PMC10071027_01
Clinical course after admission. After the diagnosis of giant cell arteritis, prednisolone 40 mg (0.6 mg/kg body weight) was administered orally. During the course, CMV-infected cells became positive, and ganciclovir was administered. After the diagnosis of AA amyloidosis, subcutaneous injections of TCZ was initiated. Diarrhea tended to improve and serum albumin tended to increase. Glucocorticoid therapy was tapered off, but the patient died and was discharged on the 80th day due to sigmoid colon perforation. TCZ, tocilizumab; sc, subcutaneous injection; PSL, prednisolone; CMV, cytomegalovirus; Alb, albumin; CRP, C-reactive protein.
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The clinical course of the patient is summarized in  Figure 1 .
Contrast-enhanced CT, endoscopy and pathological findings of the biopsied intestinal mucosa. (A) Contrast-enhanced CT showed wall thickening in the small intestine and colon. In addition, there were multiple diverticula in the colon. (B) Redness of the mucosa of the duodenum was observed. Histopathological findings of the duodenal mucosa. the Congo red method was used to detect amyloid in tissue sections. Amyloid was identified as the AA type on immunostaining using monoclonal antibodies specific to amyloid A (AA). (C) The amorphous extra-cellular material in the intrinsic layer of the duodenal mucosa was positively stained with Congo red (x100, Congo red). (D) Extra-cellular and peri-vascular deposits of amyloid reveal positive immunoreactivity with an antibody against amyloid A (x100).
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A repeated contrast-enhanced CT showed wall thickening of the small intestine and colon ( Figure 2 ). Upper gastrointestinal endoscopy revealed edematous duodenal mucosa ( Figure 2 ). AA amyloidosis was diagnosed by immunostaining ( Figure 2 ). As prednisolone alone did not improve diarrhea caused by AA amyloidosis, tocilizumab 162 mg/week was started on day 48.
Serum amyloid A1 genotyping by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis (2% agarose gel electrophoresis). Arrow (250 bp) and arrow head (269 bp) correspond to serum amyloid A1 allele 1.5 and 1.3 respectively. The patient carried SAA 1.3/1.5 heterozygosity genotype.
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