A 54-year-old man was referred to our hospital (Matsuyama Red Cross Hospital) because of 2-year duration of extended multiple nodules with abscess and fistula with pus discharge in the gluteal and perianal regions (Fig. 1a). Laboratory data identified inflammatory reaction (white blood cells [WBC], 11 430/lL, and C-reactive protein, 4.5 mg/dL) and anemia (hemoglobin levels, 8.6 g/dL). Serum amyloid A protein was elevated (50.2 lg/mL). Ileocolonoscopy showed diffuse coarse mucosa with numerous diminutive nodules throughout the colorectum (Fig. 1b). Esophagogastroduodenoscopy (EGD) identified whitish coarse mucosa with spotted hemorrhage and reddish spots in the gastric antrum (Fig. 1c) and granular mucosa in the descending duodenum (Fig. 1d). Histological examination taken from the colon, ileum, stomach, and duodenum showed massive amyloid deposits, which were positive for anti-serum amyloid A (SAA) antibody staining, in the lamina propria and around the submucosal vessels (Fig. 2). We diagnosed the patient as having secondary amyloid A amyloidosis of the gastrointestinal (GI) tract caused by severe hidradenitis suppurativa (HS). His HS was resected surgically with reconstruction by split-thickness skin grafting from his back. SSA protein at 5 months after surgery decreased to 12.2 lg/mL. EGD and ileocolonoscopy at 3 years after surgery indicated indistinctive gastric, duodenal, and colorectal mucosa; however, amyloid deposits in the GI tract remained positive under bioptic examination.