18F- FDG-PET/CT for the diagnosis of tumor thrombosis.

BACKGROUND: Venous thromboembolism is a well-recognized and relatively frequent complication of malignancy, whereas tumor thrombosis is a rare complication of solid cancers. The correct diagnosis of tumor thrombosis and its differentiation from VTE can alter patient management and prevent unnecessary long-term anticoagulation treatment. OBJECTIVES: To evaluate the contribution of 18F-fluorodeoxyglucose positron emission tomography/computed tomography to the diagnosis of tumor thrombosis and its differentiation from VTE. METHODS: PET/CT scans from 11 patients with suspected tumor thrombosis were retrospectively evaluated. Suspicion arose from positive PET/CT in eight cases, or from findings on contrast-enhanced CT in three patients. Criteria for positivity of PET/CT included increased focal or linear uptake of 18F-FDG in the involved vessel. Findings were categorized as PET/CT positive, or PET/CT negative and compared to contrast-enhanced or ultrasound Doppler, pathology where available, and clinical follow-up. RESULTS: Eight occult tumor thromboses were identified by PET/CT-positive scans. Underlying pathologies included pancreatic, colorectal, renal cell, and head-neck squamous cell carcinoma, as well as lymphoma (4 patients). Three thrombotic lesions on contrast-enhanced CT were PET/ CT negative, due to VTE (2 patients) and leiomyomatosis. Accuracy of PET/CT to differentiate between tumor thrombosis and benign VTE was 100% in this small study. CONCLUSIONS: Contrast-enhanced CT defines the extent of thrombotic lesions, while the functional information from PET/CT characterizes the lesions. It appears that PET/CT may be helpful in the diagnosis of occult tumor thrombosis and its differentiation from VTE.

Yttrium-90-ibritumomab tiuxetan (Zevalin) combined with high-dose BEAM chemotherapy and autologous stem cell transplantation for chemo-refractory aggressive non-Hodgkin's lymphoma.

OBJECTIVE: To determine the safety and outcome following standard-dose ibritumomab tiuxetan followed by BEAM high-dose chemotherapy and autologous stem cell transplantation (ASCT) in patients with chemo-refractory aggressive non-Hodgkin's lymphoma. PATIENTS AND METHODS: The study included 23 patients, median age 55 years (range, 35-66) with chemo-refractory lymphoma, either primary refractory (n = 11) or in refractory relapse (n = 12). Rituximab 250 mg/m(2) followed by ibritumomab tiuxetan 0.4 mCi/kg were given on day -14 and high-dose BEAM chemotherapy started on day -6. RESULTS: All patients engrafted. Twenty-one patients are evaluable for response; 11 achieved CR, 9 achieved PR, 5 of whom converted to CR with additional radiation therapy (overall CR rate 76%). With a median follow-up of 17 months (range, 4-27) 16 patients are alive and 12 are progression-free. The estimated 2-year overall and progression-free survival are 67% (95% CI, 46-87%) and 52% (95% CI, 31-72%), respectively. The day-100 rate of treatment-related mortality was 9% (95% CI, 2-33%) and the 2-year cumulative incidence of relapse was 31% (95% CI, 17-57%). Extensive prior therapy (>3 lines), high LDH and IPI score at ASCT, bulky disease, and progression during last chemotherapy were risk factors for reduced survival. CONCLUSION: Ibritumomab tiuxetan-BEAM and ASCT is relatively safe and may improve outcome in patients with refractory lymphoma. Although excess nonrelapse mortality can not be ruled out, relapse rate was relatively low, resulting in improved outcome. Standard-risk patients with chemo-sensitive disease may also benefit from ibritumomab tiuxetan-BEAM and ASCT. This hypothesis merits further study in larger-scale prospective randomized studies.

Combined increased and decreased skeletal uptake of F-18 FDG.

Increased uptake of F-18 FDG is the general mainstay of diagnosis, because it indicates hypermetabolic foci of pathology. This case, describing a patient with relapsing lymphoma, represents the diagnostic dilemmas of both locally decreased and diffusely increased uptake in the skeleton.

Low-dose recombinant human thyrotropin-aided radioiodine treatment of large, multinodular goiters in elderly patients.

OBJECTIVE: We aimed to assess low-dose recombinant human thyroid-stimulating hormone (rhTSH)-aided, fixed-activity radioiodine therapy of large, multinodular goiters (MNGs) in elderly patients with comorbidities. DESIGN: This was a short-term, observational study. METHODS: We measured 24-h thyroid radioiodine uptake (RAIU) of 2 microCi 131-iodine at baseline and 24 h after intramuscular injection of 0.03 mg rhTSH in 17 patients (aged 60-86 years, 12 women), who subsequently received 30 mCi 131-iodine 24 h after an identical rhTSH injection. TSH and free thyroxine (FT4) were measured at baseline and days 10, 30 and 90 after therapy. Thyroid volume was assessed by computed tomography at baseline and day 180. RESULTS: rhTSH, 0.03 mg, significantly increased mean 24-h thyroid RAIU from 25.8% +/- 10.3% to 43.3% +/- 8.4% (68% relative increase; t(16) = -8.43, P < 0.001). The proportion of patients overtly or subclinically hyperthyroid (TSH < 0.5 mU/l) decreased from 71% (12/17) at baseline to 19% (3/16) at 3 months. Mean serum FT4 peaked at slightly above normal range, 25.9 +/- 7.7 pmol/l (46% over baseline) and was 21% under baseline levels at 3 months. Mean estimated thyroid volume fell 34% from baseline to 6 months (170.0 +/- 112.8 to 113.1 +/- 97.5 ml; P < 0.01). Symptomatic relief, improved well-being, and/or reduction or elimination of antihyperthyroid medication were seen in 76% of patients. Three (18%) patients had transient neck pain or tenderness, or palpitations; one had transient asymptomatic thyroid enlargement; and three (18%) became hypothyroid by 3 months. CONCLUSIONS: Intramuscular rhTSH, 0.03 mg, followed 24 h later by 30 mCi 131-iodine, is a safe, effective and convenient treatment for MNG in elderly patients with comorbidities.

Experience with somatostatin receptor scintigraphy in the management of pulmonary carcinoid tumors.

BACKGROUND: Somatostatin receptor scintigraphy has been used widely for the evaluation of neuroendocrine tumors in the gastrointestinal tract. Its use for detecting and staging thoracic carcinoids is only sporadically reported. OBJECTIVES: To evaluate the possible roles of SRS in the management of proven or suspected pulmonary carcinoids. METHODS: We conducted a retrospective study of all patients undergoing SRS for known or suspected pulmonary carcinoids in a tertiary referral center during a 10 year period. During this period 89 patients underwent resection of pulmonary carcinoids and SRS was used for detection, staging or localization purposes in 8 of them (9%). Scans were labeled true positive, true negative, false positive, or false negative in comparison with histologic or follow-up results. RESULTS: SRS was true positive in 6/6 lung locations; true positive in 2/8, true negative in 4/8 and false positive in 2/8 lymph node locations; and true positive in 1/8, true negative in 6/8 and false negative in 1/8 distant locations. The sensitivity, specificity, positive and negative predictive values and accuracy were 90%, 83%, 83%, 91% and 87% respectively. The scans were strongly positive in the tumors and involved lymph nodes. SRS correctly localized an occult secreting pulmonary carcinoid. Granulomatous and reactive lymph nodes showed increased uptake. SRS was accurate in ruling out distant metastases. CONCLUSIONS: SRS is effective for visualizing and localizing pulmonary carcinoids. It assists in the staging of these tumors by detecting lymph node involvement and confirming or ruling out distant metastases. Inflammatory areas in the lung or lymph nodes may be falsely positive.

The role of indirect radionuclide cystography during the acute phase of pyelonephritis in young women.

OBJECTIVE: To review our experience using dynamic 99mTc-diethylenetriamine penta-acetic acid renal scintigraphy combined with indirect radionuclide cystography (IRC) in the acute phase of pyelonephritis, as a possible alternative to the conventional imaging, as investigating acute pyelonephritis usually includes imaging the upper urinary tract during the acute phase, to exclude obstruction, and delayed voiding cysto-urethrography (VCUG) when underlying vesico-ureteric reflux (VUR) is suspected. PATIENTS AND METHODS: Between 1997 and 1999, 47 young women (median age 22 years, range 18-37) were hospitalized for acute pyelonephritis. The combined study was used during the acute phase of the disease, usually within 24 h of hospitalization. The principle of IRC is based on the reappearance of radioactivity in the ureters or kidneys after previously detecting renal clearance of an intravenously injected radioisotope. The increase in radioactivity over the ureters or kidneys indicates VUR. The subsequent follow-up included VCUG, after recovery and at least 6 weeks after discharge. RESULTS: Overall, 47 patients had early IRC studies; obstruction of the urinary tract during the acute phase of the disease was excluded in all. In 13 (28%) of the patients early IRC studies showed VUR involving 21 upper tract units. The renal parenchymal scan was impaired in 17 (36%) patients, and six of these 17 also had detectable concomitant reflux on IRC. Overall, 24 IRC studies (51%) were considered positive, showing VUR, renal parenchymal pathology or both; 23 (49%) were normal. Follow-up VCUG was used in 32 patients (68%); only three (9%) detected VUR. All of the patients with VUR on follow-up VCUG had also had an abnormal early IRC study, showing either reflux (two) or findings suggestive of pathological renal parenchyma (one). CONCLUSIONS: In addition to the well-established role of renal scintigraphy in excluding obstruction of the collecting system, early IRC is characterized by high sensitivity and accurate negative predictive value for detecting VUR. It can therefore be used to screen adults presenting with acute pyelonephritis for the presence of VUR. Patients with an abnormal IRC require follow-up VCUG after complete recovery, while those with a negative study may be managed expectantly, with no further radiological evaluation. This proposed strategy may avoid up to half of the delayed VCUG studies, preclude the related inconvenience, and substantially reduce the costs.

Malignant bronchial carcinoid tumor metastatic to the pituitary in a thyroid carcinoma patient: successful treatment with surgery, radiotherapy and somatostatin analog.

A carcinoid pituitary metastasis is very rare, and is reported scarcely in a few patients. We describe an unusual case of metastatic atypical bronchial carcinoid to the anterior pituitary gland in a 47-year-old male who presented with bitemporal hemianopsia and hypopituitarism. His primary bronchial carcinoid was resected two years previously. Foci of metastatic papillary thyroid carcinoma were also identified in the lung resected for the bronchial carcinoid. He thereby underwent total thyroidectomy followed by radioiodine ablative treatment. Transsphenoidal partial removal of the suprasellar mass was performed, and atypical carcinoid metastasis was identified. He received conventional fractionated sellar radiotherapy, which was supplemented with octreotide (Sandostatin LAR) injections following a positive pituitary uptake on octreotide scan. This treatment suppressed his elevated 5-HIAA urinary excretion to a normal level. His vision has returned to normal and the pituitary mass diminished in size.