Desmoid fibromatosis involving the pancreas: A retrospective case series with clinical, cytopathologic and radiologic correlation

Desmoid-type fibromatosis (desmoid tumors) which involve the pancreas is an infrequent diagnosis which clinically can mimic both neoplastic and non-neoplastic lesions of the pancreas. The cytologic features of loosely cohesive cytologically bland (myo)fibroblastic cells are non-specific, however the long fascicular growth pattern and the presence of β-catenin mutation with positive nuclear immunohistochemical staining or molecular testing allows for definitive diagnosis. While many previously reported desmoid tumors of the pancreas have been surgically resected, conservative management with a “watch and wait” approach is also an effective mode of management for these tumors. Herein, we report the largest case series of pancreatic desmoid tumors with clinical, cytopathologic, and radiologic correlation. •Desmoid tumors of the pancreas are uncommon and can mimic neoplastic and non-neoplastic lesions of the pancreas•Most reports of pancreatic desmoids have consisted of single case reports or small case series•We present the largest case series to date of pancreatic desmoids with clinical, cytopathologic, and radiologic correlation•A conservative “watch and wait” approach is an effective mode of management