Spindle cell lipoma as rare soft tissue tumor of the parotid gland

Lipomas are the most diagnosed soft tissue tumors in the body, but parotid lipomas are relatively rare. Spindle cell lipomas (SCL) are rare variants of benign lipomas. We present a case of a 55-year-old man who was diagnosed with SCL. Clinical examination of the patient revealed a soft and painless swelling at the lower pole of the right parotid gland, which slowly progressed in size. The path to a definitive diagnosis was difficult due to atypical imaging and the suspicion of a myxoid soft tissue tumor in the fine-needle aspiration biopsy. External MRI images showed a circular lesion with an inconspicuous margin and internal heterogeneous structure. Under the clinical diagnosis of a Warthin tumor, surgical resection was performed as a lateral parotidectomy to confirm the findings. Histopathologically, the specimen showed a mesenchymal tumor with adipocytic differentiation. In addition, immunohistochemical examination of the lesional cells presented consistent positivity for CD34. Based on these findings, a diagnosis of SCL of the parotid gland was finally made. The differential diagnosis of slow-growing asymptomatic soft-tissue parotid tumors should include lipomas in common salivary gland tumors. CT and MRI may indicate adipocyte-derived soft tissue tumors. However, a definitive diagnosis can only be made by histopathological examination.

Publication History

Article published online:
12 May 2023