A Rare Presentation of Metastatic Renal Clear Cell Carcinoma to the Tongue Seen on FDG PET

Abstract

Renal clear cell carcinoma has a great metastatic potential, with possibly uncommon secondary lesions, notably in the head and neck region. The role of F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) in the staging or follow-up of urological malignancies is still not clearly defined. We report a case of metastatic renal cell carcinoma involving the tongue and a cervical lymph node, 3 years after initial nephrectomy. The use of combined positron emission tomography/computed tomography scan showed increased F-18 FDG activity in these 2 lesions that were then diagnosed and treated by surgery. Although the diagnostic performance of F-18 FDG PET is limited in the detection of primary disease, this imaging modality can be a very useful tool in the follow-up of renal clear cell carcinoma.

PET/CT Imaging in Oncology: Exceptions That Prove the Rule

“…In recent years 18 F-FDG PET/CT has worldwide demonstrated itself as one of the most important oncological diagnostic devices [3–5]. However the most common limits of this technique are represented by well-differentiated cancer forms and in general tumors with low proliferative index [6, 7].…”

Bilateral Asynchronous Renal Cell Carcinoma with Metastatic Involvement of the Tongue

“…The most common sites of metastatic RCC involvement are pulmonary (75%), regional nodal basin (65%), bone (42%), and liver (41%) [3, 4]. The head and neck and involved in 15% of cases, paranasal sinus being the most common subsite [2, 4].…”

“…The head and neck and involved in 15% of cases, paranasal sinus being the most common subsite [2, 4]. Lingual involvement is often reported in the presence of other metastatic sites, especially bones [4] and lung [2]. Rarely reported as a single metastatic focus, the presence of metastatic lingual RCC highlights the possibility of extensive metastatic involvement.…”

“…In our case, imaging revealed presence of occult RCC in the contralateral kidney. CT is the modality of choice for detection, diagnosis, and image surveillance of renal cortex tumours [4]. …”

“…In the mouth, the tongue is the second most commonly affected subsite, with an estimated postmortem incidence of 0.2% [1]. Lingual metastasis by renal cell carcinoma (RCC) is exceedingly rare, but isolated case reports are documented sporadically [2–4]. Most cases of lingual metastatic RCC occur within 5 years of primary diagnosis.…”