The role of 18 F-FDG-PET/CT in the management of differentiated thyroid cancer.

INTRODUCTION: In previous literature, 18 F-FDG-PET/ CT imaging significantly impacted differentiated thyroid cancer (DTC) therapy. Low thyroglobulin (Tg) levels and negative Iodine-131 (131I) whole-body scan (WBS), along with negative 18 F-FDG-PET/ CT, suggested a lesser likelihood of active illness. Positive 18 F-FDG-PET/CT findings, however, were associated with a variety of signs of local recurrence and regional or distant metastases in patients with suspected WBS. We aim to evaluate the utility of 18 F-FDG-PET/CT in managing DTC patients with negative 131I post-therapy WBS and elevated Tg. MATERIAL AND METHODS: We retrospectively reviewed 55 patients with DTC (76% papillary and 24% follicular). Patients underwent total thyroidectomy or several radioactive iodine (RAI) treatments or both. WBS was performed 5-7 days after RAI treatment. Inclusion criteria were elevated serum Tg, negative anti-Tg auto-antibodies (AbTg) during long-term follow-up, presence of 18F-FDG-PET/CT images, and negative or suspicious WBS. RESULTS: 54% of 18 F-FDG-PET/CTs detected at least one lesion, mainly, cervical lymph nodes (49.9%), mediastinal lymph nodes (40.4%), local recurrence (34%), and bone or tissue metastasis (36.2%). The three major sites of metastasis were lung, bone, and liver. 18 F-FDG-PET/CT identified recurrence or metastasis in 45% of patients with high serum Tg and negative WBS, modifying therapeutic management in half the patients for suitable treatment modality (surgery vs. tyrosine kinase inhibitor). CONCLUSION: The findings redemonstrate that elevated Tg with negative or suspicious WBS necessitates 18 F-FDG-PET/CT for localization of recurrence. 18 F-FDG-PET/CT is useful in managing locally recurrent or metastatic DTC with high Tg levels. It influences treatment and accurately assesses disease severity.

Hepatic granuloma mimicking recurrent lymphoma on 18F-FDG PET/CT in a patient with primary mediastinal diffuse large B-cell lymphoma.

18F-Flurodeoxyglucose (FDG) PET/CT has been considered the modality of choice in detecting, staging, restaging and following-up with lymphoma patients. However, it has an uncertain role in differentiating hepatic lymphomatous relapse from other granulomatous diseases such as in candidiasis or sarcoidosis. Therefore, it is important to correlate the imaging findings with other modalities such as ultrasound, CT scan, MRI, and histology to direct the diagnosis and treatment. We present a case of a 33-year-old woman with large B-cell lymphoma in complete remission following treatment presenting with neutropenic fever following her final cycle of chemotherapy. Ultrasound of the abdomen and enhanced CT scan of the abdomen and pelvis were negative. The FDG PET/CT scan showed multiple FDG-avid hypodense hepatic lesions that were suggestive either of lymphoproliferative involvement or nonmalignant process. However, MRI of the abdomen performed four days later was suggestive of an infectious process, rather than a lymphoproliferative disorder. A subsequent CT-guided biopsy of a hepatic lesion showed granulomatous inflammation, with no evidence of malignancy or Tuberculosis. The patient was started on Caspofungin followed by Fluconazole. After 5 weeks, the clinical condition resolved, and the subsequent FDG PET/CT showed complete resolution of the FDG-avid multiple hepatic lesions.

68Ga-Prostate-Specific Membrane Antigen, A Potential Radiopharmaceutical in PET/CT To detect primary Cholangiocarcinoma.

  68Ga Prostate-specific membrane antigen (PSMA) is an increasingly popular radiopharmaceutical tracer in prostate cancer and is becoming increasingly researched in other cancers such as breast cancer, renal cell carcinoma, glioblastoma multiforme, among others. Cholangiocarcinoma is the second most common primary hepatic malignant tumor; it is an aggressive tumor with a 5-year survival rate of less than 5 %. We herein report a case of primary cholangiocarcinoma detected on 68Ga-PSMA PET-CT conducted as part of follow up for prostate cancer and confirmed by biopsy and immunohistochemistry.

A Review of Viral-Related Malignancies and the Associated Imaging Findings.

OBJECTIVE. Imaging plays an important role in the diagnosis and staging of malignancies. Many common lymphoproliferative and other solid tumor malignancies can be viral-related. CONCLUSION. This review discusses the imaging findings that can be associated with common viral-induced malignancies. Knowledge of these imaging presentations can help narrow the differential diagnosis to reach a specific diagnosis through a precise workup and proper management.

Pediatric Moyamoya Presenting as a Subarachnoid Hemorrhage from a Ruptured Anterior Cerebral Artery Aneurysm.

BACKGROUND: The incidence of Moyamoya disease (MMD)-associated intracranial aneurysms ranges from 3% to 14% in adult patients, whereas this complication has rarely been reported in children. CASE DESCRIPTION: We herein report the first case, to our knowledge, of an extremely rare subarachnoid hemorrhage presentation of a child with a ruptured anterior cerebral artery dissecting aneurysm secondary to a newly discovered, unilateral Moyamoya-like pathology. CONCLUSIONS: MMD-associated aneurysms are extremely rare in children, and hemorrhage may be the initial presentation of the disease. Prompt intervention is essential to exclude the ruptured aneurysm that is at risk of rebleeding because of persistent hemodynamic stress.

Spontaneous epidural hematoma in a child with inherited factor XIII deficiency.

We report the case of a 2-year-old Lebanese male child, known to have congenital factor XIII (FXIII) deficiency, who presented to the emergency department with somnolence and projectile vomiting without any head trauma. He has been on a prophylactic dose of 10 IU/kg of FXIII concentrate every 4 weeks since birth, but he missed his last 2 doses due to shortage of supply. Imaging studies showed an epidural hematoma with a midline shift. The child was started on 20 IU/kg of FXIII replacement, and a left parietal craniotomy was performed immediately. He tolerated the surgery well with an uneventful postoperative course. Previous DNA analysis carried out for the family members detected a small deletion (c.1475-1476delGA) in exon 12 in this child and his eldest brother. This mutation has been previously reported once in another Lebanese child with FXIII deficiency who presented with spontaneous splenic rupture. To the best of our knowledge, this is the first case of acute nontraumatic spontaneous epidural hematoma in a child with congenital FXIII deficiency. Furthermore, patients on FXIII replacement therapy have less bleeding events, thus lifelong adherence to the prophylaxis is essential to decrease the morbidities and the mortalities associated with FXIII deficiency, most notably intracranial hemorrhages.