58-year old patient with atypical peritoneal manifestation of diffuse amyloid deposition: presentation of systemic Amyloid Light-chain (AL) amyloidosis in B-mode imaging and contrast-enhanced ultrasound (CEUS)

Purpose: Here, we present a case of with atypical peritoneal manifestation of diffuse amyloid deposition in B-mode-imaging and contrast-enhanced ultrasound (CEUS).

Material and methods: A 58-year-old patient in poor general condition presented for tumor search with an increased waist circumference, dysphagia, dyspnea and weight loss. B-mode ultrasound presented interenteric throughout the mesentery and retroperitoneum an echogenic material surrounding the intestines, which impressed soft upon compression and was thus primarily interpreted as echogenic aszites. Additionally pleural effusions on both sides, as well as pericardial effusion were observed. In contrast-enhanced ultrasound (CEUS) the interenteric material presented with a homogeneous enhancement.

Result: For tumor staging a sonographically guided biopsy of inter-enteric material was performed. After positive Congo red staining, histological examination of the material showed the findings of systemic Amyloid Light-chain (AL) amyloidosis. The bone marrow biopsy revealed the diagnosis of a multiple myeloma type IgG kappa.

Conclusion: This case describes the diagnosis of multiple myeloma with cardiac, gastral, pulmonary and renal involvement of AL amyloidosis, as well as an atypical peritoneal, interenteric and retroperitoneal tumor manifestation of the disease. This peritoneal involvement of AL amyloidosis can be diagnosed using CEUS to establish hyperechoic solid lesions.