Flow Cytometric Enumeration of Peripheral Blood CD34+ Cells Predicts Bone Marrow Pathology in Patients with Less Than 1% Blasts by Manual Count.

Background and Aims: Significance of absolute number of CD34+ cells in the peripheral blood of patients with less than 1% myeloblasts by manual differential count is unknown and our aim is to study its relevance in clinical practice. Methods: We studied 138 peripheral bloods flow cytometric analyses in patients with less than 1% myeloblasts by manual differential, when CD34+ events were present in the gate that encompassed lymphocytes, monocytes, stem cells, and blasts. Results: The average absolute number of CD34+cells in the peripheral blood was 11 CD34+cells/µL ranging from less than 1 cell/µL to 147 cells/µL. The average absolute number of CD34+ cells in patients with an abnormal expansive process involving bone marrow (metastases, myelodysplasia, granulomas, marrow infections) or if bone marrow biopsy not performed, presumed expansive marrow process was 25 cells/µL, and in patients without an expansive marrow process (or presumed negative) was 4 cells/µL (P<0.00007). Cutoff 12 CD34+ cells/µL had 93% positive predictive value for bone marrow involvement by an expansive process and 78% negative predictive value. Conclusion: Flow cytometric testing of the peripheral blood is extremely sensitive method for enumerating CD34+ cells and can detect fewer than one CD34+ cell/µL. The absolute number of CD34+ cells in the peripheral blood is a useful parameter in determining marrow involvement by an expansive process and may provide guidance with respect to the necessity for bone marrow biopsy.

Bone marrow involvement with Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous tumour. Most tumours occur in the head and neck, extremities or torso and 36% of them involve the face. Bone marrow involvement in MCC is rare and to our knowledge only nine cases reported in the English literature. Bone marrow biopsy is not usually performed to stage MCC; thus, the true incidence of bone marrow involvement may be under-reported. The majority of the cases reported in the literature have some form of immunosuppression, which suggests a strong association. We report a case of extensive bone marrow involvement from MCC in an 80-year-old Caucasian woman with a history of rheumatoid arthritis treated with adalimumab, methotrexate and prednisone. It may be prudent to include bone marrow biopsy in the staging of MCC in immune-compromised patients.

Three Synchronous Primary Extranodal Mantle Cell Lymphomas Involving Torus Tubarius, Posterior Nasopharynx, and Base of the Tongue 65 Years After Treatment of Chronic Sinusitis with Nasopharyngeal Radium Irradiation.

BACKGROUND Radiation, specifically ionizing radiation, causes broad-spectrum gene damage, including double-strand DNA breaks, single DNA strand breaks, cross links, and individual base lesions, thus causing chromosomal translocations, deletions, point mutations, and, consequently, various types of cancer. Radiation also causes genomic instability in cells, which enhances the rate of mutations in the descendants of the irradiated cell after many generations of normal replications. CASE REPORT We report the first case of mantle cell lymphoma of the torus tubarius, and the first CD10-positive mantle cell lymphoma of the Waldeyer's ring. Mantle cell lymphoma appeared 65 years after treatment of chronic sinusitis with nasopharyngeal radium irradiation. CONCLUSIONS On the basis of the medical literature about atomic bomb survivors, nuclear plant workers, and radiologists exposed to radiation, and our case, we conclude that radiation can, in a very small percentage of exposed individuals, cause non-Hodgkin lymphoma: in 0.24% of atomic bomb survivors and in at least 0.13% of the patients treated with nasopharyngeal radium irradiation. Non-Hodgkin lymphoma can occur many decades after radiation exposure, and individuals treated with nasopharyngeal radium irradiation, usually in their childhood, need continuing follow-up.

Atypical Localization of Malignant Plasma Cells in Non-Viable Cell Area on Flow Cytometry Light-Scatter Dot Plot.

BACKGROUND Multi-parameter (multicolor) flow cytometric study of the bone marrow aspirate is a very useful tool for diagnosis of plasma cell dyscrasia and for evaluation of post-therapy bone marrow for minimal residual disease. CASE REPORT We present a case of a 50-year-old man with multiple myeloma, whose plasma cells on a bone marrow aspirate flow cytometric study showed atypical placement on a light-scatter dot plot, both on forward and side scatter. The bone marrow aspirate sample was 33 hours and 11 minutes old, and the light-scatter dot plot demonstrated that plasma cells, detected by their expression of CD138, CD38, and CD56, occupied an area otherwise characteristic for dead cells and cell detritus. Expressions of CD138 and CD56 were dim (down-regulated). CONCLUSIONS Morphologically atypical plasma cells with irregular nuclear contours/polylobated nuclei from non-fresh samples can present with atypical localization in the area of dead cells. Our study of the multiple myeloma patient with normal localization of plasma cells on a light-scatter dot plot showed a fraction of plasma cells in the dead cell area with dim expression of CD138 and CD56, suggesting that plasma cells may deteriorate (age) rather rapidly, losing surface markers even in less than 24-hour-old specimens. We suggest that the non-viable cell/dead cell area should be checked for expression of CD138 so as not to miss plasma cell dyscrasia, especially if the specimen was run 24 hours after bone marrow sampling.

Coal Mine Dust Desquamative Chronic Interstitial Pneumonia: A Precursor of Dust-Related Diffuse Fibrosis and of Emphysema.

BACKGROUND: Diseases associated with coal mine dust continue to affect coal miners. Elucidation of initial pathological changes as a precursor of coal dust-related diffuse fibrosis and emphysema, may have a role in treatment and prevention. OBJECTIVE: To identify the precursor of dust-related diffuse fibrosis and emphysema. METHODS: Birefringent silica/silicate particles were counted by standard microscope under polarized light in the alveolar macrophages and fibrous tissue in 25 consecutive autopsy cases of complicated coal worker's pneumoconiosis and in 21 patients with tobacco-related respiratory bronchiolitis. RESULTS: Coal miners had 331 birefringent particles/high power field while smokers had 4 (p<0.001). Every coal miner had intra-alveolar macrophages with silica/silicate particles and interstitial fibrosis ranging from minimal to extreme. All coal miners, including those who never smoked, had emphysema. Fibrotic septa of centrilobular emphysema contained numerous silica/silicate particles while only a few were present in adjacent normal lung tissue. In coal miners who smoked, tobacco-associated interstitial fibrosis was replaced by fibrosis caused by silica/silicate particles. CONCLUSION: The presence of silica/silicate particles and anthracotic pigment-laden macrophages inside the alveoli with various degrees of interstitial fibrosis indicated a new disease: coal mine dust desquamative chronic interstitial pneumonia, a precursor of both dust-related diffuse fibrosis and emphysema. In studied coal miners, fibrosis caused by smoking is insignificant in comparison with fibrosis caused by silica/silicate particles. Counting birefringent particles in the macrophages from bronchioalveolar lavage may help detect coal mine dust desquamative chronic interstitial pneumonia, and may initiate early therapy and preventive measures.

Primary cutaneous follicle center lymphoma of the arm with a novel chromosomal translocation t(12;21)(q13;q22): a case report.

We report a reciprocal translocation between the long arms of chromosomes 12 and 21, t(12;21)(q13;q22), in a patient with primary cutaneous follicle center lymphoma. Follicle center lymphoma of the skin and follicle center cell lymphoma of the lymph node are morphologically and immunophenotypically very similar. However, the clinical behavior and prognosis of these tumors are different due to the molecular basis of these malignancies. Follicle center cell lymphoma of the lymph node is determined by the presence of a unique translocation between chromosomes 14 and 18, t(14;18)(q32;q21), BCL-2-JH gene rearrangement, that is not present in primary cutaneous follicle center lymphomas. Chromosomal translocations in the primary skin lymphomas have not been previously reported. We hope that our discovery of a new translocation t(12:21)(q13q22) will encourage further investigation into the molecular basis of this translocation and other cytogenetic abnormalities in primary cutaneous B-cell lymphomas.

Real-time RT-PCR assay for quantifying cyclin D1 mRNA in B-cell non-Hodgkin's lymphomas.

Mantle cell lymphoma (MCL) is a distinct type of non-Hodgkin's lymphoma (NHL) characterized by the t(11;14)(q13;q32), in which the ccnd1 gene is juxtaposed with the immunoglobulin heavy chain gene, resulting in up-regulation of cyclin D1. Cyclin D1 overexpression is a useful finding that supports the diagnosis of MCL. In this study, we used a 5' --> 3' exonuclease-based real-time reverse-transcriptase polymerase chain reaction (RT-PCR) method to quantify cyclin D1 mRNA in 108 B-cell NHL and nonneoplastic specimens, including 25 cases of MCL. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was also quantified to normalize cyclin D1 mRNA levels, and the data were expressed as a cyclin D1 to GAPDH ratio. At each anatomic site, MCL cases had higher cyclin D1 levels than other types of NHL or nonneoplastic specimens, without overlap. For example, in lymph node specimens, the median cyclin D1/GAPDH ratio was 147 (range, 94-160) in MCL, compared with 8.6 (range, 4-18) in chronic lymphocytic leukemia/small lymphocytic lymphoma; 5.8 (range, 1.8-24) in follicular lymphoma; 4.8 in one case of marginal zone lymphoma; and 20.2 (range, 5.8-44) in reactive specimens. Statistical analysis using one-way analysis of variance (ANOVA) showed that MCL cases had significantly higher cyclin D1 levels than other groups (P <.05). In peripheral blood specimens involved by MCL, cyclin D1 levels correlated with extent of involvement. We conclude that this real-time RT-PCR method to quantify cyclin D1 expression is helpful in distinguishing MCL from other types of B-cell NHL and from nonneoplastic specimens. This method is rapid, can be applied to the analysis of fluid specimens, and obviates the need for time-consuming and laborious detection methods that are required by traditional semi-quantitative RT-PCR methods.