CPT-11 Chemotherapy Rescued A Patient with Atypical Sclerosing Epithelioid Fibrosarcoma from Emergent Condition

Sclerosing epithelioid fibrosarcoma of the kidney

A woman in her 20s presented with headache and back pain and was found to have a left renal mass with bony metastases. She underwent nephrectomy, and on histopathology was initially diagnosed with stage 4 clear cell sarcoma of the kidney. She underwent palliative radiation and chemotherapy; however, the disease progressed and she came to our centre. We started her on second-line chemotherapy and submitted her tissue blocks for review. Due to her age and lack of sclerotic stroma in the tissue, we had our doubts about the diagnosis and hence, tissue sample was submitted for next-generation sequencing (NGS). NGS detected an EWSR1::CREBL1 fusion, clinching the final diagnosis of sclerosing epithelioid fibrosarcoma of the kidney, a singular diagnosis rarely reported in the literature. Currently, the patient is post her third line of chemotherapy, is on maintenance, and is doing well and has resumed her daily activities.

Giant Sclerosing Epithelioid Fibrosarcoma of the Thigh: A Case Report

CASE

We present a case of a 35-year-old-man with a giant sclerosing epithelioid fibrosarcoma (SEF) of the thigh. The patient presented with a history of a painful thigh mass. Plain radiographs revealed a soft-tissue mass with extensive calcifications, whereas on magnetic resonance imaging, a lobulated mass between the adductors and the posterior muscles of the thigh was noted. A wide en block resection was undertaken, and the histopathology confirmed the diagnosis of SEF. Postoperative radiation therapy was followed. The patient had no signs of recurrence at the 4-year follow-up.

CONCLUSION

The clinicopathological, imaging characteristics, and treatment options of this rare soft-tissue tumor are discussed.

¹⁸F-fluorodeoxyglucose PET/CT features and correlations with histopathologic characteristics in sclerosing epithelioid fibrosarcoma

Sclerosing epithelioid fibrosarcoma (SEF) is a clinicopathologically distinct variant of fibrosarcoma that is capable of recurrence and metastasis. Awareness of imaging features and histopathologic characteristics will be helpful for differential diagnosis from other common tumors. Here, we report a case of SEF metastasizing to the pancreas as a solitary mass mimicking primary pancreatic cancer, and summarize the reported cases with FDG PET/CT from the literature (n=4). PET/CT showed abnormal FDG accumulation (n=2), mild FDG uptake (n=1), or photopenic (n=1). The FDG PET/CT features are closely related to histopathologic characteristics regarding its differentiation and aggressiveness.

Fibrosarcoma: a challenging diagnosis

Fibrosarcoma represent a rare group of soft tissue malignancies derived from fibrous connective tissue and immature proliferating fibroblasts or undifferentiated anaplastic spindle cells. It affects patients in the fourth and fifth decade of life. Fibrosarcomas can be classified in subtypes such as low-grade fibromyxoid sarcoma (LGFMS) and sclerosing epithelioid fibrosarcoma (SEF), and others. Histological features that overlap between types of fibrosarcomas is well known and reported in the literature. We report the case of a 53-year-old patient who presented a tumor in the axillary fossa, which was initially diagnosed as a solitary fibrous tumor. Due to recurrence of the lesion, as well as the presence of distant metastases, the histological revision considered the diagnosis of breast metaplastic carcinoma, since the tumor expressed the p63 antigen and estrogen and progesterone receptors. Unexpected resistance to chemotherapy motivated the diagnosis re-evaluation, which was due to MUC4 expression and morphological characteristics concluded by a hybrid LGFMS-SEF tumor. The authors call attention to the difficult diagnosis in cases of soft tissue tumors. A broad panel of immunohistochemical research is required as the clinical course is essential to the final diagnosis.