Orthopedic Oncology cases biopsy

A 45-year-old female with known metastatic breast cancer is referred to you by her oncologist. She has already previously undergone prophylactic nailing of her left humerus and right femur for impending fracture secondary to breast cancer metastases. She is now complaining of increasing pain in the left hip and thigh, and x-rays reveal a mixed blastic and lytic lesion in the intertrochanteric femur.

She asks about image-guided biopsy of this lesion. What is the best response?

1. It is absolutely necessary to biopsy this lesion prior to prophylactic fixation to confirm diagnosis

2. The lesion could be osteosarcoma or another primary bone malignancy, or a metastasis of a new primary tumor, therefore biopsy should be performed

3. Preoperative biopsy is not needed, as she has known metastatic disease to the skeleton and a mixed lesion is consistent with this diagnosis

4. Embolization should be performed prior to biopsy, since even needle biopsy of lucent lesions has relatively high risk of bleeding

Discussion

The correct answer is (C). Indications for biopsy include an unknown aggressive-appearing lesion, the first bone lesion in cancer that has not been documented as metastatic to the skeleton, and indeterminate lesions of unknown diagnosis based on

less-invasive studies. This patient has known metastatic breast cancer to the skeleton, status post prior-prophylactic fixation of two long bones for breast cancer metastatic lesions. The fear of prophylactically fixing this lesion without a preoperative biopsy is the possibility that it could be a new malignancy; however, in this case, in particular because the mixed lytic and blastic picture is typical of breast metastasis, it is reasonable to assume these are additional breast metastases. Tissue can be sent to pathology from the operating room at the time of surgery, but a preoperative tissue biopsy is not necessarily needed. If this lesion appeared different from her prior mixed lesions in terms of imaging characteristics, or if the lesions were not consistent with her diagnosis, or any of the conditions initially mentioned, then a preoperative biopsy should be considered.

She asks about the options for surgical fixation. Her husband recently fell and broke his hip, and underwent ORIF with a sliding hip screw device. She requests a similar implant. What is your response?

1. A sliding hip screw/plate and screw construct is acceptable as long as acceptable fixation is achieved above and below the lytic lesion

2. A sliding hip screw/plate and screw construct is acceptable, however, she will have to limit her weight bearing after surgery, because it is a load-sharing device

3. A sliding hip screw/plate and screw construct is not the best implant in her setting, a long cephalomedullary device is preferred

4. A sliding hip screw/plate and screw construct is the fixation method of choice for her situation

Discussion

The correct answer is (C). In cases of prophylactic fixation of metastatic lesions to long bones, the fixation method of choice is almost always a long intramedullary nail (in extension into the head, in the humerus and femur.) This allows one procedure to achieve stable fixation of the entire length of the bone, in anticipation of future metastases developing in another area.

 

Objectives: Did you learn...?

 

 

When it is critical to biopsy a bone lesion, and when it is not critical? What is the best treatment for long bone lesions?