Beyond the lymph nodes: FDG-PET/CT in primary extranodal lymphoma

Comparison of 18F-FDG PET/CT and conventional methods in diagnosing extranodal natural killer/T-cell lymphoma

Background

The utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in natural killer (NK)/T-cell lymphoma patients is yet to be established. The aim of this study was to investigate the role of PET/CT scanning in detecting NK/T-cell lymphoma.

Methods

We analyzed the PET/CT imaging characteristics of 38 patients with a primary diagnosis of NK/T-cell lymphoma and also compared the ability of PET/CT to detect tumor lesions with conventional methods (CMs) (physical examination, computed tomography (CT) with intravenous contrast, magnetic resonance imaging (MRI), biopsies from primary sites, and bone marrow examinations)and their impact on staging and treatment options. Biopsy and clinical follow-up (including imaging) are the gold standard for diagnosis.

Results

We analyzed PET/CT images of NK/T-cell lymphomas. We found that most of the primary lesions were located in the nasal cavity, with the sinuses and the posterior pharyngeal wall being the most common sites of adjacent invasion. The majority of cases involved cervical lymph nodes, and the distribution of affected lymph nodes between the cervical and extra-cervical regions was random. There was no discernible pattern to the locations of affected tissues and organs across the body. In total, 219 lesions (including 81 nodal lesions and 138 extranodal lesions) tested positive for malignancy. The number of positive lymph node lesions detected by PET/CT and CMs was 79 (97.5 %) and 62 (76.5 %), respectively (P = 0.004). There were 53 (96.4 %) and 46 (83.6 %) cervical lymph nodes detected (P = 0.008), 26 (100 %) and 16 (61.5 %) other lymph nodes detected (P = 0.041)), respectively. The number of positive extranodal lesions detected by PET/CT and CMs was 137 (99.3 %) and 98 (71.0 %), respectively (P = 0.01), and there were no discernible differences in the upper respiratory tract. PET/CT outperformed CMs in the detection of malignant lesions by a significant margin, detecting 79 (98.8 %) extranodal lesions compared to 45 (56.3 %) by CMs (P = 0.034). PET/CT results changed the initial staging in 15.8 % of cases and the treatment plan in 10.5 % of patients.

Conclusion

Our findings indicate that 18F-FDG PET/CT scanning is crucial in identifying tumor lesions, determining staging, and devising treatment strategies for individuals diagnosed with NK/T-cell lymphoma.

Au nano-cone array for SERS detection of associated miRNA in lymphoma patients

Based on Au nano-cone array (Au-NCA) and a three-segment hybridization strategy, a novel SERS biosensor is proposed for the ultrasensitive detection of the microRNA miR-21. The uniform, stable, and reproducible Au-NCA was prepared by the single-layer colloidal ball template method. Subsequently, the target was hybridized with sequence 2. The resulting target-sequence 2 complex was then hybridized with sequence 1 anchored on Au-NCA. Thus, a three-segment sequence complex was formed. SERS measurements can be performed without the need for complex purification and amplification steps. Due to the ability of miR-21 to perform specific complementary hybridization with two sequences, SERS biosensors have superior specificity for miR-21 without interference from other miRNAs. Under the optimal conditions, the SERS biosensor was applied and the limit of detection (LOD) was as low as 3.02 aM. This method has been successfully used to the detection of miR-21 in the serum of lymphoma patients and healthy volunteers. The results are consistent with the traditional test methods. Therefore, this novel SERS biosensor shows excellent clinical translational potential in the detection of lymphoma.

Imaging of Gastrointestinal Tract Ailments

Gastrointestinal (GI) disorders comprise a diverse range of conditions that can significantly reduce the quality of life and can even be life-threatening in serious cases. The development of accurate and rapid detection approaches is of essential importance for early diagnosis and timely management of GI diseases. This review mainly focuses on the imaging of several representative gastrointestinal ailments, such as inflammatory bowel disease, tumors, appendicitis, Meckel's diverticulum, and others. Various imaging modalities commonly used for the gastrointestinal tract, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single photon emission computed tomography (SPECT), and photoacoustic tomography (PAT) and multimodal imaging with mode overlap are summarized. These achievements in single and multimodal imaging provide useful guidance for improved diagnosis, staging, and treatment of the corresponding gastrointestinal diseases. The review evaluates the strengths and weaknesses of different imaging techniques and summarizes the development of imaging techniques used for diagnosing gastrointestinal ailments.

Multimodality imaging evaluation of primary testicular extranodal natural killer/T-cell lymphoma: two case reports

Background

Extranodal natural killer/T-cell lymphoma (ENKTCL) is a distinct pathological entity and accounts for ~10% of T-cell lymphomas. The histological features of ENKTCL include angiodestruction and coagulative necrosis and the association with EBV infection. ENKTCL is typically aggressive and mainly affects the nasal cavity and nasopharyngeal region. However, some patients can present with distant nodal or extranodal involvement such as the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, and testes. Compared to ENKTCL of nasal type, primary testicular ENKTCL is very rare and has a lower age of onset and faster clinical progression, with tumor cell dissemination occurring early in the disease.

Case report

Case 1: A 23-year-old man presented with 1 month of right testicular pain and swelling. Enhancement CT revealed increased density in the right testis, uneven increased enhancement, discontinuity of the local envelope, and multiple trophoblastic vessels in the arterial phase. Testicular ENKTCL was diagnosed by post-operative pathology. The patient underwent a follow-up ¹⁸F-FDG PET/CT imaging 1 month later and found elevated metabolism in the bilateral nasal, left testicular, and right inguinal lymph nodes. Unfortunately, the patient received no further treatment and died 6 months later. Case 2: A 2-year-old male child presented with an enlarged right testicle, MRI showed a mass in the right epididymis and testicular area, which showed low signal on T1WI, high signal on T2WI and DWI, and low signal on ADC. Meanwhile, CT showed soft tissue in the lower lobe of the left lung and multiple high-density nodules of varying sizes in both lungs. Based on the post-operative pathology, the lesion was diagnosed with primary testicular ENKTCL. The pulmonary lesion was diagnosed as hemophagocytic lymphohistiocytosis associated with EBV infection. The child was given SMILE chemotherapy, but pancreatitis was induced during chemotherapy, then he died 5 months later after chemotherapy.

Conclusion

Primary testicular ENKTCL is very rare in clinical practice, typically presenting as a painful testicular mass, which can mimic inflammatory lesions and cause diagnostic challenges. ¹⁸F-FDG PET/CT plays pivotal roles in the diagnosis, staging, evaluation of treatment outcomes and prognosis evaluation in patients with testicular ENKTCL, and it is helpful to assist clinical practice to better formulate individualized treatment plans.

Extranodal NK/T-Cell Lymphoma With Widespread Cutaneous and Subcutaneous Involvement on 18 F-FDG PET/CT

ABSTRACT

Nasal-type extranodal natural killer/T-cell lymphoma is an aggressive rare type of lymphoma that mostly affects the nasal cavity and adjacent areas. However, some patients can present with distant nodal or extranodal involvement including the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, or adrenal glands. Herein, we present a unique case of extranodal natural killer/T-cell lymphoma with widespread cutaneous and subcutaneous involvement on 18 F-FDG PET/CT.

The Role of Pre-therapeutic 18F-FDG PET/CT in Pediatric Hemophagocytic Lymphohistiocytosis With Epstein-Barr Virus Infection

Objective

To evaluate the role of pre-therapeutic ¹⁸F-FDG PET/CT in pediatric hemophagocytic lymphohistiocytosis (HLH) with Epstein-Barr virus (EBV) infection.

Methods

This retrospective study included 29 HLH children (1–16 years) with EBV infection, who underwent pre-therapeutic ¹⁸F-FDG PET/CT from July 2018 to November 2020. Pathology results were considered as the reference standard. These patients were divided into two groups: EBV-induced malignancy-associated HLH (M-HLH, N = 9) and EBV-induced non-malignancy-associated HLH (NM-HLH, N = 20). The regions of interest (ROIs) of the liver, spleen (Sp), bone marrow (BM), lymph nodes (LN), hypermetabolic lesions, liver background (LiBG), and mediastinum (M) were drawn with software 3D-Slicer. The volumetric and metabolic parameters, including maximum standard uptake value (SUV_max), metabolic tumor volume, and total lesion glycolysis of these ROIs, clinical parameters, and laboratory parameters were compared between the two groups. The efficiency of the above parameters in predicting the treatment response and overall survival (OS) was analyzed.

Results

Receiver operating characteristic curve analysis indicated that SUV_max-lesions and SUV_max-LN/M (AUC = 0.822, 0.819, cut-off = 6.04, 5.74, respectively) performed better in differentiating M-HLH from NM-HLH. It had the best diagnostic performance when age was added with the SUV_max-LN/M (AUC = 0.933, sensitivity = 100%, specificity = 85.0%). The presence of extranodal hypermetabolic lesions in multiple organs indicated the M-HLH (P = 0.022). Older age, higher SUV_max-LN and SUV_max-lesions, and the presence of serous effusion were associated with poorer treatment response at the 2nd and 4th week (not reaching partial remission). Multivariate analysis showed that SUV_max-lesions > 7.66 and SUV_max-Sp/LiBG > 2.01 were independent prognostic factors for overall survival (P = 0.025, 0.036, respectively).

Conclusions

¹⁸F-FDG PET/CT could be a valuable technique for identifying the underlying malignancy and predicting prognosis in pediatric HLH with EBV infection. M-HLH could be considered when SUV_max-lesions > 6.04, SUV_max-LN/M > 5.74, and the presence of extranodal hypermetabolic lesions in multiple organs on ¹⁸F-FDG PET/CT. SUV_max-lesions and SUV_max-Sp/LiBG might be independent prognostic factors for OS.

Testicular Diffuse Large B-Cell Lymphoma-Clinical, Molecular, and Immunological Features

Simple Summary

Testicular diffuse large B-cell lymphoma (T-DLBCL) is a rare and aggressive lymphoma entity that mainly affects elderly men. It has a high relapse rate with especially the relapses of the central nervous system associating with dismal outcome. T-DLBCL has a unique biology with distinct genetic characteristics and clinical presentation, and the increasing knowledge on the tumor microenvironment of T-DLBCL highlights the significance of the host immunity and immune escape in this rare lymphoma, presenting in an immune-privileged site of the testis. This review provides an update on the latest progress made in T-DLBCL research and summarizes the clinical perspectives in T-DLBCL.

Abstract

Primary testicular lymphoma is a rare lymphoma entity, yet it is the most common testicular malignancy among elderly men. The majority of the cases represent non-germinal center B-cell-like (non-GCB) diffuse large B-cell lymphoma (DLBCL) with aggressive clinical behavior and a relatively high relapse rate. Due to the rareness of the disease, no randomized clinical trials have been conducted and the currently recognized standard of care is based on retrospective analyses and few phase II trials. During recent years, the tumor microenvironment (TME) and tumor-related immunity have been the focus of many tumor biology studies, and the emergence of targeted therapies and checkpoint inhibitors has significantly modulated the field of cancer therapies. Testicular DLBCL (T-DLBCL) is presented in an immune-privileged site of the testis, and the roles of NF-κB pathway signaling, 9p24.1 aberrations, and tumor-infiltrating immune cells, especially immune checkpoint expressing lymphocytes and macrophages, seem to be unique compared to other lymphoma entities. Preliminary data on the use of immune checkpoint inhibitors in the treatment of T-DLBCL are promising and more studies are ongoing.

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.

Diffuse large B-cell lymphoma relapse presenting as extensive neurolymphomatosis

A 56-year-old woman with a history of diffuse large B-cell non-Hodgkin lymphoma (DLBCL-NHL) in remission for two years presented with weight loss and multifocal sensory/motor symptoms. Magnetic resonance imaging (MRI) of the neuraxis and whole-body FDG PET/CT led to a diagnosis of secondary neurolymphomatosis (NL). MRI demonstrated extensive thickening and enhancement of multiple cranial nerves and peripheral nerve plexuses with corresponding elevated metabolism on FDG PET/CT. Treatment with chemotherapy resulted in complete response on FDG PET/CT and subsequently she underwent autologous stem cell transplantation. NL is a rare manifestation of lymphoma affecting the peripheral nervous system. Nonspecific neuropathic symptoms make clinical diagnosis difficult. Though nerve biopsy is considered the gold standard, MRI and FDG PET/CT are accepted alternatives for making the diagnosis. We review imaging findings in NL, describe the differential diagnosis, and discuss the limitations of the imaging modalities.

Combined positron emission tomography/computed tomography for diagnosis and monitoring of orbital adnexal lymphoma

PURPOSE

Combined whole-body F-18-fluoro-2-deoxyglucose positron emission tomography / computed tomography ([18F]FDG-PET/CT) gives precise information about tumour morphology and metabolism. The standardized uptake value (SUV) allows quantification of tumour metabolism. The diagnostic value of PET/CT in patients with suspected orbital adnexal lymphoma (OAL) was evaluated.

METHODS

Of 21 patients with suspected OAL who underwent combined whole-body PET/CT between 07/2002 and 11/2016, 16 were scanned before and five after orbital biopsy. Histological tumour determination was performed in all cases via biopsy. Correlation between SUV_max and therapeutic status, lymphoma stage (Ann Arbor classification) and histological grading was tested.

RESULTS

All lesions could be depicted by combined whole-body PET/CT. Histology confirmed two malignant T-cell and 18 malignant B cell non-Hodgkin lymphomas as well as one patient suffering from systemic lymphoma with chronic polypoid sinusitis. SUV_max levels of orbital findings were significantly lower after therapy (p < 0.001; Fisher's exact test). Higher stage lymphomas (Ann Arbor classification) expressed significantly higher SUV_max levels (p = 0.014; Fisher's exact test). There was no significant correlation of SUV_max values and histologic grading in this patient collective.

CONCLUSION

Positron emission tomography/computed tomography (PET/CT) depicted vital tumour metabolism of OALs accurately. In cases scanned after orbital biopsy and under systemic therapy, no elevated tumour metabolic activity was expressed. This underlines the reasonable application of PET/CT for therapy monitoring besides whole-body staging. Higher-stage OALs show higher metabolic activity. Yet, for adequate therapy initiation, histology remains indispensable.