Case report. Lipomatous haemangiopericytoma (fat-forming solitary fibrous tumour) involving the perineum: CT and MRI findings and pathological correlation

Perianal Solitary Fibrous Tumor in a Rare Anatomical Presentation: A Case Report and Literature Review

BACKGROUND Solitary fibrous tumors (SFTs) account for <2% of all soft tissue tumors and are slow-growing neoplasms of mesenchymal origin, which have been reported in various locations. They are frequently observed at the pleura and a perianal location is extremely rare. They show no predisposition by sex, are mainly benign, and usually occur between the 5th and 7th decades of life. CASE REPORT We report the case of an 80-year-old man with no comorbidities except hypertension, who presented with an asymptomatic perineal mass. Magnetic resonance imaging showed a solid tumor measuring 3.5×2.5 cm identified in the perineal midline. It was very close to the anal sphincter, showing no extension to the rectum or anus. The tumor was completely excised with negative margins. The postoperative course was uneventful and he was discharged home, free of any symptoms. The pathological examination showed a benign completely excised SFT, and no further treatment was necessary. At the 6-month and 1-year follow-ups, there was no sign of recurrence. CONCLUSIONS A comprehensive review of all the reported cases of perianal SFTs shows that the majority of these tumors present with no symptoms and have a favorable prognosis. Diagnosis is possible only after a pathological examination. The criterion standard of treatment is complete excision with negative margins. Once excised, the tumors have low rates of recurrence and metastasis. Tumors very close to the anal sphincter and with malignant potential need to be operated on with extra care to obtain clear margins without disrupting the continence mechanism.

Solitary Fibrous Tumor in the Perianal Region: Report of Two Cases With an Atypical Location

A solitary fibrous tumor (SFT) is a mesenchymal neoplasm of spindle cells, initially described in the pleura. The World Health Organization (WHO) classifies the solitary fibrous tumor as a neoplasm with intermediate biological potential. Diagnostic images are essential for the diagnostic and therapeutic approach in this entity. The standard of treatment for this type of lesion is surgical resection with oncological margins larger than 1 cm. The solitary fibrous tumors located in the perianal, perineal, and pelvic regions are infrequent and represent a challenge in the clinical approach, mainly because the manifestations are nonspecific. Given the low incidence of this type of neoplasm, we present two cases of SFT in the perianal region managed in a high-complexity hospital.

Fat-forming Solitary Fibrous Tumor of the Kidney - A Case Report and Literature Review

Fat-forming solitary fibrous tumors arising from the kidney are extremely rare, with only few cases reported so far. We report the case of a 49-year-old patient investigated for lumbar pain and diagnosed preoperatively with a large retroperitoneal tumor destroying the right kidney. The patient was submitted to surgery, the tumor being resected en bloc with right nephrectomy. The histopathological studies demonstrated the presence of a hemangiopericytoma-like tumor with adipocytary component; the immunohistochemical studies demonstrated the presence of cluster of differentiation 34 (CD34), while human melanoma black (HMB45) staining was negative. Therefore, the diagnostic of fat-forming solitary fibrous tumor of the kidney was established. The postoperative outcome was uneventful, the patient being discharged on the sixth postoperative day. In conclusion, although fat-forming solitary fibrous tumor of the kidney is a very rare entity, this diagnosis should be taken into consideration whenever a large retroperitoneal mass with high adipose content and renal invasion is described at the preoperative studies.

Giant Perineal Solitary Fibrous Tumor: A Rare Case Report

Background. Solitary fibrous tumor (SFT) is a fibroblastic mesenchymal tumor that was initially described from the pleura but currently arises at almost every anatomic site. It is usually benign, and surgical resection is curative. SFT involving the perineum is extremely rare. This is the third case report of a perineal SFT in the literature. Case Presentation. We reported an uncommon case of a 64-year-old man presenting with a huge perineal mass that started growing 3 years before his arrival in our service. He was asymptomatic. A contrast-enhanced CT scan revealed a heterogeneous well-circumscribed perineal mass with soft-tissue density. Invasion of the surrounding organs, distal metastasis, and lymph node swelling were absent. The complete resection of mass was done successfully. The specimen was a 23.0 × 14.0 × 8.0 cm encapsulated tumor. Mass weight was 1,170 g. After pathological analysis, we confirmed that the mass was a solitary fibrous tumor. The diagnosis was based on clinical findings and histological morphology and immunohistochemistry study. Conclusion. SFTs are usually indolent tumors with a favorable prognosis. The perineal location is extremely rare. Complete resection of the mass is the treatment of choice.

Pleural fat-forming variant of solitary fibrous tumor

The fat-forming variant of solitary fibrous tumor is rare. It occurs predominantly in the deep soft tissues of the retroperitoneum and thigh. We describe a case of fat-forming solitary fibrous tumor arising from the pleura, which was successfully treated using a video-assisted thoracoscopic approach. The patient remained free of recurrence 2 years after surgery and continues to be under long-term follow-up.

Malignant fat-forming solitary fibrous tumor (lipomatous hemangiopericytoma) in the neck: Imaging and histopathological findings of a case

Fat-forming solitary fibrous tumor (SFT) is a rare variant of solitary fibrous tumor, a mesenchymal fibroblastic neoplasia with a particular branching hypervascular pattern. This tumor is usually classified as benign and only very few fat-forming SFTs with malignant histologic features have been reported. We report a histologically malignant fat-forming solitary fibrous tumor in a 61-year-old man, located in his neck. Ultrasonography examination was first performed showing a heterogeneous lesion, predominantly hyperechoic, with sound beam attenuation, containing two hypoechoic solid nodules. Magnetic resonance imaging and computed tomography examinations demonstrated a heterogeneous and predominantly adipose mass, containing post contrast enhancing solid nodules and thin septations. Treatment consisted of total removal of the lesion. Histologically, the tumor showed hypercellularity, numerous mitoses and cytological atypia, fulfilling the criteria for malignancy. The patient had no metastasis. This rare tumor may be confused with other fat-containing lesions on imaging examinations, mainly liposarcoma.

Fat-forming variant of solitary fibrous tumour of the pleura: CT findings

The fat-forming variant of solitary fibrous tumour (SFT) was previously called lipomatous haemangiopericytoma and is a rare variant of solitary fibrous tumour. It predominantly occurs in the deep soft tissues of the retroperitoneum and thigh. Only a handful of cases involving the perineum, spine, thoracic wall and pelvic cavity have been reported in the radiological literature and the fat-forming variant of SFT involving the pleura has not been previously reported. Herein, we report the CT findings of a case of the fat-forming variant of SFT involving the pleura that was treated by excision. Chest CT showed a large lobulated heterogeneous fatty mass with a multifocal enhancing soft-tissue component in the left lower hemithorax. Although rare, the fat-forming variant of SFT of the pleura should be added to the differential diagnosis of fat-containing pleural soft-tissue tumours.

Lipomatous hemangiopericytoma of the stomach: A case report and a review of literature

Lipomatous hemangiopericytomas (LHPCs) are rare soft-tissue tumors that are histologically characterized by hemangiopericytomatous vasculature and the presence of mature adipocytes. We present the clinicopathological features of a case of gastric LHPC in a 56-year-old female, along with a literature review. Endoscopy and endoscopic ultrasound showed a submucosal tumor 0.8 cm across in the greatest dimension in the lesser curvature side of the gastric antrum. Grossly, the well-defined mass had a solid and tan-white cut surface admixed with myxoid regions and yellowish areas. Histological examination revealed a submucosal well-circumscribed lesion composed of cellular nodules with the classic appearance of an hemangiopericytoma admixed with clusters and lobules of mature adipocytes. The ill-defined tumor cells had weakly eosinophilic cytoplasm and contained spindled nuclei with occasional small nucleoli. Nuclei atypia and mitoses were absent, and no cellular atypia, necrosis or vascular invasion was observed. Immunohistochemistry showed that the tumor cells were diffusely positive for CD34, CD99, and vimentin and were focally reactive for bcl-2. This is the first known report of an LHPC in the stomach. The patient was followed for 12 mo without any evidence of metastasis or recurrence.

Fat-forming solitary fibrous tumour (lipomatous haemangiopericytoma) of the spine: case report and literature review

Solitary fibrous tumour (SFT) is a rare soft tissue tumour of uncertain histogenesis and unpredictable biological behaviour, which was first described in the pleura and subsequently in many extra-pleural locations. Fat-forming SFT is a sub-type of SFT and only a handful of cases have been reported in the literature. We present the clinical, radiological and histological features of a case of intraspinal fat-forming SFT, along with a literature review. This is the first known report of a fat-forming SFT in the spine.

[Solitary fibrous tumor of the abdomen. A rare neoplasm of vascular origin]

Solitary fibrous tumor (formerly known as hemangiopericytoma) is a rare soft tissue neoplasm, most frequently arising from the retroperitoneum and lower extremities. We present two cases of retroperitoneal solitary fibrous tumors diagnosed after surgical removal. We provide a literature review showing the basic clinical, pathologic and therapeutic features of these tumors.