Case Author(s): Jeff Chesnut, D.O. and Henry Royal, M.D. , 2/27/99 . Rating: #D2, #Q4
Diagnosis: Metastasis to skull from renal cell carcinoma
Brief history:
59 year old female undergoing metastatic workup.
Images:
Anterior and posterior images from a whole body bone scintigram are shown.
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View second image(bs).
Spot images of the head are shown.
View third image(bs).
A vertex view of the skull is shown.
Full history/Diagnosis is available below
Diagnosis: Metastasis to skull from renal cell carcinoma
Full history:
Patient is a 59 year old female who has a history of renal cell carcinoma.
Radiopharmaceutical:
Tc-99m MDP
Findings:
Whole body bone scintigrams reveal absence of the left kidney secondary to nephrectomy for renal cell carcinoma.
There is increased tracer activity at the vertex of the skull seen on both the whole-body images and spot images of the skull. A subsequent vertex view of the skull demonstrates a lesion at the vertex of the skull with a rim of markedly increased activity and a central portion of absent tracer activity.
Discussion:
The vertex of the skull may be a "blind spot" on bone scintigraphy. Even SPECT images may have difficulty demonstrating lesions in the skull vertex if the lesion lies within the tomographic transaxial plane of the slice. A vertex view of the skull is a simple and quick method of adequately examining the skull vertex. In this view, the plane of the gamma camera's crystal is oriented parallel to the plane of the vertex of the skull. A lead apron may be draped over the patient's shoulders and torso to reduce photon scatter.
Followup:
A CT scan demonstrated a lytic lesion in the skull vertex. Biopsy was positive for metastatic renal cell carcinoma. The patient is currently undergoing radiation therapy to the metastatic lesion.
View followup image(ct).
CT scan of the vertex of the skull.
Major teaching point(s):
1. The vertex of the skull may be a "blind spot" in bone scintigraphy.
2. A vertex spot view may help in visualizing the skull vertex.
3. Renal cell carcinoma metastatic to bone can result in a mixed "hot" and "cold" pattern on bone scintigraphy.
Differential Diagnosis List
1. Metastatic carcinoma
2. Trauma or surgery
3. Eosinophilic granuloma (though this patient is not in a good age-group for EG.)
4. Primary neoplasm
ACR Codes and Keywords:
References and General Discussion of Bone Scintigraphy (Anatomic field:Skeletal System, Category:Neoplasm, Neoplastic-like condition)
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Case number: bs098
Copyright by Wash U MO
