PMC8313357_01
Radiology of synovial sarcoma case. Magnetic resonance imaging prior to treatment (a, b) demonstrating the large retroperitoneal mass. (a) Fluid sensitive axial image shows the mass partially encasing the abdominal aorta and compressing and displacing the inferior vena cava. Mild right hydronephrosis is evident. (b) T2 coronal image showing extensive encasement of the aorta and right renal artery by the large retroperitoneal mass. Computed tomography imaging post 3 cycles (c, d) and 6 cycles (e, f) of neoadjuvant chemotherapy demonstrating treatment response as evidenced by marked decrease in tumor size, decreased mass effect on the vena cava, resolution of right hydronephrosis, and deceased tumor density (suggestive of necrosis).
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Magnetic resonance imaging (MRI) evaluation revealed a 13 cm transverse by 8 cm anterior-posterior by 9 cm craniocaudal smoothly marginated mass inferior to the pancreas which encased the left renal vessels, displaced the inferior vena cava (IVC) anteriorly, and partially encased the abdominal aorta (Figure 1). Teratology, and Maternal-Fetal Medicine with decision for neoadjuvant chemotherapy with doxorubicin and ifosfamide with modified dosing during the prepartum period as described in Mir et al. The patient was admitted at 29w6d for cycle 1 of chemotherapy and at that time had a repeat baseline MRI which redemonstrated the now 15.5 x 10.2 x 10.6 cm mass encasing right renal pelvis and aorta, displacing left renal vessels posteriorly and IVC anterolateral (Figure 1). Restaging CT was performed following cycle 3 demonstrating marked decrease in the size of the retroperitoneal mass (Figure 1). She went on to complete three additional neoadjuvant chemotherapy cycles (6 total) without significant complication with restaging imaging again demonstrating substantial reduction in tumor size, then measuring 3.7 cm x 6.3 cm in greatest dimension (Figure 1).
Histology of synovial sarcoma case. Diagnostic biopsy (a) demonstrated proliferation of spindle to epithelioid cells of monomorphic appearance with elongated nuclei and scant cytoplasm arranged in a whorled "herringbone" architecture (Hematoxylin and Eosin, 100x). Fli-1 immunohistochemistry (b) demonstrated strong, diffuse nuclear staining, confirming the diagnosis (200x). The posttreatment resection specimen demonstrated substantial treatment effected with the majority of residual tumor mass now comprised of areas of histiocytic infiltration (c) fibrosis, pigment deposition, and chronic inflammation (d) (Hematoxylin and Eosin, 20x).
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Histopathology from the retroperitoneal biopsy demonstrated high-grade spindle cells with areas of herringbone pattern and small round blue cells (Figure 2). Pathology from the resection specimen demonstrated a 6 cm mass that on histologic evaluation exhibited marked treatment effect with only microscopic foci of residual synovial sarcoma in a background of necrosis, pigment deposition, histiocytic infiltrate, and inflammatory cells (Figure 2).
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