Progressive mucinous histiocytosis treated successfully with thalidomide: a rare case report.

Hereditary progressive mucinous histiocytosis (HPMH) is an extremely rare progressive non-Langerhans cell histiocytic disorder presenting with only cutaneous manifestations. Patients typically present with multiple asymptomatic dome-shaped erythematous papules, usually involving the face and upper extremities. Twenty-six cases have been reported worldwide, with no spontaneous regression. Treatment with thalidomide stopped the progression of the disease in two cases. We report a case of progressive mucinous histiocytosis in a 31-year-old female patient with a history of tuberculosis who presented papular lesions on the face that later extended to the hands. She was treated with isoniazid for tuberculosis and isotretinoin for the skin lesions; the improvement was minimal during the next two months, with new lesions appearing on both hands. Thalidomide stopped the progression of the disease. The cause and pathogenesis of HPMH are undetermined. The pathogenesis of HPMH may be similar to that of lysosomal storage disease, considering the intra-cytoplasmic phospholipid deposition in both diseases, in addition to the likelihood of a role of macrophages in triggering the disease. In our patient, tuberculosis may have contributed.