1. Staging and Prognosis of Synovial Sarcoma
Synovial Cell Sarcoma of the Ankle: A Case Report and Review of the Literature
Marcus Richardson DPM1 and Randall Thomas DPM AACFAS2
1: Resident, Grant Foot & Ankle Surgery Residency Program
2: Assistant Director, Grant Foot & Ankle Surgery Residency Program. Private Practice Clintonville/Dublin Foot and Ankle Group
Case Report
Literature Review
Staging and Prognosis of Synovial Sarcoma
The case presents a 55 year old female with a painful soft tissue mass noted to the medial aspect of her left hindfoot. The small slightly mobile mass with significant pain at the tarsal tunnel and superficial to this with loculated appearance. Imaging showed a fluid -filled appearing mass, extending through the tarsal tunnel, measuring 1.3cm in diameter which was suggestive of hematoma. The MRI also revealed a tear in the posterior extensor retinaculum adjacent to the soft tissue mass. There was concern for atypical presentation of hematoma and disruption of surrounding tissues.
The patient elected to have the mass operatively removed and biopsied with primary repair of the extensor retinaculum. During surgery, the mass was excised in total and the tissue had a mixture of soft fluid filled compartments containing hard aspects with a mixed abnormal color. The specimen was sent to pathology and was found to have a variable cellular fascicular growth pattern, with tumor cells with tapering nuclei and pale cytoplasm indicative of monophonic synovial sarcoma.
The patient was referred to a surgical oncologist at a sarcoma center where it was determined that adequate recession was performed, and no further surgical intervention was necessary. The surgical oncologist determined this based on repeat MRI. No plans for any adjunct treatment and only longitudinal follow up on a yearly basis with surgical oncologist and repeat imaging. Patient has returned to activities of daily living without any restrictions.
Frequency of distal metastases based on tumor size5
Synovial sarcomas are rare and deadly soft tissue malignancies which often develop in close proximity to the joints and tendon sheaths. 5 year overall survival rate and metastatic rates being reported as high as 71% and 51% respectively1. Despite their rarity, being 100 times less frequent then cancer of the breast, lung, and prostate2, they are the most common primary soft tissue sarcoma arising from the lower extremity1.
High clinical suspicion is required for early diagnosis as early clinical presentation is often a small, painful soft tissue mass. Only 20-30% of synovial cell sarcomas present with erosion of osseous structures on radiograph making X-rays not a reliable diagnostic modality3. MRI is the preferred study of choice, as synovial sarcoma will typically present as multiloculated soft tissue mass with signal intensity similar to muscle on T1 weighted images, and increased signal intensity on T2 images1. The gold standard for diagnosis is biopsy with histological analysis. Synovial cell sarcoma is typically defined by the presence of the t(X:18) (p11.2;q11.2) involving the SS18 gene on chromosome eighteen4.
Treatment requires surgical resection, sometimes requiring complete amputation of the effected extremity and often require prolonged course of chemotherapy. Clinicians should be vigilant of soft tissue masses and keep malignant processes on their differentials.
Tumors ≤2.5 cm – 6 percent
Tumors cm – 23 percent
Tumors 5-10 cm – 38 percent
Tumors cm – 49 percent
Tumors cm - 58 percent
Tumors > 20 cm – 83 percent
American Joint Committee staging of soft tissue neoplasms6.
Pathological Report
Pathological slides displaying variably cellular fascicular growth pattern, tumor cells with tapering nuclei, and indistinct pale cytoplasm, stromal calcifications and scattered mast consistent with monophasic synovial sarcoma. The diagnosis was supported by the finding of immunopositivity for EMA. 
MRI Evaluation
Preoperative MRI
Postoperative MRI
Preoperative MRI (left) revealed a lobulated lesion measuring up to 1.3 cm within the medial subcutaneous fat located superficial to the  
inferior flexor retinaculum, which was suggestive of hematoma. No associated significant enhancement. Tear noted in the adjacent flexor retinaculum. 
Postoperative MRI (right) 6 month after resection. MRI revealing no signs of reoccurrence of soft tissue mass.
(1).Bekarev, M., Elsinger, E. C., Villanueva-Siles, E., Borzykowski, R. M., & Geller, D. S. (2013). Synovial Sarcoma of the Foot. The Journal of Foot and Ankle Surgery,52(4),
(2).Armstrong, A., Aedo, A., & Phelps, S. (2008). Synovial Sarcoma: A Case Report.Clinics in Podiatric Medicine and Surgery, 25,
(3).Boc, S. F., Das-Wattley, S., & Roberts, E. (2011). Synovial Sarcoma Arising in the Foot: Case Report. The Journal of Foot and Ankle Surgery, 50(1),
(4). Thway, K., & Fisher, C. (2014). Synovial sarcoma: Defining features and diagnostic evolution. Annals of Diagnostic Pathology, 18(6),
(5). Suit HD, Mankin HJ, Wood WC, et al. Treatment of the patient with stage M0 soft tissue sarcoma. J Clin Oncol 1988; 6:854.
(6). Rottier, F. (2008). How to Differentiate Soft Tissue Neoplasms. Podiatry Today,21(1).
Works Cited
3 views of magnetic resonance image showing the dimensions of the sarcoma
3 views of magnetic resonance image displaying complete resection of the sarcoma