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.

Nodular fasciitis of the tongue: A case report in an infant.

Nodular fasciitis is a benign lesion uncommonly found in the head and neck region. Although described previously in adults, there have been no reports of nodular fasciitis in a child's tongue. A 4 month old male infant was referred for evaluation of a rapidly growing tongue lesion. He underwent excisional biopsy of the lesion. Initial pathology suggested a spindle cell tumor. Subsequent outside facility molecular testing was obtained and Nodular Fasciitis was confirmed. Nodular fasciitis is a rare benign tumor that can be often mistaken for malignancy. Special histochemical and molecular testing is required to obtain final diagnosis.

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.