JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
September 2021
D-M05
Signalment: (JPC#2456580): Adult castrated male pig
HISTORY: Clusters of bubbles along a 20 cm length of distal small intestine were present at necropsy.
HISTOPATHOLOGICAL DESCRIPTION: Small intestine: Markedly expanding the submucosa up to 3mm, to a lesser extent multifocally expanding the lamina propria, tunica muscularis, and serosa, and elevating the overlying mucosa are numerous dilated lymphatics, up to 2mm in diameter, that have a well demarcated central clear space (emphysema). These dilated, emphysematous lymphatics are separated by submucosal connective tissue bands that measure up to 200um thick and are infiltrated and/or expanded by scant to moderate hemorrhage, fibrin, edema, moderate numbers of multinucleated giant cells, and fewer epithelioid macrophages, eosinophils, lymphocytes, and plasma cells that occasionally extend into the adjacent tunica muscularis and serosa.
MORPHOLOGIC DIAGNOSIS: Small intestine: Emphysema, intralymphatic and submucosal to transmural, multifocal to coalescing, marked, with multifocal granulomatous and eosinophilic submucosal enteritis, breed not specified, porcine.
CONDITION: Emphysema intestinalis; intestinal emphysema; pneumatosis cystoides intestinalis; pneumotosis cystica of the intestine
CAUSE: Unknown
GENERAL DISCUSSION:
- Gas-filled cystic lymphatics in the lamina propria, submucosa, tunica muscularis, subserosa, mesentery, and mesenteric lymph nodes
- Infrequent, incidental finding in weaned pigs found at time of slaughter
PATHOGENESIS:
- Unknown
- Clostridium perfringens and Escherichia coli have been isolated from lesions, but not consistently
TYPICAL CLINICAL FINDINGS:
- None
TYPICAL GROSS FINDINGS:
- Thin walled, gas filled cystic structures in intestine wall and on serosal surface
- Numerous cystic lymphatics ranging from less than 1 mm to several cm in diameter; primarily in submucosa; seen grossly in the tunica serosa
- Occurs most often in the wall of the small intestine; large intestine, mesentery, and mesenteric lymph nodes may be also involved
TYPICAL MICROSCOPIC FINDINGS:
- Gas-filled, dilated lymphatics of the lamina propria, submucosa, tunica muscularis, subserosa, mesentery or mesenteric lymph nodes
- A granulomatous to mixed inflammatory reaction may be present in surrounding submucosa
ADDITIONAL DIAGNOSTIC TESTS:
- None
DIFFERENTIAL DIAGNOSIS:
- Fluid-filled lymphatics (edema or lymphatic obstruction)
- Empty parasitic cysts
- Congenital anomalies (remnant cysts of reproductive origins)
COMPARATIVE PATHOLOGY:
- Reported in rabbits, sheep, chickens, and laboratory rats
- Prosimians: Similar gross and histologic findings in the gastric wall of white ruffed lemurs, red-ruffed lemurs, and a slow loris (gastric pneumatosis; emphysematous gastritis; pneumatosis cystoides intestinalis)
REFERENCES:
- Gelberg HB. Alimentary system and the peritoneum, omentum, mesentery, and peritoneal cavity. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:405.
- McAloose D, Stalis IH. In: Terio KA, McAloose D, St. Leger J, eds. Pathology of Wildlife and Zoo Animals. London: Elsevier/Academic Press; 2018: 330-1.
- Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:87.
