One Case presented
Skin and kidney sections from a grower pig with multiple erythematous skin lesions
Example histopathological description – Slide A
In this section of kidney, most glomeruli show variably severe congestion and haemorrhage with segmental necrosis and capillary thrombosis, scattered karyorrhectic debris, mild segmental mesangial thickening and marked fibrinous exudate into Bowman’s space. Throughout the section, cortical and medullary tubular lumens are mildly dilated and filled with eosinophilic fibrillar to hyaline material sometimes mixed with degenerate exfoliated tubular epithelial cells and neutrophils (protein casts). Multifocally, tubular epithelial cells contain refractile eosinophilic cytoplasmic globules. In the walls of many of the renal arteries, particularly the arcuate vessels, there are subendothelial fibrin deposits, nuclear karyorrhexis and some intramural eosinophils. These vessels have prominent perivascular infiltrates of eosinophils, lymphocytes and plasma cells. There is mild multifocal expansion of the interstitium mainly by mononuclear inflammatory cells with fewer granulocytes, including eosinophils.
Glomerulonephritis, global, fibrinous, acute, diffuse, severe, with vasculitis/thrombosis and moderate tubulointerstitial nephritis
Example histopathological description – Slide B
This section of haired skin includes three roughly wedge-shaped segments of dermis in which blood vessels are often nearly obliterated by intense mixed inflammatory infiltrates and by thrombosis and medial necrosis associated with fibrinoid deposits. Haemorrhage is widespread in these segments, particularly in the superficial dermis where the bases of the segments abut the overlying epidermis, whose keratinocytes show cytoplasmic pallor and variably severe nuclear karyolysis and other degenerative changes. The inflammatory infiltrates include eosinophils and lymphocytes, but many leucocytes are necrotic and unrecognisable. Collagen bundles in these segments are often separated by eosinophilic deposits and are sometimes degenerate
Dermatitis, haemorrhagic and necrotizing, subacute, multifocal to coalescing, severe, with vasculitis and focal cutaneous infarction
Porcine dermatitis nephropathy syndrome (PDNS)
Porcine circovirus type 2 (PCV2), although this is not firmly established.
PDNS is currently classified as one of a number of PCV2-associated conditions; nevertheless, the similarity of the gross renal and lymph node pathology to that of the swine fevers, and of the cutaneous and renal lesions to that of erysipelas, means that these and other systemic infections such as salmonellosis and streptococcal septicaemia/endocarditis must be excluded by appropriate laboratory tests.