Multicentric reticulohistiocytosis: response to alkylating agents in six patients

To determine the efficacy of alkylating agents in multicentric reticulohistiocytosis.

Open consecutive case series.

Tertiary-care referral clinic.

Six patients with skin-biopsy-proven multicentric reticulohistiocytosis. All had skin nodules and polyarthritis.

Five patients received cyclophosphamide (dose range, 1.25 to 2.2 mg/kg body weight) and one patient received chlorambucil (0.1 mg/kg). Therapy was administered from 6 to 24 months.

In five patients treated with cyclophosphamide a response was seen within 4 months. Four patients eventually had a complete remission and one had almost a complete remission. The four patients in complete remission had cyclophosphamide therapy discontinued after 6, 12, 16, and 18 months. Three of the four patients remained in complete remission off therapy at 6, 6, and 22 months, whereas one had a recurrence after 6 months. The one patient given chlorambucil went into a complete remission and stopped treatment after 12 months. He remained in complete remission 32 months after stopping medication.

Our experience with patients with aggressive multicentric reticulohistiocytosis shows that alkylation therapy is warranted. We conclude that a response to an alkylating agent may be expected. Whether after treatment for 6 to 18 months most patients may be able to discontinue the drug and remain in remission has yet to be shown. The rarity of multicentric reticulohistiocytosis precludes the possibility of a double-blind study.