A 55-year-old lady presented in dermatology outpatient with four month history of multiple asymptomatic discrete voilaceous patches and plaques on her arms and legs. She has no history of fever, night sweats, dyspnoea or chest pain.

She has a past history of pulmonary tuberculosis three years previously. Open lung biopsy showed extensive granulomatous inflammation with central confluent caseous necrosis. Acid fast bacilli were identified on Ziehl Neelsen staining. She was successfully treated with antituberculous therapy. She has history of hypothyroidism and diabetes mellitus. There was no family history of Tuberculosisor Sarcoidosis.

On clinical examination, she has scattered voilaceous indurated plaques on the extensor of arms, legs, and hands. Her systemic examination was unremarkable. Histopathology revealed extensive non-caseating granulomata with minimal surrounding inflammatory well defined infiltration (Figure.1). These changes were consistent with Sarcoidosis. PAS and Zeil Nelson stains were negative. Biopsy showed no mycobacterial growth on culture. Polymerase chain reaction (PCR) analysis for mycobacterium DNA was negative. Blood count, ESR, renal, liver and bone profile, calcium and phosphate, serum angiotensin converting enzyme levels were normal. Her chest X-ray and pulmonary function tests were normal. Her plaques continued to regress without any specific treatment.

Figure 1: (H&E X 40) Skin biopsy showing well defined non-caseating granuloma in the upper dermis with minimal surrounding lymphocyte inflammatory infiltration consistent with cutaneous sarcoidal reaction.

Discussion
We report a case of 55-year-old lady diagnosed with pulmonary tuberculosis three years earlier and successfully treated with antituberculous therapy, who presented with recent onset of cutaneous sarcoidosis.Sarcoidosis is a multisystemic granulomatous disease characterized by non-caseating epithelioid granulomas that may affect any organ system. Although Jonathan Hutchinson described the first case in 1869, the etiology of the disease is still unknown. Recent progress, in immunology and molecular biology, has advanced our understanding of the pathogenesis of the disease and helped to focus the search for causative agents. Due to histological similarities between tuberculosis and sarcoidosis, mycobacteria have drawn the most attention as a potential etiologic agent of sarcoidosis². This was further supported by reports of the isolation of acid-fast organism in some cases of sarcoidosis³.

Recently, several studies have shown mycobacterial DNA complex mainly mycobacterium tuberculosis and mycobacterium avium in lung tissue and bronchial lavage fluid from patients with sarcoidosis using polymerase chain reaction (PCR) assays^4,5. Other studies have failed to identify such organisms in majority of tissue samples from patients with sarcoidosis⁶.

Cutaneous involvement is seen in 25% of patients with in sarcoidosis. It may be the only site of involvement when it can be referred to as cutaneous sarcoid reaction.The concomitant presence of pulmonary tuberculosis and systemic sarcoidosis has been reported previously.⁷ This case report serves to remind us of the potential link between these two granulomatous diseases.

References

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