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case_images: Computed Tomography of the Abdomen and Pelvis without and with contrast. (A) CT without contrast demonstrates diffuse punctate calcifications throughout the peritoneum (arrows) and retroperitoneum (arrowhead). (B) CT with contrast demonstrates diffuse hepatic hypoattenuation and small ascites (new since prior CT abdomen and pelvis) and persistent peritoneal/retroperitoneal infiltration with associated calcifications consistent with amyloid. Additionally, new ascites was appreciated (asterix).
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case_images: With respect to her peritoneal AL amyloid, she was noted to have a history of chronic abdominal pain for which upper GI endoscopy was unremarkable and computed tomography (CT) of abdomen and pelvis (Fig. 1, Panel A) demonstrated peritoneal calcifications concerning for carcinomatosis and a soft tissue mass within the sigmoid mesentery concerning for a neoplastic process. CT of abdomen and pelvis with IV contrast showed diffuse hepatic hypoattenuation and small ascites (new since prior CT abdomen and pelvis 3 months ago) and persistent peritoneal/retroperitoneal infiltration with associated calcifications consistent with amyloid (Fig. 1, Panel B).
case_images: Peritoneal Histopathology. (A) H&E staining of the peritoneum in 100x magnification demonstrates fibroadipose tissue with diffuse infiltration of acellular amorphous material surrounding fat lobules (arrow). (B) 200x magnification demonstrates diffuse acellular amphophilic material infiltrating fibroadipose tissue and a blood vessel (center/right, lower), with vessel wall involvement (arrow). (C) Congo red staining of the peritoneum in 400x magnification demonstrates amyloid (staining pink/red; arrow).
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case_images: AL amyloid deposition involving fibro-adipose tissue and skeletal muscles (Fig. 2). Additional serological workup and marrow biopsy was deferred to an outpatient basis.
case_images: Bone Marrow Histopathology. (A) H&E staining of bone marrow at 100x magnification demonstrates a vessel (arrow) with wall thickened by pink amorphous material. (B) 200x magnification demonstrates same vessel (arrowhead to thickened wall). (C) Polarized light examination of Congo red stained bone marrow biopsy at 400x magnification demonstrates apple green birefringence in vascular wall consistent with amyloid.
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case_images: To confirm the diagnosis, a bone marrow biopsy (Fig. 3) of right iliac crest was performed.
case_images: Gastric Histopathology. (A) H&E staining of the gastric antrum in 100x magnification demonstrates thin layer of eosinophilic amorphous matrix around the submucosal small vessel. (B) Congo red staining of the gastric antrum in 100x magnification demonstrates submucosal perivascular amyloid deposition. (C) Congo red staining of gastric antrum biopsy in 400x magnification demonstrates perivascular orange colored amyloid protein.
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case_images: Congo red staining of antral biopsies showed amyloid protein in perivascular area (Fig. 4).