Multicentric reticulohistiocytosis: report of a case with systemic disease

Multicentric reticulohistiocytosis (RHM) is a rare non Langherhans cell histiocytosis with skin and joint involvment. Nearly all organs can be involved. Association with cancer occurs in about 25% of cases. Association with auto-immune diseases has also been recorded. Microscopic examination Shows a histiocytic nodular infiltrate made of giant cells with ground-glass appearance and PAS positive cytoplasm. Immunostaining shows cell positivity for CD68 and negativity for CD1a and S100 protein. No Birbeck granules are found at ultrostructural examination.