Specific imaging features indicate the clinical features of patients with hepatic perivascular epithelioid cell tumor by comparative analysis of CT and ultrasound imaging

Diagnostic challenges and radiological insights of rare hepatic perivascular epithelioid cell tumor: A case report and review of the literature

BACKGROUND

Hepatic perivascular epithelioid cell tumor (PEComa) is an extremely rare neoplasm that is often difficult to diagnose due to its nonspecific clinical and radiological features. This case emphasizes the importance of imaging and histopathological examination in distinguishing PEComa from other liver tumors, and the necessity of early intervention.

CASE SUMMARY

A 36-year-old woman presented with a liver mass discovered during a routine physical examination. Initially diagnosed as focal nodular hyperplasia based on contrast-enhanced computed tomography, she declined surgical intervention. Two years later, re-examination revealed an approximately 60% increase in the size of the mass and suggested the possibility of hepatocellular carcinoma. She subsequently underwent surgical resection. Postoperative histopathological and immunohistochemical analysis revealed positivity for HMB-45 and Melan-A, confirming the diagnosis of hepatic PEComa. A 13-month follow-up revealed no recurrence or metastasis.

CONCLUSION

Hepatic PEComa requires a combination of radiological and immunohistochemical evaluation for accurate diagnosis. This case highlights the importance of early surgical intervention and regular follow-up to monitor for recurrence or metastasis.

Contrast-Enhanced Ultrasound of a Hepatic Perivascular Epithelioid Cell Tumor: A Case Report and Literature Review

Primary hepatic perivascular epithelioid cell tumor (PEComa) is an exceptionally rare mesenchymal neoplasm of borderline malignancy, with limited documentation of its contrast-enhanced ultrasound (CEUS) features in medical literature. In this context, we present a 53-year-old male patient without chronic liver disease, who exhibited a well-circumscribed hypoechoic left hepatic lobe mass on conventional ultrasonography. Subsequent CEUS demonstrated characteristics indicative of malignant tumors, with specific manifestations during the arterial phase, thereby informing clinical decision-making toward surgical resection. Histopathological confirmation of capsular-invasive PEComa underscores the utility of CEUS in characterizing such lesions, particularly in middle-aged patients with incidental solitary hepatic masses lacking predisposing risk factors. These findings advocate for the integration of CEUS into diagnostic algorithms to enhance specificity in atypical hepatic tumor evaluations.

Enhanced diagnostic accuracy of contrast-enhanced ultrasound in liver space-occupying lesions: superior sensitivity and specificity over conventional ultrasound

AIMS

To evaluate the clinical value of contrast-enhanced ultrasound (CEUS) in diagnosing liver space-occupying lesions.

METHODS

A total of 487 patients with liver space-occupying lesions were examined using both conventional ultrasound and CEUS. The diagnostic results from the two methods were compared, with pathological findings used as the gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the area under the receiver operating characteristic curve were calculated for each method to assess their diagnostic value.

RESULTS

Among the 487 lesions, 220 were malignant and 267 were benign. The relative blood flow (rBF) in the arterial phase of malignant lesions was significantly higher than that of benign lesions, while the rBF in the delayed phase was significantly lower (P<0.05). In diagnosing malignant lesions, CEUS had a higher detection rate than conventional ultrasound (75% vs. 43.18%, P<0.001). CEUS also demonstrated a higher diagnostic agreement for lesions ≤1 cm compared to conventional ultrasound (85.16% vs. 49.47%, P<0.001). The accuracy, sensitivity, specificity, PPV, and NPV of CEUS were all higher than those of conventional ultrasound (all P<0.05).

CONCLUSION

CEUS is effective in diagnosing liver space-occupying lesions, with superior sensitivity and specificity compared to conventional ultrasound.

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.

Very Rare Liver Tumor: PEComa Case Report with and a Review of Literature

Perivascular epithelioid cell tumors (PEComas) are very rare mesenchymal tumors. In addition to being rare in general, they are even rarer in the liver. There are various subtypes and there is only one case of liver PEComa reported in the clear cell type in the literature to date. We present the second clear cell type liver PEComa in this case by reviewing the literature data. The hypodense, smooth-edged, ovoid lesion was detected on computed tomography (CT) for performing abdominal pain in a 41-year-old female patient. Magnetic resonance imaging (MRI) was then performed for lesion characterization. The lesion was hypointense on T1-weighted imaging (T1WI), hyperintense on T2-weighted imaging (T2WI). In dynamic phases, it showed marked enhancement on the arterial phase and capsular enhancement with central washout on the portal and late venous phases. The posterior branch of the right portal vein extended into the mass. The lesion was excised and the pathological result was epithelioid clear cell subtype of PEComa. Although the imaging findings are generally nonspecific and certain diagnosis is made histopathologically, radiologists should consider PEComa in the differential diagnosis in the presence of intensely enhanced lesion on the right lobe in female patients. Also, the "large vessel sign" may help in the diagnosis.

Multimodal imaging study of hepatic perivascular epithelioid cell tumors: a case report

Hepatic perivascular epithelioid cell tumors (PEComas) are rare interstitial tumors that are often misdiagnosed as hepatocellular carcinomas due to their unique vascular enhancement patterns. Herein, we present a case of a 61-year-old man who was incidentally found to have a lesion in the left medial segment of the liver during a chest computed tomography (CT) examination performed 4 days prior to his presentation for chest discomfort. Imaging revealed solid components with density similar to that of normal liver tissue and areas of low-density adipose tissue within the lesion. The solid components exhibited increased uptake of fluorine-18 fluorodeoxyglucose on positron emission tomography/CT. Magnetic resonance imaging demonstrated areas with unevenly high signal intensity in both T1-weighted imaging (T1WI) in-phase and T2-weighted imaging (T2WI) sequences, while T2WI in the opposite phase displayed areas with unevenly low signal intensity, indicating the presence of fatty components. Contrast-enhanced T1WI displayed a "fast in and fast out" enhancement pattern. These distinct imaging features contribute to the diagnosis of hepatic PEComas and distinguish it from hepatocellular carcinoma.

Perivascular epithelioid cell tumors of the liver misdiagnosed as hepatocellular carcinoma: Three case reports

BACKGROUND

Hepatic perivascular epithelioid cell neoplasms (PEComas) are rare. Diagnostic and treatment experience with hepatic PEComa remains insufficient.

CASE SUMMARY

Three hepatic PEComa cases are reported in this paper: One case of primary malignant hepatic PEComa, one case of benign hepatic PEComa, and one case of hepatic PEComa with an ovarian mature cystic teratoma. During preoperative imaging and pathological assessment of intraoperative frozen samples, patients were diagnosed with hepatocellular carcinoma (HCC), while postoperative pathology and immunohistochemistry subsequently revealed hepatic PEComa. Patients with hepatic PEComa which is misdiagnosed as HCC often require a wider surgical resection. It is easy to mistake them for distant metastases of hepatic PEComa and misdiagnosed as HCC, especially when it's combined with tumors in other organs. Three patients eventually underwent partial hepatectomy. After 1-4 years of follow-up, none of the patients experienced recurrence or metastases.

CONCLUSION

A clear preoperative diagnosis of hepatic PEComa can reduce the scope of resection and prevent unnecessary injuries during surgery.