Case 1, male, 9 years and 5 months old, 291 g body weight (BW), was euthanized because of sudden severe hypothermia (34.1°C), seizures, and moderate vomiting (approximately 4-6 ml) with a small amount of blood. It had been treated for 5 years and exhibited frequent vomiting that fluctuated between mild (<3 ml) and heavy (>7 ml). Case 1 showed changes in BW with vomiting and tested negative for infectious pathogens (Table 1). Case 2, female, 6 years and 11 months old, 353 g BW, died the day after sudden severe hypothermia (34.7°C) and heavy vomiting with hematemesis. This marmoset had been treated for frequent, fluctuating, mild to moderate vomiting without persistent diarrhea or weight loss for 2 years, and the frequency of heavy vomiting without hematemesis increased 1 month before its death. Both animals were treated with drugs as needed (Table 1).
Table 1 Drugs and tests employed in cases 1 and 2.
Serum biochemical tests (Table 2) and complete blood counts (CBCs; Table 3) were performed for both animals. The last serum biochemistry panel before euthanasia suggested chronic maldigestion (hypoalbuminemia) and acute renal injury (azotemia, markedly elevated creatinine, hyperglycemia, hypercalcemia, hyperphosphatemia, and low Na/K ratio) in case 1 and mild maldigestion (slight hypoalbuminemia, reduced blood urea nitrogen, and creatinine) in case 2 (Table 2). We did not perform any antemortem imaging.
Table 2 Serum biochemical profiles in cases 1 and 2.
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Cases,
Age (year, month)
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Case 1, 7y7m
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Case 1, 9y5m
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Case 2, 5y7m
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Case 2, 6y9m
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Reference interval from our laboratorya
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Reference interval from reference 8b
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unit
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TP
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g/dL
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6.7
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7.6
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6.3
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5.3
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6.1 – 6.5
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5.2 – 6.4
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ALB
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g/dL
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3.6
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1.3
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3.6
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2.3
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3.1 – 3.5
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3.1 – 4.0
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GLOB
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g/dL
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3.2
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6.3
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2.7
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3.0
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2.1 – 4.3
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ND
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A/G ratio
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1.1
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0.2
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1.3
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0.8
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1.1 – 1.2
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ND
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ALP
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µkat/L
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2.1
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2.5
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1.6
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0.5
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0.4 – 2.0
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0.7 – 1.9
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ALT
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µkat/L
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0.1
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0.3
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0.3
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0.1
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0.1 – 1.9
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0.1 – 0.2
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AMY
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µkat/L
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1.4
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1.8
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1.3
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1.1
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1.1 – 1.2
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2.9 – 4.8
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TBIL
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µmol/L
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5.1
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5.1
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6.8
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5.1
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3.4 – 8.5
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1.7 – 3.4
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BUN
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mmol/L
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1.1
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45.0
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25.0
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0.7
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7.6 – 8.4
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5.1 – 9.1
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CRE
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µmol/L
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35.4
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636.5
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44.2
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8.8
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28.0 – 35.2
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8.8 – 35.4
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GLU
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mmol/L
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7.7
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19.3
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9.3
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8.7
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5.2 – 14.3
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3.9 – 8.6
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Ca, total
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mmol/L
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2.2
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2.6
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2.0
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2.2
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2.1 – 2.2
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1.9 – 2.6
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PHOS
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mmol/L
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1.3
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7.8
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1.6
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1.2
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0.5 – 1.7
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0.9 – 1.5
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Na+
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mmol/L
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156.0
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132.0
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142.0
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156.0
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152.1 – 154.3
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147.4 – 152.5
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K+
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mmol/L
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4.4
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10.6
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2.8
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4.8
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4.3 – 4.6
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2.7 – 3.5
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Na/K ratio
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35.5
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12.5
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50.7
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32.5
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33.7 – 35.7
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ND
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TP: total protein; ALB: albumin; GLOB: globrin; A/G ratio: alubimin/globrin ratio; ALP: alkaline phosphatase; ALT: alanine aminotransferase; AMY: amylase; TBIL: total bilirubin; BUN: blood urea nitrogen; CRE: creatinine; GLU: glucose; Ca, total: calcium, total; PHOS: phosphorus; Na+: sodium;
K+: potassium; Na/K ratio: sodium/potassium ratio; ND: not described.
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a Data from our marmoset colony (adults [older than 2y] housed indoors; n = 21).
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b Data for adult (older than 2y) common marmosets (n=41) were obtained
from ref 8.
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Table 3 Complete blood count results in cases 1 and 2
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Cases,
Age (year, month)
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Case 1, 7y7m
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Case 2, 5y7m
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Case 2, 6y9m
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Reference interval from our laboratory a
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White blood cell (×109/L)
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6.1
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7.1
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6.4
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4.4 – 7.3
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Red blood cell count (×1012/L)
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5.97
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7.28
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5.1
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4.8 – 6.1
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Hemoglobin (g/l)
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129
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158
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111
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104.8 – 130.9
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Hematocrit (%)
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42.2
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49
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36.1
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32.5 – 41.3
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Mean corpuscular volume (fL)
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70.7
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67.4
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70.7
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66.6 – 69.4
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Mean corpuscular hemoglobin (pg/cell)
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21.6
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21.8
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21.7
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21.3 – 22.3
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Mean corpuscular hemoglobinconcentration (g/L)
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306
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323
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307
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316.4 – 325.7
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Platelet count (×109/L)
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1029
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583
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669
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531.2 - 647.8
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a. Data from our marmoset colony (adults [older than 2y] housed indoors; n = 14).
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The necropsy of case 1 was performed soon after euthanasia. The stomach and proximal to the descending parts of the duodenum were markedly dilated (18.3 mm in diameter at the proximal duodenum; reference interval of our laboratory (n=7): 7.0 mm±1.6 mm), as measured before opening the lumen, accompanying intraabdominal fibrous adhesion among the ascending colon, stomach, and descending part of the duodenum. The necropsy of case 2 was performed the morning after she died. The diameter of the region proximal to the descending part of the duodenum was 21.0 mm, with fibrous adhesions formed among the stomach, duodenum, and colon (Figure 1a, 1b). A sanguineous exudate was retained in the lumen of the dilated stomach and duodenum. The findings of odd-shaped, edematous gastric mucosa with diffuse numerous bubble-like structures (Figure 1b) matched the typical features of human GE and PI2,6,19. Thus, in addition to the major symptoms of vomiting and hypoalbuminemia, the gross necropsy findings in both cases were compatible with the diagnostic criteria of MDDS3,11.
After gross examination, the tissues of both animals were immediately fixed in 10% neutral buffered formalin, and then paraffin-embedded 5-μm-thick staining sections were prepared at a commercial laboratory for histopathological examination. In case 1, numerous diffusely distributed vacuoles of various sizes were observed in the lamina progeria mucosae, submucosa, and subserosa of the stomach and duodenum (Figure 2a-b, and 2d). Gastritis with ulcers reached the submucosa. Dilated and congested portal veins in Glisson’s capsules of the liver were also observed, which indicated HPVG (Figure 2e).
In case 1, immunohistochemical staining for CD31 and prospero homeobox 1 (Prox1) was performed to distinguish the conditions from chronic lymphocytic enteritis, lymphangioma, and lymphangiectasis. The results showed that the walls of diffusely distributed vacuoles were mostly negative, and some vacuoles with positive endothelial cells were blood and lymph vessels (Figure 3a-b). Thus, the vacuoles were gas cysts6,19 without an endothelium-lined cystic structure and were unlikely to have developed from lymph vessels.
Case 1 showed marked congestion of the liver (with centrilobular congestion and liver cell necrosis) and bilateral kidneys. Mild chronic hepatitis with slight fibrosis, hemosiderin deposition in the liver, and acute and chronic cholecystitis, which are common histopathological findings in MDDS11, were also observed. Except for cholecystitis, these findings indicated circulatory failure, consistent with acute renal failure, as suggested by the serum biochemistry results.
In case 2, numerous diffusely distributed vacuoles of various sizes were observed in the propria mucosae and submucosa of the stomach and duodenum and in the jejunum (Figure 2c). In the liver, bacteremia with numerous rods, neutrophil infiltration, and liver cell necrosis around the main trunk of the portal vein were found (Figure 2f). Circulatory failure due to septic shock was suspected from similar findings of liver and kidney congestion in case 1. The presence of neutrophilic infiltration indicated an inflammatory response to septicemia.