HISTOID LEPROSY

HISTORY

Coined by Wade in 1960

Gk: ‘Histo’ – Tissue ; ‘Eioid’ – Resemblance

Wade documented MB cases on Dapsone / De Novo

Immunological Profiling by Sehgal et al

INTRODUCTION

First described as a subtype of LL

Pts on long-standing DAPSONE Monotherapy

Initial Improvement Relapse

Drug Resistance / Inadequate treatment / Mutant Organisms

DEFINITION

Histoid Leprosy is an expression of MB Leprosy, characterized by well-demarcated, Papulo-Nodular cutaneous and subcutaneous lesions over apparently normal skin, with infrequent Reactional episodes.

EPIDEMIOLOGY

Age distribution : 10 – 84 Y (commonly 20-39 Y)

Incidence : 3.2% Sehgal & Srivastava 2.8% Kalla et al

Male : Female – 5.7 : 1 ; 20% had ENLKaur, I., Dogra, S., De, D. and Saikia, U.N. (2009), Histoid leprosy: a retrospective study of 40 cases from India. British Journal of Dermatology, 160: 305–310. doi: 10.1111/j.1365-2133.2008.08899

CLINICAL FEATURES

Disseminated, 03-50 in number, Papulonodular, firm soft, erythematous Copper Coloured, hemispherical / dome-shaped / umblicated, Shiny glistening lesions over apparently normal underlying skin over Face, Back, Buttocks and Limbs

Koebnerization ? Pseudo-isomorphic

CLINICAL FEATURES

CLASSIFICATION OF LESIONS :

Subcutaneous NodulesDeeply fixed Cutaneous NodulesSuperficially placed Cutaneous NodulesSoft NodulesPlaques

SUBCUTANEOUS NODULE

aa

CUTANEOUS NODULES

n

KOEBNERIZATION

CUTANEOUS PLAQUES

CLINICAL FEATURES

FACIES: - Old wrinkled atrophic skin with absent eyebrows

- Normal facies without any manifestation of leprosy

Eyebrows and nasal mucosa (cartilage) are spared in most cases

DIFFERENTIAL DIAGNOSES

Conventional Lepromatous nodules / LLENLVon Recklinghausen’s disease / NF-1Molluscum ContagiosumKeloidsPKDLCutaneous SarcoidosisDermofibromaCutaneous Tumours

DIAGNOSIS

HISTORY Treatment history (Duration / Drugs /

Compliance)CLINICAL FEATURES

Histoid Facies / Characteristic Papulo-Nodular cutaneous lesions over apparently normal skin

INVESTIGATIONSSSSHPEIMMUNOLOGY

INVESTIGATIONS

SSS

Abundant Uniform Solid-Stained Red long rods with tapering ends

Bacilli / few Globi (lack of Globea, matrix substance secreted by metabolism of bacilli)

a

INVESTIGATIONS

HPE

Epidermal AtrophyMild AcanthosisFlattening of Rete Ridges

Dermal Histoid Lepromas – Expansive , well –circumscribed granulomas, covered by Pseudocapsule

HPE

Layers of cells in Granuloma Innermost layer - Polygonal Periphery - Spindle shaped histiocytes, containing long AFB arranged in groups along long axis – ‘HISTOID HABITUS’

Numerous Solid-stained bacilli, few Globi

Absence of ETS / Foam (ETS hampers Bacillus metabolism and death) preserved Bacilli in lepra (Virchow) cells

TUBERCULOID CONTAMINATION

Subcutaneous Histoid Lepromas

Definite foci of epitheloid cells located withinlesion substance or encircling fibrous capsule

? Tuberculoid component of Earlier Borderline phase

INVESTIGATIONS

IMMUNOPROFILE (Sehgal et al)

Lowered cell mediated immunityEnhanced humoral immune

response (Raised IgG, IgA, IgM)Diminished complements

TREATMENT

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