Uncommon Detection of Leiomyoma in the Penile Corpus Spongiosum Using FDG PET/CT: A Case Report.

ABSTRACT: Primary tumors of the penile corpus spongiosum are rare. Hereby we describe the scintigraphic findings of a case of penile leiomyoma within the corpus spongiosum tissue, which was incidentally detected on FDG PET/CT. The benign neoplasm was growing in close proximity to the urethra showing increased focal FDG uptake on sequential PET/CT studies. Subsequently, the patient experienced obstructive urinary symptoms, and the tumor was resected. We concluded that the possibility of neoplasm should be kept in mind while evaluating a patient with persistent focal penile FDG uptake, which may be the first and only manifestation of the disease.

Incidental Detection of Dual Spinal Meningiomas on 68 Ga-DOTATATE PET/CT Masquerading as Metastatic Disease in a Patient With Pulmonary Carcinoid Tumor.

ABSTRACT: Simultaneous occurrence of multiple meningiomas of the spine appearing at different neuroaxial levels is extremely rare event. We present the scintigraphic findings of incidentally detected multiple meningiomas of the spine on 68 Ga-DOTATATE PET/CT during the evaluation of a patient with pulmonary carcinoid tumor. These scintigraphic findings could result in a "false-positive" interpretation by exhibiting highly increased uptake similar to that of metastases of neuroendocrine neoplasm. Nuclear medicine physicians should be aware of this potential pitfall in somatostatin receptor imaging to prevent misinterpretation.

The Usefulness of Short-Interval Sequential FDG PET/CT Studies in Defining the Benignity of Hypermetabolic Lipomatous Tumor.

ABSTRACT: We present an interesting case of incidentally detected lipomatous tumor in an oncological patient that could result in a false-positive interpretation by exhibiting intense FDG activity similar to that of a malignant neoplasm. Careful evaluation of FDG uptake changes on sequential short-interval PET/CT studies was helpful in defining the benign nature of the tumor as the hypermetabolism was gradually disappearing obviating the need for a major surgery.

Progressive Transformation of Germinal Centers Simulating Malignant Axillary Lymphadenopathy in a Breast Cancer Patient on FDG PET/CT.

ABSTRACT: A 64-year-old woman with breast cancer underwent FDG PET/CT for follow-up. The study revealed highly increased FDG uptake in newly diagnosed enlarged axillary lymph nodes, which were worrisome for malignancy. Histopathology revealed a rarely diagnosed benign disease of progressive transformation of germinal centers mimicking malignant lymphadenopathy. As imaging findings of this entity, which usually involves the axillary and cervical areas, have been reported in very few studies, nuclear medicine physicians should be familiar with this potential "false-positive" FDG uptake representing an interpretative pitfall, especially during evaluation of breast cancer patients.

Incidental Detection of Radiotracer Uptake in Spindle Cell Lipoma on 18 F-PSMA PET/CT.

ABSTRACT: An 84-year-old man underwent 18 F-prostate-specific membrane antigen (PSMA) PET/CT for staging of a newly diagnosed prostate adenocarcinoma. PET/CT revealed high 18 F-PSMA uptake in a thigh mass, which was initially suspected for a metastasis. Histopathology revealed a rare entity of spindle cell lipoma, which should be added to the reported list of neoplasms that can show "false-positive" PSMA uptake during evaluation of patients with prostate carcinoma representing a potential interpretative pitfall.

Radioiodine Uptake in Incidentally Detected Neuroendocrine Tumor: Correlative Imaging With FDG PET/CT and 68 Ga-DOTATATE PET/CT.

ABSTRACT: Radioiodine whole-body scintigraphy has long been used for detection of differentiated thyroid carcinoma with high avidity in functioning thyroid tissues. However, uptake is not completely specific, and "false-positive" uptake in nonthyroidal tumors have rarely been reported. Herein, we present a case of incidentally detected neuroendocrine tumor showing high radioiodine uptake initially suspected to be thyroid metastasis. Correlative imaging with FDG PET/CT and 68 Ga-DOTATATE PET/CT is presented, and literature survey is discussed. We conclude that neuroendocrine tumor should be added to the reported list of neoplasms that can show "false-positive" uptake representing a potential interpretative pitfall.

[NUCLEAR MEDICINE AND MOLECULAR IMAGING: FROM BASIC SCIENCE TO THE FRONT IN INNOVATIVE IMAGING AND TREATMENT].

INTRODUCTION: In recent years, nuclear medicine has become a diverse and central profession that influences the diagnosis and treatment of patients with diseases from all fields of medicine. Imaging through nuclear medicine is a significant step in the process of making therapeutic decisions and evaluating patients with malignancy, infectious or inflammatory process, heart problems, neurological disorders and more. The advantages of diagnostic methods from the field of nuclear medicine arise from their non-invasiveness and from the possibility of providing functional and metabolic information at a very early stage during the course of the disease. In the last two decades, hybrid imaging devices, PET-CT (positron emission tomography (PET)-computed tomography (CT)) and then SPECT-CT (single-photon emission computerized tomography (SPECT) - computed tomography (CT)) and PET-MRI (positron emission tomography (PET)- magnetic resonance imaging (MRI)) have been developed. Thereby, the field has undergone a major revolution accompanied by a significant increase in the volume of scans thanks to the improved diagnostic accuracy possible with the latest imaging devices. Recently, another breakthrough has occurred with the successful implementation of a unique method of treatment in nuclear medicine, Theranostics. This is just the beginning. More accurate and faster digital imaging devices have been developed with the ability to reduce patient exposure to radiation, state-of-the-art molecular imaging markers have been developed and new theranostics medications are being developed. Along with the development of artificial intelligence tools, further significant changes are expected to take place in this high-tech field. The main purpose of the review is to provide a source of information to the reading public, even if they are unfamiliar with the subject, for innovations in this field and demonstrating the role of nuclear medicine in diagnosing a number of diseases and planning personalised medical treatment for patients with a view on nuclear medicine in Israel.

Incidental Detection of Radiotracer Uptake in Intracranial Dermoid Cyst on 18F-Prostate-Specific Membrane Antigen PET/CT During Staging for Prostate Carcinoma.

ABSTRACT: A 68-year-old man underwent 18F-prostate-specific membrane antigen (PSMA) PET/CT for staging of a newly diagnosed prostate adenocarcinoma. Unexpectedly, PET/CT revealed high focal 18F-PSMA brain uptake, which initially was suspected for a brain metastasis. Corresponding CT and MRI scans revealed characteristic imaging features of an intracranial dermoid cyst at this site. This is an exceptional location for a dermoid cyst, which had been followed up conservatively with no substantial changes. This case shows that dermoid cyst should be added to the reported list of benign neoplasms that shows "false-positive" PSMA uptake during evaluation of patients with prostate carcinoma, representing a potential interpretative pitfall.

Incidental Detection of Malignant Melanoma Brain Recurrence on 68Ga-Prostate-Specific Membrane Antigen PET/CT.

A 76-year-old man with a prior medical history of resected malignant melanoma of the skull underwent Ga-prostate-specific membrane antigen (PSMA) PET/CT due to rising tumor markers of a known prostate carcinoma. Unexpected high Ga-PSMA brain uptake was encountered around the surgical cavity in the skull with initially no specific structural changes on anatomical imaging. Successive CT and MRI eventually revealed local melanoma brain recurrence at this site. This interesting case demonstrates the diagnostic potential of Ga-PSMA PET/CT imaging for detection of malignant melanoma brain recurrence.

Post Contusion Breast Hematoma Mimicking Malignancy on FDG PET/CT.

A 32-year-old woman was treated for breast carcinoma. Posttreatment FDG PET/CT scan revealed complete response, but in the contralateral breast, unexpected incidental intense FDG uptake was seen with a differential diagnosis of both malignant and benign causes. Medical history revealed recent breast contusion. The lesion was further evaluated by mammogram and ultrasound, which were compatible with deep breast bruise. Histopathology showed no malignancy. Subsequent FDG PET/CT study showed breast uptake normalization. This case shows that postcontusion breast hematoma can cause a potential pitfall mimicking breast malignancy on FDG PET/CT.

FDG PET/CT of Mediastinal Epithelioid Hemangioendothelioma.

Epithelioid hemangioendothelioma is a rare low- to intermediate-grade malignant vascular neoplasm with a variable clinical course and currently no standardized treatment. We present a case of a 65-year-old woman diagnosed as having mediastinal epithelioid hemangioendothelioma, a location which is very exceptional. FDG PET/CT was more sensitive than CT for staging, revealing intense FDG uptake in the primary tumor and in the metastatic disease. Despite high FDG uptake, the disease was stable with no further specific treatment. Only few reports utilizing FDG PET/CT are available; review of the literature on this subject is included.

68Ga-DOTATATE PET/CT in Focal Fatty Sparing of the Liver.

Ga-DOTATATE imaging is commonly used for the detection of metastatic disease in neuroendocrine tumors. We present a case of a 69-year-old woman postsurgery for lung carcinoid tumor in which sequential follow-up Ga-DOTATATE PET/CT studies identified focal hepatic uptake that was presumed to represent a liver metastasis. However, correlative imaging with MRI revealed a focal fatty sparing of the liver composed of benign hepatic parenchyma at that area accompanied with diffuse liver steatosis in the background of the "pseudolesion." This report demonstrates a potential "false-positive" hepatic finding that can strikingly mimic a metastasis in neuroendocrine tumor imaging.

Postchemotherapy Histiocyte-Rich Pseudotumor of the Spleen Simulating Residual Disease in a Patient With Non-Hodgkin Lymphoma on FDG PET/CT.

A 64-year-old man was treated with multiagent chemotherapy owing to high-grade non-Hodgkin lymphoma presenting as a bulky disease involving the spleen. Interim and posttreatment sequential FDG PET/CT scans revealed a residual splenic mass showing markedly intense FDG uptake suspected of a residual viable lymphoma. To definitely decide about the appropriate treatment, a laparoscopic splenectomy was performed. Histopathologic specimen was compatible with the rare diagnosis of postchemotherapy histiocyte-rich pseudotumor of the spleen, a potential pitfall simulating viable disease on FDG PET/CT.

18F-FDG PET/CT in Intramuscular Mantle Cell Lymphoma With Elongated Lymphomatous Neurovascular Extension.

Skeletal muscle involvement by lymphoma is rare, particularly for mantle cell lymphoma. We describe a 65-year-old man who presented with a rapidly growing left thigh mass. FDG PET/CT characterized the mass as malignant. Interestingly, an unusual hypermetabolic elongated tumorous extension was demonstrated arising from the intramuscular mass disseminating alongside the neurovascular bundle of the thigh up to the groin. Histopathology revealed intramuscular mantle cell lymphoma. In this case, we aim to highlight this interesting FDG PET/CT imaging finding, which can serve as a clue allowing one to strongly suggest lymphoma as the leading diagnosis.

Evolution of a Schmorl's Node and a Degenerative Osteophyte on Sequential 68Ga-DOTATATE PET/CT Scans: Potential Pitfalls in Neuroendocrine Tumor Imaging.

Schmorl's node (SN) arises from the herniation of the nucleus pulposus of the disc through the cartilaginous endplate into the body of the vertebra. Our report describes a patient with carcinoid tumor who underwent a series of Ga-DOTATATE PET/CT scans for follow-up, demonstrating gradually increasing focal vertebral uptake in absence of CT abnormality, suspicious for a metastasis. Both CT and MRI eventually revealed classical findings of a SN. Also observed in the same vertebra is a degenerative osteophyte showing intense Ga-DOTATATE uptake. This interesting case shows 2 benign spinal lesions, which potentially can simulate bone metastasis in patients with neuroendocrine tumors.

FDG PET/CT of Cardiac Angiosarcoma With Pulmonary Metastases.

We present a case of an adolescent girl with a cardiac mass which was characterized as malignant on FDG PET/CT. In addition, FDG PET/CT revealed multiple hypermetabolic pulmonary lesions. The final diagnosis was primary cardiac angiosarcoma with pulmonary metastases, a rare malignancy especially in female patients at this age group. We emphasize the potential role of FDG PET/CT in patients with a cardiac neoplasm and present a literature review of FDG uptake in benign versus malignant cardiac tumors.

Technical Pitfall in 68Ga-Prostate Specific Membrane Antigen Imaging: Altered Biodistribution Caused by Free 68Ga-Citrate Due to Radiolysis Showing Increased Vascular Activity.

As with any new molecular imaging modality, accurate characterization of abnormalities on Ga-PSMA PET/CT imaging can be accomplished only if one is aware of the normal distribution pattern, physiological variants, and potential sources of false imaging findings. Altered biodistribution can have a significant impact on scan interpretation. Presented here is a rare case in which radiopharmaceutical radiolysis occurred causing excessive free Ga-citrate showing as an increased vascular activity. As Ga-PSMA PET/CT imaging is a relatively new imaging technique, it is important to be aware of such a potential technical pitfall in clinical practice in order to prevent scan misinterpretation.

Peliosis Hepatis Simulating Metastatic Liver Disease on FDG PET/CT.

A 20-year-old man with gastrointestinal symptoms and weight loss underwent FDG PET/CT, which revealed multiple hypermetabolic hepatic lesions concerning for metastatic liver disease. The outcome of liver biopsy was consistent with the diagnosis of peliosis hepatis which is a rare benign disease characterized by multiple blood-filled cystic spaces in the hepatic parenchyma. The findings of peliosis on FDG PET/CT are not well reported in the literature. These interesting images emphasize the importance of including peliosis hepatis in the differential diagnosis of multiple hypermetabolic hepatic lesions on FDG PET/CT, which could simulate malignancy.