Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Comprehensive review of pancreatic acinar cell carcinoma: epidemiology, diagnosis, molecular features and treatment

Pancreatic acinar cell carcinoma is a rare form (0.2-4.3%) of pancreatic neoplasm with unique clinical and molecular characteristics, which largely differ from pancreatic ductal adenocarcinoma. Pancreatic acinar cell carcinoma occurs more frequently in males and can occur in children. Serum lipase is elevated in 24-58% of patients with pancreatic acinar cell carcinoma. Pancreatic acinar cell carcinomas tend to be large at diagnosis (median tumour size: ~5 cm) and are frequently located in the pancreas head. Radiologically, pancreatic acinar cell carcinoma generally exhibits a solid appearance; however, necrosis, cystic changes and intratumoral haemorrhage can occur in larger lesions. Immunostaining is essential for the definitive diagnosis of pancreatic acinar cell carcinoma. Compared with pancreatic ductal adenocarcinoma, pancreatic acinar cell carcinoma has a more favourable prognosis. Although radical surgery is recommended for patients with pancreatic acinar cell carcinoma who do not have distant metastases, the recurrence rate is high. The effectiveness of adjuvant therapy for pancreatic acinar cell carcinoma is unclear. The response to FOLFIRINOX is generally favourable, and some patients achieve a complete response. Pancreatic acinar cell carcinoma has a different genomic profile compared with pancreatic ductal adenocarcinoma. Although genomic analyses have shown that pancreatic acinar cell carcinoma rarely has KRAS, TP53 and CDKN2A mutations, it has a higher prevalence of homologous recombination-related genes, including BRCA1/2 and ATM, than pancreatic ductal adenocarcinoma, suggesting high sensitivity to platinum-containing regimens and PARP inhibitors. Targeted therapies for genomic alternations are beneficial. Therefore, genetic testing is important for patients with pancreatic acinar cell carcinoma to choose the optimal therapeutic strategy.

An Unusual Cause of Pancreatic Tumor

Pancreatic tuberculosis (TB) is a rare condition that can be challenging to distinguish from other pancreatic neoplasms. We present the case of a 48-year-old Indian male who complained of persistent vague epigastric pain for two months. Other physicians saw him and treated him like a dyspeptic case. He gave a history of daily alcohol consumption. Routine investigations, including amylase and lipase levels, were within normal limits. However, an abdominal ultrasound revealed a cystic lesion in the body of the pancreas, prompting further investigation. A subsequent abdominal CT scan revealed a tumor of 6x4 cm in diameter with solid and cystic components in the pancreatic body. Although tumor markers were not remarkable, inflammatory markers showed elevated levels of ESR (erythrocyte sedimentation rate) of 95 mm/hr and CRP (C-reactive protein) of 83 mg/L, with normal hemoglobin. Endosonography (EUS) with fine needle aspiration (FNA) was performed to achieve a definitive diagnosis. EUS was performed with a linear echoendoscope, which revealed the mass, which had solid and cystic components. Fluid was aspirated from the cystic part and FNA passes were performed in the solid part. Microscopic examination and aspirated fluid culture confirmed the presence of Mycobacterium tuberculosis, while the solid part revealed caseation-indicated granulomas, indicative of TB. The patient was promptly initiated on a seven-month course of three anti-TB medications, leading to normalization of ESR and CRP levels during the treatment period. A follow-up abdominal CT scan showed complete resolution of the pancreatic lesion, indicating successful management. This case is rare and all the data in the literature is mainly in the form of case reports. Using EUS with FNA has transformed the diagnosis of pancreatic malignancy into a curable disease that could be easily managed with anti-TB medications.