18F-PSMA-1007 PET/CT uptake in multiple angiolipomas caused by PSMA expression in capillaries: a case report

Prostate specific membrane antigen (PSMA) avid nonprostatic benign and malignant disease: a pictorial review

Prostate specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET-CT) is revolutionising the management of prostate cancer (PC) in primary staging and assessment of biochemical recurrence (BCR) through its higher diagnostic accuracy compared to both conventional imaging and previously available PET radiopharmaceuticals. PSMA is a transmembrane glycoprotein, highly expressed in prostate cancer, with its extracellular domain the target for PSMA PET radiopharmaceuticals. However, PSMA expression is not prostate specific and resultant PSMA uptake on PET-CT is not restricted to pathologies arising from the prostate gland. The increasing use of PSMA PET-CT has revealed PSMA uptake in a variety of non-prostatic benign and malignant diseases, which adds complexity to PET-CT interpretation and subsequent clinical management. This pictorial review will provide a thorough knowledge and understanding of the comprehensive range of PSMA avid non-prostatic benign and malignant diseases demonstrable on PSMA PET-CT, whilst highlighting the complimentary nature of other imaging modalities.

Intense prostate-specific membrane antigen receptor expression in coronary artery pypass graft scar tissue: A potential molecular imaging pitfall

68Gallium-PSMA positron emission tomography/computer tomography has been utilized recently for the diagnosis and staging of prostate cancer. PSMA is a transmembrane protein that is expressed not only in the prostate gland but also in other tissues. While some pitfalls have been addressed, there are still uncertainties. Herein, we report a 79-year-old male with prostate cancer who underwent a PSMA scan after coronary artery bypass graft surgery, revealing disease progression and PSMA-avid foci at the surgical stitch sites. This report discusses the immunohistochemical and molecular imaging mechanisms underlying PSMA expression in surgical scar tissues, providing critical insights for optimizing radiologic reporting in such situations.

False Positive Findings of [18F]PSMA-1007 PET/CT in Patients After Radical Prostatectomy with Undetectable Serum PSA Levels

Background

PET-CT using prostate-specific membrane antigen (PSMA)-targeting radiopharmaceuticals labeled with ⁶⁸Ga or ¹⁸F has emerged as the most sensitive staging tool in prostate cancer (PC). Nonetheless, the occurrence of false positive (FP) findings presents a major concern of this approach. In this prospective study, we investigated the frequency and pattern of false-positive findings of [¹⁸F]PSMA-1007 PET/CT in patients after radical prostatectomy with undetectable serum PSA levels. Any discrete non-physiological accumulation of [¹⁸F]PSMA-1007 in this population is by definition FP.

Methods

Seventeen men after radical prostatectomy, whose serum PSA levels were <0.05 ng/mL at 2–24 months after surgery were prospectively recruited. PET/CT was acquired at both 1 and 2 h after injection of [¹⁸F]PSMA-1007.

Findings

Three studies (18%) were interpreted as completely normal. Thirty-five foci of “non-physiological” uptake were observed in the remaining 14 (82%) patients, including a single skeletal focus in four patients, multiple skeletal foci in five patients and soft tissue uptake in eight, including in a desmoid tumor and in pelvic lymphocele. The SUV_max of all lesions was in the range of 1–7, except for the desmoid tumor which measured 12.7. All foci were visible in both the 1- and the 2 h studies, presenting a minor (<10%), statistically insignificant increase of SUV_max during this time-interval.

Interpretation

FP [¹⁸F]PSMA-1007-avid foci are found in about 80% of patients with undetectable serum PSA levels. Thus, focal uptake of [¹⁸F]PSMA-1007 outside its physiological distribution is not a categorical sign of metastasis and can arise from non-specific uptake of the ligand. The interpretation of [¹⁸F]PSMA-1007 PET/CT studies should always consider the clinical context, and lesions with SUV_max < 7 are suspicious for FP.

Multiple angiolipoma of the hand, back, and abdomen; a case report

Introduction

Angiolipoma is a rare and benign variant of lipoma that usually occurs as single or multiple entities. The aim of this study is to present a case of multiple angiolipoma located in the hand, back, and abdomen.

Case report

A 38-year-old male presented with multiple swellings in his body for a 6-year duration. Physical examination revealed 3 painless masses in the hands, back, and abdomen. Laboratory findings were normal and ultrasound (US) examination suggested multiple body lipoma. The patient was managed with total excision and histopathological examination confirmed the diagnosis of benign angiolipoma. No reoccurrence was observed upon follow-up.

Discussion

Angiolipoma mainly composed of a mixture of proliferating blood vessels and mature adipose tissues, with a degree of vascularity much higher than that of a normal lipoma. It has a slow growing nature that it can be presented as single or multiple neoplasia. It is reported to be more common in the young adult population with male predominance.

Conclusion

Angiolipoma is a rare variant of lipoma. It rarely occurs in the hands, especially as a painless mass. Histopathology is required for definitive diagnosis.

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Angiolipoma is a rare and benign variant of lipoma.

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It mostly occurs as single or multiple entities in trunk and upper extremities.

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It is rarely reported in other areas, including the hands.

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This report presents a rare case of multiple angiolipoma of the hand, back, and abdomen.

Comparison of 68Ga-PSMA PET/CT and multiparametric MRI for the detection of low- and intermediate-risk prostate cancer

Purpose

To assess ⁶⁸Ga-PSMA PET/CT for detection of low- and intermediate-risk prostate cancer (PCa), high-risk PCa in comparison with mpMRI, respectively, and to determine which of low- and intermediate-risk PCa are more likely to be detected by ⁶⁸Ga-PSMA PET/CT.

Methods

We conducted a retrospective analysis of patients who had undergone a prostate biopsy and/or radical prostatectomy and who were scanned with ⁶⁸Ga-PSMA PET/CT and mpMRI between June 2019 and March 2021. The mpMRI images were scored with the Prostate Imaging-Reporting and Data System Version 2.1 (PI-RADS) and were classified as either negative (PI-RADS 1–3) or positive (PI-RADS 4–5). Suspicious ⁶⁸Ga-PSMA PET/CT lesions were reviewed for each relevant patient and classified by double-trained board-certified nuclear medicine physicians. The results were evaluated with the histopathological outcome. All patients were classified according to the D’Amico classification, and the clinical data were combined for stratified analysis.

Result

A total of 101 patients who were pathologically diagnosed with PCa were analyzed. Of the 101 patients, 88 (80.6%) patients presented with a pathologic mpMRI, and 85 (79.1%) with a pathologic ⁶⁸Ga-PSMA PET/CT. In the high-risk PCa cohort, ⁶⁸Ga-PSMA PET/CT was positive in 64/66 (97.0%) patients and yielded a higher detection rate than that for the mpMRI patients (58/66, 87.9%; p < 0.05). However, mpMRI provided superior diagnostic confidence in identifying low- and intermediate-risk PCa (30/35, 85.7% vs. 21/35, 60.0%; p < 0.05). When the age threshold exceeded 62.5 years and the serum prostate specific antigen (PSA) threshold exceeded 9.4 ng/ml, a higher uptake of PSMA was more likely to occur in the lesions of low- and intermediate-risk PCa.

Conclusion

The diagnostic performance of ⁶⁸Ga-PSMA PET/CT was superior to that of mpMRI in the high-risk PCa cohort, which was consistent with prior studies. Furthermore, in the initial diagnosis of low- and intermediate-risk PCa, we found that mpMRI showed a higher diagnostic accuracy than ⁶⁸Ga-PSMA PET/CT did. Low- and intermediate-risk PCa patients with a PSA ≥ 9.4 ng/ml and age ≥ 62.5 years were more likely to have a positive ⁶⁸Ga-PSMA PET/CT result.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-022-00881-3.