Page 96 - Textbook of Pathology, 6th Edition

80 system, lungs, heart and blood vessels, GI system, and
 TABLE 4.9: Morphology of Major Lesions in SLE.
haematopoietic system. Fatigue and myalgia are present in
1. RENAL LESIONS (LUPUS NEPHRITIS) most cases throughout the course of disease. Severe form of
EM-shows large deposits in mesangium, subepithelial or
subendothelial. illness occurs with fever, weight loss, anaemia and organ
IM-shows granular deposits of immune complex (IgG and C3) on related manifestations.
capillaries, mesangium and tubular basement membranes. For making the diagnosis of SLE, four or more of the
Six WHO classes of lupus nephritis based on patterns: following diagnostic criteria need to be fulfilled:
Class I: Minimal disease lupus nephritis: Seen in <5% cases. 1. Malar rash characterised by fixed erythema, flat or raised
LM shows no change.
IF shows mesangial deposits. over malar (mala= zygomatic bone) eminences.
SECTION I
Class II: Mesangial proliferative lupus nephritis: Seen in 10-25% 2. Discoid rash characterised by erythematous circular raised
cases. patches with keratotic scaling or follicular plugging.
LM shows mesangial expansion; pure mesangial hypercellularity. 3. Photosensitivity seen as rash on exposure to sunlight.
IF shows subepithelial or subendothelial deposits.
4. Oral ulcers which may extend to nasopharynx.
Class III: Focal lupus nephritis: Seen in 20-35% cases. 5. Non-erosive arthritis affecting two or more joints; may be
LM shows focal or segmental endothelial and mesangial cell associated with tenderness, swelling and effusion.
proliferation in <50% glomeruli.
IF shows focal subendothelial deposits. 6. Serositis as pleuritis or pericarditis.
Three subclasses: 7. Renal manifestations seen as proteinuria >0.5 gm/dl (>3+)
Class IIIA: Active lesions (focal proliferative). and cellular casts.
Class IIIA/C: Active on chronic lesions (focal proliferative and 8. Neurologic manifestations seen as seizures or psychosis.
sclerosing). 9. Haematologic derangements seen as haemolytic anaemia, or
Class IIIC: Chronic inactive lesions with scars (focal sclerosing). thrombocytopenia (<100,000/μl), or leucopenia (>4,000/μl).
Class IV: Diffuse lupus nephritis: Seen in 35-60% cases. 10. Immunological derangements seen as positive tests for anti-
LM shows diffuse, segmental or global involvement of >50% dsDNA, antiSm, and/or anti-phospholipid antibody.
glomeruli; proliferation of endothelial, mesangial and epithelial cells; 11. Antinuclear antibodies seen as abnormal titre of ANA by
epithelial crescents.
IF shows diffuse subendothelial deposits. immunofluorescence or any other equivalent method.
Two subclasses: The disease usually runs a long course of flare-ups and
Class IV-S: 50% of involved glomeruli have segmental lesions. remissions; renal failure is the most frequent cause of death.
Class IV-G: 50% of involved glomeruli have global lesions.
Each of these subclasses (IV-S and IV-G) has active, active on Scleroderma (Progressive Systemic Sclerosis)
chronic lesions, and chronic lesions.
General Pathology and Basic Techniques
Class V: Membranous lupus nephritis: Seen in 10-15% cases. Just like SLE, scleroderma was initially described as a skin
LM shows diffuse basement membrane thickening. disease characterised by progressive fibrosis. But now, 2 main
IF shows global or segmental subepithelial deposits. types are recognised:
May be seen in combination with class III or IV.
Class VI: Advanced sclerotic lupus nephritis: Seen as end-stage 1. Diffuse scleroderma in which the skin shows widespread
disease. involvement and may progress to involve visceral structures.
LM shows global sclerosis of > 90% of glomeruli.
2. CREST syndrome of progressive systemic sclerosis
2. LESIONS OF SMALL BLOOD VESSELS (ACUTE NECROTISING characterised by Calcinosis (C), Raynaud’s phenomenon (R),
VASCULITIS) Esophageal hypomotility (E), Sclerodactyly (S) and
Affects all tissues; commonly skin and muscles involved. Telangiectasia (T).
LM shows fibrinoid deposits in the vessel wall; perivascular infiltrate
of mononuclear cells. ETIOPATHOGENESIS. The etiology of this disease is not
3. CUTANEOUS LESIONS (ERYTHEMATOUS ERUPTIONS) known. However, antinuclear antibodies are detected in
Butterfly area on nose and cheek. majority of cases of systemic sclerosis. Immunologic
LM shows liquefactive degeneration of basal layer of epidermis; mechanisms have been implicated in the pathogenesis of
oedema at dermoepidermal junction; acute necrotising vasculitis in lesions in systemic sclerosis which finally cause activation
dermis. of fibroblasts. The immune mechanisms leading to stimulation
IF shows immune complex deposits (IgG and C3) at dermo- of fibroblasts may act in the following ways:
epidermal junction.
1. Elaboration of cytokines such as by fibroblast growth factor
4. CARDIAC LESIONS (LIBMAN-SACKS ENDOCARDITIS) and chemotactic factors by activated T cells and
Vegetations on mitral and tricuspid valves, may extend to mural macrophages.
endocardium, chordae tendineae. 2. Endothelial cell injury due to cytotoxic damage to endo-
LM of vegetations shows fibrinoid material, necrotic debris,
inflammatory cells, haematoxylin bodies may be present; connective thelium from autoantibodies or antigen-antibody complexes.
tissue of endocardium and myocardium may show focal inflammation This results in aggregation and activation of platelets which
and necrotising vasculitis. increases vascular permeability and stimulates fibroblastic
(LM = Light microscopy; IF = Immunofluorescence microscopy). proliferation.

features may be present. The severity of disease varies from MORPHOLOGIC FEATURES. Disseminated visceral
mild to intermittent to severe and fulminant. Usually targeted involvement as well as cutaneous lesions are seen in
organs are musculoskeletal system, skin, kidneys, nervous systemic sclerosis.