muramidase and Bone-Marrow-Neoplasms

Histiocytic sarcoma (HS) is a very rare neoplasm that often shows an aggressive clinical course and systemic symptoms, such as fever, weight loss, adenopathy, hepatosplenomegaly and pancytopenia. It may present as localized or disseminated disease. We describe here a 63-yr-old male who manifested systemic symptoms, including fever, weight loss and generalized weakness. Abdominal and chest computed tomography failed to show specific findings, but there was suspicion of multiple bony changes at the lumbar spine. Fusion whole body positron emission tomography, bone scan and lumbar spine magnetic resonance imaging showed multiple bone lesions, suggesting a malignancy involving the bone marrow (BM). Several BM and bone biopsies were inconclusive for diagnosis. Necropsy showed replacement of the BM by a diffuse proliferation of neoplastic cells with markedly increased cellularity (95%). The neoplastic cells were positive for lysozyme and CD68, but negative for T- and B-cell lineage markers, and megakaryocytic, epithelial, muscular and melanocytic markers. Morphologic findings also distinguished it from other dendritic cell neoplasms.

Topics: Antigens, CD; Antigens, Differentiation, Myelomonocytic; Bone Marrow; Bone Marrow Neoplasms; Diagnosis, Differential; Histiocytic Sarcoma; Humans; Magnetic Resonance Imaging; Male; Muramidase; Positron-Emission Tomography; Tomography, X-Ray Computed

We report a case of primary acute myelomonocytic leukemia involving the bone marrow that resembled sarcomatoid carcinoma. The neoplastic cells in bone marrow biopsy specimens formed cohesive-appearing clusters and cords separated by an immature fibroblastic proliferation and myxoid stroma. Blasts in the bone marrow aspirate smears formed clusters and sheets, and a subset of blasts exhibited erythrophagocytosis. Dysgranulopoiesis was also present. Lineage was confirmed by immunohistochemical analysis of formalin-fixed, paraffin-embedded tissue. The tumor cells showed strong reactivity for lysozyme, myeloperoxidase, CD45, and CD68 and were negative for keratin, S100, CD20, and CD3. The serum lysozyme concentration (110 microgram/mL) was 13 times greater than the normal value (8 microgram/mL). Cytogenetic studies performed on bone marrow aspirate material revealed a complex karyotype, including trisomy 8 and abnormalities of chromosome 11q. We report this case of acute myelomonocytic leukemia because the neoplastic cells appeared cohesive and spindled, resembling sarcomatoid carcinoma, and therefore caused diagnostic difficulty. Other monocytic neoplasms with similar resemblance to carcinoma or sarcoma have been reported in the literature, suggesting that the tendency to appear cohesive may be an inherent characteristic of neoplastic cells with monocytic differentiation.

Topics: Biomarkers, Tumor; Bone Marrow; Bone Marrow Neoplasms; Carcinosarcoma; Cytarabine; Cytogenetics; Diagnosis, Differential; Fatal Outcome; Humans; Idarubicin; Immunohistochemistry; Leukemia, Myelomonocytic, Acute; Male; Middle Aged; Muramidase