bubble_chart Overview

Bone tumor is the most common benign tumor of the nasal cavity and paranasal sinuses, occurring more frequently in the sinuses. It typically grows very slowly and tends to stop developing on its own after adulthood. The frontal sinus is the most common site of occurrence, followed by the ethmoid sinus, while the maxillary sinus and sphenoid sinus are rarely affected. Occasionally, it may also occur within the nasal cavity.

bubble_chart Etiology

Regarding the causes of bone tumors, the following theories exist: ① Originating from residual embryonic cartilage, hence often occurring at the junction of the ethmoid bone (cartilage ossification) and the frontal bone (membrane ossification); ② Trauma or inflammation leading to bone membrane hyperplasia in the sinus walls; ③ Bone tumors result from hyperplastic ethmoid sinus air cells extending into other sinuses, forming bony mucoid membrane vesicles, which, through chronic inflammation, cause secretion retention, connective tissue hyperplasia, and ossification. Other theories include endocrine disorders and genetic factors.

bubble_chart Pathological Changes

Bone tumors all occur on the bony walls of the sinuses or nasal cavity, covered by a mucous membrane on the surface, appearing spherical or nodular, with a smooth surface, hard texture, and either pedunculated or broad-based. They are usually solitary but occasionally multiple. Bone tumors within the sinuses may spontaneously detach from their pedicles, forming "dead bone tumors" within the sinus cavity. The nasal cavity may also occasionally exhibit the phenomenon of "dead bone tumors." Bone tumors can be classified into three types:

1. Compact type: Also known as the hard type, ivory type, or ebony bone tumor. Those originating from membranous tissue develop into this type, composed of dense lamellar bone, as hard as ivory, relatively small, often pedunculated, and slow-growing. They mostly occur in the frontal sinus but may also be found in the nasal bone.

2. Spongy type: Also called the soft type or spongy type. Those originating from cartilaginous tissue develop into spongy bone tumors. They consist of ossified fibrous tissue with irregularly arranged bone tissue, sometimes containing osteoblasts. They are soft in texture, broad-based, larger in size, and grow relatively faster. Sometimes, the center may liquefy into a cystic cavity, with a harder bony capsule on the surface. They are commonly found in the ethmoid sinus.

3. Mixed type: Those originating from both types of tissue develop into mixed bone tumors. Most or the peripheral parts of the tumor are often of the compact type, while the core or basal parts are of the spongy type, resulting in a hard exterior and soft interior. They frequently occur in the frontal sinus.

In addition to the simple types of bone tumors, there are various mixed types, such as fibrous bone tumors and vascular bone tumors.

bubble_chart Clinical Manifestations

The disease is more common in males, predominantly occurring in young individuals under the age of 30. Small bone tumors generally do not cause symptoms and are often incidentally discovered on sinus X-rays. Larger bone tumors, depending on their location and extent of invasion, can lead to various symptoms. Bone tumors in the nasal bone present as localized hard swellings. The main symptoms of nasal cavity bone tumors are local mechanical obstruction, which may result in nasal congestion, nasal discharge, headache, and in advanced stages, invasion of adjacent organs. Since bone tumors frequently occur in the frontal sinus, obstruction of the nasofrontal duct can lead to headache. In the advanced stage, the tumor often extends beyond the sinus cavity, invading the nasal cavity and orbit, causing nasal symptoms, exophthalmos, displacement of the eyeball, diplopia, decreased vision, impaired eye movement, headache, and significant facial deformity. If the tumor progresses into the cranial cavity and compresses the brain, it may lead to intracranial symptoms or induce intracranial infections.

bubble_chart Diagnosis

Local examination reveals a smooth, hard mass covered with normal mucosa, often complicated by polyps and sinusitis. X-ray imaging aids in the diagnosis of this condition, helping to determine its nature, location, extent, and attachment site. Surgical exploration and postoperative biopsy can confirm the diagnosis.

bubble_chart Treatment Measures

Since bone tumors grow very slowly and tend to stop developing on their own after adulthood, small bone tumors in adult patients without obvious symptoms do not require treatment but should be regularly monitored with X-rays. For large tumors that cause facial deformities or significant symptoms, surgical removal may be performed. Larger bone tumors can be excised through a facial incision, while small frontal sinus bone tumors can be removed via a frontal bone flap reconstruction, preserving the sinus mucosa and the nasofrontal duct to minimize postoperative deformities and facilitate sinus drainage. Special care must be taken during surgery to avoid injuring the posterior wall of the frontal sinus or the cribriform plate to prevent intracranial complications. If the dura mater is torn during the procedure, it can be repaired with fascia lata. Any residual deformities can be addressed with plastic surgery at a later stage.

bubble_chart Complications

Frontal sinus bone tumors are prone to complications such as sinusitis, mucocele, pneumocephalus, intracranial infection, and cerebrospinal fluid rhinorrhea.