Case of the Month

ACUTE PARVOVIRUS B19 INFECTION MIMICKING MYELODYSPLASTIC SYNDROME OF THE BONE MARROW

Provided by Dr. Khorsand, MD

CASE HISTORY:

The patient, a 36 year old female, went to the emergency room with a fever and flank pain. She was admitted and was found to be pan cytopenic with a WBC of 1.7, K/mm3. Absolute neutrophil count of 1.1, hemoglobin of 11.6, hematocrit of 33.3 and platelet count of 124 K/mm3. A bone marrow aspiration and biopsy was performed.

MICROSCOPIC FINDINGS:

Bone marrow aspirate and biopsy examination revealed a cellular bone marrow with left shift in granulocytic cell lines and marked absence of erythroid precursors. Giant megaloblastoid proerythroblast were easily identified with large intranuclear inclusions resembling nucleoli. Bone marrow biopsy was quite cellular with focal increase in the number of giant proerythroblasts with prominent intranuclear eosinophilic inclusion bodies. Parvovirus B19 IgM serology was elevated at 9.8 with reference range at <0.9.

DIAGNOSIS:

ACUTE PARVOVIRUS B19 INFECTION MIMICKING MYELODYSPLASTIC SYNDROME OF THE BONE MARROW

DISCUSSION:

Parvovirus B19 is the only known human pathogenic parvovirus with a high degree of tropism to human bone marrow and replicates only in erythroid progenitor cells. In patients with underlying hemolytic disorder, infection with parvovirus B19 causes transient aplastic crisis. In immunosuppressed patients, the infection may cause pure red cell aplasia and chronic anemia. Diagnosis is based on examination of bone marrow and serologic confirmation. In normal patients, parvovirus B19 infection is often associated with neutropenia and thrombocytopenia.

The cellular receptor for parvovirus B19 is a neutral glycosphingolipid called globaside, found on erthyroid progenitors. A giant proerythroblast, 25-32 ┬Ám in diameter with a large eosinophilic nuclear inclusion body is the characterisitic finding. IgM antibody to B19 appears 10-14 days after infection.

 

REFECERENCES:

  1. H. Baurmann, T.F. Schwartz, J. Oertel, S. Serke

Annals of hematology, Jan 1992, Volume 64, pp-43-45

  1. Kevin E. Brown, Neal S. Young

Stem Cell 1996; 14: 151-163

 

Wright stain; X100: giant megaloblastoid proerythroblasts with nuclear inclusions
Wright stain; X100: giant megaloblastoid proerythroblasts with nuclear inclusions
Wright stain; X100: giant proerythroblast with a few immature blast cells
Wright stain; X100: giant proerythroblast with a few immature blast cells
H&E stain; X20: cellular bone marrow with marked absence of erythroid precursors and left shift in myeloid series
H&E stain; X20: cellular bone marrow with marked absence of erythroid precursors and left shift in myeloid series
H&E stain; X10: cellular bone marrow with marked absence of erythroid precursors and left shift in myeloid series