Primary pancreatic low-grade mucosa-associated lymphoid tissue lymphoma presenting with multiple masses

18F-FDG PET/CT assists the diagnosis of primary pancreatic lymphoma: Two case reports and literature review

Primary pancreatic lymphoma (PPL) is a rare malignancy, which is defined as a mass centered in pancreas with involvement of contiguous lymph nodes and distant spread may exist. Accurate diagnosis of PPL prior to pathological confirmation remains challenging, underscoring the critical significance of preoperative imaging assessments. This case report collected two instances of PPL that underwent initial evaluation via 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) between August 2021 and July 2022. Correspondingly, pertinent literature encompassing 18F-FDG PET/CT data related to PPL was meticulously reviewed. Including our aforementioned pair of cases, a cumulative total of 25 instances of PPL were assembled. The distinctive profile of 18F-FDG PET/CT images of PPL predominantly manifests as hypermetabolic lesions with diminished density. Primarily characterized by singular lesions and comparatively substantial volumetric dimensions, a total of eleven cases revealed contiguous lymph node engagement, with five instances displaying distant dissemination encompassing lymph nodes in multiple locations. Amongst these, ten patients underwent sequential 18F-FDG PET/CT follow-up post-intervention. In comparison to pancreatic carcinoma, PPL lesions exhibited heightened hypermetabolism, augmented volumetric proportions, and distinct patterns of distant metastasis. This study indicates that the pivotal role of 18F-FDG PET/CT in the diagnosis and assessment of therapeutic efficacy in PPL is unequivocal. Combined with the clinical attributes of patients, the integration of 18F-FDG PET/CT augments the differential diagnostic capacity differentiating PPL from pancreatic carcinoma.

Synchronous Pancreatic Masses

Any mass lesion in the pancreas usually raises the possibility of undiagnosed pancreatic cancer. With the advancement of imaging modalities, we are seeing an increasing number of incidental findings, some of which may be clinically significant. When dealing with incidental pancreatic findings, it is critical to keep a broad differential in mind in addition to ruling out pancreatic malignancy. We present 3 rare cases of patients with 2 or more synchronous solid masses in the pancreas caused by pancreatic cancer, type 1 autoimmune pancreatitis, and sarcoidosis.

Primary Pancreatic Lymphoma: Recommendations for Diagnosis and Management

BACKGROUND

Primary pancreatic lymphoma (PPL) is a rare disease representing 0.1% of all malignant lymphomas, which lacks well-defined diagnostic and therapeutic protocols. We conducted a systematic review to analyze demographic, diagnostic and therapeutic features of PPL.

METHODS

This review identified small series and single case reports. Sources were MEDLINE, PubMed, and the Cochrane library from January 2001 to December 2020. Data were screened, extracted and the risk of bias analyzed by three independent reviewers.

RESULTS

A total of 107 eligible papers (17 small series, 90 single case reports) describing 266 patients were identified. Patients had a median age of 53.1 (range 3-86) years and were males in 64.6% of cases. Abdominal pain and jaundice were the most common presenting symptoms, affecting 75.3% and 41.8% of patients, respectively. PPL had a median size of 60.6 mm (range 16-200) and it was localized in the pancreatic head in 63.7% of cases. At diagnosis most patients underwent ultrasonography followed by computed tomography. PPL typically showed low echogenicity, and lower contrast enhancement than solid tumors. Histopathological specimens were obtained by percutaneous or endoscopic biopsies in 47.7% of patients; abdominal surgery was performed in 33.5% of cases. Overall, diffuse large B-cell lymphoma was the most frequent histological diagnosis (53.6%). However, patients aged <18 years were affected by Burkitt lymphoma in 52.4% of cases. Most patients (53.6%) received immunochemotherapy (IC) or IC plus radiotherapy (14%). Demolitive surgery appeared to be associated with impaired survival. Central nervous system (CNS) relapse or progression was observed in 20% of patients.

CONCLUSION

PPL is a rare entity, with some peculiar features at modern imaging. For diagnostic purposes percutaneous or endoscopic biopsies might be preferable, as opposed to surgery. No definite data is available about the optimal treatment, which should be tailored on the histological type and associated with CNS prophylaxis.

Indicators for Malignant Transformation in Patients With Lymphoepithelial Lesion

PURPOSE

Salivary lesion (LEL) represents a unique disease, and some patients have malignant transformations. The study aims were to estimate the frequency of malignant transformation and the subtype of the malignant component and to identify factors associated with malignant transformation and subtype of the malignant component in patients with LEL.

PATIENTS AND METHODS

This study was based on a retrospective cohort study between 2005 and 2017 from patients who were diagnosed as LEL. The predictor variable was composed of a set of variables grouped into demographic, clinical, and pathologic features. The outcome variables were malignant transformation status and subtype of the malignant components. All parameters between the predictor variables and outcome variables were analyzed using the χ² test and a logistic regression model.

RESULTS

The sample was composed of 252 cases of LEL (including with or without malignant transformation) with a mean age of 50.3 years; 58 (58 of 252; 23.0%) were males, 194 (194 of 252; 77.0%) were females. The parotid gland was the most common site of LEL (206 of 252; 81.7%), and 36.5% (92 of 252) of the patients had a history of Sjögren syndrome (SS). Masses greater than 2 cm in diameter had evidence of malignant transformation (P < .001). Factors associated with the subtype of malignant components were a history of SS (P < .001) and Epstein-Barr virus infection. The percentages of nonmalignant transformations, LEL with extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma), and LEL progressing to lymphoepithelial carcinoma were 44.8 (113 of 252), 47.6 (120 of 252), and 7.6% (19 of 252), respectively.

CONCLUSIONS

More than half of cases have a malignant transformation, and MALT lymphoma is the most common malignant subtype. A larger mass (>2 cm) is an independent indicator of malignant transformation in LEL patients. History of SS among LEL patients is considered a risk factor for MALT lymphoma.

Adenocarcinoma involving the whole pancreas with multiple pancreatic masses

A 77-year-old man was referred to our hospital for further investigation of pancreatic masses. Imaging studies revealed hypovascular masses in the pancreatic head and body. Total pancreatectomy was performed under the diagnosis of double primary pancreatic carcinomas. Macroscopic examination revealed 3 nodules: one each in the pancreatic head, body, and tail. Microscopically, all 3 lesions showed similar carcinoma cells, which communicated with each other via the intraductal component, indicating a single large tumor. Incidentally, we also identified an adenocarcinoma of the common bile duct (CBD). The final diagnosis was synchronous double cancer involving the whole pancreas and the CBD.