Prostate-Specific Membrane Antigen Expression in Adrenocortical Carcinoma on 68Ga-Prostate-Specific Membrane Antigen PET/CT. Clin Nucl Med. 2018;43:449-451. [PMID: 29578871 DOI: 10.1097/rlu.0000000000002064]

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.

Radiopharmaceuticals for Treatment of Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) represents a rare tumor entity with limited treatment options and usually rapid tumor progression in case of metastatic disease. As further treatment options are needed and ACC metastases are sensitive to external beam radiation, novel theranostic approaches could complement established therapeutic concepts. Recent developments focus on targeting adrenal cortex-specific enzymes like the theranostic twin [123/131I]IMAZA that shows a good image quality and a promising therapeutic effect in selected patients. But other established molecular targets in nuclear medicine such as the C-X-C motif chemokine receptor 4 (CXCR4) could possibly enhance the therapeutic regimen as well in a subgroup of patients. The aims of this review are to give an overview of innovative radiopharmaceuticals for the treatment of ACC and to present the different molecular targets, as well as to show future perspectives for further developments since a radiopharmaceutical with a broad application range is still warranted.

Adrenal functional imaging

Given the more widespread use of conventional imaging techniques such as magnetic resonance imaging or computed tomography, recent years have witnessed an increased rate of incidental findings in the adrenal gland and those adrenal masses can be either of benign or malignant origin. In this regard, routinely conducted morphological imaging cannot always reliably distinguish between cancerous and noncancerous lesions. As such, those incidental adrenal masses trigger further diagnostic work-up, including molecular functional imaging providing a non-invasive read-out on a sub-cellular level. For instance, [¹⁸F]FDG positron emission tomography (PET) as a marker of glucose consumption has been widely utilized to distinguish between malignant vs benign adrenal lesions. In addition, more adrenal cortex-targeted radiotracers for PET or single photon emission computed tomography have entered the clinical arena, e.g., Iodometomidate or IMAZA, which are targeting CYP11B enzymes, or Pentixafor identifying CXCR4 in adrenal tissue. All these tracers are used for diagnosing tumors deriving from the adrenal cortex. Furthermore, radiolabeled MIBG, DOPA, and DOTATOC/-TATE are radiotracers that are quite helpful in detecting pheochromocytomas originating from the adrenal medulla. Of note, after having quantified the retention capacities of the target in-vivo, such radiotracers have the potential to be used as anti-cancer therapeutics by using their therapeutic equivalents in a theranostic setting. The present review will summarize the current advent of established and recently introduced molecular image biomarkers for investigating adrenal masses and highlight its transformation beyond providing functional status towards image-guided therapeutic approaches, in particular in patients afflicted with adrenocortical carcinoma.

68Ga-PSMA-11 PET/CT in Isolated Bilateral Adrenal Metastases From Prostate Adenocarcinoma

ABSTRACT

A 65-year-old man with treated prostate adenocarcinoma underwent 68Ga-PSMA-11 PET/CT scan for restaging due to significantly increased serum PSA levels. PET/CT showed bilateral adrenal masses with high 68Ga-PSMA-11 uptake. There was no other lesion suspicious for metastasis. The laboratory and imaging findings were consisted with isolated bilateral adrenal metastases from prostate adenocarcinoma. The patient received docetaxel chemotherapy in combination with androgen deprivation therapy. PSA levels gradually decreased during chemotherapy. Follow-up MRI showed the bilateral adrenal masses significantly decreased in size. This case demonstrates the usefulness of 68Ga-PSMA-11 PET/CT in identifying atypical metastasis from prostate adenocarcinoma.

An overview on prostate-specific membrane antigen uptake in malignancies other than prostate cancer: A pictorial essay

Prostate-specific membrane antigen (PSMA) is a Type II transmembrane glycoprotein which is extremely overexpressed in prostate cancer epithelial cells. Recently, PSMA-targeted small molecule labeled with 68Ga and 99mTc allowed precise molecular imaging of prostate cancer and PSMA-targeted small molecule labeled with 177Lu leads to the development of radionuclide-targeted therapy of prostate cancer. Despite its name, it has been shown that PSMA has been expressed in several malignancies which can be due to significant neovascularization. Present pictorial assay reports the nonspecific tracer uptake in some malignancies during 68Ga-PSMA positron-emission tomography/computed tomography imaging and 99mTc-PSMA scintigraphy.

Giant nonfunctional ectopic adrenocortical carcinoma on the anterior abdominal wall: A case report

BACKGROUND

Adrenocortical cancer (ACC) is an infrequent and often aggressive malignancy with a very poor prognosis. It can be classified as functional or nonfunctional. Nonfunctional ACC is hampered by the absence of specific signs or symptoms; only abdominal pain with or without incidental adrenal occupation is typically present.

CASE SUMMARY

We report a rare case of a patient with a 30 cm × 15 cm × 8 cm ectopic ACC on the anterior abdominal wall without organ adhesion. A 77-year-old male was admitted to our hospital because of a huge abdominal mass, which, by ultrasonography, had an unclear border with the liver. Computed tomography showed that the mass was not associated with any organ but was adherent to the anterior abdominal wall. The patient underwent tumor resection, and a postoperative pathology examination showed a neuroendocrine tumor, which was diagnosed as ACC. The patient was disease-free at the 9-mo follow up.

CONCLUSION

The anterior abdominal wall is a rare site of ACC growth.

Gallium-68-Labeled Prostate-Specific Membrane Antigen-11 PET/CT of Prostate and Nonprostate Cancers

OBJECTIVE. The purpose of this study is to provide a concise summary of the current experience with ⁶⁸Ga-labeled prostate-specific membrane antigen (PSMA)-11 imaging of prostate and nonprostate malignancies and benign conditions. CONCLUSION. PSMA is overexpressed in prostate cancer and in the neovasculature of many other malignancies. The relevance of PSMA as a biologic target, coupled with advances in the design, synthesis, and evaluation of PSMA-based radionuclides for imaging and therapy, is anticipated to play a major role in patient care.

Oligometastatic prostate cancer and salvage lymph node dissection: systematic review

INTRODUCTION

We provide a comprehensive description of the physio-pathological theories behind oligometastatic prostate cancer (PCa) and analyze modern imaging techniques, presenting a systematic review of the available evidences regarding salvage lymph node dissection (sLND).

EVIDENCE ACQUISITION

A systematic review was attempted. The PubMed/Medline database was searched for "salvage" AND ("lymph node dissection" OR "lymphadenectomy") AND "prostate" AND "cancer." Only English publications were targeted. Relevant original articles addressing the role of sLND in PCa were selected.

EVIDENCE SYNTHESIS

Biochemical response (BR) was reported in 10-79.5% of the cases overall. These results were not durable and biochemical recurrence occurred in 54.5-93.8% of the cases, within 5 years. Furthermore, 50-80% of patients received some kind of adjuvant treatment right after sLND, regardless post-operative prostate-specific antigen levels. Surgery-related morbidity was low, with a 0-27% incidence of Clavien-Dindo III complications. No sLND-related deaths were observed.

CONCLUSIONS

sLND is not associated with a durable response over time but may postpone HT and its related complications, in selected patients. Although a limited morbidity was reported, sLND remains technically demanding and a careful selection of patients is advisable.

Nonspecific Uptake of 68Ga-Prostate-Specific Membrane Antigen in Diseases other than Prostate Malignancy on Positron Emission Tomography/Computed Tomography Imaging: A Pictorial Assay and Review of Literature

⁶⁸Ga-labeled prostate-specific membrane antigen (PSMA) ligand positron emission tomography/computed tomography imaging (PET/CT) is a rapidly evolving imaging modality for prostate cancer. Many studies have proved its superiority in staging, restaging, and detecting the recurrent prostate cancer. However, case reports describing the incidental tracer uptake in benign and nonprostatic malignancies are also reported in the literature, thus questioning the specificity of the tracer. This pictorial assay illustrates the nonspecific tracer uptake encountered during PSMA PET/CT imaging, knowledge of which can increase the confidence of interpreting physicians and may also open a new path for peptide receptor radionuclide therapy in nonprostatic malignancies.