Anterior Approach for CT-Guided
Biopsy of Iliac Bone Lesion


Robert F. DeMayo, Jonathan Susman, M.D.,
& Ziv J. Haskal, M.D.
New York Presbyterian Hospital
Case Reference No. CC-0800-07

The patient is a 45-year-old man with a history of malignant myopericyorna, a recently described type of sarcoma showing perivascular myoid differentiation, involving the left thigh. He underwent excision of the tumor and external beam radiotherapy and was in good health for six months, when he presented to an outside hospital with an acute myocardial infarction. Echocardiography revealed a mobile mass adherent to the lateral wall of the left ventricle. A body CT scan showed a lesion of the right iliac bone. The patient was transferred to our medical center for further evaluation, where he subsequently suffered a second, more severe myocardial infarction. Emergent cardiac catheterization revealed complete obstruction of the left anterior descending artery, presumably by tumor embolus, and the patient briefly required an intra-aortic balloon pump. The patient was referred to our department for CT-guided percutaneous biopsy of the iliac bone lesion to substantiate the diagnosis of metastatic sarcoma and exclude the possibility of a new primary tumor.

Fig. 1. Lesion in right iliac bone with intervening bowel anteriorly.

Fig. 2. Bowel has shifted out of biopsy path.

Fig. 3. Biopsy needle in lesion.

As is evident on the CT scan (Fig. 1), the lesion disrupts the anterior cortex of the right iliac bone adjacent to the sacroiliac joint, while the posterior cortex is unaffected. Therefore, a posterior approach would necessitate drilling through the intact cortex deep to the gluteus maximus muscle, a lengthy and painful procedure. Given the unstable cardiac status of the patient and the need to perform the biopsy using minimal anesthesia, we chose an anterior, transperitoneal approach instead. We were prepared, based on the initial CT scan, to pass through intervening bowel (Fig. 1), but a repeat CT scan just prior to biopsy showed the bowel had shifted out of our path (Fig. 2). Using an anterior approach, we advanced a 19-gauge needle introducer directly into the lesion through the break in the cortex (Fig. 3). Through our introducer, we performed fine needle aspiration and obtained several core biopsies using a 20-gauge biopsy gun. To increase the probability of a diagnostic biopsy while avoiding the risks of introducing a larger needle, we then used the 19-gauge introducer itself as a biopsy needle to obtain additional aspiration specimens, which were sent for cell block analysis. Pathology demonstrated a histologic appearance and immunohistochemical properties consistent with a diagnosis of malignant myopericytoma.

Questions:

1) Would you favor traversing bowel, if needed, in this setting, rather than using the posterior approach?

2) What is the largest needle that can safely be used for a percutaneous transcolonic biopsy?

3) Should prophylactic antibiotics be routinely administered in this setting?

4) Are there particular biopsy devices that you find useful in this setting?

Reference:

1. Granter SR, Badizadegan K, Fletcher CDM Myofibromatosis in adults, glomangiopericytoma, and myopericytoma A spectrum of tumors showing perivascular myoid differentiation. Am J Surg Pathol 1998; 22(5): 513-52.