Newly Diagnosed Primary Gum Lymphoma on FDG PET/CT

Primary Pancreatic Lymphoma on FDG PET/CT

A 69-year-old man underwent FDG PET/CT to evaluate a right upper abdominal mass. The images showed peripherally increased activity with central photopenic region in the head of the pancreas, which was consistent with pancreatic malignancy. Histopathologic findings showed characteristic findings of diffuse large B-cell lymphoma. The activity was diminished on follow-up PET/CT after 8 courses of chemotherapy.

FDG PET/CT Demonstrated Precursor B-cell Lymphoblastic Lymphoma in a Pediatric Patient With Hemophilia B

A 4-year-old boy with history of hemophilia B presented with increasingly enlarged scalp masses. Although they were initially thought as hematomas, unresponsiveness to the therapy lead to suspicion of malignancy, which prompted FDG PET/CT. The FDG PET/CT images demonstrated increased FDG uptake in the scalp masses and cervical lymph nodes. The pathology from the left scalp mass and the left cervical lymph nodes revealed precursor B-cell lymphoblastic lymphoma.

A Rare Case of Neutrophil-Rich, ALK-Negative Anaplastic Large Cell Lymphoma in the Lung Mimicking a Pulmonary Abscess on 18F-FDG PET/CT

A 21-year-old man complained of cough, fever, and hemoptysis for 15 days. Peripheral neutrophil cell (33.8 × 10/L) was markedly increased, and a mass in the left lung was detected by chest radiography. F-FDG PET/CT was referred for characterizing the lesion and found a large mass with multiple cavities in the left lung, which had markedly high uptake of F-FDG, mimicking pulmonary abscess. Surprisingly, the lesion was eventually proved to be neutrophil-rich anaplastic large cell lymphoma. After 4 cycles' chemotherapy, the lesion shrank significantly.

Castleman disease versus lymphoma in neck lymph nodes: a comparative study using contrast-enhanced CT

BACKGROUND

The purpose of this study was to determine the contrast-enhanced CT characteristics for differentiating between Castleman disease (CD) and lymphoma in neck lymph nodes.

METHODS

This retrospective study evaluated the number (solitary or multiple), strength of contrast-enhancement, type of contrast-enhancement, surrounding vessels, contrast-enhanced Hounsfield unit (HU) values, and anatomical distributions of lymph nodes in 34 patients with confirmed CD and 55 patients with newly diagnosed untreated lymphoma. Independent t-tests, receiver operating characteristic (ROC) curve analysis, and chi-square tests were used to evaluate the variables and CT features.

RESULTS

Several significant differences were found between CD and lymphoma. The interval between first contrast-enhanced CT and biopsy/surgery was significantly longer in the CD group (mean 72 ± 105 days, median 60 days) than in the lymphoma patients (mean 30 ± 2 days, median 12 days; p = 0.015). The lymphoma patients presented significantly more often with fatigue and fever (p = 0.023 and p = 0.016 respectively) than did the CD subjects. HU values of nodules after enhancement were significantly higher in the CD patients than in the lymphoma patients. In cases involving multiple lymph nodes, in all the CD cases, all affected nodes were located in only the left or right side of the neck, not bilaterally. ROC analysis showed a significant difference in contrast-enhanced CT attenuation values between lymphoma and CD (p < 0.001, area under the curve = 0.954), with a cut-off value of 92.5 HU. We constructed a decision tree according to these imaging characteristics.

CONCLUSIONS

Contrast-enhanced CT can be useful for differentiating between CD and lymphoma.