How to cite:

Cuber PJ, Wojewoda T, Wysocki WM. An extrapleural solitary fibrous tumor with low metastatic potential in a young female. NOWOTWORY J Oncol 2022; 72: 130.

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Solitary fibrous tumors (SFT) for decades were reported only in the pleura (until the 1990s) and were considered a histomorphological entity similar to hemangiopericytoma. Currently both these neoplasms are merged together by the WHO and defined as fibroblastic neoplasms with intermediate behavior, rarely metastasizing [1].

A 25-year-old female with a 5 cm tumor on her thigh, adjacent but superficial to the fascia, with high vasculature as seen on the MRI (fig. 1), underwent a wide local excision for suspected sarcoma. Pathology reported SFT with low metastatic potential as based on the WHO risk criteria (age = 0, mitotic index = 2, tumor size = 0, necrosis = 0; altogether 2 points). Surgery was R0, with the tumor capsule intact (fig. 2). The presence of STAT6 nuclear staining is characteristic for SFT.

Figure 1. In the upper-posterior portion of the thigh, a well-circumscribed 5 cm tumor adjacent to the fascia can be seen

Figure 2. A microscopic image of a solitary fibrous tumor of the thigh (courtesy of Dariusz Pabis, MD)

Thorax (30%), meninges, (27%) and abdomen (20%) are leading locations for SFT; SFT occurs mainly >50 years (40–70). Extra-pleural locations warrant a careful pathological work-out to rule out other more frequent soft tissue tumors. A recurrence of any SFT variant is always possible, with a risk
of de-differentiation [2].

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