Lupus vulgaris developing at the site of misdiagnosed scrofuloderma

Abstract

Cutaneous tuberculosis is a rare form of extrapulmonary tuberculosis primarily occurring in developing countries. The recent increase in the incidence of tuberculosis, especially due to human immunodeficiency virus (HIV) infections, has led to a resurgence of extrapulmonary forms of this disease. We describe a case of lupus vulgaris in a 33-year-old woman who had a 5-year history of a slowly growing plaque on her neck. The lesion was located at the site of surgery repairing the scar resulting from the incision of a subcutaneous abscess during childhood. This lesion was misdiagnosed as bacterial abscess. Histopathologic examination of the plaque revealed non-caseating tuberculoid granulomas consisting of lymphocytes, epithelioid and giant cells. Staining for acid-fast bacilli and culture from biopsied tissue was negative. Polymerase chain reaction (PCR) for detection of Mycobacterium tuberculosis DNA, performed on a skin biopsy specimen, was positive. A diagnosis of lupus vulgaris developing at the site of a previous misdiagnosed scrofuloderma was made. Conventional antitubercular therapy with rifampicin, isoniazid and ethambutol was administered for 6 months, resulting in resolution of the lesion.

Cutaneous tuberculosis: epidemiologic, etiopathogenic and clinical aspects - Part I

“…14 In addition to the endogenous source, it may develop upon the drainage scar of scrofulodermas or rarely be acquired by exogenous Mtb inoculation. 33 …”

Association of lupus vulgaris and multifocal tuberculous dactylitis and arthritis with multiple tuberculous scars

“…Lupus vulgaris is characterized by macule or papule, with a brownish‐red color and soft consistency that form larger plaques by peripheral enlargement and coalescence. If untreated, the disease course may continue many years and lead to significant impairment of function and disfiguration 6 . Our patient had multiple tuberculosis scars on her feet and face.…”

Scrofuloderma Following BCG Vaccination

“…Cutaneous tuberculosis is caused by Mycobacterium tuberculosis and Mycobacterium bovis (1). Scrofuloderma, one of the most common forms of cutaneous tuberculosis, results from a tuberculous process in an underlying focus, such as tuberculous lymphadenitis and tuberculosis of the epididymis, bone, and joints, with formation of cold abscesses, and a secondary breakdown of the overlying skin (2–4). Sometimes vaccination with the Bacillus Calmette‐Guerin (BCG) vaccine is also a cause of scrofuloderma (1,4).…”