Renal Cell Carcinoma Metastasis to Ipsilateral Parotid and Submandibular Glands: Report of a Case with Sonoelastographic Findings

BACKGROUND: Renal cell carcinoma (RCC) – also known as hypernephroma or grawitz tumor – accounts for 3% of the adulthood malignancies. Approximately 30–40% of the patients have metastasis at the time of the diagnosis and most common sites for metastasis are lung, regional lymph nodes, bone and liver. A total of 8–14% of the patients with RCC has head and neck metastasis. However, metastasis to major salivary glands is rarely seen. In this paper, we aimed to report a RCC case with metastasis to parotid and submandibular glands that has the same sonographic and sonoelastographic findings with the primary tumor. CASE REPORT: 66-year old woman with RCC history was referred to our radiology department for neck ultrasound (US) with painful swelling in the right parotid gland region. A well-defined, 37×21 mm sized hypoechoic heterogeneous solid mass was detected in the superficial-deep lobe of the right parotid gland. The mass was prominently hypervascular in color Doppler ultrasonography scan. Coincidentally, a 13×13 mm hypoechoic lobulated solid mass was detected in the right submandibular gland with similar sonographic findings. Real-time sonoelastography (SEL) was performed to the masses and both of them were blue-green colored that indicates hard tissue. An US and SEL evaluation was also performed to the renal mass (RCC) of the patient. The primary mass was also similar in sonographic and SEL appearance as salivary gland masses. In the patient history, she revealed chemotherapy-radiotherapy treatment 1.5 years ago due to inoperable mass in the mid-lower pole of the left kidney diagnosed as clear cell RCC with vascular invasion, liver, lung and brain metastasis. Because of known primary tumor, the masses in the salivary glands were suspected to be metastatic and a tru-cut biopsy was performed. Pathological result was reported as clear cell RCC metastasis. CONCLUSIONS: The etiology of RCC is still unknown and metastatic involvement can be seen at unexpected tissue and organs. Metastatic disease should be considered when a salivary gland mass detected in patients with RCC history. SEL examination would be helpful in differentiation of the origin of the metastatic lesion with known SEL features.