First report of a case of osteoma of the larynx.

Abstract

Osteomas are common in otolaryngology, as they often involve the skull and facial bones. On rare occasions, these tumors have also been found in the temporal bone and the tongue. Until now, osteomas have not been encountered in the larynx. We describe the case of a patient who came to our institution with hoarseness and dysphagia and who was found to have an osteoma of the larynx. Radiographic imaging, endoscopy, and pathologic classification confirmed the diagnosis. To our knowledge, this is the first reported case of an osteoma of the larynx.

Introduction

Osteomas are benign, slow-growing tumors made up of densely sclerotic well-formed bone projecting out from the cortical surface. These lesions most often involve the skull and facial bones, and they are the most common benign tumor of the sinonasal tract. [1] They occur most often in the frontoethmoid sinuses, and less often in the maxillary and sphenoid sinuses.

On rare occasions, osteomas have been found in the tongue and temporal bone. Multiple occurrences of extraosseous osteomas involving the tongue have been reported in approximately 30 patients. [2] In the temporal bone, mastoid osteomas are rare, and osteomas involving the ossicles are extremely rare, as only a few cases have been reported. [3]

In this article, we describe the case of a patient with hoarseness and dysphagia who was found to have an osteoma of the larynx. To the best of our knowledge, this is the first published report of an osteoma involving the larynx.

Case report

A 68-year-old man had a 5-year history of progressive hoarseness and dysphagia. He reported increasing dysphagia, especially when eating solid foods, and mild odynophagia. He denied any shortness of breath or respiratory distress. The rest of his medical history was noncontributory.

Physical examination revealed a large interarytenoid mass involving the posterior third of the vocal folds (figure 1). All other physical findings were normal.

Computed tomography (CT) with intravenous contrast was performed, and multiple 5-mm axial scans were taken of the neck. They detected a dense, calcified lesion arising from the superior aspect of the cricoid cartilage and protruding through the vocal folds into the supraglottis (figure 2).

The patient underwent direct laryngoscopy with excision of the lesion. Laryngoscopy detected a rough, hard, mucosa-covered mass coming off the right posterosuperior aspect of the cricoid cartilage. The mass, which was approximately 2 cm in length, extended into the larynx. A Lewy suspension apparatus was utilized and a 14-gauge needle was inserted for jet ventilation. Then a [CO.sub.2] laser was used to make an incision over the visible portion of the lesion that extended posteriorly into the larynx. A cleavage plane was then formed, and the lesion was excised en bloc with endoscopic instruments. Bronchoscopy found no other pathology.

The bony lesion was sent for pathologic examination, which revealed that an outer rim of squamous epithelium was surrounding areas of wide trabeculae of mature lamellar bone (figure 3). These features are consistent with those of an osteoma.

Postoperatively, the patient's voice and dysphagic symptoms greatly improved. At 1-year followup, there was no evidence of osteoma on laryngeal examination and CT (figure 4).

Discussion

Although most malignant neoplasms that arise in the larynx are squamous cell carcinomas, less common types of neoplasms are included in the differential diagnosis. The list of other malignant neoplasms includes variants of squamous cell carcinoma (e.g., verrucous carcinoma), carcinomas of glandular origin (e.g., neuroendocrine, adenocarcinomatous, adenoid cystic, and mucoepidermoid tumors), sarcomas of structural origin (e.g., fibrosarcoma, chondrosarcoma, osteosarcoma, rhabdomyosarcoma, leiomyosarcoma, and liposarcoma), and tumors of lymphocytic origin (e.g., lymphoma and plasmacytoma). Benign mesenchymal neoplasms include squamous papillomatoses, granulation tissue lesions, hemangiomas, rhabdomyomas, lipomas, pleomorphic adenomas, neurofibromas, granular cell tumors, and chondromas.

Laryngeal tumors that actually originate in the laryngeal skeleton are uncommon, representing less than 1% of all tumors of the larynx. The male-to-female ratio is 4-to-1, and the age at onset ranges from 40 to 60 years.

Of the 250 cases that have been reported--all before 1989--72% were chondromas and the rest were chondrosarcomas. [4]

The posterolateral portion of the cricoid cartilage is the most common site (70%) of cartilaginous neoplasms of the larynx, followed by the thyroid cartilage (20%) and the body of the arytenoid (l0%). [5] Bony tumors of the larynx are extremely rare. Osteosarcoma of the larynx has been described in the literature, [6] but a benign bone-forming tumor of the larynx such as an osteoma has not.

An osteoma is a protruding tumor mass made up of abnormally dense but otherwise normal bone formed in the periosteum. Even though osteomas are uncommon overall, they are the most common benign neoplasm of the nose and paranasal sinuses. Some 75% of osteomas arise in the frontoethmoid region; they have also been found in the tongue, temporal bone, ossicles, and now the larynx.

Osteomas are rock-hard, irregularly nodular or granular masses of bone. Histologically, wide trabeculae of mature bone array in an irregular pattern. Osteoid seams can be prominent, and osteoblasts might be evident. The two types of lesions are the ivory form (made up of hard, compact bone with minimal fibrous tissue) and the cancellous form (consisting of mature cancellous bone).

Pathologically, the differential diagnoses of osteoma include ossifying fibroma, osteoblastoma, osteosarcoma, and chondrosarcomatous osteosarcoma. Osteomas are also part of Gardner's syndrome, an autosomal-dominant disease characterized by intestinal polyposis, osteomas, and soft tissue tumors such as dermoid cysts and fibromas. [7]

The etiology of osteoma is unknown. Accepted theories point to embryologic, traumatic, and infectious causes. According to the embryologic theory, osteomas that arise at the junction of the developing membranous frontal bone and the cartilaginous ethmoid bone predispose to the development of cell rests and later tumor formation. [8] The trauma theory refers to injury during the period of maximum bone growth. [9] Infection is believed to stimulate osteoma formation. [10]

The first symptoms of an osteoma vary according to its site of origin. Most tumors that affect the posterior lamina of the cricoid cartilage grow inwardly into the lumen of the larynx, and the first symptoms in these cases are a change in the character of the voice, dysphagia, odynophagia, and a slowly progressive dyspnea. Occasionally, a cricoid lesion grows outwardly, and the patient's first symptom is a neck mass.

A radiographic diagnosis of osteoma can be made easily by CT. These lesions are usually well-defined, bony masses that do not enhance on intravenous contrast. CT defines the full extent of the osteoma and helps in planning the surgical approach.

Surgical excision is generally regarded as the mainstay of treatment for symptomatic osteomas. [11] These lesions rarely, if ever, recur following complete removal. Although there are no data available regarding laryngeal osteomas, the surgical approach is similar to that of cartilaginous tumors of the larynx. Most cartilaginous tumors of the larynx occur in the region of the cricoid. The cricoid cartilage is the cornerstone of the larynx, and the removal of half or more of this cartilage would seriously weaken laryngeal support and require reconstruction or a total laryngectomy. Another alternative to laryngectomy is the partial removal of the cartilage and immediate reconstruction with an epiglottic flap and a sternocleidomastoid muscle flap. [12]

In our patient, we used suspension laryngoscopy with jet ventilation, a [CO.sub.2] laser, and endoscopic instruments to excise the cricoid osteoma. This approach allows the surgeon to preserve laryngeal function and the patient to return to normal activity. At 1-year follow up, our patient was symptom and disease free.

From the Department of Otolaryngology and Communicative Disorders, Long Island Jewish Medical Center, The Long Island Campus of the Albert Einstein College of Medicine, New Hyde Park, N.Y.

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