RESUMO
Multiple studies have demonstrated prostate-specific membrane antigen (PSMA) expression in the neo-vasculature of non-prostate tumors including clear cell renal cell carcinoma (ccRCC). However, PSMA expression in rare renal tumors including MiTF family translocation renal cell carcinoma has not been previously characterized. We examined PSMA expression by immunohistochemistry in a series of MiTF family translocation renal cell carcinomas as well as in several genetically related tumors including alveolar soft part sarcoma and PEComas with TFE3 rearrangements. PSMA expression was also studied in several cases of ccRCC and papillary RCC. Overall, PSMA immunohistochemistry was performed in 61 samples from 58 patients. Vascular PSMA expression was seen with the highest frequency in ccRCC [88% (14/16)] (38% focal, 50% diffuse). Translocation RCC (tRCC) demonstrated the second highest frequency of PSMA expression [71% (22/28)] (57% focal, 14% diffuse), followed by alveolar soft part sarcoma [50% (4/8)] (38% focal, 12% diffuse). No PSMA expression was seen in PEComas with TFE3 rearrangement (0/3) or papillary RCC (0/6). PSMA expression was only present in tumor-associated neo-vasculature. A patient with oligometastatic tRCC underwent 68 Ga-PSMA-11 PET imaging which detected multiple putative metastatic lesions not detected on conventional computed tomography imaging performed 2 weeks prior, supporting the potential utility of PSMA imaging in tRCC. These findings have potential implications for the utility of PSMA guided diagnostic and therapeutic agents in both common and uncommon renal cell carcinoma subtypes as well as genetically related mesenchymal neoplasms.
Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Sarcoma Alveolar de Partes Moles , Humanos , Carcinoma de Células Renais/diagnóstico , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/metabolismo , Neoplasias Renais/metabolismo , Translocação Genética , Imuno-HistoquímicaRESUMO
OBJECTIVE: PET imaging using radiotracers that target prostate-specific membrane antigen (PSMA) are increasingly being used in the evaluation of men with prostate cancer (PCa). It is therefore of increasing importance for imaging specialists to recognize potential pitfalls of this novel imaging technique. In this report, we describe a series of benign elastofibroma dorsi with uptake of the PSMA-targeted PET radiotracer F-DCFPyL. PATIENTS AND METHODS: We retrospectively analyzed the imaging data of 75 men with PCa who were consecutively imaged with F-DCFPyL PET/CT. Acquired images were reviewed for the presence of radiotracer uptake in the region of the scapular tip adjacent to the chest wall. Only those lesions with discrete radiotracer uptake corresponding to an area on CT with the characteristic appearance of an elastofibroma were considered positive. RESULTS: In total, 18/75 (24.0%) patients had evidence of at least one elastofibroma dorsi on F-DCFPyL PET/CT. Eight (44.4%) of these patients had unilateral lesions, all of which were right sided. Detected lesions had a median maximal diameter of 2.3 cm (range: 1.3-8.4 cm) and a median perpendicular thickness to the chest wall of 0.9 cm (range: 0.6-2.5 cm). The median maximum standardized uptake value of detected lesions was 1.4 (range: 1.1-2.4) and the median maximum standardized uptake value corrected to lean body mass was 1.1 (range: 0.8-1.7). CONCLUSION: This study is the first to report uptake of a PSMA-targeted PET radiotracer in elastofibroma dorsi. Radiotracer uptake in these benign lesions should not be falsely mistaken as sites of metastatic PCa.
Assuntos
Antígenos de Superfície/metabolismo , Glutamato Carboxipeptidase II/metabolismo , Lisina/análogos & derivados , Tomografia por Emissão de Pósitrons/métodos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/metabolismo , Neoplasias de Tecidos Moles/diagnóstico por imagem , Neoplasias de Tecidos Moles/metabolismo , Ureia/análogos & derivados , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Simulação por Computador , Diagnóstico Diferencial , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Lisina/farmacocinética , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Modelos Biológicos , Compostos Radiofarmacêuticos/farmacocinética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Distribuição Tecidual , Ureia/farmacocinéticaAssuntos
Carcinoma de Células Renais/patologia , Neoplasias Renais/patologia , Imagem Molecular/métodos , Anticorpos Monoclonais/administração & dosagem , Biópsia/efeitos adversos , Biópsia/métodos , Anidrase Carbônica IX/metabolismo , Carcinoma de Células Renais/diagnóstico por imagem , Fluordesoxiglucose F18/administração & dosagem , Humanos , Rim/patologia , Neoplasias Renais/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Tecnécio Tc 99m Sestamibi/administração & dosagem , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios XRESUMO
Renal cell carcinoma (RCC) is common with more than 60,000 new cases in the United States yearly. No curative therapies are available for metastatic RCC. Improved methods of imaging metastatic RCC would be of value in identifying sites of occult disease and potentially for judging response to therapy. A 58-year-old man with known metastatic clear cell RCC was imaged with both 18F-FDG and 18F-DCFPyL PET/CT. 18F-DCFPyL is a small molecule inhibitor of the prostate-specific membrane antigen (PSMA), a target known to be highly expressed on solid tumor neovasculature. Relative to 18F-FDG, 18F-DCFPyL identified more lesions and demonstrated higher tumor radiotracer uptake.