PMC9634459_01
Solitary fibrous tumor: clinical findings. Firm subcutaneous nodule (arrow) overlying the right lateral supraorbital rim. This image is published with the patient's consent.
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Exam revealed a flesh-colored, soft, rubbery, mobile mass with no overlying skin changes, measuring 2.2 cm in diameter, overlying her right lateral supra-orbital rim (Figure 1).
Solitary fibrous tumor: histologic findings. Dermal neoplasm consisting of spindle cells arranged in a "patternless" pattern featuring hemangiopericytoma-like vessels (arrows) dispersed throughout shown at both low (A,B) and high power (C) (hematoxylin and eosin, H&E, x2.5, x10, and x20). The spindle cell population exhibits diffuse nuclear STAT6 positivity (D) (STAT6 immunohistochemistry x20). Note that the vascular endothelial cells do not stain positive for STAT6 (D). STAT6, signal transducer and activator of transcription 6.
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Histologic sections revealed a spindle cell neoplasm arranged in a "patternless" pattern, with hemangiopericytoma-like vessels dispersed throughout (Figure 2).
Proposed approach to management of superficial solitary fibrous tumor. Complete removal of tumor is advised following pathologic diagnosis if partial biopsy is obtained. SFT risk score is calculated via the model proposed by Demicco et al. (see Table 1). Serial examinations should include at a minimum: evaluation of the primary excision site, regional lymphatic examination, and review of systems. Further studies (e.g., imaging, laboratory evaluation) are guided by examination findings as well as the review of systems. If at any time metastatic or recurrent disease is suspected, prompt referral to radiation and/or medical oncology for management is recommended. STAT6, signal transducer and activator of transcription 6; PET, positron emission tomography; CT, computed tomography; SFT, solitary fibrous tumor.
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Additional IHC staining for STAT6 was obtained and showed diffuse nuclear positivity, confirming the diagnosis of a superficial SFT (Figure 3).