Retroperitoneal low-grade fibromyxoid sarcoma

Abstract

Introduction: Low-grade fibromyxoid sarcoma is an uncommon deep-seated soft-tissue sarcoma that occurs rarely in young adults and children. Although surgical resection provides a long-term prognosis, late local recurrence and metastasis may occur.

Case presentation: A 44-year-old woman with no prior medical history presented with breathing and abdominal discomfort. Contrast-enhanced computed tomography scan revealed a retroperitoneal tumor protruding into the thoracic cavity and pleural effusion on the left side. Tumor biopsy revealed sarcoma. We performed complete resection of the tumor along with part of the diaphragm and replaced the diaphragm with a prosthetic patch. Histopathologic findings indicated low-grade fibromyxoid sarcoma. The patient experienced no postoperative complications and received no adjuvant therapy. Furthermore, she survived 4 years after surgery without recurrence.

Conclusion: Complete surgical resection is effective for low-grade fibromyxoid sarcoma; therefore, it is important to plan appropriately for complete resection when biopsy reveals malignant findings.

Keywords: Evans tumor; low‐grade fibromyxoid sarcoma; retroperitoneal sarcoma.

Fig. 1

Contrast‐enhanced CT at the first visit for breathing and abdominal discomfort. (a) A tumor with a diameter of 14.4 cm and contrast enhancement was detected on the cranial side of the left kidney in horizontal images (arrow head). (b) The tumor had invaded the diaphragm in the coronal images (circle).

Fig. 2

Intraoperative photo obtained during diaphragm restructured with a prosthetic patch. (a) Dissection of the retroperitoneal tumor was possible medially between the descending colon and spleen, caudally between the kidney, and cranially with the diaphragm. (b) Retroperitoneal tumor resection and combined diaphragmatic resection were performed for the retroperitoneal tumor. (c) The diaphragm was reconstructed by suturing a prosthetic patch to the position where the diaphragm was located (arrow).

Fig. 3

Gross findings of the excised retroperitoneal tumor and histological findings of the excised retroperitoneal tumor. (a) The tumor was resected along with the diaphragm. The lesion protruding into the thoracic cavity, which was identified on CT scan, was also removed (circle). (b) The cut surface of the tumor after formalin fixation was whitish, and the tumor was solid. (c) Hematoxylin and eosin staining revealed that spindle‐shaped cells proliferated in a relatively dense arrangement against the background of abundant collagen bundles. (d) Immunohistochemistry indicated that the tumor was negative for CK AE1/AE3. (e) Immunohistochemistry indicated that the tumor was positive for MUC4.