Pancreaticoduodenectomy for Mass-Forming Localized Duodenal Amyloidosis: A Case Report

Localized duodenal amyloidosis is extremely rare, with only a few cases having been documented in the literature. To the best of our knowledge, we report the first case of localized amyloid light-chain (AL) λ-type duodenal amyloidosis diagnosed after pancreaticoduodenectomy (PD).

A 71-year-old asymptomatic man was referred to our hospital after plain radiography revealed a calcified mass in the upper abdomen. Contrast-enhanced CT revealed a 58-mm exophytic mass with prominent peripheral calcification on the dorsal aspect of the descending duodenum, showing continuity with the pancreatic head vasculature. Endoscopic ultrasonography (EUS) could not evaluate the internal structure because of acoustic shadowing from dense calcification, thereby precluding EUS-guided tissue acquisition. Because malignancies, including gastrointestinal stromal tumors and lymphoma, could not be excluded, a subtotal stomach-preserving PD was performed for diagnostic and therapeutic purposes. Histopathological examination revealed extensive amyloid deposition that tested positive for Congo red staining, direct fast scarlet, and λ-light chain, while showing negative staining for κ-light chain, amyloid transthyretin, and serum amyloid A, thereby establishing a diagnosis of localized ALλ-type amyloidosis. A comprehensive systemic workup, including echocardiography, cardiac MRI, serum and urine immunofixation electrophoresis, and free light chain assays, excluded systemic amyloidosis. The patient was managed with observation alone without chemotherapy and remained recurrence-free for 2 years postoperatively.

When preoperative tissue diagnosis is not feasible because of extensive calcification and malignancy cannot be excluded, surgical resection, including PD, for localized ALλ-type duodenal amyloidosis should be considered as both a diagnostic and therapeutic intervention. After a diagnosis of localized amyloidosis is made, the exclusion of systemic disease and long-term follow-up are essential to monitor for local recurrence, the emergence of clonal disease, and potential progression to systemic disease.