Rhabdomyoma is considered a benign tumor, rare and is originated from wrinkled muscle cells (1,2). This tumor can have two forms: the cardiac one, which is the most frequent, especially in children, and often associated to other malformations as tuberous sclerosis (50% of the cases), phacomatosis or disorders of glycogen metabolism, and the extracardiac one, which is more rare with few cases reported (3,4).
Extracardiac rhabdomyomas can have three histological classifications: adult, fetal and genital. The two formers with predilection for the head and neck region (90%), especially aerodigestive tract (pharynx, larynx and oral cavity) or soft tissues, although it can occur in other places such as eye socket (orbits), bladder, esophagus, stem and extremities. Fetal and adult forms can differ in relation to age: the fetal one occurs in children usually less than three year of age and the adult one is more common at fifties, with predilection for male (4:1) (1,4,5).
We will introduce below a case of a patient with adult rhabdomyomas affecting extrinsic laryngeal muscle, image and cytological (aspiration punction) findings, surgical access and histopathological aspects related to the tumor as well. CASE REPORT
A male patient, 34, healthy, had nodule complaint on the neck. He denied other types of complaints, weight loss, tabagism or ethylism. When physically examined, he presented painless mass, fiber elastic consistency in submandibular area and left midline cervical (level III), with approximately from 2 to 3 centimeters in diameter.
In that time, cervical ultrasonography was requested that presented solid nodule formation in left midline cervical, measuring 3.3 x 3.1 x 3.0 cm. The result from fine needle aspiration punction (FNAP) was not concluded. The punction redone at the same hospital was well-matched with cytological aspect of reactional lymphoid tissue. Hemogram, serologies to toxoplasmosis and cytomegalovirus were requested, and results were normal. In that moment, clinical observation and return appointment in a three-month period was suggested to re-evaluation.
After six months patient had returned with cervical bulging, with no other symptom. When physically examined it was observed an increase on cervical mass described (approximately 4 cm in the greater diameter, levels II - III); oroscopy and nasofibroscopy were in normal condition. Computed tomography scan showed solid nodule, clear outlines, uniform attenuation with contrast captation, previously to common carotid artery and jugular vein, measuring 3.8 X 3.7 X 2.5 cm. The lesion shifts left submandibular glands upwards, not presenting clear cleavage plane with it, reaching left parapharyngeal space, with impression over larynx, eliminating left aryepiglottic fold, and associating to rarefaction focus of thyroid cartilage. It is also observed the lymph nodes enlarged on submandibular area, with up to 1.5cm in level II in bilateral terms (Picture 1).
Picture 1. Axial cut CT with contrast displaying mass on left submandibular area with extension to parapharyngeal and mucosopharyngeal spaces.
After that, patient had a computed tomography scan, which showed a lesion on left submandibular space, measuring about 5 cm in its larger diameters, which displaces submandibular gland in upwards, without presenting clear cleavage plane with its inferior pole. It is also observed that lesion infuses itself to hyoid bone, reaching hypopharynx submucosa, misshaping lateral wall of pyriform sinus (Picture 2).
Picture 2. Sagital Image MR displaying superior displacement of submandibular gland (1) by tumor (2). Clear separation between submandibular gland and tumor is not observed.
Under this condition, a fine needle aspiration punction (FNAP) was done in another hospital, and cytological result was neolplasm of skeleton muscle cells, suggested by adult rhabdomyoma (Picture 3).
Picture 3. Material Cytology of FNAP: skeleton muscle cells with peripheral nuclei, one of them with plain nucleolus, and plentiful, eosinophilic and granular cytoplasm (Papanicolaou color).
The patient was submitted to surgical treatment with comprehensive removal of tumoral lesion (Pictures 4 and 5). The final histopathological result was adult rhabdomyoma (Picture 6). Immunological and histochemical exams were done and both presented positive results to muscle actin (HHF35); positive result to myoglobin on cytology, negative result on histology and negative on cytokeratins (AE1+AE3) for both (Picture 7).
Picture 4. Surgical field: to observe tumor relation (4) with superior laryngeal nerve (1), lateral carotid vessels (2), constrictor muscle of pharynx.
Picture 5. Tumor aspect in macroscope term.
Picture 6. Surgical specimen material histology: presence of polygonal skeleton cells, with extensive and eosinophilic cytoplasm, with central or peripheral nuclei (Hematoxyllin and Eosin color)
Picture 7. Immunocytochemical exam presenting positive cytoplasmatic result to myoglobin on cell of FNAP (avidin-biotin-peroxidase)
Adult Extracardiac Rhabdomyoma is a rare type of tumor with a high predilection for the head and neck region, although it can occur in other areas such as vagina, bladder, stem and extremities (1,6). It is more often found on muscles from pharyngeal arches and on cervical area, and the most affected places are: larynx, submandibular area, pharyngeal space, oral cavity and rhinopharynx (3,7).
In clinical terms, such tumor is usually presented as a slow-growth and painless cervical mass, for being benign and its symptoms are associated to place (7,8). In more rare cases, the tumor can be presented as a multicenter lesion, affecting the previously mentioned areas (3).
Although its histogenesis is well established, its precise nature is uncertain. Due to its grade of different cells and its slow growth, some authors suggest that adult rhabdomyoma is not a true neoplasm, but a reactive tissue lesion or hamartoma (2,4). Therefore, current studies showed the occurrence of clonal chromosome abnormality on tumor, what reinforces the hypothesis of a true neolplasm treatment (9).
The tumor diagnosis is the pathological anatomy exam, and it can be easily defined, only few cases present diagnostic difficulty and they need to be distinguished from other tumors or reactive lesions such as glanular cell tumor, hibernoma, fetal rhabdomyoma, rhabdomyosarcoma and the normal skeleton muscle tissue (1). Immunohistochemical was done and affirmed the difference of skeleton muscle tissue.
Obtaining diagnosis from cytological exam (FNAP) might be difficult, thus the access to clinical-radiology data is important, because by its high grade of tumor distinguishion, the tumor can be histologically similar to normal skeleton muscle tissue (7,10).
From the pathological anatomy exam of surgical specimen material, it can be observed the following: large, polygonal cells with small-rounded center, placed on central area, prominent and plentiful nucleolus, eosinophilic and glanular cytoplasm with presence of large cytoplasmatic vacuoles on the edge in some cells (1,9,10).
Adult extracardiac rhabdomyoma does not present malign changes and its treatment is done through surgical removal, and the tumor lesion usually presents cleavage plane with adjacent structures (11). It is important to mention the necessity of a comprehensive lesion removal, thus there can be recurrence (in about 15% of the cases), due to incomplete removal. Lesion recurrence usually occurs many years after its removal, because of its slow growth. There are reported cases with 30 year-after-surgery recurrences (3,9).
In this situation, soon after cervicotomy, under the plastim plane, we could observe the lobulated mass, irregular outline, which presented cleavage plane with other structures, what was easily separated. The tumor stretched up to pyriform sinus area, before carotid artery and jugular vein (5). Lesion was deeply joined to constrictor muscle of pharynx, and it could separate the superior laryngeal nerve (6). The tumor was presented as a lobulated mass and uniform aspect in microscopic terms (7).
After twenty months after surgery, patient developed well and with no clinical signs of recurrence. FINAL COMMENTS
Adult extracardiac rhabdomyoma should be pointed out on differential diagnosis of cervical masses. When diagnosing, it is important the clinical-radiological and histopathological data combinations in order to distinguish from normal skeleton tissue and other neoplams (glanular cell tumor, hibernoma, rhabdomyosarcoma). During treatment, the lesion removal should be complete, avoiding recurrence. BIBLIOGRAPHY
1. Weiss SW, Goldblum JR. In: Weiss SW, Goldblum JR. Enzinger's and Weiss's Soft Tissue Tumors. 4 th ed. St. Louis: Mosby: 2001, p. 769-783.
2. Kappadia S, Meis J, Frisman DM, et al. Adult rhabdomioma of the head and neck. Hum Pathol, 24:608-17, 1992.
3. Schemen L, Spiro R, Tuazon R. Multifocal adult rhabdomiomas of the head and neck. Head & Neck, 14:395-400, 1992.
4. Rosenman D, Gertner R, Fradis M, et al. Rhabdomioma of the larynx. J Laryngol Otol, 100:607-610, 1986.
5. Modlin B. Rhabdomioma of the larynx. Laryngoscope, 92:580-582, 1982.
6. Di-SantAgnese PA, Knowles DM. Extracardiac rhabdomyoma: a clinicopathologic study and review of literature. Cancer, 46:780-89, 1980.
7. Stringer SP, Glose LG, Merkel MA, et al. Adult parapharyngeal extracardiac rhabdomioma. Head & Neck, 10:422-6, 1988.
8. Weitzel GJ, Myers EN. Rhabdomioma of the pharynx. Laryngoscope, 86:98-103, 1974.
9. Gibas Z, Miettinen M. Recurrent parapharyngeal rhabdomioma. Evidence of neoplastic nature of the tumor from cytogenetic study. Am J Surg Phatol 16:721-8, 1992.
10. Domanski HA, Dawinskiba S. Adult rhabdomyoma in fine needle aspirates. A report of two cases. Acta Cytologica, 44:223-6, 2000.
11. Whinter LK. Rhabdomyoma of the hypopharynx and larynx. Report of two cases and a review of the literature. J Laryngol Otol, 90:1041-51, 1976.
1. Assistant Doctor and PhD of Otorhinolaryngology Discipline at HCFMUSP
2. Preceptor Doctor of the Division of Otorhinolaryngology Clinic at HCFMUSP
3. Post-Graduating Doctor of Otorhinolaryngology Discipline at HCFMUSP
4. Associated Professor of Otorhinolaryngology Discipline at HCFMUSP
5. PhD Professor of Pathology Department - HCFMUSP
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Article received on February 15, 2005 and accepted with its corrections on August 02, 2005.