Solitary bone metastasis - initial presentation of renal cell carcinoma

Case contributed by Ammar Ashraf
Diagnosis certain


Neck pain radiating down to shoulders (more on right) for one month. No history of trauma. No history of fever, anorexia, or weight loss.

Patient Data

Age: 55 years
Gender: Male

The ill-defined anterior cortex of the C5 vertebral body that appears also more radiolucent than adjacent vertebrae. This is suspicious of a neoplastic process, like metastasis, or plasmacytoma/multiple myeloma; possibility of an infective process is less likely. For further evaluation by MRI and radionuclide bone scan.

Collapsed 5th cervical vertebral body with diffusely altered signal intensity, It is hypointense on T1 & hyperintense on T2 weighted images and shows vivid enhancement on post-contrast images. The collapsed vertebra is seen to display mildly heterogeneous solid soft tissue matrix lesion which shows poorly defined margins with more inclination to the right side with encasement of the related segment of the right vertebral artery. No significant fluid components are seen. The related discs display no gross signal changes or post-contrast enhancement. This is associated with a mild posterior bulge effacing the ventral cervical subarachnoid space. Prime diagnostic consideration should include an aggressive neoplastic process with prime differential diagnosis including plasmacytoma, metastatic disease, and multiple myeloma.

There is a re-demonstration of a hypervascular/enhancing lytic mass in the right half of the 5th cervical vertebral body (as seen in the previous MRI cervical spine). It is causing lateral displacement and partial encasement of the right vertebral artery; however, the vertebral artery is patent, well-opacified, and is not showing any critical stenosis. No other suspicious osseous lesion is seen in the visualized skeleton.

A large mass is seen arising from the lateral side of the left kidney on early 5-minutes blood pool images. No abnormal radiotracer accumulation/uptake is seen in the neck either on the initial blood pool or on the 3 hours delayed phase images. Normal symmetrical distribution of the radiotracer throughout the axial and appendicular skeleton noted on 3 hours delayed whole-body images. These bone scan findings in correlation with the previous x-ray & MRI scan findings are suggestive of an aggressive osteolytic lesion (likely solitary metastasis) involving the 5th cervical vertebra (showing no radiotracer uptake), with a high suspicion of a primary lesion in the left kidney.

A large exophytic well defined heterogeneous echogenicity solid mass lesion measuring 6.8 x 9.20 cm, showing increased vascularity on color Doppler ultrasound, is seen arising from the left kidney.

An exophytic cortically based sizable mass lesion measuring 7.6 x 7.6 x 8.5 cm, showing peripheral enhancement and large central non-enhancing (necrotic?) area is seen arising from the mid pole of the left kidney. The mass is highly vascular with hypertrophied left renal artery. Large draining veins are noted in the left perirenal space. No evidence of left renal vein invasion. Bilateral renal veins and IVC are patent. No focal mass lesion is seen in the right kidney. No evidence of local invasion of adjacent organs or significant abdominal lymphadenopathy is noted. Mild degenerative changes are seen in the visualized skeleton.  A small well-defined sclerotic focus is seen in the 1st lumbar vertebral body, which is likely a bone island. No suspicious osseous lesion is seen in the visualized skeleton.

A few scattered sub-centimeter soft tissue density nodules, suspicious of metastases, are seen in both lungs. No significant cervical or mediastinal lymphadenopathy is seen. There is re-demonstration of an aggressive lytic lesion (likely metastatic) in the right half of the 5th cervical vertebral body. No other suspicious osseous lesion is seen in the visualized skeleton. Bulky right thyroid lobe and nodules in right thyroid lobe & isthmus.

X-ray showing evidence of previous surgery (anterior cervical corpectomy and cervical spine fusion).

Case Discussion

Later on, MRI of the dorso-lumbar spine was performed which did not show any suspicious focal osseous lesion. Thyroid gland ultrasound examination and ultrasound-guided FNAC of the thyroid nodules were also performed which were negative for malignancy.

Then the patient underwent ultrasound-guided biopsy of the left renal mass, which was positive for grade 1 clear cell renal cell carcinoma.

Later on patient underwent laparoscopic left radical nephrectomy.

Histopathology (left radical nephrectomy): 6.5 x 6 X 6 cm, grade 2 clear cell renal cell carcinoma, with tumor extension into the perinephric tissue.  No necrosis or lymphovascular invasion identified. Negative resection margins. No lymph nodes submitted or found.

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