Solitary fibrous tumour of the liver with IGF-II-related hypoglycaemia. A case report

Contrast-enhanced ultrasound (CEUS): one step forward in the identification of "high risk" solitary fibrotic tumors of the liver

BACKGROUND

Solitary fibrous tumors of the liver (SFTL) are rare neoplasms, whose identification and definition of malignant potential are challenging.

CASE PRESENTATION

A 62-year-old patient underwent conventional imaging and CEUS to characterize an indeterminate liver lesion after other imaging techniques were inconclusive. In fact, all diagnostic techniques concluded that it was a partially fibrotic lesion, while CEUS determined its extra-hepatocellular origin and malignant potential, initially hypothesized to be a cholangiocarcinoma. Due to the possible risk of seeding following a biopsy procedure, the patient was a candidate for surgery. Subsequently, histopathological examination revealed SFTL.

CONCLUSION

CEUS confidently characterized the malignancy and hypothesized the origin of the liver lesion, thus aiding in treatment planning.

Diagnostics and Treatment of Extrameningeal Solitary Fibrous Tumors

Solitary fibrous tumors (SFT) are rare mesenchymal neoplasms that account for less than 2% of all soft tissue masses. In the latest WHO 2020 Classification of Soft Tissue Tumors, extrameningeal SFT was listed as intermediate (rarely metastasizing) or malignant neoplasms. Due to the lack of characteristic clinical features, their diagnosis and treatment remain challenging. The pathogenesis of SFT is often associated with the presence of fusions of the NAB2-STAT6 gene on the 12q13 chromosome. Cytoplasmic CD34 positive staining is considerably characteristic for most SFTs; less frequently, factor XII, vimentin, bcl-2, and CD99 are present. A key factor in the diagnosis is the prevalent nuclear location of STAT6 expression. Radical resection is the mainstay of localized SFTs. In the case of unresectable disease, only radiotherapy or radio-chemotherapy may significantly ensure long-term local control of primary and metastatic lesions. To date, no practical guidelines have been published for the treatment of advanced or metastatic disease. Classical anthracycline-based chemotherapy is applicable. The latest studies suggest that antiangiogenic therapies should be considered after first-line treatment. Other drugs, such as imatinib, figitumumab, axitinib, and eribulin, are also being tested. Definitive radiotherapy appears to be a promising therapeutic modality. Since standards for the treatment of advanced and metastatic diseases are not available, further investigation of novel agents is necessary.

Two case reports of rare diseases occurring in rare parts: splenic vein solitary fibrous tumor and liver solitary fibrous tumor

Solitary fibrous tumor (SFT) is a rare soft tissue tumor originating from mesenchymal cells. Here we report two new cases of SFT. One case was a 37-year-old female patient whose primary tumor site was located in the splenic vein and the primary tumor resulted in splenomegaly and hypersplenism; its recurred for many times after surgical resection and eventually transferred to the liver, 4 operations were performed during 10 years of follow-up, and the patient is in a good condition right now. The second case was a 54-year-old male patient whose primary tumor site was located in the liver, spleen and left side of the chest wall. We performed two operations to remove these tumors, totally. Six years later, SFT recurred in the liver, given that the tumor was too large to be surgical resected completely, we chose orthotopic liver transplantation (OLT), and no tumor recurred during 6 years' follow-up, he is also in a good condition right now. The reports of these two cases of SFT are exceedingly rare, especially the splenic vein SFT is the first report case, which helps expand the understanding of SFT. Although the current mainstream treatment of SFT is surgical resection, liver transplantation may be a new option treatment for the huge liver SFT.

Doege-Potter syndrome by malignant solitary fibrous tumor of the liver: A case report and review of literature

BACKGROUND

Solitary fibrous tumor of the liver (SFTL) is a rare occurrence with a low number of cases reported in literature. SFTL is usually benign but, 10%-20% cases are reported to be malignant with a tendency to metastasize. The majority of malignant SFTL cases are associated with a paraneoplastic hypoglycaemia defined as Doege-Potter syndrome. Surgery is the best therapeutic treatment, however, long- life follow-up is recommended.

CASE SUMMARY

A 74-year-old man, was admitted to the emergency department after a syncopal episode with detection of hypoglycaemia resistant to medical treatment. The computed tomography revealed a solid mass measuring 15 cm of the left liver. An open left hepatectomy was performed with complete resection of tumor. Histopathological analyses confirmed a malignant SFTL.

CONCLUSION

Large series with long-term follow-up have not been published neither have clinical trials been undertaken. Consequently, the methodical long-term follow-up of surgically treated SFTLs is strongly recommended.

Solitary fibrous tumor in the liver: case report and literature review

Background

Solitary fibrous tumors (SFTs) are uncommon mesenchymal neoplasms that present most commonly at intrathoracic sites. SFTs of the liver are rare, with only a few having been reported in the English-language literature. We report a rare case of a hepatic SFT and literature review.

Case presentation

A 49-year-old woman underwent surgery for a cranial hemangiopericytoma two decades previously. She currently presented with malaise. Abdominal computed tomography (CT) showed a huge, sharply demarcated mass in the anterior segment of the liver. Tumor marker levels were within the normal range. Following central bisegmentectomy of the liver, histological examination of the specimen revealed that the tumor was composed of spindle and fibroblast-like cells with collagenous stroma. Immunohistochemically, the spindle cells were negative for CD34 but positive for STAT6. The NAB2–STAT6 fusion gene was detected by the reverse transcription polymerase chain reaction. A diagnosis of SFT was thus confirmed histopathologically and genetically.

Conclusions

The SFT of the liver is an uncommon finding. Because there are no specific imaging features, it is difficult to diagnose the hepatic SFT preoperatively. We consider that careful surgical resection and postoperative follow-up are necessary for hepatic SFTs.

Successful Multimodal Treatment of an IGF2-Producing Solitary Fibrous Tumor With Acromegaloid Changes and Hypoglycemia

Doege–Potter syndrome with acromegaloid facial changes is extremely rare. Uncooked cornstarch along with glucocorticoids have been used as supportive care in patients with non–islet cell tumor hypoglycemia (NICTH). Preoperative embolization of hepatic solitary fibrous tumors (SFT) with NICTH has yielded unsatisfactory results. Herein we present the case of a 61-year-old man with a 3-month history of severe frequent hypoglycemic episodes and acromegaloid facial changes. During a spontaneous hypoglycemia (26 mg/dL), laboratory values showed a hypoinsulinemic pattern with low levels of GH, IGFPB3, and an IGF2/IGF1 ratio of 8.5:1. Cross-sectional imaging revealed a large (16 × 13 × 11 cm) hepatic tumor, and cytology was consistent with SFT. A preoperative right portal embolization was performed in an effort to induce normal remnant liver hypertrophy to allow for safe tumor resection. After the procedure, uncooked starch treatment followed by prednisone was started, achieving complete remission of hypoglycemic episodes in the preoperative setting. He subsequently underwent partial hepatectomy. The histologic diagnosis was compatible with a potentially malignant SFT. The patient had an excellent outcome with complete remission of hypoglycemia, improvement of facial acromegaloid changes, and no further evidence of disease. To our knowledge, this is the first case of a patient with Doege–Potter syndrome with acromegaloid facial changes induced by a potentially malignant liver SFT, treated successfully with a multimodal approach consisting of uncooked cornstarch, low-dose prednisone, preoperative embolization, and complete surgical resection. The use of cornstarch and low-dose glucocorticoids may be an adequate treatment in advance of undergoing surgery.

Ex situ hepatectomy and liver autotransplantation for a treating giant solitary fibrous tumor: A case report

A solitary fibrous tumor (SFT) is a rare mesenchymal tumor. Ex situ hepatectomy and liver autotransplantation are novel methods for the treatment of complicated liver tumors, for example, those involving vascular structures, including the inferior vena cava, which are unresectable by conventional approaches. The present study describes a rare case of a massive hepatic SFT in a 32-year-old female who underwent ex situ hepatectomy and liver autotransplantation to achieve a radical resection. The surgery was without complications. Post-operative histopathological and immunohistochemical examinations revealed an SFT of the liver. The patient was discharged 29 days after the surgery with fully recovered liver function. The routine check-up 3 months after surgery indicated normal liver function and no evidence of recurrence. Additionally, an exhaustive review of available literature was performed to provide a complete overview of the current status of SFTs. In summary, the present study found that ex situ hepatectomy and liver autotransplantation are suitable surgical techniques for treating a giant SFT, as well as other liver neoplasms that are considered unresectable by conventional surgery.

Imbalanced Expression of IGF2 and PCSK4 Is Associated With Overproduction of Big IGF2 in SFT With NICTH: A Pilot Study

CONTEXT

Nonislet cell tumor hypoglycemia (NICTH) is a rare but serious paraneoplastic syndrome associated with large tumors. The high molecular weight IGF2, known as "big" IGF2, is produced by culprit tumors and leads to severe hypoglycemia. The detailed mechanism of its production in NICTH, however, remains unclear.

OBJECTIVE

To clarify the mechanism of production of big IGF2 in light of the processing of pro-IGF2 in patients with solitary fibrous tumor (SFT) and NICTH.

DESIGN

We enrolled 14 patients with SFT and divided them based on the presence or absence of hypoglycemia. In light of the processing of pro-IGF2 in SFT with hypoglycemia, we, retrospectively, compared the production levels of big IGF2 and the expression levels of IGF2 and proprotein convertase subtilisin/kexin type 4 (PCSK4), a proteolytic enzyme of pro-IGF2.

RESULTS

In all patients with NICTH, big IGF2 was detected in serum by western immunoblotting analysis. Moreover, we showed that two patients without hypoglycemia also had a small amount of big IGF2 in their serum. By immunohistochemical analysis, the protein expression level of IGF2 was significantly higher in the NICTH group than in the non-NICTH group (P = 0.043). The IGF2/PCSK4 protein expression-level ratio in the NICTH group was significantly higher than that in the non-NICTH group (P = 0.021).

CONCLUSION

In patients with SFT and hypoglycemia, an imbalance of IGF2 and PCSK4 expression could lead to increased serum levels of big IGF2.

Solitary fibrous tumor of the liver. Case report and review of the literature

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor. Given its origin, it can appear in almost any location. In the literature, only 50 cases of SFT in the liver parenchyma have been reported. Despite its rarity, this entity should be included in the differential diagnosis of liver masses. We report the first case with imaging data from five years prior to diagnosis, which was treated by right portal embolization and arterial tumor embolization, and subsequent liver resection. We also present an exhaustive review of the cases described to date.

Solitary fibrous tumour of the liver-report on metastasis and local recurrence of a malignant case and review of literature

Background

Solitary fibrous tumours (SFT) are neoplasms of mesenchymal origin that predominantly arise from the pleura. SFT of the liver (SFTL) are a rare occurrence with little number of cases reported in English literature. Malignant cases of hepatic SFT are an even rarer occurrence. For this reason, the prognostic evaluation of SFTLs is unknown and difficult to measure.

Methods

A search on English literature on “Solitary Fibrous Tumour of the Liver” was conducted on common search engines (PubMed, Google). All published articles, case reports and literature reviews and their reference lists were reviewed.

Case report

This paper presents a 61-year-old male who was referred to a tertiary hospital in April 2010 with marked hepatomegaly. USS, CT and MRI scans were suggestive of a neoplasm, and the patient underwent a subsegmental IVb resection in June 2010. The specimen demonstrated histological and immunohistochemical features of malignant SFTL with clear resection margins. The patient was followed up regularly for 3 years with imaging and no suggestion of recurrence. Six years after the initial surgery, the patient represented with worsening right upper quadrant pain and dyspnoea secondary to extensive tumour recurrence adjacent to the resection site and metastatic deposits in the pleura. The patient was managed symptomatically and discharged for community follow-up after palliative involvement.

Conclusions

SFTL are rare with only 84 cases reported in the English Literature including the present case. The average age of patients is 57.1 and occurs in females more than males (1.4:1). Most SFTLs follow a benign course, however, 17.9% of cases displayed malignant histological features. Only three cases including the current case are reported to have both local recurrence and metastasis. Surgical resection remains the mainstay of treatment and appears to be curative of most cases. The rarity of this tumour makes it difficult to evaluate its prognosis and natural course.

Solitary Fibrous Tumor of the Liver: a Review of the Current Knowledge and Report of a New Case

INTRODUCTION

Solitary fibrous tumors of the liver (SFTL) are uncommon tumors; to the present day, less than 50 cases has been reported in the English scientific literature, most of which behaved as benign tumors. The present article reports a new case of SFTL and has the main purpose of updating the current knowledge of SFTL because due to its rarity, its clinical presentation, study, treatment, and prognosis are not well known. The clinical presentation, radiologic study, surgical treatment, immunohistochemical study, and prognosis are updated and comprehensively discussed.

METHODS

Using the common search engines, a search of the English literature was conducted for "Solitary Fibrous Tumor of The Liver," and the relevant articles were retrieved, reviewed, and analyzed.

RESULTS

All published articles reported anecdotal SFTLs, or SFTLs were included in large series analyzing solitary fibrous tumors on different sites.

CONCLUSION

The SFTL is an uncommon neoplasm. The clinical presentation is habitually indolent and its behavior is uncertain. In some cases, the SFTL acts as an aggressive sarcoma with poor prognosis. Currently, only surgery offers a therapeutic opportunity for these patients. Due to the lack of current knowledge of long-term behavior of supposedly benign SFTLs and to the lack of specific therapies, methodical long-term follow-up is essential to ensure the survival of patients treated for SFTL.

Giant Solitary Fibrous Tumor of Orbit

Solitary fibrous tumors (SFTs) have been reported in various locations in the body. Solitary fibrous tumors are extremely rare tumors, especially when located in the orbit. Diagnosis of SFT cannot be made based on histopathology only because it exhibits a variable microscopic appearance, and necessitates immunohistochemistry to confirm the diagnosis. A 51-year-old man was admitted to our clinic for the evaluation of a mass bulging in his left eye. Clinical examination revealed a painless mass extruding out of the orbital cavity with dimensions of 8 × 7  cm. Exenteration of the left eye including the upper and lower eyelid and reconstruction of the orbital cavity using a temporoparietal fascia flap and a temporal muscle flap was performed. SFT of orbital region is known as a slow growing and painless tumor. Based on previous studies, increased mitotic rate of the tumor gives the impression that the tumor has a malignant nature. Until now a small number or orbital SFTs were reported and none of them presented with a giant mass protruding out of the orbital cavity. We present a unique case of orbital SFT filling the whole orbital cavity and protruding outward as a giant mass. This case has been reported to expand our knowledge in this debated entity.

Gastric cancer induced non-islet cell tumor hypoglycemia: A case report and literature review

Multiple types of non-pancreatic tumors can induce hypoglycemia, known as non-islet cell tumor-induced hypoglycaemia. The disease is rare. Hypoglycemia, tumor and low insulin or low C peptide level often suggest the diagnosis of the disease. Hypoglycemia frequency and severity may be associated with quick tumor progression and high malignancy. Thus, clinicians should raise their awareness of this disease to make correct diagnosis and treatment.

An update on primary hepatic solitary fibrous tumor: An examination of the clinical and pathological features of four case studies and a literature review

BACKGROUND

Primary hepatic solitary fibrous tumor is a rare neoplasm that originates in the submesothelial tissue of the liver and is frequently misdiagnosed because of its rarity and unfamiliar characteristics.

AIM

To analyze, summarize and update the clinical and pathological features of primary hepatic solitary fibrous tumor.

METHODS

We systematically extract the clinical data of 4 cases from the relevant medical records, analyze the macroscopic, histological and immunohistochemical features and review the 59 previously reported cases in the English literatures.

RESULTS

The patients' mean age 50.75 years (range, 49-52 years), and the gender ratio was 1:1. The tumors ranged in size from 2.3 to 12.0cm (average diameter, 7.85cm). The tumors were composed of spindle cells with oval, fusiform or banded nuclei that were arranged in bundled, storiform or peculiar random patterns. Mitosis and hemangiopericytoma-like vessels were occasionally observed. Immunohistochemically, three cases were positive for Signal transduction and activator of transcription 6, cluster of differentiation 34, B-cell lymphoma-2 and vimentin but were negative for nervous, muscular and hepatocellular markers. Hepatic lobectomy was performed in all cases, and one patient received adjuvant chemotherapy simultaneously. One patient suffered two recurrences without metastasis, and the remaining patients experienced favorable outcomes.

CONCLUSIONS

A consensus on the essential and definite diagnostic criteria for primary hepatic solitary fibrous tumor must be reached in a timely manner. Signal transduction and activator of transcription 6 is a highly sensitive and specific immunohistochemical marker for primary hepatic solitary fibrous tumor.

Hypoglycemia mediated by paraneoplastic production of Insulin like growth factor-2 from a malignant renal solitary fibrous tumor - clinical case and literature review

BACKGROUND

Hypoglycemic episodes are infrequent in individuals without a history of diabetes mellitus or bariatric surgery. When hypoglycemia does occur in such individuals, an uncommon but important diagnosis to consider is non-islet cell tumor hypoglycemia (NICTH). We report a case of NICTH associated with paraneoplastic insulin-like growth factor-2 (IGF-2) production and review current relevant medical literature.

CASE PRESENTATION

A 60 year old male with no relevant past medical history was referred to the endocrinology clinic with 18 month history of episodic hypoglycemic symptoms and, on one occasion was noted to have a fingerstick glucose of 36 mg/dL while having symptoms of hypoglycemia. Basic laboratory evaluation was unrevealing. Further evaluation however showed an elevated serum IGF-2 level at 2215 ng/mL (reference range 411-1248 ng/mL). Imaging demonstrated a large right suprarenal mass. A right nephrectomy with resection of the mass demonstrated a malignant solitary fibrous tumor. Post resection, the patient's IGF-2 levels normalized and hypoglycemic symptoms resolved.

CONCLUSION

Due to the structural and biochemical homology between IGF-2 and insulin, elevated levels of IGF-2 can result in hypoglycemia. A posttranslational precursor to IGF-2 known as "big IGF" also possesses biologic activity. Review of recent reported cases of NICTH identified widespread anatomic locations and varied pathologic diagnoses of tumors associated with paraneoplastic production of IGF-2 causing hypoglycemia. Definitive management of hypoglycemia associated with paraneoplastic production of IGF-2 consists of resection of the tumor responsible for IGF-2 production. Accumulating literature provides a firm basis for routine IGF-2 laboratory evaluation in patients presenting with spontaneous hypoglycemia with no readily apparent cause.

Management of non-islet-cell tumor hypoglycemia: a clinical review

CONTEXT

Non-islet cell tumor hypoglycemia (NICTH) is a rare but serious paraneoplastic syndrome in which a tumor secretes high molecular weight IGF-II, causing hypoglycemia. Complete tumor resection is curative but is often delayed or unfeasible. There is no clear "standard of care" for managing these patients.

EVIDENCE ACQUISITION

PubMed searches were conducted for: "non-islet-cell tumor hypoglycemia," "NICTH," "Doege-Potter," "Doege-Potter syndrome," "high molecular weight IGF-II," and "big IGF-II." Relevant articles were reviewed in detail. We limited our review to English-language articles, focusing on 1988-2013 (corresponding with the elucidation of the pathophysiology of NICTH).

EVIDENCE SYNTHESIS

The available literature exists as case reports or small case series, with a void of higher-order treatment studies. Thus, an evidence-based approach to data synthesis was difficult. Nevertheless, the available literature is presented objectively with an attempt to describe clinically useful trends and findings in the management of NICTH.

CONCLUSIONS

Appropriate identification of NICTH and prompt and complete tumor resection represents ideal management. However, when prompt resection is not feasible, iv glucose or dextrose often does not suffice to prevent hypoglycemia. In such cases, we suggest consideration of local antitumor therapies for disease control and trial of glucocorticoids alone or in combination with GH. Continuous glucagon infusion can be successful if the patient has a positive response to a glucagon stimulation test, and parenteral nutrition may allow higher glucose delivery, but both are limited by the need for continuous iv infusion. Diazoxide and octreotide have no role in NICTH.

Primary solitary fibrous tumors of liver: a case report and literature review

A 42-year-old male presented right upper abdomen pain for more than 6 days, which misdiagnose calculus of intrahepatic duct and acute cholecystitis. An approximately 1.5 cm x 1.0 cm x 1.0 cm nodule was found and resected in left lateral lobe of hepatic. Pathological examination showed spindle cell and fibroblast -like cells within the collagenous stroma. Immunohistochemically, these spindle tumor cells showed diffuse Vim and Bcl-2 positive reactivity, but S-100 protein and HMB45 were negative. The post-operative course was uneventful. Solitary fibrous tumors of the liver, although rare, should be differentiated from mesenchymal lesions of the liver.

Tumors, IGF-2, and hypoglycemia: insights from the clinic, the laboratory, and the historical archive

Tumors of mesenchymal and epithelial origin produce IGF-2, which activates pathways in the tumors. In a minority of patients, the tumors (hepatomas, fibromas, and fibrosarcomas are the most common among many) release into the circulation enough IGF-2-related peptides to mimic the fasting hypoglycemia characteristic of patients with insulin-producing islet-cell tumors. Rarely, markedly elevated IGF-2 levels produce somatic changes suggestive of acromegaly. Typically, the elevated IGF-2 levels are associated with suppressed plasma levels of insulin, IGF-1, and GH. Complicating the pathophysiology are the IGF binding proteins (IGFBPs) that can bind IGF-2 and IGF-1, modifying hormone metabolism and action. IGFBP concentrations are often altered in the presence of these tumors. At the cellular level, the 3 hormone-related ligands, IGF-2, IGF-1, and insulin, all bind to 4 (or more) types of IGF-1 receptor (IGF-1R) and insulin receptor (IR). Each receptor has its own characteristic affinity for each ligand, a tyrosine kinase, and overlapping profiles of action in the target cells. The IGF-2R, in addition to binding mannose-6-phosphate-containing proteins, provides an IGF-2 degradation pathway. Recent evidence suggests IGF-2R involvement also in signal transduction. Surgery, the treatment of choice, can produce a cure. For patients not cured by surgery, multiple therapies exist, for the tumor and for hypoglycemia. Potential future therapeutic approaches are sketched. From 1910 to 1930, hypoglycemia, insulin, insulinomas, and non-islet-cell tumors were recognized. The latter third of the century witnessed the emergence of the immunoassay for insulin; the IGFs, their binding proteins, and assays to measure them; and receptors for the insulin-related peptides as well as the intracellular pathways beyond the receptor. In closing, we replace non-islet-cell tumor hypoglycemia, an outdated and misleading label, with IGF-2-oma, self-explanatory and consistent with names of other hormone-secreting tumors.

Sunitinib malate and figitumumab in solitary fibrous tumor: patterns and molecular bases of tumor response

Antiangiogenic treatment activity has been reported in solitary fibrous tumor (SFT), a rare and little chemosensitive sarcoma. We explored the activity of sunitinib malate (SM) in SFT and studied receptor tyrosine kinase (RTK) activation profile. Eleven patients with progressive metastatic SFT resistant to chemotherapy were treated with continuous-dosing 37.5 mg/d SM on a named-use basis. One of them also received the insulin-like growth factor I receptor (IGFIR) inhibitor figitumumab after developing secondary resistance to SM. Besides, biochemical, molecular, and fluorescence in situ hybridization analyses were done in eight naïve SFTs whose cryopreserved material was available to clarify RTK upstream and downstream signaling. In two cases treated with SM and belonging to the naïve series, both pretreatment and posttreatment samples were available. Ten patients were evaluable for response to SM. The best response according to the Choi criteria was six partial response (all with Response Evaluation Criteria in Solid Tumors stable disease), one stable disease, and three progressive disease. Responses lasted >6 months in five patients. The eight naïve samples showed high expression/phosphorylation of PDGFRB, epidermal growth factor receptor, and IGFIR/IR, in the presence of their cognate ligands. Downstream pathways revealed expression/activation of Akt, extracellular signal-regulated kinase 1-2 and, closely related to SFT subtypes, of S6 and 4E-BP1. In two patients, whose pretreatment and posttreatment clinical and molecular status were available, biochemical data confirmed the activity of SM, although they also suggested a possible time-dependent shift of dominant RTK from PDGFRB to IGFIR/insulin receptor. A Response Evaluation Criteria in Solid Tumors partial response to figitumumab corroborated these findings. SM has antitumor activity in SFT, possibly through a PDGFRB-mediated mechanism, but treatments with IGFIR/insulin receptor and possibly epidermal growth factor receptor inhibitors are worth testing.

[Solitary fibrous tumor: imaging findings and review of the literature]

Solitary fibrous tumors of the liver are uncommon. First reported in the pleura, this tumor has also been reported in other locations both within and outside the thorax. It rarely affects the liver parenchyma. The clinical, radiological, and immunohistochemical findings characterize the lesion and distinguish it from other tumors with a similar appearance. We present the case of a solitary fibrous tumor in the liver; we place special emphasis on the findings at ultrasonography, computed tomography, and magnetic resonance imaging. Finally, we review the literature.