Solitary Fibrous Tumor of the Parotid Gland: A Case Report

Document Type: Case Report

Authors

1 Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.

2 Department of Radiology, McMaster University, St. Joseph’s Hospital, Hamilton, Ontario, Canada.

Abstract

Introduction:
Solitary fibrous tumor is a rare, mesenchymal neoplasm that has been reported in numerous sites. Occurrence in the parotid gland is exceedingly rare.
 
Case Report:
A 53-year-old man with a 2 cm solitary fibrous tumor of the left parotid gland, that was observed clinically and operatively and thought to be a neoplasm arising from Stensen's duct, is described. A pre-operative CT scan demonstrated a well-circumscribed, solid, avidly-enhancing nodule superficial to the masseter muscle, deep to the platysma, and intimately associated with the parotid duct. Multiple fine needle aspirations yielded scant fibrous tissue and lymphocytes. A superficial parotidectomy was performed. The histopathological and immunohistochemical findings were in keeping with solitary fibrous tumor, fibrous variant, with a low mitotic rate and a peripherally-entrapped parotid duct surrounded by abundant periductal collagen and lymphocytes. At a 2-year follow up, there was no evidence of tumor recurrence or metastasis.
 
Conclusion: 
Solitary fibrous tumor should be suspected in the context of a slow-growing, well-circumscribed, solid, avidly-enhancing nodule of the parotid gland. Grossly intimate association with the parotid duct may reflect peripheral entrapment. Fine needle aspirations that predominantly yield collagen without spindle cell clusters should be correlated with clinical and radiological findings, as it is expected in tumor sampling of the fibrous variant. Although solitary fibrous tumor of the parotid gland usually exhibits benign behavior, it is best regarded as potentially malignant. Patient management and follow-up should be tailored to each individual and clinicopathological risk assessment of the recurrent/metastatic potential.  

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1. Klemperer P, Rabin CB. Primary neoplasms of the pleura. Arch Pathol 1931; 11:385–412.

2. Thompson M, Cheng LH, Stewart J, Marker A, Adlam DM. A paediatric case of a solitary fibrous tumour of the parotid gland. Int J Pediatr Otorhinolaryngol 2004; 68(4):481-7.

3. Liu Y, Tao X, Shi H, Li K. MRI findings of solitary fibrous tumours in the head and neck region. Dentomaxillofac Radiol. 2014; 43(3):20130415.

4. Gengler C, Guillou L. Solitary fibrous tumour and haemangiopericytoma: evolution of a concept. Histopathology 2006; 48(1):63-74.

5. Bauer JL, Miklos AZ, Thompson LD. Parotid gland solitary fibrous tumor: a case report and clinicopathologic review of 22 cases from the literature. Head Neck Pathol 2012; 6(1):21-31.

6. Doyle LA, Vivero M, Fletcher CD, Mertens F, Hornick JL. Nuclear expression of STAT6 distinguishes solitary fibrous tumor from histologic mimics. Mod Pathol 2014; 27(3):390-5.

 

7. Messa-Botero OA, Romero-Rojas AE, Chinchilla Olaya SI, Díaz-Pérez JA, Tapias-Vargas LF. Primary malignant solitary fibrous tumor/ hemangiopericytoma of the parotid gland. Acta Otorrinolaringol Esp 2011; 62(3):242-5.

8. Suárez Roa Mde L, Ruíz Godoy Rivera LM, Meneses García A, Granados-García M, Mosqueda Taylor A. Solitary fibrous tumor of the parotid region. Report of a case and review of the literature. Med Oral 2004; 9(1):82-8.

9. Alonso-Rodríguez E, González-Otero T, Castro-Calvo A, Ruiz-Bravo E, Burgueño M. Parotid gland solitary fibrous tumor with mandibular bone destruction and aggressive behavior. J Clin Exp Dent 2014; 6(3):e299-302.

10. Demicco EG, Park MS, Araujo DM, Fox PS, Bassett RL, Pollock RE. Solitary fibrous tumor: a clinicopathological study of 110 cases and proposed risk assessment model. Mod Pathol 2012; 25(9):1298-306.