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.

Incidental Detection of Metastatic Malignant Melanoma on 68Ga-Prostate-Specific Membrane Antigen PET/CT Imaging: Correlative Imaging With FDG PET/CT and Review of the Literature.

An 80-year-old man with suspected recurrent prostate carcinoma underwent Ga-PSMA PET/CT, which showed enlarged axillary lymph nodes with intensely increased Ga-PSMA uptake, an atypical site for prostate cancer metastasis. Fine-needle aspiration biopsy revealed metastatic malignant melanoma. FDG PET/CT revealed congruent intense FDG uptake. Therefore, malignant melanoma should be included in the list of malignancies that can be seen positive on Ga-PSMA PET/CT. In unclear Ga-PSMA PET-positive lesions, further clarification with other imaging techniques or biopsy is mandatory to avoid scan misinterpretation. Review of the literature revealed other non-prostate cancer causes of elevated PSMA uptake classified into neoplastic and nonneoplastic conditions.

Dilated Internal Thoracic Vertebral Venous Plexus Simulating Bone Metastases on FDG PET/CT.

A 42-year-old woman with a newly diagnosed malignant thymoma underwent FDG PET/CT, which demonstrated an increased uptake in anterior mediastinal tumor and several pleural masses in the right hemithorax, compatible with "drop metastases." In addition, contrast-enhanced CT images showed hyperdense abnormality in T2 vertebral body, congruent with intensely increased FDG uptake, raising suspicion of skeletal metastasis. This is a rare but important potential pitfall either in CT and FDG PET/CT-a "false-positive" bony lesion not attributed to skeletal metastasis but to dilated internal thoracic vertebral venous plexus associated with collateral circulation due to superior vena cava syndrome.