Response to Immunotherapy in Sclerosing Epithelioid Fibrosarcoma: Case Report and Literature Review

Abstract

Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare subtype of sarcoma that appears histologically low-grade yet usually has a clinically aggressive course with a high rate of local recurrence and distant metastasis. However, these recurrences and metastases often occur years after initial treatment. Metastases can be to the lung as well as extra-pulmonary sites. In this case report, we discuss a patient who developed SEF in the deep soft tissue with metastases. This patient underwent checkpoint inhibitor therapy, with disease response. Thus, SEF is a sarcoma subtype with a unique tumor biology, and immunotherapy may be a promising avenue for treatment.

Keywords: ipilimumab; nivolumab; pazopanib; pembrolizumab; sarcoma; sclerosing epithelioid fibrosarcoma.

Figure 1. December 2022 CT chest with multiple mass-like consolidations. The yellow arrows point to the consolidations.

Figure 2. May 2023 MRI of left thigh primary tumor. The yellow arrow points at the tumor.

Figure 3. A) May 2023 MRI brain with a yellow arrow pointing to left thalamic metastasis. B) May 2023 MRI brain with a yellow arrow pointing to right cerebellar metastasis.

Figure 4. August 2023 CT chest showing response to radiation and immunotherapy.

Yellow arrows point to the same mass-like consolidations from Figure 1, which are decreased in size.

Figure 5. August 2023 MRI brain showing metastases in the A) right medulla, B) left thalamus, C) right periventricular white matter, D) left parieto-occipital region, and E) right cerebellum. Yellow arrows in each figure point to metastases.