Differentiated thyroid cancer: Case report of false positive 131I uptake on whole body scintigraphy in a patient with bilateral femur osteonecrosis.

OBJECTIVE: Differentiated thyroid cancer (DTC) is one of the fastest growing cancers worldwide. Despite the generally good prognosis of thyroid carcinoma, about 5% of patients will develop metastatic disease, exhibiting a more aggressive behavior. Radioiodine whole-body scintigraphy (WBS) has been used in the detection of DTC. Radioiodine is a sensitive marker for detection of thyroid cancer; however, radioiodine uptake is not specific for thyroid tissue. It can also be seen in healthy tissue as well as in inflammation, or in a variety of benign and malignant non-thyroidal entities. SUBJECT AND METHODS: The subject of the present case report is a 52 years old man with brain metastatic DTC who received radioiodine therapy and corticosteroids as palliative therapy. Whole-body scintigraphy revealed bilateral iodine uptake of the femur. Corticosteroid therapy is among the most widely recognized risk factor for osteonecrosis, which at the present case had to be recognized as a false positive (iodine-131) 131I uptake in order to avoid diagnostic error. RESULTS: Post therapeutic whole body scintigraphy revealed no uptake in the thyroid bed as well as pathologic uptake of radioiodine in both femurs. The magnetic resonance imaging (MRI) of the femurs combined with the history of long term exposition on high doses of corticosteroids evidenced diagnosis of steroid-induced osteonecrosis of the femurs. CONCLUSION: Radioiodine WBS plays an important role in clinical decision making for the evaluation and the management of patients with DTC. Despite its high range of sensitivity and specificity, a variety of reports of false positive whole body scans has demonstrated a diversity of causes. Comprehension of the physiology of iodine uptake and of the pathophysiology of clinical entities which end up giving false positives scans, provides clinicians a useful tool in order to avoid diagnostic and therapeutic errors as far as DTC is concerned.

Dasatinib associated lymphadenopathy in a chronic myeloid leukemia patient: A case report.

RATIONALE: Dasatinib associated lymphadenopathy (DAL) is a rare adverse event in chronic myeloid leukemia patients (CML). A case of voluminous lymphadenopathy in the context of DAL is presented. PATIENT CONCERNS: A 40-year-old male patient was diagnosed with BCR-ABL1 positive chronic stage CML 2 years ago and achieved complete molecular response on nilotinib, which was switched to dasatinib due to nilotinib intolerance. After 5 months on dasatinib, the patient presented with a large mass in the axillary region. DIAGNOSIS: Common infectious and autoimmune etiologies of lymphadenopathy were ruled out. The positron emission tomography/computed tomography (PET/CT) demonstrated a hypermetabolic lymphadenopathy highly suspicious of lymphoma. The subsequent biopsy excluded lymphoma or extramedullary blastic transformation of CML and revealed reactive lymphadenopathy with mixed (cortical and paracortical) pattern. Clinical history and clinicopathological correlation suggested the diagnosis of DAL. INTERVENTION: Dasatinib was discontinued and the patient remained in close follow-up. TKI treatment with nilotinib was reinitiated. OUTCOMES: Lymphadenopathy resolved clinically at 4 weeks and normalization of PET/CT findings was documented at 9 weeks after cessation of the drug. TKI treatment with nilotinib was reinitiated with good tolerance. LESSONS: DAL may present with voluminous lymphadenopathy consistent with malignancy in clinical and imaging workup. We describe the spectrum of lesions associated with DAL and identify common features with drug-induced lymphadenopathy.

Diagnostic Value of 18F-FDG-PET/CT in Patients with FUO.

Conventional diagnostic imaging is often ineffective in revealing the underlying cause in a considerable proportion of patients with fever of unknown origin (FUO). The aim of this study was to assess the diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in patients with FUO. We retrospectively reviewed 18F-FDG-PET/CT scans performed on 50 consecutive adult patients referred to our department for further investigation of classic FUO. Final diagnosis was based on histopathological and microbiological findings, clinical criteria, or clinical follow-up. Final diagnosis was established in 39/50 (78%) of the patients. The cause of FUO was infection in 20/50 (40%), noninfectious inflammatory diseases in 11/50 (22%), and malignancy in 8/50 (16%) patients. Fever remained unexplained in 11/50 (22%) patients. 18F-FDG-PET/CT scan substantially contributed to the diagnosis in 70% of the patients, either by identifying the underlying cause of FUO or by directing to the most appropriate site for biopsy. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of 18F-FDG-PET/CT for active disease detection in patients with FUO were 94.7%, 50.0%, 84.0%, 85.7%, and 75.0%, respectively. In conclusion, whole-body 18F-FDG-PET/CT is a highly sensitive method for detection of the underlining cause of FUO or for correctly targeting suspicious lesions for further evaluation.

18F-FDG PET/CT in treatment response evaluation of Burkitt lymphoma: complete remission of a peritoneal super scan.

Peritoneal lymphomatosis, defined as the disseminated intraperitoneal lymphomatous infiltration, is a rare presentation usually of non-Hodgkin lymphoma and is associated with aggressive histological subtypes of the malignancy. Recently, the term "peritoneal super scan" has been introduced in positron emission tomography/computed tomography (PET/CT) in a patient with Burkitt lymphoma to describe hypermetabolic lymphomatous involvement of the entire peritoneum, leading to suppression of tracer uptake in organs with otherwise normally increased fluorine-18-fluorodeoxyglucose (18F-FDG) uptake. Herein, we report on a patient with Burkitt lymphoma, initially presenting with a peritoneal super scan in PET/CT demonstrating complete metabolic response to R-CHOP (rituximab, cyclophosphamide, adriamycin, vincristine, and prednisolone) therapy.

[Neuroendocrine tumors: Peptide receptors radionuclide therapy (PRRT)].

Neuroendocrine tumors (neuroendocrine tumors-NET) are a heterogeneous group of neoplasms with a common embryological origin and diverse biological behavior, derived from cells of the neuroendocrine system, the system APUD (amine precursor uptake and decarboxylation). They are characterized by overexpression of all five somatostatin receptors (SSTR1-SSTR5), particularly type 2 (SST2). Surgical resection of the tumor is the treatment option, with a possibility of complete remission in patients with limited disease. Somatostatin analogs (octreotide and lanreotide) are the treatment of choice in patients with residual disease, particularly when it comes to NET non-pancreatic origin. Systemic chemotherapy is administered primarily to patients with poorly differentiated carcinomas. PRRT treatment is recommended in case of non-responsiveness of the disease. The ideal candidates for PRRT are patients with unresectable disease of high and intermediate differentiation. Somatostatine analogs radiolabelled with Indium-111 ((111)In), Yttrium-90 ((90)Y), Lutetium-177 ((177)Lu) and Bismuth-213 ((213)Bi), are selectively concentrated in the tumor cells, causing maximum tissue damage to tumors and with fewer effects on healthy tissue and the immune system. In the current review, it was demonstrated that patients with unresectable grade 1 or 2 disease showed increased PFS (progression free survival) and OS (overall survival), while quality of life was improved after PRRT treatment as compared to somatostatin analogs, chemotherapy and other targeted therapies.