Negative E-cadherin expression on bone marrow myeloma cell membranes is associated with extramedullary disease

Background: The loss of E-cadherin expression and the induction of N-cadherin are known as hallmarks of the epithelial-to-mesenchymal transition, an essential initial step in the process of metastasis in solid tumors. Although several studies have reported expressions of these cadherins in patients with multiple myeloma (MM), their clinical significance is unknown as MM cells are non-epithelial. Methods: In this study, we examined the expression of E- and N-cadherins by immunohistochemistry using bone marrow (BM) biopsy specimens from 31 newly diagnosed MM patients and in subsequent biopsy specimens from six of these. Results: Negative E-cadherin expression on BM myeloma cell membranes was significantly associated with the presence of soft-tissue masses arising from bone lesions and breaking through the cortical bone, referred to as extramedullary disease (EMD). Conclusions: Given the aggressive nature of EMD, our study suggests that screening for E-cadherin using BM immunohistochemistry is one measure that could predict the development of EMD in patients with MM.

Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia Incidentally Detected by Fluorodeoxyglucose-positron Emission Tomography/Computed Tomography at a Health Checkup

We herein report a case of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL) that was incidentally detected by fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG PET)/computed tomography (CT) at a health checkup. At that time, the findings of a physical examination and blood tests were all normal, except for the diffuse bone marrow uptake (maximum standardized uptake value: 6.3). One month later, when the blood counts remained in the normal ranges, a bone marrow examination confirmed the diagnosis of Ph-ALL. Although a diffuse bone marrow uptake of ¹⁸F-FDG is observed in some benign conditions, physicians should also consider the possibility of hematological malignancies, including acute leukemia, even when that is the only abnormal finding.

Negative E-cadherin expression on bone marrow myeloma cell membranes is associated with extramedullary disease

Background: The loss of E-cadherin expression and the induction of N-cadherin are known as hallmarks of the epithelial-to-mesenchymal transition, an essential initial step in the process of metastasis in solid tumors. Although several studies have reported expressions of these cadherins in patients with multiple myeloma (MM), their clinical significance is unknown as MM cells are non-epithelial. Methods: In this study, we examined the expression of E- and N-cadherins by immunohistochemistry using bone marrow (BM) biopsy specimens from 31 newly diagnosed MM patients and in subsequent biopsy specimens from six of these. Results: Negative E-cadherin expression on BM myeloma cell membranes was significantly associated with the presence of soft-tissue masses arising from bone lesions and breaking through the cortical bone, referred to as extramedullary disease (EMD). Conclusions: Given the aggressive nature of EMD, our study suggests that screening for E-cadherin using BM immunohistochemistry is one measure that could predict the development of EMD in patients with MM.

[PAX5-positive plasma cell leukemia presenting as lymphocytosis]

An 82-year-old Japanese male patient was initially diagnosed with lymphocytosis. His complete blood count revealed a white blood cell count of 30.9×10⁹/l with 81% abnormal lymphocytes. The abnormal lymphocytes included monoclonal clones of CD38⁺ and CD138⁺cytoplasmic κ⁺ and IgG-κ M-protein, which led to the final diagnosis of plasma cell leukemia (PCL). Bortezomib and dexamethasone therapy was initiated, but the patient succumbed to the disease on the 8th day of hospitalization. A cytogenetic examination revealed a t (9;14)(p13;q32) translocation and the Western blotting confirmed high PAX5 expression. Similar to our present case, PCL cases with "lymphocytosis" have been widely reported, which some speculating the involvement of PAX5 overexpression in the pathogenesis. Such cases, including ours, may be classified as a unique group of disorders (PCL presenting as "lymphocytosis"), which requires accurate differential diagnosis and subsequent urgent multidisciplinary intensive treatment.