[1349] Myeloid Neoplasms Secondary to Plasma Cell Myeloma: Clinicopathological Study of 11 Cases.

Deepti M Reddi, Elizabeth L Boswell, Chungyi M Lu, Endi Wang. Duke University Medical Center, Durham, NC; University of California San Francisco

Background: Plasma cell myeloma (PCM) has a prolonged clinical course, and secondary malignancies occasionally occur, mostly after treatment for PCM. The risk, etiology, pathogenesis and prognosis of this complication have not been well characterized. Here, we report 11 cases of myeloid neoplasms arising after PCM.
Design: With institutional approval, 11 cases of myeloid neoplasms after diagnosis of PCM were retrieved from our pathology database, and their clinicopathological findings were retrospectively evaluated.
Results: Of 11 cases, 6 are male and 5 are female. Patient age at the diagnosis of PCM ranges from 45 to 71 years with median of 58. Secondary myeloid neoplasms include high risk Myelodysplastic Syndrome (MDS) in 3 cases, intermediate risk MDS in 2 cases, low risk MDS in 5 cases and Polycythemia Vera in 1 case. Ten cases received treatment for PCM. Of these, 6 cases had low dose Melphalan based therapy, 2 had autologous stem cell transplant, 1 case had other chemotherapy and remaining case was treated with Thalidomide/Revlimid. The latency from initiation of treatment to diagnosis of myeloid neoplasm ranges from 9 to 209 months with median of 45. One patient developed low risk MDS 21 months after PCM without PCM treatment. All the cases presented with progressive anemia or cytopenia before the diagnosis of myeloid neoplasm. All but one case showed persistent/residual PCM at the diagnosis with median of 20% plasma cells in bone marrow. Nine of 11 cases showed morphologic features of myelodysplasia on bone marrow biopsy, while 2 cases did not at the diagnosis of secondary malignancy. Nine cases had cytogenetic study performed at the diagnosis, and all demonstrated clonal abnormalities, including 2 cases without morphologic dysplasia. These include -7/7q- in 4 cases, -5/5q- in 3 cases, 20q- in 2 cases and +8 in 1 case, all of which had other abnormalities except for one case with isolated 20q-. Nine cases had follow up, ranging from 18 to 126 months with median of 32. Of these, 4 died of disease progression, and 5 are alive.
Conclusions: Myeloid neoplasms occur after PCM with variable intervals. Most cases had complex cytogenetic abnormalities with changes related to myeloid neoplasm. While majority of the cases had exposure to cytotoxic regimens, mostly Melphalan, one case developed MDS without treatment, which raises a possibility that PCM patients may have an intrinsic predisposition to secondary myeloid malignancy.
Category: Hematopathology

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 161, Monday Morning


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