18 F-FDG and 68 Ga-FAPI-04 in the Evaluation of Aggressive Perivascular Epithelioid Cell Tumor

18 F-FAPI for Imaging Metastatic Perivascular Epithelioid Cell Neoplasm

ABSTRACT

We compared 18 F-FAPI and 18 F-FDG PET/CT findings of metastatic perivacular epitheliod cell tumor in a 23-year-old woman. Apart from showing strong uptake of a left upper lung mass that showed moderate uptake on 18 F-FDG, 18 F-FAPI PET/CT additionally presented hypermetabolism in diffuse multifocal lesion throughout the body. This case suggests that 18 F-FAPI PET/CT might play a more beneficial role than 18 F-FDG PET/CT in identifying and assessing the extent of perivascular epithelioid cell tumors.

Hepatic perivascular epithelioid cell tumor resembling hepatic adenoma and hepatocellular carcinoma on preoperative imaging: a case report

Perivascular epithelioid cell tumor (PEComa), an uncommon mesenchymal neoplasm, arises from specialized perivascular epithelioid cells exhibiting distinct features of smooth muscle and melanocytic differentiation with unpredictable behavior. PEComa tends to occur more commonly in the uterus and kidneys; its occurrence in the liver is exceedingly rare. We presented a case of a 29-year-old woman with hepatic PEComa and evaluated the tumor with MRI, integrated 18F-fluorodeoxyglucose (FDG), and 68Ga-fibroblast activation protein inhibitor (FAPI) PET/CT scans at presentation. The patient had a history of intermittent utilization of oral contraceptive drugs for several years. An abdominal ultrasound in a physical examination from an outside institution revealed a mass in the liver. A contrast-enhanced abdominal MRI revealed restricted diffusion on diffusion-weighted imaging (DWI) and rapid contrast enhancement and washout patterns in the hepatic lesion, suggesting hepatic adenoma (HA) or hepatocellular carcinoma (HCC). Further assessment was carried out using 18F-FDG and 68Ga-FAPI PET/CT scans. The hepatic lesion was non-FDG avid, whereas increased tracer uptake was observed on the 68Ga-FAPI PET/CT. Subsequently, laparoscopic partial resection of liver segment V was performed. Immunohistochemical analyses demonstrated positive staining for HMB45, Melan-A, and SMA while showing negative results for AFP, glypican-3, hepatocyte, and arginase-1. The results were indicative of a hepatic PEComa diagnosis based on these findings. We also review the current literature on the clinical characteristics, pathological features, and challenges in the diagnosis of hepatic PEComa.

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.

68 Ga-FAPI and 18 F-FDG PET/CT in Intravenous Leiomyomatosis

ABSTRACT

Intravenous (IV) leiomyomatosis is a rare IV disease. Our case presents 68 Ga-FAPI and 18 F-FDG PET/CT findings of IV leiomyomatosis in a 37-year-old woman. Intravenous leiomyomatosis shows only mild FDG but intense 68 Ga-FAPI activity on PET/CT studies. In this case, 68 Ga-FAPI was superior to 18 F-FDG PET/CT in detecting IV leiomyomatosis.

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.

Laparoscopic radical nephroureterectomy in the oblique supine lithotomy integrative position for rare renal malignant perivascular epithelioid cell tumor with renal vein cancerous thrombosis: A case report and literature review

RATIONALE

Perivascular epithelioid cell tumor (PEComa) is a mesenchymal tumor that arises from perivascular epithelioid cells and can differentiate into melanocytes and smooth muscle cells. Malignant renal perivascular epithelioid cell tumor is extremely rare. Due to the lack of specific clinical manifestations and imaging features, diagnosing PEComa depends on postoperative pathology and immunohistochemistry. Surgery is the primary treatment for malignant PEComa because the efficacy of radiotherapy and chemotherapy is uncertain. There is still a lack of unified diagnostic criteria and treatment guidelines for renal malignant PEComa, especially with vascular invasion. Hence, the treatment experience depends on a small number of cases reported worldwide.

PATIENT CONCERNS

A 68-year-old woman was admitted to our hospital due to intermittent hematuria for over 8 months. The color Doppler ultrasound and computed tomography scan revealed a mass in the lower middle part of the left kidney.

DIAGNOSIS

Rare renal malignant perivascular epithelioid cell tumor with renal vein cancerous thrombosis.

INTERVENTIONS

A laparoscopic radical left nephroureterectomy in the oblique supine lithotomy position was performed.

OUTCOMES

The operation process went smoothly, and no pulmonary embolism occurred after the operation. The final pathological diagnosis was a renal malignant perivascular epithelioid cell tumor. After a 12-month follow-up, no recurrence or metastasis was found.

LESSONS

Renal malignant PEComa is an extremely rare mesenchymal tumor diagnosed mainly based on pathology. Surgery is currently the effective treatment for malignant PEComa. For the surgical treatment of malignant renal PEComa with vascular invasion, laparoscopic radical nephroureterectomy in the oblique supine lithotomy integrative position has many benefits, as exemplified by our current case.