Imaging of primary non-Hodgkin's lymphoma of the liver

AIM: To describe the radiological findings in primary liver lymphoma, which is a rare entity, presenting usually as a localized liver mass. MATERIALS AND METHODS: We reviewed retrospectively the imaging findings at presentation, of patients in whom a diagnosis of primary liver lymphoma was finally made histologically. The study period covered a 10-year period between January 1990 and December 1999. There were seven patients, all men, with a mean age of 49.6 years. Each patient presented with hepatobiliary disease without peripheral adenopathy. Imaging prior to diagnosis included ultrasonography (seven patients), computed tomography (seven patients) and magnetic resonance imaging (MRI) (two patients). Appearances during and after aggressive chemotherapy were reviewed. RESULTS: Imaging appearances were of either single or multiple liver lesions simulating liver metastases. On ultrasound all foci of primary hepatic lymphoma (PHL) were hypoechoic relative to normal liver. Computed tomography (CT) showed hypoattenuating lesions in all cases, and two cases showed rim enhancement following contrast administration. The MRI appearances were variable, and no pathognomonic feature of PHL was identified, so that histology was required in all patients to establish the diagnosis. CONCLUSIONS: This paper demonstrates the spectrum of findings encountered on various imaging modalities in PHL. We conclude that although PHL is a rare condition, it should always be considered in the differential diagnosis of liver metastases when no primary tumour is apparent.     

Follicular lymphoma with hepatic accumulation on FDG-PET/CT masquerading IgG4-related disease

Follicular lymphoma is clinically classified as a common type of indolent non-Hodgkin''s lymphoma, and its clinical diagnosis is difficult because B symptoms and elevated soluble interleukin-2 receptor (sIL-2R) levels are less frequent in follicular lymphoma than in other lymphomas. We report a case of follicular lymphoma masquerading immunoglobulin G4-related disease (IgG4-RD) with elevated IgG4 levels. A 67-year-old man presented to our hospital with a 1-year history of deep right supraclavicular and para-aortic lymph node lymphadenopathy on plain computed tomography (CT) findings along with elevated IgG4 levels, and the ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scan showed heterogeneous diffuse FDG uptake in the liver, and FDG uptake was noted at multiple sites in the enlarged right supraclavicular and para-aortic lymph nodes. Excisional biopsy of the right supraclavicular lymph node, performed under general anesthesia, showed a tumor-like structure mimicking a normal germinal center in the lymphoid follicle; immunostaining was positive for B-cell lymphoma 2 and CD10 proteins with some plasma cells stained with IgG, only 30% of them were positive for IgG4, and no marked fibrosis characteristic of IgG4-RD was observed; therefore, follicular lymphoma was diagnosed, and all symptoms, including FDG uptake, improved with rituximab monotherapy. Differential diagnoses of slowly progressive generalized lymphadenopathy over the years with elevated serum IgG4 levels include IgG4-RD, Castleman''s disease, and indolent lymphoma. Multiple accumulation in the liver on FDG-PET/CT, if found, may suggest indolent lymphoma among them.     

Comparison of Positron Emission Tomography and Bremsstrahlung Imaging to Detect Particle Distribution in Patients Undergoing Yttrium-90 Radioembolization for Large Hepatocellular Carcinomas or Associated Portal Vein Thrombosis

PurposeTo compare positron emission tomography/computed tomography (PET/CT) imaging with bremsstrahlung single photon emission computed tomography (SPECT) in patients after yttrium-90 (⁹⁰Y) microsphere radioembolization to assess particle uptake.Materials and MethodsThis prospective study comprised patients with large (> 5 cm) hepatocellular carcinoma (HCC) or tumor-associated portal vein thrombus (PVT), or both. After radioembolization for HCC, patients underwent bremsstrahlung SPECT/CT and time-of-flight PET/CT imaging of ⁹⁰Y without additional tracer administration. Follow-up imaging and toxicity was analyzed. Imaging analyses of PET/CT and bremsstrahlung SPECT/CT were independently performed.ResultsThere were 13 patients enrolled in the study, including 7 with PVT. Median tumor diameter was 7 cm. PET/CT demonstrated precise localization of ⁹⁰Y particles in the liver, with specific patterns of uptake in large tumors. In cases of PVT, PET/CT showed activity within the PVT. When correlated to short-term follow-up imaging, areas of necrosis correlated with regions of uptake seen on PET/CT. Compared with bremsstrahlung imaging, PET/CT demonstrated at least comparable spatial resolution with less scatter. Quantitative uptake in nontreated regions of interest showed significantly reduced scatter with PET/CT versus SPECT/CT (1% vs 14%, P < .001).ConclusionsEvaluation of ⁹⁰Y particle uptake with PET/CT potentially demonstrates high spatial resolution and low scatter compared with bremsstrahlung SPECT/CT. Confirmation of particles within PVT on PET/CT correlates with response on follow-up imaging and may account for the efficacy of radioembolization in patients with PVT.     

Hepatocellular carcinoma of diffuse type: MR imaging findings and clinical manifestations

PURPOSE: To assess MR imaging findings and clinical manifestations of diffuse-type hepatocellular carcinoma (HCC). MATERIALS AND METHODS: We retrospectively reviewed our experience with diffuse HCC from November 1994 to October 2001. MR imaging findings and clinical features were assessed. RESULTS: Twenty-two consecutive patients with diffuse-type HCC (19 men and three women, age range 16-80 years [mean, 52 years]) were identified in a review of liver MR studies. This represented 13% of all patients with HCC imaged during this time period. Diffuse HCC showed a permeative, infiltrative pattern with ill-defined borders and no evidence of convex margination in all cases. At least 50% of the liver volume was involved with tumor. Diffuse-type HCC showed hypointensity in 15 patients, mixed intensity in three, and isointensity in four on T1-weighted images; heterogeneous hyperintensity in 16 patients; and homogeneous hyperintensity in six on T2-weighted MR images. Diffuse-type HCC showed patchy enhancement in 12 patients, miliary enhancement in nine, and minimal enhancement in one on postcontrast early-phase images, and showed heterogeneous wash-out in all patients on postcontrast late-phase images. Proximal portal venous tumor thrombosis was seen in all patients. Serum alpha-fetoprotein (AFP) value was elevated (>10 ng/mL) in 14 of 18 patients, and 13 showed a value greater than 500 ng/mL. The four patients who did not have elevated AFP had tumors which were indistinguishable from those in patients with elevated AFP; they also did not have a distinctive clinical history. CONCLUSION: Diffuse-type HCC was typically seen as an extensive, heterogeneous permeative hepatic tumor, with portal venous tumor thrombosis on MR images in all cases. Early enhancement, observed as patchy in 12 and miliary in nine of 22 patients, was a distinctive imaging feature. Elevated serum AFP value was a common finding; however, 22% had normal values.     

Pulmonary drug toxicity: FDG-PET findings in patients with lymphoma

Objective The objective of this study was to evaluate the prevalence and positron emission tomography (PET) imaging features of pulmonary drug toxicity in patients with lymphoma during or just following chemotherapy. Methods A total of 677 PET scans on 460 patients with lymphoma (351 non-Hodgkin’s lymphoma, 92 Hodgkin’s disease, and 17 both Hodgkin’s and non-Hodgkin’s lymphoma) were performed for the evaluation of chemotherapy response. In 51 patients, abnormal accumulation on both sides of the chest was reported. A review of medical records, ¹⁸fluorodeoxyglucose (¹⁸FDG)-PET scans, and chest computed tomography (CT) was performed, and cases with probable drug toxicity were identified. Inclusion criteria of probable drug toxicity were abnormal but symmetrical FDG accumulation in both lungs seen during or just following the completion of chemotherapy, the abnormal accumulation or corresponding abnormal CT findings resolved on sub sequent studies, exclusion of clinical diagnosis of pneumonia, radiation pneumonitis, or lymphoma involvement. Results In 10 patients (six men and four women, average age 47.3), 2.2% of cases, probable drug toxicity was identified. In all 10 cases, diffuse and subpleural-dominant FDG accumulation was seen on FDG-PET scans, and scattered or diffuse ground-glass opacities were observed on chest CT. Four patients reported symptoms, and six patients did not report any symptoms. Conclusions Diffuse and peripheral-dominant FDG accumulation in the lung, which may represent pulmonary drug toxicity, was not uncommon in patients with lymphoma who underwent chemotherapy. FDG-PET scan might be able to detect pulmonary drug toxicity in asymptomatic patients.     

Composite Cutaneous Lymphoma (Iatrogenic Immunodeficiency-Associated Lymphoproliferative Disorder) in a Patient with Rheumatoid Arthritis Treated with Methotrexate: Staging and Evaluation of Response to Therapy with <Superscript>18</Superscript>F-FDG PET/CT

A 67 year old woman with a 10 year history of rheumatoid arthritis (RA) treated with methotrexate and prednisone, presented with a 2 year history of worsening multiple cutaneous plaques of variable appearance. Two distinct skin lesions were biopsied to reveal a composite cutaneous lymphoma, possibly caused by long term methotrexate therapy. An [18F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) was performed to stage the malignancy, and was later repeated to evaluate response to chemotherapy, which guided subsequent management. We present the PET/CT imaging findings of this very rare iatrogenic (methotrexate induced) immunodeficiency-associated lymphoproliferative disorder.     

Extensive Extranodal Involvement of Rare Sites in Non Hodgkin’s Lymphoma Detected on 18F- FDG PET-CT: A Case Report

We present a case of a 23 year-old male treated for Hodgkin’s lymphoma who developed diffuse large B-cell lymphoma (DLBCL) 8 years after achieving remission. ¹⁸F-fluorodeoxyglucose positron emission tomography computed tomography (¹⁸F-FDG PET-CT) was done, which revealed extensive extranodal involvement of bilateral atria, bilateral kidneys, ileo-caecal junction and left testis along with mesenteric and retroperitoneal lymph nodal involvement. Renal and cardiac lesions were not detected by contrast-enhanced CT. Simultaneous lymphomatous involvement of rare sites such as heart, kidneys and testis in a single patient has not been reported before.     

Imaging of primary adrenal lymphoma: case report and literature review

Primary adrenal lymphoma is very rare, and correct preoperative diagnosis is difficult because of its nonspecific imaging findings. We report a case of bilateral primary adrenal lymphoma, with the largest dimension of 18 cm, which is the largest one reported so far, to our knowledge. Computed tomography (CT) and magnetic resonance (MR) findings were not specific enough to establish a correct diagnosis, but positron emission tomography/CT (PET/CT) showed high fluorodeoxyglucose (FDG) uptake, indicating its malignant nature. We describe the imaging findings and review the related literature to highlight this uncommon entity.     

18F-FDG PET/CT in detection of gynecomastia in patients with hepatocellular carcinoma

ObjectiveWe retrospectively investigate the prevalence of gynecomastia as false-positive 2-[¹⁸F]fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) imaging in patients with hepatocellular carcinoma (HCC).MethodsAmong the 127 male HCC patients who underwent ¹⁸F-FDG PET/CT scan, the ¹⁸FDG uptakes at the bilateral breasts in 9 patients with gynecomastia were recorded as standard uptake value (SUVmax) and the visual interpretation in both early and delayed images.ResultsThe mean early SUVmax was 1.58/1.57 (right/left breast) in nine gynecomastia patients. The three patients with early visual score of 3 had higher early SUVmaxs.ConclusionGynecomastia is a possible cause of false-positive uptake on ¹⁸F-FDG PET/CT images.     

Effects of radiotherapy determined by11C-methyl-l-methionine positron emission tomography in patients with primary cerebral malignant lymphoma

Summary Two cases of histologically proven primary cerebral malignant lymphoma were examined serially with positron emission tomography (PET) using¹¹C-methyl-l-methionine (¹¹C Met). Lesions delineated by¹¹C Met accumulation extended beyond enhancing areas on either X-ray computed tomography (CT) or magnetic resonance imaging. High uptake of¹¹C Met accurately showed biologically active and residual tumours, at a time when disappearance of a contrast-enhancing lesion on CT seemed to indicate involution. PET provides valuable information on the extent of tumour and assessment of radiotherapy in malignant lymphoma.     

18F-FDG PET, combined FDG-PET/CT and MRI for evaluation of bone marrow infiltration in staging of lymphoma: a systematic review and meta-analysis

Background and purpose

Evaluation of bone marrow infiltration is an essential step in the staging of lymphoma. The accuracy of ¹⁸F-fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG PET), combined ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) and magnetic resonance imaging (MRI) in diagnosing bone marrow involvement of lymphoma has never been systematically assessed, and the present systematic review was aimed at this issue.

Methods

MEDLINE, EMBASE, Cochrane library and some other databases, from January 1995 to July 2010, were searched for initial studies. All the studies published in English or Chinese relating to the diagnostic value of ¹⁸F-FDG PET, PET/CT and MRI for patients with bone marrow involvement of lymphoma were collected. We extracted data to calculate sensitivity, specificity, SROC curves and AUC and to test for heterogeneity. The statistic software called “Meta-Disc 1.4” was used for data analysis.

Result

In 32 included studies, PET/CT had the highest pooled sensitivity, 91.6% (95%CI: 85.1, 95.9) and highest pooled specificity, 90.3% (95%CI: 85.9, 93.7). PET/CT also had the highest pooled DOR, 68.89 (95%CI: 15.88, 298.92). The AUC of PET, PET/CT, and MRI were 0.9430, 0.9505 and 0.8764. There was heterogeneity among studies and no evidence of publication bias.

Conclusion

PET/CT was a highly sensitive and specific modality in diagnosing patients with bone marrow involvement in lymphoma. Compared with MRI and PET alone, PET/CT can play important roles in the staging of lymphoma.     

Drug-induced pneumonitis detected earlier by 18F-FDG-PET than by high-resolution CT: a case report with non-Hodgkin’s lymphoma

Drug-induced pneumonitis is a serious and an unpredictable side effect of chemotherapy in patients with malignant lymphoma. We present the case of a 51-year-old man who developed drug-induced pneumonitis during chemotherapy for non-Hodgkin’s lymphoma in which pneumonitis was detected earlier by ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) than by high-resolution computed tomography (HRCT). After five courses of chemotherapy, ¹⁸F-FDG-PET was performed for assessing residual lesions, and diffuse lung uptake was incidentally observed. No symptoms were present, and HRCT performed immediately following PET revealed no abnormalities. Mild dyspnea appeared 3 days after PET, and additional HRCT revealed patchy ground-glass opacities disseminated with the appearance of interlobular septum thickening. Drug-induced pneumonitis was finally diagnosed, and treatment was initiated. ¹⁸F-FDG-PET can be an imaging modality for detecting drug-induced pneumonitis at an extremely early stage in which HRCT is incapable of revealing any abnormal changes.     

Systemic Lupus Erythematosus Associated Pitfalls on <Superscript>18</Superscript>F-FDG PET/CT: Reactive Follicular Hyperplasia,Kikuchi-Fujimoto Disease,Inflammation and Lymphoid Hyperplasia of the Spleen Mimicking Lymphoma

Systemic lupus erythematosus (SLE) is associated with a variety of inflammatory processes that can affect the lymph nodes, brain, kidneys, and spleen. We present two patients with SLE in whom SLE-associated conditions complicated interpretation of ¹⁸F-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) imaging of the lymph nodes and the spleen. The imaging findings mimicked lymphoma, but histopathological evaluation showed benign processes including reactive follicular hyperplasia in the lymph nodes, Kikuchi-Fujimoto disease in perisplenic lymph nodes, and inflammatory changes and lymphoid hyperplasia in the spleen.     

FDG-PET/CT in re-staging of patients with lymphoma

The aim of this study was to evaluate the clinical significance of combined fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) in patients with lymphoma, and to compare the FDG-PET/CT staging results with those of FDG-PET and CT alone. Twenty-seven patients were studied. Each patient had clinical follow-up for >12 months and entered complete follow-up evaluation. Patient-based evaluation showed a sensitivity of 78% for CT alone, 86% for FDG-PET alone, 93% for CT and FDG-PET read side by side, and 93% for combined FDG-PET/CT imaging. Region-based evaluation showed a sensitivity for regional lymph node involvement of 61%, 78%, 91% and 96% respectively. FDG-PET/CT imaging is superior to CT alone (P=0.02) and has additional benefit over FDG-PET alone due to exact anatomical localisation. We conclude that FDG-PET/CT imaging is accurate in re-staging lymphoma and offers advantages over separate FDG-PET and CT imaging.     

Iatrogenic Cushing's syndrome on 18F-FDG-PET/CT: A pitfall in metabolic assessment of oncologic response

Iatrogenic Cushing's syndrome has very well-known stigmata on physical examination but can pose a diagnostic challenge when it rarely presents radiologically. We present a classic albeit rarely encountered imaging appearance of Iatrogenic Cushing's on ¹⁸F-FDG-PET/CT, with diffuse subcutaneous white adipose proliferation and metabolic activation in a 7-year old patient one-month after starting a high dose steroid regimen for lymphoma. There was an extreme shift in the expected FDG biodistribution with dominant localization to the subcutaneous adipose tissue. This metabolic shift led to sub-threshold visceral biodistribution, rendering the scan non-diagnostic with regards to assessment of oncologic response. Aside from detailing the characteristic imaging findings of Iatrogenic Cushing's and its clinical importance, we discuss the physiologic basis of this imaging pattern and the rarer differential diagnosis to consider when this pattern of uptake is encountered on ¹⁸F-FDG-PET/CT.     

Primary Endobronchial Marginal Zone B-Cell Lymphoma of Bronchus-Associated Lymphoid Tissue: CT Findings in 7 Patients

Objective

To investigate CT and ¹⁸F-flurodeoxyglucose (¹⁸F-FDG) positron-emission tomography/CT findings of primary endobronchial marginal zone B-cell lymphoma of the bronchus-associated lymphoid tissue (BALT).

Materials and Methods

From June 2006 through April 2012, seven patients (six female, one male; age range, 21-61 years; mean age, 49 years) were examined who were pathologically diagnosed with the primary endobronchial marginal zone B-cell lymphoma of BALT. We evaluated the locations and characteristics of the lesions on CT and ¹⁸F-FDG-PET/CT scans. The lesions were classified into the following three patterns: 1) solitary intraluminal nodule; 2) several tiny nodular protrusions; and 3) diffuse wall thickening.

Results

A solitary intraluminal nodule was observed in four patients (57.1%), several tiny nodular protrusion in two patients (28.6%), and diffuse wall thickening in one patient (14.3%). The lesions were categorized into 3 major locations: confined to the trachea (n = 3), confined to the lobar bronchus (n = 2), and diffuse involvement of the trachea and both main bronchi (n = 2). All lesions demonstrated homogeneous iso-attenuation as compared with muscle on pre- and post-enhancement scans. Secondary findings in the lungs (n = 3; 42.9%) included postobstructive lobar atelectasis (n = 1), air trapping (n = 1), and pneumonia (n = 1). On ¹⁸F-FDG-PET/CT (n = 5), 4 lesions showed homogeneous uptake with maximum standardized uptake values (mSUV), ranging 2.3-5.7 (mean mSUV: 3.3). One lesion showed little FDG uptake.

Conclusion

Primary endobronchial marginal zone B-cell lymphoma of the BALT manifests as three distinct patterns on CT, with the solitary intraluminal nodule presenting as the main pattern. Most lesions demonstrate homogeneous but weak FDG uptake on ¹⁸F-FDG-PET/CT.     

F-18 FDG PET/CT evaluation of radiotherapy response in rare case of mucosa-associated lymphoid tissue lymphoma

We experienced two cases of mucosa-associated lymphoid tissue (MALT) lymphoma arising at unusual locations and used F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to evaluate their response to radiation therapy (RT). A 62-year-old male with proven prostatic MALT lymphoma and a 43-year-old woman with proven duodenal MALT lymphoma had diffuse FDG uptake in the lesion. Both cases were treated with RT; following FDG, PET/CT showed decreased FDG uptake in each lesion. Neither patient had evidence of recurrence at more than 18 months after RT. FDG PET/CT is useful for indicating the treatment site in MALT lymphoma and in evaluation of therapeutic response following RT.     

女性生殖系统淋巴瘤CT及MRI表现

目的：探讨女性生殖系统淋巴瘤的计算机体层成像（computed tomography,CT）及磁共振成像（magnetic resonanceimaging,MRI）特征,以期提高治疗前的诊断准确度。方法：回顾并分析13例女性生殖系统淋巴瘤患者的CT及MRI资料,其中7例行MRI平扫+增强扫描,6例行CT平扫+增强扫描。结果：13例患者中,弥漫性大B细胞淋巴瘤12例（92.3%）,滤泡性淋巴瘤1例（7.7%）,其中以卵巢受累最多见（6/13,46.2%）,其次是宫颈（5/13,38.5%）和子宫体（2/13,15.4%）。共检查发现14个病灶（MRI和CT各7个）,其中1例卵巢淋巴瘤为双侧受累。所有病灶均为实性肿块,64.3%(9/14)的病灶信号或密度相对均质;35.7%(5/14)的病灶边缘可见小囊变区,均见于卵巢淋巴瘤。行CT扫描的7个肿块中,平扫均表现为等密度肿块,内部未见出血及钙化;行MRI扫描的7个肿块中,表现为T1加权成像（T1-weighted imaging,T1WI）等或稍低信号,T2加权成像（T2-weighted imaging,T2WI）以中等信号为主（6/7...     

Bilateral Tubo-Ovarian Abscess Mimics Ovarian Cancer on MRI and 18F-FDG PET/CT

A 20-year-old woman, who presented with a several-week history of abdominal pain, was referred for magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) after an ultrasound showed complex cystic masses arising from both ovaries. The MRI and ¹⁸F-FDG PET/CT imaging characteristics of the ovarian masses were strongly suspicious for malignancy, and the masses were surgically removed. Histopathological evaluation revealed a bilateral tubo-ovarian abscess, with no evidence of malignancy. This case highlights a potentially serious pitfall in the evaluation of suspicious pelvic masses by ¹⁸F-FDG PET/CT, whereby a complex bilateral tubo-ovarian abscess may mimic the PET/CT imaging characteristics of an ovarian or pelvic malignancy.     

Intravascular large B-cell lymphoma with diffuse FDG uptake in the lung by 18FDG-PET/CT without chest CT findings

We report a rare case of intravascular large B-cell lymphoma (IVLBCL) with diffuse fluorodeoxyglucose (FDG) uptake in the lung by (18)FDG-positron emission tomography/computed tomography (PET/CT). CT showed nodular shadow, whereas diffuse FDG uptake in PET/CT suggested IVLBCL in the lung. A random skin biopsy provided histological evidence of IVLBCL. The patient responded well to combination chemotherapy. Only two cases of IVLBCL in which diffuse pulmonary FDG uptake was demonstrated have been reported previously. FDG-PET/CT plus random skin biopsy may be useful for the early diagnosis of IVLBCL with pulmonary involvement even without convincing radiological findings in the lung.