ABSTRACT
Malignant solitary fibrous tumors are rare growths of mesenchymal origin that can appear almost anywhere in the body; the most common location being the pleura. We present the case of a 61-year-old female with a left- sided pleural- based mass with apparent boney invasion, which was identified on a workup for shoulder pain. Ultrasound examination revealed an anechoic mass with Doppler color flow concerning for vascularity. Fine needle aspiration revealed a predominantly bloody aspirate with rare histiocytes. The patient underwent exploratory thoracoscopy with resection of the pleural- based mass for tissue diagnosis. The final pathology was consistent with a malignant solitary fibrous tumor with the tumor focally present at the surface of the inked margin. A subsequent chest wall resection was performed with negative margins. While the majority of solitary fibrous tumors are benign, 10%–20% of these cases are malignant and prognosis is unpredictable. Complete resection is essential and lifelong surveillance is warranted, as relapse is common.
