Acute myelofibrosis in progressive systemic sclerosis. Report of a case developing during long term chlorambucil therapy and discussion of pathogenetic factors.

A case of acute myelofibrosis occurring in the course of long-term chlorambucil therapy for cardiac manifestations of progressive systemic sclerosis (PSS) is reported. Although hematologic malignancies have been known to develop consequent to long-term use of alkylating agents, and bone marrow suppression is well known, acute myelofibrosis has not, to our knowledge, been reported as a complication of this therapy, nor has any specific myeloproliferative syndrome been described consequent to such therapy in a patient with PSS. As abnormal fibroblastic proliferation is central to both PSS and myelofibrosis, it may be speculated that the patient with scleroderma may be predisposed to this particular expression of hematologic dyscrasia. The roles of fibroblastic proliferation, and immunologic and vascular factors in these two illnesses are currently poorly understood.