Rhabdomyosarcoma is a type of cancer that develops from primitive muscle cells, forming in various soft tissues throughout the body. When this malignancy occurs in or around the eye, it is called orbital rhabdomyosarcoma. This condition involves a tumor within the orbit, the bony cavity that houses the eyeball and its associated structures. Understanding this manifestation is important for recognizing its characteristics and management approaches.
What is Rhabdomyosarcoma of the Eye?
Rhabdomyosarcoma is a soft tissue sarcoma, meaning it originates in tissues like muscle, fat, blood vessels, or fibrous tissue. Orbital rhabdomyosarcoma is the most common primary malignancy of the orbit in children, though it can also affect adults. The average age of diagnosis in children is 7 to 8 years old. Approximately 25-35% of all rhabdomyosarcoma cases arise in the head and neck region, with about 7% specifically affecting the orbit.
There are two main types of rhabdomyosarcoma relevant to the eye: embryonal and alveolar. Embryonal rhabdomyosarcoma accounts for about 80% of orbital cases and is generally associated with a better outlook. Alveolar rhabdomyosarcoma, while less common in the orbit, is considered a more aggressive subtype. These types differ in how their cells appear under a microscope.
Identifying Symptoms and Diagnosis
Symptoms of orbital rhabdomyosarcoma often develop rapidly because the tumor can grow quickly. A common initial sign is proptosis, or a bulging eyeball. Other signs include a red, swollen, or droopy eyelid (ptosis), difficulty moving the affected eye, vision changes, or a noticeable mass around the eye.
Diagnosis typically begins with a physical examination, focusing on the eye and surrounding areas. Imaging studies are then performed to visualize the tumor and determine its extent. These include computed tomography (CT) scans, which show if the tumor has invaded orbital bones, and magnetic resonance imaging (MRI) scans, which provide detailed images of soft tissues. A positron emission tomography (PET) scan may also be used.
The definitive diagnosis requires a biopsy, where a tissue sample from the suspicious area is collected and examined by a pathologist. This biopsy helps confirm the type of cancer and guides further treatment planning.
Treatment Options
Treatment for orbital rhabdomyosarcoma usually involves a multidisciplinary approach, combining several different therapies to target the cancer effectively.
Chemotherapy
Chemotherapy is a systemic treatment, meaning it uses medications to kill cancer cells throughout the body. It is often a primary component of treatment, administered to reduce tumor size before other interventions or to eliminate any cancer cells that may have spread beyond the primary site. The specific chemotherapy regimen depends on the tumor’s characteristics and the patient’s overall health.
Radiation Therapy
Radiation therapy uses high-energy rays to destroy cancer cells and is a common local control method for orbital rhabdomyosarcoma. It is often administered after chemotherapy or in conjunction with it to target the tumor directly and reduce the risk of local recurrence. The dosage and field of radiation are carefully planned to maximize tumor destruction while minimizing damage to surrounding healthy tissues, especially the delicate structures of the eye.
Surgery
Surgery may be considered for tumor removal, though its feasibility depends on the tumor’s size, location, and extent of spread. The goal is to remove as much of the tumor as safely possible while preserving vision and orbital function. In some cases, organ-sparing surgeries are performed to avoid extensive removal of eye structures. The decision to perform surgery is made by a team of specialists, including neurosurgeons and ENT surgeons.
Outlook and Follow-Up Care
The outlook for individuals with orbital rhabdomyosarcoma has significantly improved over the years, with current treatments offering a high survival rate, sometimes exceeding 90%. Several factors influence the prognosis, including the stage of the disease at diagnosis, the size of the tumor, and the patient’s age. Tumors detected early and confined to the orbit generally have a more favorable outcome. The histological type of the tumor also plays a role; embryonal types typically have a better prognosis than alveolar types.
Long-term follow-up care is very important after treatment for orbital rhabdomyosarcoma. This involves regular monitoring for any signs of cancer recurrence, including imaging scans and physical examinations. Follow-up care also addresses potential late effects of treatment, such as vision changes (e.g., radiation cataract or dry eye) and cosmetic concerns (e.g., orbital hypoplasia or droopy eyelids). Supportive care and rehabilitation services are also part of the ongoing management, helping patients manage any physical or functional challenges that may arise from the disease or its treatment.