DOI:10.2214/AJR.05.0110
AJR 2006; 186:269-270
© American Roentgen Ray Society
Renal Oncocytoma Displaying Intense Activity on 18F-FDG PET
Michael A. Blake,
Margaret McKernan,
Bindu Setty,
Alan J. Fischman and
Peter R. Mueller
Massachusetts General Hospital Boston, MA 02114
A 77-year-old woman with a history of endometrioid carcinoma of the left
ovary and uterus (treated by total hysterectomy with bilateral
salpingo-oophorectomy and chemotherapy in 1998) presented with nausea and
progressively enlarging retroperitoneal lymphadenopathy on CT. The patient
also had a history of a benign renal mass that was being followed. CT-guided
biopsy in December 2002 yielded a pathologic diagnosis of oncocytoma rather
than well-differentiated renal cell carcinoma.
18F-FDG PET/CT (Reveal XVI, CPS Innovations) was performed to
evaluate for metastatic endometroid carcinoma in the setting of enlarging
retroperitoneal nodes. CT images showed a 4.4-cm enhancing solid mass in the
upper pole of the right kidney, which had shown slow interval growth over time
(Figs. 1A and
1C). Coregistered
CT/18F-FDG PET images (Figs.
1B and
1D) showed intense
hypermetabolism in the renal mass. The mean standardized uptake value of the
mass normalized for body weight was 12.3. There was also intense
hypermetabolism in the retroperitoneal lymphadenopathy (not shown in the
figures).
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Fig. 1A —77-year-old woman with renal oncocytoma. Axial (A and
B) and coronal (C and D) enhanced CT and fused PET/CT
images of large enhancing right renal mass (arrows) demonstrating
intense 18F-FDG activity.
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Fig. 1C —77-year-old woman with renal oncocytoma. Axial (A and
B) and coronal (C and D) enhanced CT and fused PET/CT
images of large enhancing right renal mass (arrows) demonstrating
intense 18F-FDG activity.
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Fig. 1B —77-year-old woman with renal oncocytoma. Axial (A and
B) and coronal (C and D) enhanced CT and fused PET/CT
images of large enhancing right renal mass (arrows) demonstrating
intense 18F-FDG activity.
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Fig. 1D —77-year-old woman with renal oncocytoma. Axial (A and
B) and coronal (C and D) enhanced CT and fused PET/CT
images of large enhancing right renal mass (arrows) demonstrating
intense 18F-FDG activity.
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With a paucity of reports in the literature of hypermetabolic
18F-FDG uptake in renal oncocytoma and interval growth of the renal
mass, there was concern that the renal lesion could represent a
well-differentiated renal cell carcinoma (RCC), although the intensity of
18F-FDG uptake would be unusual for RCC. Metastatic disease of the
kidney, while also a possibility, was felt to be less likely given the slow
rate of growth. Since periaortic lymphadenopathy adjacent to the duodenum was
felt to be responsible for clinical symptoms of nausea and vomiting, the
decision was made to perform a coordinated right nephrectomy and
retroperitoneal lymphadenectomy. Pathology revealed the renal mass to be an
oncocytoma, whereas the retroperitoneal nodes were shown to be involved with
metastatic high-grade carcinoma of müllerian origin, consistent with the
endometrioid.
To our knowledge, there has only been one previous mention in the
literature of 18F-FDG PET activity in a renal oncocytoma—an
incidental false-positive lesion in a series evaluating the efficacy of
18F-FDG PET for characterization of RCC
[1]. However, the intensity of
18F-FDG uptake was not quantified. Multiple studies have documented
relatively low sensitivity (31-77%)
[1-4]
for detection of primary RCC with 18F-FDG PET, but a recent series
of 66 patients reported a specificity of 100%
[4]. As a greater number of
institutions elect a conservative (nonsurgical) approach to management of
oncocytomas, it is important to recognize that oncocytomas can yield
false-positive results on 18F-FDG PET, and absolute radiologic
differentiation of oncocytoma from RCC remains elusive.
References
- Aide N, Cappele O, Bottet P, et al. Efficiency of [(18)F]FDG PET in
characterising renal cancer and detecting distant metastases: a comparison
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: 1236-1245[Medline]
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R. Positron emission tomography in diagnosis of renal cell carcinoma [in
German]. Urologe A 1996;35
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- Miyakita H, Tokunaga M, Onda H, et al. Significance of
18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for detection of
renal cell carcinoma and immunohistochemical glucose transporter 1 (GLUT-1)
expression in the cancer. Int J Urol2002; 9:15
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- Kang DE, White RL, Zuger JH, Sasser HC, Teigland CM. Clinical use
of fluorodeoxyglucose F 18 positron emission tomography for detection of renal
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