We describe a rare case of secondary
malignant fibrous histiocytoma (MFH) following
Langerhans cell histiocytosis (LCH). A 23-year-old Japanese male exhibited systemic
lymphadenopathy, multiple lung
tumors, and osteolytic changes in bilateral iliac bones in 1989. A biopsy specimen from the left iliac bone revealed an infiltration of
S-100 protein-positive histiocyte-like cells intermingled with eosinophils, which confirmed the diagnosis of
eosinophilic granuloma, a type of LCH. Although the patient was treated with
prednisolone initially, the disease did not respond well and progressed gradually over time. The patient subsequently received multiple courses of
chemotherapy and immunosuppressive therapy with many kinds of
anticancer agents for 6 years. He also received
radiotherapy totaling 136.8 Gy for lung
tumors and osteolytic lesions of the pelvis. In 1997, because of the LCH refractoriness, biopsy was performed again from the right inguinal lymph node. Microscopic examinations demonstrated a mixture of spindle-shaped cells and histiocyte-like cells, which appeared to be in a storiform pattern. The
tumor cells were immunohistologically positive for CD68 and
vimentin, but negative for CD1a and
S-100 protein. Therefore, the patient was diagnosed with MFH. Although
chemotherapy was continued, the patient died of
pneumonia during the neutropenic period following
chemotherapy. Autopsy revealed systemic invasion of MFH and dissemination of
mucormycosis. LCH was not detected histologically in any tissues.