Submitting Author: Xie, Ming, MD
Institution: William Beaumont Hospital, OUWB School of Medicine, Troy, MI 48085
Session: AML with myelodysplasia-related changes

In 2006, a 59 year-old female was found to have leukocytosis and monocytosis. A bone marrow biopsy was performed and the diagnosis of chronic myelomocytic leukemia (CMML-1) was made. The patient was followed-up clinically.

In 2008, MRI study showed a mass involving left ankle and subtalar joints. The left ankle shaving specimen was submitted for histological study, and a diagnosis of extramedullary myeloid tumor, consistent with blast transformation of CMML was made after extensive pathological studies. The subsequent bone marrow biopsy reported acute myeloid leukemia with monocytic features and was positive for chromosome evolution. The patient then was treated for acute myeloid leukemia.

The specimen 'left ankle shavings" was submitted, consisting of fragments of soft yellow and white tissue. The specimen was formalin fixed and embedded in paraffin.

Microscopic examination shows large solid sheets of mononuclear cell infiltrate, with some mitoses, apoptosis and focal tumor necrosis. Some cells show epithelioid features. The morphological impression initially was synovial sarcoma, with differential diagnosis including epithelial tumor, other bone/soft tissue tumors, melanoma and hematopoietic neoplasms.

Immunohistochemical findings of the atypical infiltrating cells are:

- negative stain for AE1/AE3, SMA, Desmin, S-100, Melan-A, CD3, CD5, CD20, CD79a, CD1a, CD117, and myeloperoxidase.

- equivocal stain for CD10, CD99, Lca, CD31.

- positive stain for CD68, Vimentin, CD34 and Lysozyme.

In 2006, bone marrow biopsy with CMML showed one abnormal cell line with chromosome 7q deletion [46, XX,del (7) (q22)]

In 2008, bone marrow with blast transformation to acute myeloid leukemia showed chromosome evolution with one abnormal near-tetraploid cell line: 87-93<4n>, XXX, -X, i(1) (q10), +2, -3, +7, +8, -9, -10, -11, +12, +12, -14, +16, -18, +20 [cp17].

in 2006, RT-PCR study was negative for BCR/ABL (major breakpoint)

1.Extra-medullary myeloid sarcoma (chloroma), consistent with blastic transformation from chronic myelomonocytic leukemia (CMML-1).

2. Unusual location, left ankle

3. Epithelioid cellular features.

4. Morphological features resembling synovial sarcoma, epithelioid tumor, and other bone/soft tissue tumors

Extramedullary myeloid sarcoma, consistent with blastic transformation from chronic myelomonocytic leukemia (CMML-1), with cytogenetic evolution.

Extramedullary myeloid sarcoma, consistent with blastic transformation from chronic myelomonocytic leukemia (CMML-1), with cytogenetic evolution

Case 80