Disseminated BCG infection resembling langerhans cell histiocytosis in an infant with severe combined immunodeficiency: a case report.

We present a very rare congenital immunologic disease, severe combined immunodeficiency syndrome (SCID) in 6-months-old-boy with prolonged mucocutaneous candidiasis, severe anaemia, skin rash similar to the infiltrative eczema of Langerhans cell histiocytosis (LCH) and subcutaneous nodules with histiocytic infiltration. Laboratory findings show profound absence of humoral and cell-mediated immunity. Pathology specimens analysis of subcutaneous nodule revealed numerous S-100 protein and Cd1a negative histiocytes, occupied by BCG intracellular growth. Histopathology and immunohistochemistry confirmed the diagnosis of BCG dissemination. BCG vaccination in infants with SCID can lead to life threatening dissemination, resembling to the infiltrative eczema of LCH and may mislead the clinician.