Promising Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Human Immunodeficiency Virus Associated Non-Hodgkin's Lymphoma.

This case report explores the potential role of FDG PET/CT in HIV -associated systemic non-Hodgkin's lymphoma (HIV-NHLs). In our locality, there are a cumulative total of 5523 reported HIV infections cases since 1984. We reported a case of HIV-related Burkitt's lymphoma (BL) and a case of diffuse large B-cell lymphoma (DLBCL) that underwent PET/CT examination in our PET centre. In HIV-NHLs patients, we must be reminded that not all hypermetabolic foci represent lymphomatous lesions. There is a close correlation between the pattern of lymphoid tissue activation in FDG PET/CT and HIV progression in patients without HIV-related malignancy. The unique patterns of lymphoid tissue activation observed in HIV-infected patients have great clinical implications. Secondly, HIV-infected patients are prone to suffer from opportunistic infections due to immunosuppression, particularly in those with high levels of HIV viral loads. FDG PET/CT cannot reliably differentiate metabolic active lymphoma from other benign diseases such as inflammation in the context of low CD4 count and high viral loads. In those cases, benign markedly hypermetabolic foci can be erroneously interpreted as lymphoma, particularly in those normal-sized lymph nodes. Furthermore, FDG PET/CT may be useful for assessing the efficacy of HAART in suppressing HIV replication and detecting its complication such as lipodystrophy. FDG PET/CT may play a potential useful role in staging and management of HIV -associated systemic non-Hodgkin's lymphoma. Plasma variables such as viral loads and CD4 count must be taken into account during image interpretation. FDG PET/CT as a potential useful tool for diagnosis, treatment response assessment and disease relapse detection in HIV -associated systemic non-Hodgkin's lymphoma worth to be further explored.

Prevalence of detecting unknown cerebral metastases in fluorodeoxyglucose positron emission tomography/computed tomography and its potential clinical impact.

To determine the prevalence of incidental finding of unknown cerebral metastases and explore the clinical impact of detecting unknown brain metastases among individuals underwent whole body fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) with brain included in field of view. A retrospective review of 1876 patients who underwent whole body PET/CT examination in our clinical PET center for oncological evaluation from January 2009 to September 2009 was performed. The total number and prevalence of unknown brain metastases detected by PET/CT were calculated. Patients diagnosed with cerebral metastases by PET/CT were further analyzed via the electronic patient record system for relevant clinical and radiological findings. Positive predictive value of PET/CT for the diagnosis of cerebral metastases was calculated with reference to contrast enhanced magnetic resonance imaging (MRI) or contrast enhanced CT. Of the 1876 subjects, 71 patients (3.8%) were diagnosed with cerebral metastases by PET/CT. 31 patients were already diagnosed with brain metastases before PET/CT. Among the 40 patients with unknown brain metastasis, 24 (60.0%) underwent either MRI (n = 5) or CT (n = 19) after PET/CT, of which 17 patients were confirmed with cerebral metastases. The true positive rate was 70.8% (17/24), while the false positive rate of PET/CT was 29.2% (7/24). Nearly 94.1% (16/17) patients with confirmed cerebral metastases on MRI or CT had subsequent change in management. Among the remaining 16 patients with positive findings of cerebral metastases without further radiological correlation, 43.8% (7/16) patients had change in management after PET/CT. A total of 57.5% (23/40) patients had change in management after PET/CT. The point prevalence of detecting unknown cerebral metastases by PET/CT was 2.1% (40/1876). 94.1% patients with newly diagnosed brain metastases confirmed with either MRI or CT received immediate treatment for cerebral metastasis in this retrospective study. PET/CT demonstrated significant clinical impact by identifying cerebral lesions with mass effect and hence that timely treatment was offered.

Thyrotoxicosis: a rare presenting symptom of Hurthle cell carcinoma of the thyroid.

Hurthle cell carcinoma of the thyroid is a rare type of thyroid neoplasm. The most common clinical presentation is a single palpable thyroid nodule. The neoplasm typically presents as a nonfunctioning or cold nodule on a Tc-99m sodium pertechnetate or radioiodine thyroid scan. We report a case of Hurthle cell carcinoma of the thyroid in a woman presenting with thyrotoxicosis. The Tc-99m thyroid scan was also interesting in that the nodule was a hot or hyperfunctioning area, resulting in a rare scintigraphic finding in a rare tumor. Clinicopathologic aspects and related issues are further discussed.

Primary hyperparathyroidism in Hong Kong: an analysis of 44 cases.

Primary hyperparathyroidism is increasingly being diagnosed subsequent to the detection of hypercalcaemia using multichannel auto-analyser screening. This paper provides a local picture of the clinical presentation and management of primary hyperparathyroidism. A retrospective review was conducted of 44 patients with primary hyperparathyroidism who were treated at the Queen Elizabeth Hospital between January 1987 and July 1996. Twenty-five (56.8%) of the patients were asymptomatic. Only three (6.8%) patients gave radiograms that had features indicating primary hyperparathyroidism; seven (15.9%) had renal stones. The patients underwent one or more of the following localisation procedures: computerised tomography, ultrasonography, thallium-technetium subtraction scanning, and technetium Tc 99m sestamibi scanning. The latter method was the most sensitive (64.3%). Ten adenomas that could not be localised by any of these procedures were successfully removed during surgery. Surgery was successful in 94.4% of cases and surgical outcome was comparable to that reported in the literature.

Anticonvulsant activity and selective inhibition of nicotinamide adenine dinucleotide-dependent oxidations by 10-(2-arylimino-3-acetylamino-4-thiazolidonyl) phenothiazines.

Several Several 10-(1-acetyl-4-arylthiosemicarbazido) phenothiazines and their corresponding cyclized 10-(2-arylimino-3-acetylamino-4-thiazolidonyl)phenothiazines were synthetized and characterized by their sharp melting points and elemental analyses. All compounds inhibited nicotinamide adenine dinucleotide (NAD)-dependent oxidation of pyruvate and alpha-ketoglutarate selectively, whereas NAD-independent oxidation of succinate remained unaltered. All phenothiazine derivatives exhibited anticonvulsant activity, which was reflected by the 20-60% protection observed against pentylenetetrazol-induced convulsions in mice. The ability of substituted thiosemicarbazidophenothiazines to inhibit cellular respiratory activity was reduced considerably by cyclization to the corresponding substituted thiazolidinophenothiazines. On the other hand, cyclization generally resulted in increased anticonvulsant activity. Thus, the anticonvulsant activity possessed by these substituted phenothiazines bore no relationship with their ability to inhibit selectively the NAD-dependent oxidations. Selective inhibition of NAD-dependent oxidation of pyruvate and alpha-ketoglutarate in isolated rat brain mitochondria by some 10-(1-acetyl-4-arylthiosemicarbazido) phenothiazines was concentration dependent and competitive in nature.