Cytologic findings of an adult rhabdomyoma in the parapharyngeal space: A report of a case and review of the literature

Abstract

Adult extracardiac rhabdomyomas are rare benign mesenchymal tumor arising from skeletal muscle. While they are often located in the larynx and pharynx, the incidence in the parapharyngeal area is extremely rare with only 1 documented cytology case report to date. We report a case of an adult extracardiac rhabdomyoma in the parapharyngeal space diagnosed cytologically with subsequent histologic confirmation. The patient is a 57-year-old man with history of weight loss, hematuria, dysphagia, and airway encroachment. Computerized tomography of his abdomen showed a large left renal mass. While the patient was in the operating room for the resection of his renal mass, a fine-needle aspiration from left the parapharyngeal mass was performed. The smears showed uniform bland polygonal cells with abundant eosinophilic cytoplasm and peripherally located nuclei. Immunohistochemical stains performed on the cell block showed the tumor cells were desmin positive and negative for S-100 and PAX-8, supporting the diagnosis of an adult rhabdomyoma. Subsequent resection of the mass confirmed the diagnosis of an adult extracardiac rhabdomyoma.

Mesenchymal neoplasms of the parotid gland and parapharyngeal space: an FNA cytologic study of 22 nonlipomatous tumors

“…Because the cytomorphologic features of each of these neoplasms has been thoroughly illustrated in prior publications, 20‐33 only brief descriptions of selected neoplasms are furnished below. Aspirates of the schwannoma cases were moderate‐to‐high cellular with isomorphic spindle cells arranged in three‐dimensional syncytial microfragments often having a ragged fibrillar edge and dispersed in a clean background.…”

“…In the MSRSGC, 8 (36%) aspirates would be classified as neoplasm: benign, 6 (27%) malignant, 4 (18%) neoplasm: salivary gland neoplasm of uncertain malignant potential (SUMP), 2 (9%) non-diagnostic, 1 (4.5%) suspicious for malignancy, and 1 (4.5%) non-neoplastic. 19 Because the cytomorphologic features of each of these neoplasms has been thoroughly illustrated in prior publications, [20][21][22][23][24][25][26][27][28][29][30][31][32][33] only brief descriptions of selected neoplasms are furnished below. Aspirates of the schwannoma cases were moderate-to-high cellular with isomorphic spindle cells arranged in three-dimensional syncytial microfragments often having a ragged fibrillar edge and dispersed in a clean background.…”

Rhabdomyoma of the tongue base

“…Rhabdomyomas in the head and neck are rare tumors and have been reported at variable locations like the lip, tongue, tongue base, soft palate, cheek, orbita, nasopharynx, larynx, the parapharyngeal and paratracheal space, hypopharynx or even multifocal. 2,[4][5][6][7][8][9][10][11] Extracardiac rhabdomyoma cannot be diagnosed by clinical examination only. Histopathological examination is necessary to secure the diagnosis and to exclude differential diagnoses like granular cell tumor, hibernoma, oncocytoma, paraganglioma, histiocytosis and of course rhabdomyosarcoma.…”

“…1 Tissue for histopathological analysis can be collected by direct or needle biopsy/cytology. 4,10 Before deciding on the definitive treatment, the extent of the rhabdomyoma should be determined by proper imaging methods like sonography, MRI or CT. 6 For rhabdomyoma of the head and neck a surgical approach is most common. 2,8 Complete resection is required to prevent recurrence.…”

Rhabdomyoma of the parapharyngeal space

“…El diagnóstico definitivo del RA es anatomopatológico y describe a un tumor de bordes definidos, pardo, lobulado 2 ; microscópicamente presenta células poligonales con vacuolas gigantes que contienen glucógeno, y un núcleo central a partir del cual se irradian filamentos de citoplasma, dando el aspecto de "células araña" típicas de esta entidad (9); además contienen proteínas específicas del tejido muscular como miosina y actina, que se evidencian con inmunohistoquímica (2,4). Esto es esencial para el diagnóstico diferencial anatomopatológico al distinguir entidades con características similares, como el tumor de células granulares que es negativo para desmina; o el rabdomiosarcoma que presenta atipia y polimorfismo nuclear) (6).…”