HISTOPATHOGENESIS OF HANSEN’S DISEASE

BY:Dr. RASHMI SINGH

JR-1 ,SKIN&VD

IMPORTANT FEATURES

PATHOGENESIS

Poor growth in culture, but grows in armadillo,

foot pad of mice. Has affinity for schwan cells of peripheral nerves due to : alpha2 laminin in basal laminin present in peripheral

nerves only. peripheral nerves being cooler are more affected .

FLOWCHART OF PATHOGENESIS

AFB IN ZIEHL NEELSEN STAINED SLIDE

INDERMINATE LEPROSY:PERINEURAL INFILTRATION OF LYMPHOCYTES AROUND A DERMAL NERVE

HPE OF HANSEN’S DISEASE

• CAN BE DEALT WITH UNDER :

A.AGRANULOMATOUS which includes: Indeterminate leprosy

B.GRANULOMATOUS which includes : TT BT BB BL LL REACTIONS AND MISCELLANEOUS

INDETERMINATE LEPROSY

HPE: EARLY INDERMINATE LEPROSY: Occasional AFB either in non inflammed nerves ,erector

pylorum muscle or subepidermal zone. LATE INDERMINATE LEPROSY : Varying no. of lymphocytes in perineural sheath with few

AFB bacilli. Baton shaped nuclei with longitudinal orintation is

replaced by disoriented nuclei and loss of normal wavy pattern of nerve.

LL: A WELL FORMED GRANULOMA WITH NUMEROUS M.LEPRA SINGLE AND IN CLUMPS

GRENZ ZONE SEPERATING GRANULOMA FROM THINNED EPIDERMIS

DIAGRAMATIC REPRESENTATION OF LL GRANULOMA IN DERMIS

LEPROMATOUS LEPROSY

Macrophage granuloma is hallmark. A strip of subepidermal zone AKA GRENZ ZONE

seperates granuloma from epidermis. Nerves are not infiltrated with either lymphocytes or

macrophages till late stage. Bacillii are innumerable with considerable no. of globi.

BL:BRANCHING GRANULOMA

BORDERLINE LEPROSY

Granuloma is predominantly of macrophage type with few clumps of epithelioid cells.Mostly branching granulomas.Lymphocytes are sparse.

BB:SHOWING ONION PEEL APPEARANCE

MIDBORDERLINE LEPROSY

Admixture of equal number of macrophage and epitheloid cells.Scattered lymphocytes and less in no. than epitheloid cells.Subepidermal zone is clear.Giant cells are absent diferentiating it from BT.Cut section of nerve shows onion peel appearance.

BT:SHOWING GRANULOMA WITHOUT A DISTINCT COLLAR OF LYMPHOCYTES

BORDERLINE TUBERCULOID

Epitheloid cell granuloma with admixture of few macrophages.Distinct collar of lymphocytes around epithelioid granuloma is lacking.Lymphocytes are moderate in no.with few giantcells.Nerves are replaced by granuloma.Spurs of granuloma along course of nerve can be seen.

TT:SHOWING GRANULOMA WITH A DISTINCT COLLAR OF LYMPHOCYTES

TUBERCULOID LEPROSY

Characterised by epitheloid cell granuloma.Has a tendency to erode a small chunk of epidermis.Obliteration of subepidermal zone.Compact focalized granuloma with mantle of dense

lymphocytes.Granuloma may or may not show central caseation.Nerve may be completely replaced by granuloma.

HPE SHOWING TYPE 1 REACTION

TYPE1 REACTION

Infiltration of granuloma with neutrophils. Dilatation of lymphatics in upper dermis. Intense edema with seperation of collagen and pale

appearance of grranuloma. Macrophage differentiating to epitheloid cells. Influx of more lymphocytes. Disorganized granuloma called tissue panic.

HPE SHOWING TYPE2 REACTION

TYPE 2 REACTION

Features of lepromatous granuloma. Acute inflammatory cell infilteration as neutrophils. Deposition of immune complexes in arterioles and

venules with resulting vasculitis. With increasing severity vessels are obliterated by

thrombosis . Finally ischemia and necrosis results.

MISCELLANEOUS

LUCIO PHENOMENONHISTOID LEPROSY

HPE:SHOWS LEUCOCYTOCLASTIC VASCULITIS AND FOAMY HISTIOCYTES

LUCIO PHENOMENON

First described by RAFAEL LUCIO in 1851. Lucio leprosy presents with ulcerative skin lesions. Thrombosis of vesels leading to local ischemia and

ulceration called LUCIO PHENOMENON. Histology showsvasculitis ,thrombosis and neutrophilic

infiltrate.

HPE: SHOWING NUMEROUS HISTIOCYTES WITH EOSINOPHILIC AND FOAMY CYTOPLASM

HISTOID LEPROSY

First described by WADE in 1963. Presents as localized crops of shiny nodules. Nodules may be large and pedunculated. Histology shows hypercellular granuloma with spindle

shaped cells . Appears as a centrifugal ggrowth compressing fibrous

tissue into clear pseudocapsule. Cells are highly bacillated with predominantly solid

organisms.

REGRESSING LEPROSY

More appreciated in macrophage granuloma.Decrease in no. of macrophage.Cytoplasm of cell becomes foamy with SOAP

BUBBLE appearance.Due to accumulation of fat from disintegrating

cells and bacilli.