This article is more than 5 years old. Information may no longer be current.
A 69-year-old man with right thigh pain
Click Here to Manage Email Alerts
A 69-year-old man presented to our clinic with a 3-year history of gradually worsening atraumatic right thigh pain exacerbated by weight-bearing and hip motion. It did not wake him from sleep.
Of note, he previously underwent chemotherapy and radiation without resection for a right iliac crest Ewing’s sarcoma in the 1970s, and had subsequently done well without evidence of recurrence. He was a non-smoker, without other history of malignancy. On exam, his gait was antalgic and he preferred using a cane in his left hand. He had no palpable mass. Although hip range of motion caused mild discomfort, he was entirely neurologically normal distally. Plain radiographs demonstrated a large right supra-acetabular lytic lesion (Figure 1).
What is your differential diagnosis?
See answer on next page.
This anteroposterior view of the pelvis demonstrates a large destructive lytic lesion in the supra-acetabular region with heterogeneous cloudy ossification within it extending into the anterosuperior iliac spine expanding the cortex with extension almost to the sacroiliac joint.
Images: Gundle KR and Conrad EU
Radiation-induced sarcoma of the pelvis
The patient presented with a large lytic lesion of the right ilium, at age 69 years, and with a history of Ewing’s sarcoma that had been treated with chemoradiation without surgery about 40 years ago at another institution. A differential diagnosis would include metastatic disease, a late recurrence of Ewing’s, and lymphoma, but our concern was primarily for a radiation-induced sarcoma.
After a work-up including CT scan of the chest, abdomen and pelvis, as well as pelvic MRI and a positron emission tomography scan (Figure 2), an open biopsy was performed and pathology confirmed a high-grade osteosarcoma.
Post-radiation sarcoma
Radiation therapy is an integral part of multimodal treatment for a wide variety of malignancies, including breast cancer, retinoblastoma, soft tissue sarcoma, and for Ewing’s sarcoma. A rare, but serious, collateral outcome of such treatment is the development of a radiation-induced sarcoma, with estimates between 0.03% and 0.8% of patients who receive radiation.
This axial T2-weighted MRI demonstrates a heterogeneous mass of the right ilium with cystic, T2 hypointense and T2 hyperintense regions with expansion of the cortex.
Although high quality evidence is difficult to obtain on the subject, there is believed to be a dose dependency and a long latency period (3 years to 55 years) between radiation treatment and subsequent malignancy. Unfortunately, 5-year survival is low with post-radiation sarcoma at 11% to 50%. Negative-margin resection has been associated with improved survival, which is facilitated by early diagnosis and location in the extremities.
Management of our patient
His case was presented at our multidisciplinary sarcoma tumor board. One particular detail that limited options for neoadjuvant chemotherapy was prior administration of doxorubicin, which limits options for repeat doxorubicin due to concern for cardiotoxicity. In discussion with the patient, we decided to proceed with surgical excision to be followed by postoperative adjunct chemotherapy.
A type 2 acetabular resection was proposed, followed by reconstruction with a pelvic allograft and total hip replacement. Preoperatively, imaging was uploaded to a Stryker II Navigation system (Stryker; Kalamazoo, Mich.) to template the planned resection and select locations to utilize for point-to-point registration based on the planned exposure. He received preoperative embolization by interventional radiology. Intraoperatively, he was positioned in a well-padded lazy lateral position. A single extended ilioinguinal incision along the lateral iliac crest to the symphysis pubis allowed approach to the pelvis and the outer wall of the ilium. The vessels were carefully dissected to the level of the common iliacs and vessel loops placed to allow for proximal control if necessary. The superior gluteal artery was identified on both sides of the sciatic notch, and ligated. The ureter was identified, with normal peristalsis noted, and protected throughout. Distally, the dissection reached the hip capsule, which was released to allow for later repair. Through this single incision, the femoral neck was cut to facilitate later arthroplasty, and increase exposure to the ischium. The femoral canal was prepared by standard methods.
These images from preoperative planning using the navigation guidance system demonstrate the planned sacroiliac osteotomy (yellow plane). Fastidious planning of this margin allowed a reconstructable resection to be performed while maintaining a margin around the tumor.
At this point, the navigation system was brought in with the distance from camera to the operative field at less than a meter, and the dynamic reference base (patient tracker) was pinned to the uninvolved posterior ilium. Point-to-point registration was performed with less than 1 mm of mean registration error, and we visually assessed the correlation between navigation system and patient anatomy (Figure 3). With confirmation of resection planes and orientation by navigation, an oscillating saw was used to complete the pubic, inferior ischium, and posterior ilium cuts and the specimen removed. Frozen sections of these margins were negative, and we began the reconstruction.
This anteroposterior view of the pelvis demonstrates the completed reconstruction with an allograft hemipelvis fixated to the native pelvis with plates along the anterior column and superiorly and inferiorly at the posterior ilium. In addition, a total hip arthroplasty has been placed.
A pelvic allograft, which had been thawing in normal saline, was iteratively marked and cut to fit the patient’s anatomy. The acetabulum was provisionally reamed extracorporally to minimize stress on the subsequent osseous fixation. The allograft was then was stabilized with an anterior reconstruction plate to the intact pubis and superior and inferior posterior reconstruction plates to the intact ilium. With the allograft secure, we proceeded with final acetabular reaming, trialing, and placement of total hip arthroplasty implants (Figure 4). During trialing, the navigation system confirmed that planned location of the implants was within 5 mm of the prior center of the femoral head in all planes. Navigation also confirmed that the lesser trochanter had been returned to its preoperative location, as an additional assessment of leg length and overall reconstruction. We then copiously irrigated, placed multiple drains and performed a multilayer soft tissue closure. A 2-mm drill was used to create a series of bone tunnels for approximation of the external oblique and remaining gluteal fascia to the allograft.
Immediately postoperatively the patient was kept toe-touch weight-bearing with range of motion restrictions and an abduction brace for support. After a single night’s stay in the ICU and a week-long in-patient stay for mobilization, the patient was discharged home. At 6 weeks postoperatively, the patient’s wound has healed, and he has begun to advance his weight-bearing status.
References:
Campanacci D, et al. Int Orthop. 2012;doi: 10.1007/s00264-012-1677-4.
Delloye C, et al. J Bone Joint Surg Am. 2007;doi: 10.2106/JBJS.E.00943.
Mavrogenis AF, et al. J Surg Oncol. 2012;doi: 10.1002/jso.22122.
Patel SR. Curr Treat Options Oncol. 2000;1(3):258-61.
Sheppard DG, et al. Clin Radiol. 2001;56(1):22-29.
Young PS, et al. Bone Joint J. 2015;doi: 10.1302/0301-620X.97B2.34461.
For more information:
Kenneth Gundle, MD, and Ernest U. Conrad III, MD, are from the Department of Orthopaedic Surgery, University of Washington, Seattle, WA. They can be reached at 1959 N.E. Pacific St., Box 356500, Seattle, WA 98195. Gundle’s email: kgundle@uw.edu; Conrad’s email: chappie.conrad@seattlechildrens.org.
Disclosures: Gundle reports no relevant financial disclosures. Conrad serves as the Medical Director for LifeNet Health Northwest Tissue Division and is an unpaid consultant for Stryker.