The lacrimal gland, often referred to as the tear gland, is a small, almond-shaped structure situated in the upper, outer part of each eye socket, specifically within the lacrimal fossa of the frontal bone. Its primary function involves producing the watery component of tears, which are then secreted onto the eye’s surface. These tears play a role in lubricating, nourishing, and protecting the cornea and conjunctiva, as well as helping to remove foreign particles.
A lacrimal gland tumor represents an abnormal growth of cells within this specific gland. These growths can arise from either the larger orbital lobe or the smaller palpebral lobe of the gland. While any abnormal growth in this area can be concerning, lacrimal gland tumors are relatively uncommon, accounting for approximately 5-10% of all orbital tumors.
Types of Lacrimal Gland Tumors
Lacrimal gland tumors are broadly categorized into benign (non-cancerous) and malignant (cancerous) types, a distinction that significantly influences their behavior and required medical approach. Benign tumors generally grow slowly and do not spread to other parts of the body, while malignant tumors are more aggressive and possess the ability to invade surrounding tissues or metastasize. The most frequently encountered benign epithelial tumor of the lacrimal gland is the pleomorphic adenoma.
Pleomorphic adenomas, also known as benign mixed tumors, are slow-growing, painless, and present as a well-defined mass. While benign, there is a risk of these tumors transforming into a malignant form, known as carcinoma ex pleomorphic adenoma.
Malignant lacrimal gland tumors are serious. Adenoid cystic carcinoma is the most prevalent malignant epithelial tumor. This tumor is aggressive, causing pain, rapid progression, and spreading along nerves (perineural invasion). Pleomorphic adenocarcinoma is another malignant type, arising from the transformation of a pre-existing pleomorphic adenoma.
Signs and Symptoms
A lacrimal gland tumor can manifest through various physical signs. A common indication is a visible or palpable lump in the upper eyelid’s outer corner, which may alter the eyelid’s contour. This lump can be felt as a firm, non-tender mass.
As the tumor expands, it can displace the eyeball, leading to proptosis. The pressure from the growing mass can cause double vision (diplopia).
Pain or pressure around the eye can also occur, particularly with aggressive tumor types like adenoid cystic carcinoma, which invade nerves and bone. While benign tumors are painless, a sudden onset of pain or rapid increase in symptoms in a long-standing mass might suggest malignant transformation. Changes in tear production can also be observed.
The Diagnostic Process
Diagnosing a lacrimal gland tumor begins with a thorough clinical examination. This involves assessing symptoms, examining the eye for proptosis and eyelid changes, and evaluating eye movement and vision. The doctor will also palpate the area around the lacrimal gland.
Following the initial examination, imaging tests are performed to visualize the tumor and assess its extent. Computed tomography (CT) scans provide detailed images of bone structures. Magnetic resonance imaging (MRI) offers superior soft tissue contrast, visualizing the tumor’s size, shape, and relationship to surrounding structures. These imaging modalities can suggest if a tumor is benign or malignant.
The most definitive step in diagnosis is a biopsy. This procedure involves taking a tissue sample from the tumor for microscopic examination. The biopsy provides the tumor type and determines if it is benign or malignant. For certain tumors like pleomorphic adenomas, an incisional biopsy is avoided before complete surgical removal.
Treatment Approaches
Treatment for lacrimal gland tumors depends on the tumor type, size, and whether it is benign or malignant. Surgery is the primary treatment for most lacrimal gland tumors. The goal of surgical intervention is complete tumor removal. For benign lesions, a lateral orbitotomy is a common technique.
For malignant tumors, surgical removal may be more extensive. This could involve wide surgical excision, or in advanced cases, orbital exenteration. Achieving clear surgical margins reduces local recurrence.
Radiation therapy plays a role in managing lacrimal gland tumors. It can be used as an adjuvant therapy after surgery to reduce local recurrence. Radiation might also be considered as a primary treatment for tumors difficult to remove surgically.
Chemotherapy is reserved for malignant lacrimal gland tumors that have spread (metastasized) or for specific tumor types. For aggressive tumors like adenoid cystic carcinoma, neoadjuvant intra-arterial chemotherapy can reduce tumor size and make surgical removal more feasible.
Post-Treatment Considerations and Outlook
Following treatment for a lacrimal gland tumor, continuous monitoring is important. The long-term outlook varies based on the tumor type and its advancement at diagnosis. Benign tumors have a favorable prognosis with a low chance of recurrence. However, incomplete removal of benign tumors can lead to local recurrence.
Malignant tumors present a guarded prognosis due to their aggressive nature and potential for recurrence and metastasis. Long-term survival rates for these malignant tumors can be lower. Regular follow-up appointments with the medical team are necessary to monitor for any signs of recurrence or spread.
Patients may experience various long-term effects. Removal or damage to the lacrimal gland can lead to chronic dry eye. Other potential effects include changes in eye appearance or double vision. The specific post-treatment plan is tailored to each individual for managing side effects and ensuring recovery.