The Appearance of Osseous PEComa on F-18 FDG PET/CT

Epithelioid Rhabdomyosarcoma Demonstrated on 99m Tc-MDP Bone Scintigraphy and 18 F-FDG PET/CT

A 60-year-old woman presented with the gradual aggravation of left hip pain. 99m Tc-MDP bone scintigraphy and 18 F-FDG PET/CT demonstrated intense radiotracer accumulation at the osteolytic lesion in the left acetabulum and pubis. The pathology confirmed the diagnosis of epithelioid rhabdomyosarcoma, a variant of rhabdomyosarcoma which is characterized by epithelioid morphology.

Hepatic perivascular epithelioid cell tumor: a retrospective analysis of 36 cases

Background and aims

Hepatic perivascular epithelioid cell tumor (PEComa) is a rare type of mesenchymal neoplasm and lacks systematic reports. The aim was to analyze the features of hepatic PEComa in order to provide our own experience for diagnosis and management from a single center.

Methods

We retrospectively analyzed clinical data, imaging findings, pathology, treatments and prognosis of 36 patients with hepatic PEComa in the First Affiliated Hospital of Zhengzhou University from January 2016 to September 2023.

Results

29 females and 7 males (median age, 47.8 years) were included in this study. The majority (26/36, 72.2%) of patients were diagnosed incidentally with non-specific symptoms. Abnormal enhancement of enlarged blood vessels (27/36,75%) can be observed on CT/MRI and only 7 patients (19.4%) were correctly diagnosed by imaging examinations. The positive immunohistochemical expressions were HMB-45(35/36,97.2%), Melan-A (34/35,97.1%), SMA (23/26,88.5%) and CD34(86.7%,26/30). Treatments include resection (24/36,67.7%), radiofrequency ablation (6/36,16.7%), transcatheter arterial chemoembolization(1/36,2.7%), conservative clinical follow-up(2/36,5.6%), and sirolimus-chemotherapy (3/36,8.3%). During the follow-up period (range, 2-81 months), except for one patient with a single intrahepatic recurrence and 3 malignant patients died in 6 months, the remaining patients had no signs of recurrence and metastasis.

Conclusions

Hepatic PEComa has no specific clinical features and mainly depends on clinicopathological characteristics for accurate diagnosis. Resection is the best treatment for benign PEComa, but TACE and radiofrequency ablation can also be considered in case of contraindications for surgery.

Comparison of 18 F-FDG and 68 Ga-FAPI PET/CT in a Patient With Hepatic Perivascular Epithelioid Cell Neoplasm

ABSTRACT

The prevalence of hepatic perivascular epithelioid cell neoplasm (PEComa) is extremely low, and imaging diagnosis is very difficult. We presented 18 F-FDG and 68 Ga-FAPI PET/CT findings in a 58-year-old woman with pathologically confirmed hepatic PEComa. The tumor showed intense 68 Ga-FAPI uptake but only mild 18 F-FDG activity on PET/CT studies. This case suggested that 68 Ga-FAPI PET/CT might be a useful tool for evaluation of hepatic PEComa with remarkable tumor-to-liver ratios.

Pancreatic Perivascular Epithelioid Cell Tumor Revealed by 68 Ga-DOTATATE PET/CT

ABSTRACT

We report 68 Ga-DOTATATE PET/CT findings of pancreatic perivascular epithelioid cell tumor in a 55-year-old woman. 68 Ga-DOTATATE PET/CT showed increased radioactivity in the region of pancreatic body, which suggested malignant tumor. However, postoperative pathological findings demonstrated the presence of perivascular epithelioid cell tumor. This case emphasizes the need to increase awareness of this tumor in the differential diagnosis of pancreatic nodules with moderate DOTATATE activity.

18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Response Assessment of Perivascular Epithelioid Cell Tumor of the Pelvic Cavity to Irinotecan and Temozolomide

Perivascular epithelioid cell tumors (PEComas) are a rare variety of mesenchymal tumors composed of distinctive cells that show a focal association with blood vessel walls and usually express melanocytic and smooth muscle markers. We present a case of 38-year-old male, diagnosed with PEComa of the pelvic cavity who underwent serial ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography scans for the assessment of response to the chemotherapeutic combination of irinotecan and temozolomide.

Primary perivascular epithelioid cell tumor (PEComa) in bone: A review of the literature and a case arising in the humerus with multiple metastases

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First case PEComa primary arising in humerus was described.

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Histology is the basic to determine malignancy of PEComa.

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TFE3 gene investigation is the key of therapy selection.

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mTOR inhibitor is believed to be effective for patients without TFE3 rearrangement.

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More study is needed to understand the role of molecular test and imaging in PEComa.

Introduction

Perivascular epithelioid cell tumors (PEComas) are a family of mesenchymal tumors that rarely arise as a primary bone tumor.

Material and methods

We report a case of primary malignant bone PEComa. A literature review via PubMed, Embase and Web of Science databases with the keyword “PEComa” and “bone” was performed.

Results

We reported a 33-year-old female with primary malignant bone PEComa in right distal humerus. The patient received an inhibitor of the mammalian target of rapamycin (mTOR) protein based on negative molecular investigation result of transcription factor E3 (TFE3) rearrangement, and additional therapies including palliative radiotherapy, anti-angiogenics and immunotherapy when the disease progression was detected. The patient was alive with the disease twenty-three months postoperatively. A total of nineteen related literature cases were retrieved and reviewed. Taking current case into account, ten males and ten females with median age of 24 years (range, 3–93 years) were identified, who were most frequently affected in tibia. The median follow-up duration of 24 months (range, 3–96 months). One patient died due to this disease, and six patients showed metastases. Three patients experienced recurrence, and two of them experienced twice and three times, respectively.

Conclusion

To our knowledge, this is the first case of primary malignant bone PEComa arising in humerus. Clinicopathological and radiological correlation is mandatory to the correct diagnosis and to determine its malignancy. More studies are required to understand the role of molecular test and imaging in selecting suitable treatment and mechanisms of treatment resistance.

Malignant Perivascular Epithelioid Cell Tumor of Lung on FDG PET/CT

Chest CT images were acquired in a 67-year-old man to evaluate a left lung mass revealed by chest radiography. The image findings suggested possible pulmonary malignancy. FDG PET/CT was performed for staging, which showed the abnormally increased activity in the lung mass with hypermetabolic lymph node. Pathology from the biopsy confirmed malignant perivascular epithelioid cell tumor.

Update on the imaging of malignant perivascular epithelioid cell tumors (PEComas)

Malignant perivascular epithelioid cell tumors (PEComas) are a histologic group of mesenchymal neoplasms that share a distinctive histological phenotype, the perivascular epithelioid cell. These tumors are known for their perivascular distribution. Malignant PEComas have a female predominance and are associated with aggressive disease and poor prognosis, making timely diagnosis critical to management. Imaging features of malignant PEComas are nonspecific and mimic other benign and malignant neoplasms. Surgery is the mainstay in the management of malignant PEComas. Promising novel molecular targeted therapies like m-TOR inhibitors have been shown to be effective in the metastatic setting. The aim of this review is to familiarize radiologists with the imaging appearances of and potential therapies for primary and metastatic malignant PEComa.

The role of (18)F-FDG PET/CT imaging in patient with malignant PEComa treated with mTOR inhibitor

Malignant perivascular epithelioid cell tumor (malignant PEComa) is a rare disease for which the diagnostic criteria and treatment options have not been established. Since PEComa is associated with upregulation of mammalian target of rapamycin (mTOR) pathway which controls Glut-1 (glucose transporter) function, increased ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake may indicate the over activation of mTOR pathway and may guide selectively inhibiting mTOR pathway treatment. We report a malignant PEComa patient who presented for ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) restaging. The tumor had shown significant avidity on PET/CT as well as an evident response to sirolimus (rapamycin, Rapamune™) that supports the utility of mTOR inhibitors as an effective treatment for malignant PEComa. Therefore, ¹⁸F-FDG PET/CT is helpful in restaging and guiding treatment for malignant PEComa with mTOR inhibitors.

Malignant perivascular epithelioid cell tumor (PEComa) of the femur: a case report and literature review

BACKGROUND

We describe a case of malignant perivascular epithelial cell tumor (PEComa) arising primarily in the distal left femur of a 47-year-old male.

CASE PRESENTATION

The patient presented with pain accompanied by progressive swelling of his left thigh. Computed tomography (CT) scan and magnetic resonance imaging (MRI) revealed an osteolytic lesion. Curettage of the lesion was reported as a clear cell tumor with recommendation for exclusion of a metastatic clear cell carcinoma. However, thorough examinations did not find any primary site elsewhere, apart from the presence of bilateral pulmonary metastases. Evaluation of the submitted H & E slides identified a malignant PEComa which was further confirmed by subsequent immunohistochemical study.

CONCLUSIONS

The occurrence of PEComa as a primary bone lesion is extremely rare. We present here a malignant PEComa of the distal left femur, and summarize the clinicopathological characteristics of this rare entity with literature review.

VIRTUAL SLIDES

The virtual slide (s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5729035221600545 .

Primary perivascular epithelioid cell neoplasm (PEComa) of bone: report of two cases and review of the literature

Primary perivascular epithelioid cell neoplasms (PEComas) of bone are rare mesenchymal tumors. Histologically, they are composed predominantly of perivascular epithelioid cells and have the capacity to metastasize. PEComas have been reported within intra-abdominal and intra-pelvic organs. To the best of our knowledge, only seven primary PEComas of bone have been described in the English literature. We present two cases of PEComa of bone, one arising from the distal fibula and one from the acetabulum. Both were treated by surgical excision and one also received adjuvant chemotherapy.