Acquired Pelger-Huet anomaly associated with Mycoplasma pneumoniae pneumonia

Pseudo-Pelger-Huët anomaly induced by medications: a clinicopathologic study in comparison with myelodysplastic syndrome-related pseudo-Pelger-Huët anomaly

Pseudo-Pelger-Huët anomaly (PPHA) has been documented in association with transplant medications and other drugs. This iatrogenic neutrophilic dysplasia is reversible with cessation or adjustment of medications but is frequently confused with myelodysplastic syndrome (MDS) based on the conventional concept that PPHA is a marker for dysplasia. We investigated the clinicopathologic features in iatrogenic PPHA and compared them with MDS-related PPHA. The 13 cases studied included 5 bone marrow/stem cell transplantations, 3 solid organ transplantations, 1 autoimmune disease, 3 chronic lymphocytic leukemias, and 1 breast carcinoma. For 12 cases, there was follow-up evaluation, and all demonstrated at least transient normalization of neutrophilic segmentation. All 9 cases of MDS demonstrated at least 2 of the following pathologic abnormalities on bone marrow biopsy: hypercellularity (8/9), morphologic dysplasia (8/9), clonal cytogenetic abnormality (7/9), and increased blasts (3/9), whereas these abnormalities were typically absent in iatrogenic PPHA. Iatrogenic PPHA displayed a higher proportion of circulating PPHA cells than in MDS (mean, 47.4%; SD, 31.6% vs mean, 12.3%; SD, 9.8; P < .01). A diagnostic algorithm is proposed in which isolated PPHA is indicative of transient or benign PPHA unless proven otherwise.

Historical perspective and clinical implications of the Pelger-Hüet cell

The unique historical aspects of Pelger and Huet's discovery of the Pelger-Huet cell highlight the diagnostic challenge that this morphologic finding presents to the physician. Making the diagnosis of the benign autosomal dominant anomaly is complicated by the morphologically similar pseudo-Pelger-Huet cell, which can signify underlying myeloid dsyplasia. This article relates the history of the Pelger-Huet anomaly as well as describes the clinical significance and diagnostic workup for the finding of a Pelger-Huet cell on peripheral smear.

Acquired and reversible Pelger-Huët anomaly of polymorphonuclear neutrophils in three transplant patients receiving mycophenolate mofetil therapy

Deficient nuclear segmentation and abnormal chromatin condensation define Pelger-Huët anomaly of polymorphonuclear neutrophils. Next to the hereditary irreversible form, acquired forms both reversible and irreversible have been described. We describe three transplant patients who were all investigated for a left shift in the absence of symptoms or signs of infection and in whom acquired reversible Pelger-Huët anomaly was discovered. The abnormal PMN phenotype was induced by mycophenolate mofetil (MMF). MMF is a necessary but not sufficient condition for the development of the anomaly. In our three patients a dose-response effect was observed regarding plasma MMF concentration and severity of neutrophil dysplasia. Except for one slightly elevated value, the patients' plasma MMF levels were within the therapeutic range. None of the patients, one who was neutropenic at presentation and two who were non-neutropenic, developed infectious complications. From our three cases as well as those of other authors, we identify previous graft rejection episodes as a potential predisposing factor for the development of PHA. In the first patient, drug withdrawal led to normalization of PMN morphology. In the other two patients, the left shift disappeared after dose reduction. In these latter two patients, a form of desensitization to the effect of MMF on neutro- phils was observed following re-augmentation of MMF dose.

Infectious diseases manifested in the peripheral blood

Although primary diagnosis of infectious disease is uncommonly made from morphologic examination of a blood smear in the United States, knowledge of the distinctive morphologic features of various organisms, coupled with an understanding of the clinical and epidemiologic features of various disorders, permits recognition and diagnosis of uncommonly encountered infections. Furthermore, nonspecific manifestations of infection may provide an important clue in guiding a further diagnostic work-up.