A rare case of rhabdomyoma of the larynx causing airway obstruction.

Abstract

Rhabdomyomas are benign tumors of skeletal muscle derivation. Rhabdomyomas of the head and neck are unusual, and laryngeal rhabdomyomas of the adult type are rare. When they do occur, patients may present with symptoms that have progressed slowly over several years. In extraordinary cases, stridor and airway obstruction manifest. We report a case of adult rhabdomyoma of the larynx that features some of its typical and atypical presenting characteristics. This case also exemplifies the favorable prognosis that results following complete yet conservative surgical excision.

Introduction

Rhabdomyomas are rare benign neoplasms that are derived from striated muscle. They are more common in the myocardium than in skeletal muscle. Rhabdomyoma can be differentiated into three types: adult, fetal cellular, and fetal myxoid:

* Adult-type tumors, which are confined to the head and neck, typically feature well-defined margins and contain large, densely packed round cells with granular eosinophilic cytoplasm and cross-striations.

* Tumors of the fetal cellular type are extremely rare. They occur in children younger than 4 years of age and in the head and neck of elderly men. These tumors are poorly defined and are made up of immature, elongated, spindle-shaped skeletal muscle elements in various stages of differentiation; mature cells are few. (1) Fetal cellular rhabdomyomas in children have a predilection for the posterior auricular area. (2)

* Fetal myxoid rhabdomyomas are tumorlike polypoid masses with loose, edematous, and myxoid stroma. These tumors may be found in the vagina and vulva of middleaged women. (1)

Most extracardiac rhabdomyomas occur in the head and neck region, (2) and most are of the adult type. (1) In 1988, Helliwell et al reported a large series of 115 extracardiac rhabdomyomas and demonstrated that most occurred in the head and neck. (2) In 1995, Johansen and Illum published a review of 23 reported cases of rhabdomyoma of the larynx and reported that 15 of them were of the adult type. (1) In the latter study, most patients had presented with progressive hoarseness and dysphagia as their chief complaints; only 1 of these patients had presented with acute airway obstruction, and 1 other patient had presented with dyspnea along with dysphagia. In 1994, Roberts et al reported a case of laryngeal rhabdomyoma that featured worsening dyspnea with positional stridor. (3)

In this article, we report a case of adult rhabdomyoma of the larynx that typified the common indolent progression of dysphagia and dysphonia but featured a more acute presentation of upper airway obstruction.

Case report

A 66-year-old man was referred to the otolaryngology service for evaluation of a possible supraglottic mass that had been suggested by routine endoscopic gastroduodenoscopy performed during an assessment of dysphagia. The patient relayed a 3-year history of progressive dysphagia (primarily with solids) and a vocal coarseness. He also related that he had experienced some difficulty breathing over the previous several months and that his breathing was significantly noisy when he was supine and during minimal exertion. He reported no odynophagia, unexpected weight loss, fevers, or other aerodigestive or systemic symptoms. He had no history of congenital defects, head and neck cancer, radiation therapy, or relevant trauma.

On physical examination, a notable inspiratory upper airway noise could be appreciated on auscultation. Nasopharyngoscopy detected a large, smooth, pedunculated mass emanating from the vocal process of the right arytenoid. With each inspiration, the mass would ball-valve into the laryngeal introitus and cause a near-total airway obstruction.

The patient was taken urgently to the operating suite, where extirpation of the mass via suspension laryngoscopy was performed (figure 1). The mass was attached by an insubstantial stalk that was pedicled to the vocal process of the right arytenoid. The patient did not require a surgically created airway, and he experienced no complications.

[FIGURE 1 OMITTED]

On gross examination, the excised specimen was a smooth soft-tissue mass with a homogenous tan-brown surface. It measured 2.0 x 1.4 x 1.3 cm. Microscopic examination demonstrated that the large tumor mass was made up of large polygonal cells with distinct cell borders and abundant granular eosinophilic cytoplasm. Crossstriations and large vacuoles were noted in the cytoplasm of many of the cells. The nuclei were uniformly large with prominent nucleoli. No mitotic activity was identified. The cytoplasmic granules were positive on periodic acid-Schiff staining and diastase-labile, indicating the presence of glycogen. Immunohistochemical analysis revealed strong reactivity in the tumor cells for desmin (figure 2).

[FIGURE 2 OMITTED]

The patient made a full recovery and reported a complete cessation of dysphagia, dysphonia, and airway obstruction. At the 18-month follow-up, he exhibited no evidence of tumor recurrence.

Discussion

The term rhabdomyoma was first used in 1864 by Zenker to describe a striated muscle tumor. (4) Rhabdomyomas are generally benign, never metastasize, (5) and rarely recur. (3,6,7) Rhabdomyomas of the heart are usually hamartomatous growths, and they have been associated with phakomatoses such as tuberous sclerosis. Extracardiac rhabdomyomas account for only 2% of skeletal muscle tumors, and 70% of them occur in the head and neck. (5) They are thought to arise from unsegmented mesoderm in the branchial arches. (8) Most reported cases of extracardiac rhabdomyoma have involved solitary masses; the few that have occurred multifocally were associated with no clinically significant difference in treatment or outcome. (9) Adult rhabdomyoma occurs more frequently in men than women (4:1). (4) The reported ages of affected patients have ranged from 16 to 76 years (mean: 52). (1)

The most common symptoms of laryngeal rhabdomyoma are hoarseness, a foreign-body sensation, and dysphagia. The duration of symptoms is usually long, typically years. In rare cases, progressive airway obstruction has occurred; such obstructions were usually secondary to a pedunculated supraglottic mass that blocked the airway during inspiration or when it was in a dependent position. (3)

Histologic analysis is essential for diagnosis. Adult rhabdomyomas have been confused with granular cell tumors during initial evaluation. (6,7,10) Battifora et al used light and electron microscopy to compare the two tumors. (11) They found that rhabdomyomas are characterized by the presence of a sarcolemma sheath, rodlike cytoplasmic bodies, and cross-striations on light microscopy. Ultrastructural studies showed actin filament and Z bands. There were no contractile elements found in the granular cell tumor. The differential diagnosis also includes rhabdomyosarcoma, oncocytoma, and alveolar soft-tissue sarcoma.

The curative treatment of rhabdomyomas of the supraglottic airway is complete surgical excision. This is most easily approached via suspension laryngoscopy. Successful removal of these typically poorly vascularized tumors can be achieved with microlaryngeal instrumentation. Overall, the long-term prognosis is excellent, and recurrence rates are very low.

References

(1.) Johansen EC, Illum P. Rhabdomyoma of the larynx: A review of the literature with a summary of previously described cases of rhabdomyoma of the larynx and a report of a new case. J Laryngol Otol 1995;109:147-53.

(2.) Helliwell TR, Sissons MC, Stoney PJ, Ashworth MT. Immunohisto-chemistry and electron microscopy of head and neck rhabdomyoma. J Clin Pathol 1988;41:1058-63.

(3.) Roberts DN, Corbett MJ, Breen D, et al. Rhabdomyoma of the larynx: A rare cause of stridor. J Laryugol Otol 1994; 108:713-15.

(4.) Boedts D, Mestdagh J. Adult rhabdomyoma of the larynx. Arch Otorhinolaryngol 1979;224:221-9.

(5.) Di Sant' Agnese PA, Knowles DM 11. Extracardiac rhabdomyoma: A clinicopathologic study and review of the literature. Cancer 1980;46:780-9.

(6.) Zbaren P, Lang H, Becker M. Rare benign neoplasms of the larynx: Rhabdomyoma and lipoma. ORL J Otorhinolaryngol Relat Spec 1995;57:351-5.

(7.) Hamper K, Renninghoff J, Schafer H. Rbabdomyoma of the larynx recurring after 12 years: Immunocytochemistry and differential diagnosis. Arch Otorhinolaryngol 1989;246:222-6.

(8.) Winther LK. Rhabdomyoma of the hypopharynx and larynx. Report of two cases and a review of the literature. J Laryngol Otol 1976;90:1041-51.

(9.) Neville BW, McConnel FM. Multifocal adult rhabdomyoma. Report of a case and review of the literature. Arch Otolaryngol 1981;107:175-8.

(10.) Wood GS, Brammer R, Durham JC, Dichtel W.Adult rhabdomyoma of the larynx. Ear Nose Throat J 1993;72:296-8.

(11.) Battifora HA, Eisenstein R, Schild JA. Rhabdomyoma of larynx: Ultrastructural study and comparison with granular cell tumors (myoblastomas). Cancer 1969;23:183-90.

Kevin Jensen, DO; Keith Swartz, MD

From the Department of Otolaryngology, Wilford Hall Medical Center, Lackland Air Force Base, Tex.

Reprint requests: Capt. Keith Swartz, MD, Chief, Otolaryngology Element, 10th MDSS (SGSC), 4102 Pinion Dr., USAFA, CO 808405300. Phone: [phone]; fax: [phone]; e-mail: keith. [e-mail]

The views and opinions expressed in this article are those of the authors and do not necessarily represent those of the United States Air Force or the Department of Defense.