Introduction
Methemoglobin (MetHb) and sulfhemoglobin (SHb) measurements are useful in the evaluation of cyanosis. When one or both values are elevated, additional analysis is important to establish the etiology of the disorder. Methemoglobinemia occurs from acquired or hereditary causes with diverse treatment considerations, while true sulfhemoglobinemia is only acquired and treatment is restricted to toxin removal. Some toxic exposures can result in a dual increase in MetHb and SHb. Hereditary conditions, such as M‐Hemoglobin variants (M‐Hbs), can result in increased MetHb and/or SHb values but are clinically compensated and do not require treatment if they are cyanotic but otherwise clinically well.
Methods
Herein, we report 53 hemoglobin variant cases that have associated MetHb and SHb levels measured by an adapted Evelyn‐Malloy laboratory assay method.
Results
Our data indicate M‐Hbs cause variable patterns of MetHb and SHb elevation in a fairly reproducible pattern for the particular variant. In particular, α globin chain M‐Hbs can mimic acquired sulfhemoglobinemia due to an isolated increased SHb value.
Conclusion
If the patient appears clinically well other than cyanosis, M‐Hbs should be considered early in the evaluation process to differentiate from acquired conditions to avoid unnecessary testing and treatment regimens and prompt genetic counseling.
Mutation analysis should be offered to all at-risk couples with borderline HbA₂, especially those with values between 3.5% and 4.0% and microcytic hypochromic indices. Significant mutations different from those in other ethnic populations were seen in this small institution-based study.
Only one case of primary non-secretory plasma cell leukemia with atypical morphology has been reported thus far. Here we report another such case of plasma cell leukemia diagnosed on fl ow cytometry, as morphological heterogeneity and lack of monoclonal immunoglobulins in both serum and urine, made it diffi cult to come to a conclusive diagnosis based purely on morphology.
The association of acute myeloid leukemia (AML) with plasmacytosis is a known, although rare event. There are very few case reports documenting an increase in the number of plasma cells at the time of AML diagnosis. Here, we present the case of a 65-year-old male diagnosed as acute myelomonocytic leukemia with exuberant plasmacytosis, which posed a difficulty in diagnosis. Paracrine interleukin-6 production by leukemic blast cells is thought to contribute to this associated reactive plasma cell proliferation.
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