Primary renal sclerosing epithelioid fibrosarcoma with metastasis to lung after 17 years.

Abstract

A 54-year-old female with a history of hepatitis C, right renal tumor post nephrectomy and benign uterus tumor post total hysterectomy was admitted to our hospital due to left lower lobe lung nodule. Eighteen years ago before entry, she received right radical nephrectomy for palpable tumor with size in 9 × 9 × 7 cm, and the pathologic study reported mesoblastic nephroma then. After nephrectomy, she received regular follow-up at urology department. She was referred to chest surgery department as a left lower lobe lung nodule was noted at regular followed-up abdominal computer tomography (CT). The soft tissue nodule was 2.0 cm in diameter. No any systemic symptoms were complained during this period. She received PET-CT scan first which demonstrated two soft tissue lesions (largest one about 2.0 × 1.2 cm) with mildly increased FDG uptake in the left lower lobe of lung (SUVmax: early 1.3, delayed 1.4). As tissue proof is needed, she was admitted to our hospital for surgical excision. Operation with video-assisted thoracic surgery with wedge resection of left lower lobe was done first, and the specimen was sent for frozen section. We got information from pathologist as “spindle cell with severe fibrosis” with inadequate evidence of a malignancy. We performed lobectomy for this patient. She recovered well and then was discharged after 1 week of operation. The final pathologic report demonstrated sclerosing epithelioid fibrosarcoma, metastatic. Immunohistologic stain showed positive for vimentin and negative for CK, WT-1, CD34, SMA, or TTF-1. As these presentations cannot fit any primary mesenchymal neoplasm of lung, we surveyed her previous specimen of nephrectomy 18 years ago, which was diagnosed as “mesoblastic nephroma” then. And we found that both lung and kidney specimens have strong MUC-4 expression (Figures 1A and 1B), and bear EWSR1 gene break apart confirmed by FISH. A diagnosis of primary renal sclerosing epithelioid fibrosarcoma (SEF) with lung metastasis is preferred. Sclerosing epithelioid fibrosarcoma(SEF) is a low-grade variant of fibrosarcoma, which was first published by Meis-Kindblom in 1995,1 and was recognized by WHO classification of soft tissue tumors since 2002.2 It presented rounded carcinoma-like epithelioid cells arranged into compact nests, cords, and single cell patterns within a highly sclerotic stroma. According to the currently published literature, it has wide age range from 17 to 61, typically occurring in middle aged adults.3 And the mostly attacked locations are lower extremities, trunk, upper extremities, head and neck, and visceral organs. Less intra-abdominal SEF was reported, and the most reported location is kidney. Only seven cases were reported previously, and five were reported with distant metastases. The longest period is 36 months. We will describe a case with primary renal SEF with lung metastasis after 17 years since first diagnosed. We appreciate the dedication of urologists and pathologists. With their contribution, the patient could be found a tumor over left lung and was diagnosed with previous renal origin. As far as we could search the literature, there were few cases with renal origin SEF with distant metastases, and among them this patient was with the longest metastasis-free duration, 17 years. The authors declare no conflict of interest.