Coexisting Sarcoid Reaction and Sarcoidosis Requiring Differentiation from Pancreatic Adenocarcinoma Recurrence: A Case Report.

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is one of the most severe malignant tumors. The recurrence rate is high, even after radical surgery. A sarcoid reaction is a histological finding that occurs in the lymph nodes in response to malignant tumors, infections, or foreign substances. Its histopathology is similar to that of sarcoidosis. Here, we report a case of coexisting sarcoid reaction and sarcoidosis that required differentiation from PDAC recurrence.

CASE PRESENTATION: A 65-year-old woman was diagnosed with locally advanced PDAC. She underwent modified FOLFIRINOX (folinic acid, fluorouracil, irinotecan, and oxaliplatin) therapy for 6 months, after which the tumor shrunk, and there were no new metastatic lesions. Additionally, she underwent chemoradiation therapy (50 G/25 Fr and S-1), and a distal pancreatectomy with en bloc celiac axis resection and splenectomy were performed. Pathological diagnosis was PDAC, T2N0M0. Pathological findings of the regional lymph nodes showed no malignancy and noncaseating epithelioid cell granulomas, which were thought to be a sarcoid reaction. She received S-1 therapy for 6 months as adjuvant chemotherapy. On contrast-enhanced CT 1 year after the operation, enlarged para-aortic lymph nodes and multiple grainy pulmonary shadows were detected. Although recurrence was suspected, tumor marker levels did not increase. PET-CT revealed fluorodeoxyglucose accumulation in several lymph nodes, such as the para-aortic or neck, as well as in the bilateral femoral muscles. No accumulation was observed in the lung parenchyma. These findings were atypical of postoperative recurrence. Endoscopic ultrasonography-guided lymph nodes and body-surface ultrasonography-guided femoral muscle biopsies were performed. No malignancy was found in all the specimens, and noncaseating epithelioid cell granulomas were found. Propionibacterium acnes-specific antibody staining showed that the regional lymph nodes removed during surgery were negative, and the para-aortic lymph nodes and femoral muscles were positive. The patient was diagnosed with a sarcoid reaction to PDAC and muscular sarcoidosis. The patient remained recurrence-free for 3 years and 2 months postoperatively.

CONCLUSIONS

When enlarged lymph nodes are detected after surgery for a malignant tumor, we have to consider recurrence at first; however, it is important to make careful assessments because other factors are occasionally present.