Chondromyxoid fibroma of the sacrum: A case report and literature review

Clinical manifestations, classification, and surgical management of sacral tumors and the need for personalized approach to sacrectomy

Background:

Although comprising 7% of all spinal tumors, sacral tumors present with a litany of issues due to their slow growth and difficulty in detection. As a result, sacral tumors can grow unperturbed for years until a patient presents for an incidental workup of an unassociated minor trauma or an offending primary tumor source that has metastasized to the sacrum; in most cases, this includes primary tumors of the breast, prostate, and lung. The goal of this review is to outline the pathophysiology underlying sacral tumors including the various tissues and structures that can be targeted for treatment, along with a discussion of the surgical approach to sacrectomy.

Methods:

An extensive review of the published literature was conducted through PubMed database with articles simultaneously containing both search terms “sacral tumors” and “sacrectomy.” No date restrictions were used.

Results:

The search yielded 245 related articles. Cross-checking of articles was conducted to exclude of duplicate articles. The articles were screened for their full text and English language availability. We finalized those articles pertaining to the topic.

Conclusion:

Once a sacral tumor has reached the point of diagnostic detection, invasive sacrectomy is typically utilized (through an anterior, posterior, or combination approach) to locally isolate and resect the tumor and minimize risk of future tumor growth and additional bone loss. While institutions have varying criteria for surgical approaches, a combination of anterior and posterior approach has traditionally been used in total and high sacrectomies due to the control it provides surgeons toward the rectum and vasculature anterior to the sacrum. A posterior-only approach can be performed for tumors that failed to invade pelvic organs or extend past the lumbosacral junction. Early detection with screenings can help avoid invasive sacrectomy by identifying the onset of tumor formation in the sacrum, particularly for highly metastatic cancers.

Chondromyxoid Fibroma of the Sacral Spine

Background and Importance. Chondromyxoid fibromas are rare tumors of cartilaginous origin typically found in long bones. They usually present during the second and third decades of life. In this case report, we describe the case of a 60-year-old male who presented with back pain and was later found to have a sacral mass. Further immunohistochemical analysis determined that the mass was a chondromyxoid fibroma. Clinical Presentation. A 60-year-old male presented with worsening lower back pain over the course of 2 years. Magnetic resonance imaging demonstrated a destructive mass centered at S4 with heterogeneous enhancement. The patient underwent an S3-to-Co1 laminectomy for gross total resection of the tumor. Histology demonstrated a biphasic, lobulated appearance, characteristic of a chondromyxoid fibroma. The tissue stained faintly positive for multicytokeratin, and it was negative for markers S-100 protein and brachyury, indicating that it was not a chordoma. Conclusion. Only 8 cases have documented sacral chondromyxoid fibroma. As these are exceedingly rare tumors, especially within the sacral spine, the differential diagnosis includes other malignant tumors more likely to be found in the spine, particularly chordomas and chondrosarcomas. Immunohistochemistry and histology are essential in making a definitive diagnosis. This case provides a comprehensive illustration of the clinical presentation, radiographic findings, and immunohistochemistry of sacral chondromyxoid fibroma.

Patient-Specific Three-Dimensional Model for a Safe Surgical Pathway in Sacral Chondrosarcoma

Sacral tumors are amongst the most challenging procedures to treat because of the complex anatomy. This study determined whether patient-specific models change preoperative planning decisions made in preparation for en bloc resection of complex sacral mass surgical procedures. Imaging showed a big encapsulated mass at the S2-3 level involving the neural foramina and obscuring the nerve roots. High-resolution images were acquired and utilized to generate a patient-specific 3D tumor model. The visual and tactile inspection of 3D models allowed the best anatomical understanding, with faster and clearer comprehension of the surgical anatomy. The 3D sacral model was for observation of previously unapparent anatomical details; with this new technology, surgeon can observe their planned surgical intervention, explore the patient-specific anatomy and extension of the tumor, and sharpen their procedure choices. Moreover, multiple planes showed how far the angles on the plane would extend for osteotomy of the sacrum. Another result was identifying correct guides and safe venture landmarks. The study helped to establish safe osteotomy line wherever the nerve roots were retained and enabled osteotomy by preserving bilaterally the S1 and S2 nerve roots for wide excision of wide excision of primary sacral tumor to get adequate bowel and bladder functions. Finally, it helped to determine whether or not the remaining bone in the sacrum is sufficient for spinopelvic stability and needed fixation. It was decided spinopelvic fixation was not necessary for this case. Surgical intervention of sacral tumors varies depending on the tumor, its size, extension, and location. Surgery can have profound risks including unnecessary nerve root resection spinopelvic instability and suboptimal oncological resection. 3D models help to transfer complex anatomical information to clinicians and provide guidance in the preoperative planning stage, for intraoperative navigation and for surgical training purposes.