Epithelioid Sarcoma of the Oral Cavity: A Retrospective Clinicopathologic Study of Three Rare Cases

Introduction

Epithelioid sarcoma (ES) accounts for <1% of all sarcomas and is characterized by, partial or complete, epithelioid cytologic features and epithelial immunophenotypic properties. Involvement of the oral cavity is rare with only 7 well-documented examples reported to date.

Material and methods

Three archived cases of intraoral ES were retrieved from the files of the authors including information regarding demographics, tumor location, treatment and follow-up.

Results

Among the 3 intraoral ES cases, two were primary, proximal-type, and the third metastatic originating from ES of the right arm. Both primary tumors occurred in females, 17 and 68 years old, and affected the tongue. The clinical features ranged from an asymptomatic, well-demarcated, 0.4 cm, circular macule to a 3.8 cm submucosal mass which caused lingual enlargement. The metastatic ES affected a 39-year-old male presenting as poorly-demarcated, hemorrhagic, violaceous, multinodular growth of the mandibular gingiva/alveolar mucosa. Microscopically, all lesions were characterized by sheets of pleomorphic epithelioid cells with enlarged vesicular nuclei exhibiting coarse chromatin and 1-2 prominent eosinophilic nucleoli, abundant eosinophilic cytoplasm and distinct cytoplasmic borders. A rhabdoid and/or spindle cytomorphology was focally observed. Immunohistochemically, neoplastic cells revealed strong and diffuse positivity for keratins, weak-to-moderate ERG reactivity, and uniform loss of SMARCB1 (INI1). The 68-year-old female was treated with partial glossectomy and remains disease-free 23 months post-surgery. The adolescent female underwent resection of bilateral pulmonary metastases, received chemotherapy, and is currently alive with disease 10 months post-diagnosis. Lastly, the individual with metastatic intraoral ES is alive with disease with notable numerous cutaneous, pulmonary, and skeletal bone metastases.

Conclusions

Although infrequent, intraoral involvement occurs in ES. The epithelioid cytomorphology in conjunction with strong immunoexpression of epithelial markers in ES may cause a diagnostic pitfall. A battery of epithelial and non-epithelial immunohistochemical markers in conjunction to SMARCB1 (INI1), is necessary for the diagnosis.