Recurrent Marginal Zone Lymphoma with Bone Marrow Involvement Detected by ¹8F-FDG PET/CT and Biopsy: A Diagnostic Challenge.

BACKGROUND Marginal zone lymphoma is a low-grade, B-cell, non-Hodgkin lymphoma. Bone marrow involvement (BMI) of leukemia or lymphoma can usually be displayed in fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (¹8F-FDG PET/CT) with high standardized uptake values (SUV), while diffuse homogeneous ¹8F-FDG bone marrow uptake (BMU) in PET/CT primarily reflects hyperplastic bone marrow status. This report is of a 74-year-old man presenting with anemia and a diagnosis of recurrent marginal zone lymphoma with bone marrow involvement identified with 18F-FDG PET/CT imaging and biopsy. CASE REPORT A 64-year-old man with severe anemia and body weight loss of 7 kg in 1 month was diagnosed with marginal zone lymphoma, stage III, in July 2011. He went into complete remission in April 2012 after 6 cycles of chemotherapy, with Hb restored. Anemia and diffuse homogeneous ¹8F-FDG BMU in PET/CT were then noted during a routine check-up in October 2021, and recurrent disease was established through positive biopsy of subcutaneous nodules and bone marrow. Subsequent complete remission after 6 cycles of combination therapy was validated with pathologically negative BMI, the resolution of the slightly enhanced ¹8F-FDG BMU in PET/CT, and restored hemoglobin. CONCLUSIONS This report has highlighted the importance of follow-up for patients with lymphoma and supports the diagnostic role of ¹8F-FDG PET/CT imaging and the pathological verification in identifying malignant involvement in bone marrow.

Primary MALT lymphoma of the breast: pathological and radiological characteristics.

PURPOSE: Primary Mucosa-associated lymphoid tissue (MALT) lymphoma is a rare diagnosis in the breast, and clinical diagnosis based on radiological features is often challenging. This study aimed to evaluate the clinicopathological, and radiological characteristics of the patients diagnosed with primary breast MALT lymphoma. METHODS: This study examined 18 cases of primary MALT lymphoma of the breast diagnosed at a single tertiary center between January 2002 to December 2020. Medical charts, radiological imaging and original pathology slides were reviewed for each case. RESULTS: All cases were female (gender assigned at birth) and presented with a palpable mass or an incidental imaging finding. Imaging presentation ranged from mammographic asymmetries, circumscribed masses, and ultrasound masses lacking suspicious features. Seventeen cases were biopsied under ultrasound; one received a diagnostic excision biopsy. Microscopic examination of the breast specimens demonstrated atypical small lymphocyte infiltration with plasmacytoid differentiation and rare lymphoepithelial lesions. Immunohistochemistry was performed in all cases and established the diagnosis. Most patients were treated with radiotherapy, and only three were treated with chemotherapy. The median follow-up period was 4 years and 7.5 months, and all patients were alive at the last follow-up. CONCLUSION: Primary MALT breast lymphomas are usually indolent and non-systemic, and local radiotherapy may effectively alleviate local symptoms. Radiological findings show overlap with benign morphological features, which can delay the diagnosis of this unusual etiology. Although further studies involving a larger cohort could help establish the clinical and radiological characteristics of primary breast MALT lymphomas, pathology remains the primary method of diagnosis. TRIAL REGISTRATION NUMBER: University Health Network Ethics Committee (CAPCR/UHN REB number 19-5844), retrospectively registered.

Non-resolving pneumonia: primary pulmonary MALT lymphoma.

Mucosa-associated lymphoid tissue (MALT) lymphoma is an uncommon extranodal low-grade B-cell lymphoma. Pulmonary MALT lymphomas originate from bronchial MALT and are also referred to as bronchial-associated lymphoid tissue lymphomas. MALT lymphomas of the lung are slow-growing tumours and usually present as asymptomatic chronic alveolar opacities visible on chest radiographs or with non-specific pulmonary symptoms. Here we described a case of a male patient in his early 50s with cough and chest pain for 4 years. His CT chest scan showed consolidation in the lingula and left lower lobe. Histopathology of the specimen obtained from cryobiopsy of the lung lesion showed a dense monomorphic lymphoid infiltrate, and immunohistochemistry confirmed the diagnosis of MALT lymphoma. The prognosis of pulmonary MALT lymphomas is good with >80% 5-year survival rates. This case highlights that MALT lymphoma should be considered as a differential diagnosis while evaluating cases with non-resolving consolidation.

MALT Lymphoma in Histologic Transformation: FDG-Avid but Pentixafor-Negative.

ABSTRACT: An 81-year-old woman experienced compression symptoms due to diffuse enlargement of the thyroid gland. The cytopathological results of thyroid fine-needle suggested malignancy. Therefore, she underwent bilateral thyroidectomy. Postoperative pathology indicated mucosa-associated lymphoid tissue (MALT) lymphoma. Three months later, she found a progressively enlarged mass in her neck. The biopsy showed MALT lymphoma with highly aggressive B-cell lymphoma transformation. 18F-FDG PET/CT showed increased metabolism in multiple lymph nodes. However, some of these lymph nodes were negative in 68Ga-pentxafor PET/CT. Our case demonstrated that 68Ga-pentixafor may have limited value in evaluating MALT lymphoma transformation.

Influence of Respiratory Motion on Dose Distribution in Gastric Mucosa-associated Lymphoid Tissue Lymphoma Radiotherapy.

BACKGROUND/AIM: The present study investigated the effect of respiratory motion on planned radiotherapy (RT) dose for gastric mucosa-associated lymphoid tissue (MALT) lymphoma using four-dimensional dose (4D-dose) accumulation. PATIENTS AND METHODS: 4D-computed tomography (4D-CT) images of 10 patients with gastric MALT lymphomas were divided into 10 respiratory phases. Further, the 3D-dose was calculated using 3D conformal RT (3D-CRT) and volumetric modulated arc therapy (VMAT) plans based on the average intensity projection (AIP) images. Then, both plans were recalculated according to each phase image. Moreover, the dose distributions in each phase were transferred to the AIP images using deformable image registration. The 4D-dose distribution was calculated by summing the doses of each phase, and it was compared with the dosimetric parameters of the 3D-dose distribution. RESULTS: For 3D-CRT, the D95 and D99 of the 4D-dose in the planning target volume (PTV) were significantly lower than those of the 3D-dose, with mean differences of 0.2 (p=0.009) and 0.1 Gy (p=0.021), respectively. There were no significant differences in the other PTV and organ-at-risk dosimetric parameters of 3D-CRT or in any dosimetric parameters of VMAT between the 3D- and 4D-dose distributions. CONCLUSION: The effect of respiratory motion on the planned 3D-CRT and VMAT dose distributions for gastric MALT lymphoma is minimal and clinically negligible.

CT radiomics analysis discriminates pulmonary lesions in patients with pulmonary MALT lymphoma and non-pulmonary MALT lymphoma.

PURPOSE: The aim of this study is to create and validate a radiomics model based on CT scans, enabling the distinction between pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma and other pulmonary lesion causes. METHODS: Patients diagnosed with primary pulmonary MALT lymphoma and lung infections at Fuzhou Pulmonary Hospital were randomly assigned to either a training group or a validation group. Meanwhile, individuals diagnosed with primary pulmonary MALT lymphoma and lung infections at Fujian Provincial Cancer Hospital were chosen as the external test group. We employed ITK-SNAP software for delineating the Region of Interest (ROI) within the images. Subsequently, we extracted radiomics features and convolutional neural networks using PyRadiomics, a component of the Onekey AI software suite. Relevant radiomic features were selected to build an intelligent diagnostic prediction model utilizing CT images, and the model's efficacy was assessed in both the validation group and the external test group. RESULTS: Leveraging radiomics, ten distinct features were carefully chosen for analysis. Subsequently, this study employed the machine learning techniques of Logistic Regression (LR), Support Vector Machine (SVM), and k-Nearest Neighbors (KNN) to construct models using these ten selected radiomics features within the training groups. Among these, SVM exhibited the highest performance, achieving an accuracy of 0.868, 0.870, and 0.90 on the training, validation, and external testing groups, respectively. For LR, the accuracy was 0.837, 0.863, and 0.90 on the training, validation, and external testing groups, respectively. For KNN, the accuracy was 0.884, 0.859, and 0.790 on the training, validation, and external testing groups, respectively. CONCLUSION: We established a noninvasive radiomics model utilizing CT imaging to diagnose pulmonary MALT lymphoma associated with pulmonary lesions. This model presents a promising adjunct tool to enhance diagnostic specificity for pulmonary MALT lymphoma, particularly in populations where pulmonary lesion changes may be attributed to other causes.

Primary rectal mucosa-associated lymphoid tissue lymphoma masquerading as proctitis.

A 29-year-old male presented with recurrent mucous bloody stools for more than a year. Colonoscopy revealed ill-defined, mildly congested and edematous mucosa with scattered erosion spots in the lower rectum, highly suspicious for proctitis. Histopathology showed diffuse infiltration of small to medium-sized lymphoid cells in the lamina propria. Immunohistochemistry indicated these cells were positive for CD20, CD79a, CD19, kappa and lambda light chains (partial), and negative for CD3, CD5, CD10, cyclin D and BCL-6. These results were consistent with mucosa-associated lymphoid tissue (MALT) lymphoma. Further investigations consisting of upper endoscopy, bone marrow biopsy, and whole-body PET/CT scan did not detect any extrarectal lesions. Based on these findings, the diagnosis of stage I primary rectal MALT lymphoma was made. The patient underwent 15 fractions of radiotherapy with a total dose of 30 Gy. His symptoms were alleviated following the treatment. A follow-up colonoscopy performed 3 months later showed complete resolution of the lesion.

Nodular Pulmonary Amyloidosis Preceding Gastric Mucosa-associated Lymphoid Tissue Lymphoma, Initially Suspected to Be Lung Cancer.

Nodular pulmonary amyloidosis, a subtype of pulmonary amyloidosis, is a unique disease that can mimic lung cancer on radiographic imaging and is related to lymphoproliferative disorders. In this report, we describe a case of a 76-year-old male who presented with a solitary nodule in his left lower lung lobe on computed tomography that increased from 6 mm to 13 mm in diameter over 40 months. Lung cancer was suspected; however, transbronchial lung biopsy revealed deposition of an eosinophilic and homogeneous amorphous substance, which showed apple-green birefringence under polarized light after Congo red staining, and immunohistochemistry analysis returned positive results for immunoglobulin lambda light-chain. Upper gastrointestinal endoscopy revealed a gastric mucosa-associated lymphoid tissue (MALT) lymphoma. These findings indicated that this was a case of nodular pulmonary amyloidosis that preceded a diagnosis of MALT lymphoma.

[Clinicopathological Features and Imaging Characteristics of Pulmonary Mucosa-associated Lymphoid Tissue Lymphoma].

BACKGROUND: Pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma is a rare disease. We report seven cases of pulmonary MALT lymphoma. CASES: Chest computed tomography (CT) revealed various morphological features, including a solitary mass, a solid nodule, and ground-glass opacity. Multiple nodules were observed in one patient. However, the tumor margins were ill-defined in all seven cases, and air bronchograms were identified in five cases. The solitary mass was found to extend along the pulmonary lymphatic vessels. Six patients underwent R0 resection, while one underwent an open lung biopsy. Histopathological findings in all seven cases showed lymphoepithelial lesions. Regarding their immunohistological findings, all patients were diagnosed with pulmonary MALT lymphoma. Two patients received postoperative chemotherapy with rituximab. The progression-free survival time was 52 (range, 22-122) months. Postoperative course was uneventful in all patients. CONCLUSION: MALT lymphoma is characterized by an ill-defined margin, air bronchogram, and tumor extension along the pulmonary lymphatic vessels, all of which aid in diagnosis. MALT lymphoma is a low-grade lymphoma, and the prognosis is favorable. Therefore, follow-up examination without treatment can be one of the therapeutic options if patients are diagnosed with pulmonary MALT lymphoma.

Lymphoma-Sink Effect in Marginal Zone Lymphoma Based on CXCR4-Targeted Molecular Imaging.

PURPOSE: Recent studies investigating a tumor-sink effect in solid tumors reported on decreasing uptake in normal organs in patients with higher tumor burden. This phenomenon, however, has not been evaluated yet for theranostic radiotracers applied to hematological neoplasms. As such, we aimed to determine a potential "lymphoma-sink effect" in patients with marginal zone lymphoma (MZL) imaged with C-X-C motif chemokine receptor (CXCR) 4-directed PET/CTs. PROCEDURES: We retrospectively analyzed 73 patients with MZL who underwent CXCR4-directed [68Ga]Ga-PentixaFor PET/CT. Normal unaffected organ uptake (heart, liver, spleen, bone marrow, kidneys) was quantified using volumes of interests (VOIs) and mean standardized uptake values (SUVmean) were derived. MZL manifestations were also segmented to determine the maximum and peak standardized uptake values SUV (SUVmax/peak) and volumetric parameters, including lymphoma volume (LV), and fractional lymphoma activity (FLA, defined as LV*SUVmean of lymphoma burden). This approach resulted in 666 VOIs to capture the entire MZL manifestation load. We used Spearman's rank correlations to determine associations between organ uptake and CXCR4-expressing lymphoma lesions. RESULTS: We recorded the following median SUVmean in normal organs: heart, 1.82 (range, 0.78-4.11); liver, 1.35 (range, 0.72-2.99); bone marrow, 2.36 (range, 1.12-4.83); kidneys, 3.04 (range, 2.01-6.37); spleen, 5.79 (range, 2.07-10.5). No relevant associations between organ radiotracer uptake and MZL manifestation were observed, neither for SUVmax (ρ ≤ 0.21, P ≥ 0.07), SUVpeak (ρ ≤ 0.20, P ≥ 0.09), LV (ρ ≤ 0.13, P ≥ 0.27), nor FLA (ρ ≤ 0.15, P ≥ 0.33). CONCLUSIONS: Investigating a lymphoma-sink effect in patients with hematological neoplasms, we observed no relevant associations between lymphoma burden and uptake in normal organs. Those observations may have therapeutic implications, e.g., for "cold" SDF1-pathway disrupting or "hot," CXCR4-directed radiolabeled drugs, as with higher lymphoma load, normal organ uptake seems to remain stable.

Radiomics analysis of T1WI and T2WI magnetic resonance images to differentiate between IgG4-related ophthalmic disease and orbital MALT lymphoma.

BACKGROUND: Preoperative differentiation between IgG4-related orbital disease (IgG4-ROD) and orbital mucosa-associated lymphoid tissue (MALT) lymphoma has a significant impact on clinical decision-making. Our research aims to construct and evaluate a magnetic resonance imaging (MRI)-based radiomics model to assist clinicians to better identify IgG4-ROD and orbital MALT lymphoma and make better preoperative medical decisions. METHODS: MR images and clinical data from 20 IgG4-ROD patients and 30 orbital MALT lymphoma patients were classified into a training (21 MALT; 14 IgG4-ROD) or validation set (nine MALT; six IgG4-ROD). Radiomics features were collected from T1-weighted (T1WI) and T2-weighted images (T2WI). Student's t-test, the least absolute shrinkage and selection operator (LASSO) and principal component analysis (PCA) were conducted to screen and select the radiomics features. Support vector machine (SVM) classifiers developed from the selected radiomic features for T1WI, T2WI and combined T1WI and T2WI were trained and tested on the training and validation set via five-fold cross-validation, respectively. Diagnostic performance of the classifiers were evaluated with area under the curve (AUC) readings of the receiver operating characteristic (ROC) curve, and readouts for precision, accuracy, recall and F1 score. RESULTS: Among 12 statistically significant features from T1WI, four were selected for SVM modelling after LASSO analysis. For T2WI, eight of 51 statistically significant features were analyzed by LASSO followed by PCA, with five features finally used for SVM. Combined analysis of T1WI and T2WI features selected two and four, respectively, for SVM. The AUC values for T1WI and T2WI classifiers separately were 0.722 ± 0.037 and 0.744 ± 0.027, respectively, while combined analysis of T1WI and T2WI classifiers further enhanced the classification performances with AUC values ranging from 0.727 to 0.821. CONCLUSION: The radiomics model based on features from both T1WI and T2WI images is effective and promising for the differential diagnosis of IgG4-ROD and MALT lymphoma. More detailed radiomics features and advanced techniques should be considered to further explore the differences between these diseases.

Synchronous gastric MALT lymphoma and gastric adenocarcinoma of fundic gland type arising from a hamartomatous inverted polyp in a Helicobacter pylori naive patient.

We present a rare case that showed the coexistence of gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma in Helicobacter pylori-naive stomach. A 72-year-old man was followed up after surgery for epithelial carcinoma of the glottis at the Department of Otolaryngology. He underwent an upper gastrointestinal endoscopy for an abnormal PET-CT accumulation, which revealed gastric adenocarcinoma of fundic gland type in the gastric fundus and MALT lymphoma in the upper gastric body. Hence, we performed an endoscopic submucosal dissection for gastric cancer and diagnosed gastric adenocarcinoma of fundic gland type derived from a hamartomatous-inverted polyp. Subsequently, Gastric MALT lymphoma was treated with radiation therapy because the API2-MALT1 gene was positive and the Helicobacter pylori infection was negative. A complete response was observed. Even in Hp-naive stomachs, cases such as the present case are complicated by special types of gastric cancer and MALT lymphoma, and endoscopic examination should be performed with these diseases in mind.

A case report of a collision tumor composed of pancreatic ductal adenocarcinoma and peri-pancreatic mucosa-associated lymphoid tissue lymphoma.

BACKGROUND: Collision tumors are composed of two distinct tumor components. Collision tumors composed of pancreatic ductal adenocarcinoma and malignant lymphoma occurring in the pancreas have not been previously described in the scientific literature. In this case report, we describe a unique patient with a collision tumor composed of pancreatic ductal adenocarcinoma and peri-pancreatic mucosa-associated lymphoid tissue (MALT) lymphoma occurring in the pancreas. CASE PRESENTATION: An 82-year-old woman presented to our hospital complaining of dizziness. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large lymphoid lesion spreading from the peri-pancreatic tissue heading to the hepatic hilar plate, involving the hepatoduodenal ligament and the entire duodenum, also showing a hard tumor in the pancreas head. We performed echo-guided needle biopsies for each tumor and diagnosed a collision tumor composed of pancreatic ductal adenocarcinoma and low-grade B cell lymphoma. The patient underwent pancreaticoduodenectomy. The resected specimen showed an elastic hard tumor, 90 × 75 mm in size, located in the pancreatic head, and a whitish-yellow hard tumor involving the lower bile duct, 31 mm in size, located in the center of the pancreatic head. Pathological and immunohistochemical examination proved that pancreatic ductal adenocarcinoma and MALT lymphoma originating from the peri-pancreatic head collided in the pancreatic head. CONCLUSIONS: To best of our knowledge, this is the first report of a surgically resected collision tumor of pancreatic ductal adenocarcinoma and MALT lymphoma originating from the peri-pancreatic head. A needle biopsy is useful when inconsistent findings are observed on diagnostic CT and MRI of tumor lesions since there is the possibility of a collision tumor.

MALT lymphoma of the colon: an endoscopic challenge.

Colonic lymphoma involving the mucosa-associated lymphoid tissue (MALT) is an uncommon pathology, with an unknown pathogenesis and varied endoscopic appearance. We present the case of a 78-year-old female with challenging endoscopic findings that resulted in the diagnosis of a colonic MALT lymphoma.

FDG-PET/CT discriminates between patients with and without lymphomas in primary Sjögren's syndrome.

OBJECTIVES: To assess the usefulness of [18F]-fluorodeoxyglucose (FDG)-PET/CT (i) to discriminate between primary SS (pSS) patients with and without lymphomas and (ii) to evaluate systemic disease activity in pSS. METHODS: ACR-EULAR-positive pSS patients who underwent FDG-PET/CT were included. Scans were visually evaluated and quantitative analysis was performed by measuring standardized uptake values (SUV) of salivary and lacrimal glands and systemic regions. Receiver operating characteristic curve analyses were performed to find SUV cut-off values to discriminate between lymphoma and non-lymphoma. RESULTS: Of the 70 included patients, 26 were diagnosed with a pSS-associated lymphoma, mostly of the mucosa-associated lymphoid tissue type (23/26). Lymphoma patients showed higher FDG uptake in the parotid and submandibular glands, and more frequently showed presence of nodular lung lesions, compared with non-lymphoma patients. The accuracy of the maximum SUV (SUVmax) in the parotid and submandibular gland to predict lymphoma diagnosis was good, with optimal cut-off points of 3.1 and 2.9. After combining these three visual and quantitative findings (nodular lung lesions, parotid SUVmax > 3.1 and submandibular SUVmax > 2.9), sensitivity was 92% when at least one of the three features were present, and specificity was 91% in case at least two features were present. Furthermore, FDG-PET/CT was able to detect systemic manifestations in pSS patients, mostly involving lymph nodes, entheses and lungs. CONCLUSIONS: FDG-PET/CT can assist in excluding pSS-associated lymphomas in patients without PET abnormalities, possibly leading to a decrease of invasive biopsies in suspected lymphoma patients. Furthermore, FDG-PET/CT is able to detect systemic manifestations in pSS and can guide to the best biopsy location.

Primary hepatic mucosa-associated lymphoid tissue lymphoma mimicking hepatocellular carcinoma in a patient with chronic hepatitis B: a case report.

Primary hepatic lymphoma is a rare disease, and primary hepatic mucosa-associated lymphoid tissue (MALT) lymphoma accounts for only 0.3% of all primary hepatic lymphomas. Herein, we report a case of primary hepatic MALT lymphoma in a male patient in his mid-40 s with chronic hepatitis B infection. The patient visited our department for further examination of a hepatic nodule initially visualized through abdominal pelvic computed tomography (CT). Based on imaging studies and elevated levels of tumor markers, the tumor was suspected to be hepatocellular carcinoma. A laparoscopic inferior sectionectomy (segment 5 and 6) was performed, and immunohistochemical staining revealed that the tumor was positive for CD20, B-cell lymphoma 2, pan-cytokeratin (CK), and CK19 markers. Pathological findings revealed it to be a primary hepatic MALT lymphoma. After surgery, bone marrow biopsies and fluorodeoxyglucose-positron emission tomography integrated with CT scanning confirmed that there was no other involvement. The patient did not receive chemotherapy, and there was no recurrence during the 24-month follow-up period. Hepatocellular carcinoma is the most common malignancy in patients with chronic hepatitis B, but rare tumors such as primary MALT lymphoma can also occur, so a careful approach is required for their differentiation.