Mycobacterium tuberculosis as a sarcoid factor? A case report of family sarcoidosis

PATIENT Male, 26 FINAL DIAGNOSIS: Sarcoidosis Symptoms: Disseminated lung parenchymal changes Medication: - Clinical Procedure: - Specialty: Pulmonology. OBJECTIVE Rare disease. BACKGROUND Sarcoidosis is a granulomatous inflammatory disease that is induced by unknown antigen(s) in a genetically susceptible host. Although the direct link between Mycobacterium tuberculosis (MTB) infection and sarcoidosis can be excluded on the basis of a current knowledge, the non-infectious mechanisms may explain the causative role of mycobacterial antigens. The co-incidence of tuberculosis (TB) and sarcoidosis, and higher incidence of mycobacterial DNA in biological samples of sarcoid patients, have been reported by many authors. CASE REPORT We present a case in which MTB infection in 1 family member triggered a sarcoid reaction in the infected subject and 2 other non-infected family members. We discuss different aspects of diagnosis and differentiation, as well as up-to-date hypotheses on the possible mechanisms leading to sarcoid inflammation in patients exposed to MTB. CONCLUSIONS This case series documents the possibility of familial spreading of sarcoidosis, and points to MTB as a potential etiological factor.