Pediatric acute leukemia presenting as bilateral renal enlargement. Report of a case with fine needle aspiration cytologic features suggestive of megakaryocytic differentiation

BACKGROUND: Fine needle aspiration (FNA) cytologic diagnosis of acute myeloid leukemia involving the kidney has rarely been reported, but acute leukemia with cytologic features suggestive of megakaryocytic differentiation has not been described before. CASE: An 8-month-old male presented with an abdominal swelling, bilateral cervical and inguinal lymphadenopathy and enlarged left epididymis. Ultrasonography of the abdomen revealed a space-occupying lesion in the liver and bilateral enlargement of the kidneys. FNA smears from the right kidney and right submandibular lymph node showed numerous blast cells. Since rare blast cells were positive for myeloperoxidase, a cytodiagnosis of involvement by acute myeloid leukemia (AML) was made. However, following the hematologic diagnosis of acute megakaryoblastic leukemia (M7) from peripheral blood and bone marrow smear examination, FNA smears were reviewed. There were cytoplasmic blebs or protrusions in the blast cells and cytologic features suggestive of their differentiation toward micro-megakaryocytes and megakaryocytes. There was also evidence of shedding of platelets, including numerous giant platelets. The reviewed FNA cytodiagnosis was suggestive of AML (M7). CONCLUSION: Extramedullary involvement by acute megakaryoblastic leukemia (M7) can be suspected based on cytomorphologic features in FNA smears.     

Pathogenic simian/human immunodeficiency virus SHIV(KU) inoculated into immunized macaques caused infection, but virus burdens progressively declined with time

Using the simian immunodeficiency virus/human immunodeficiency virus (SHIV)-macaque model of AIDS, we had shown in a previous report that a live, nonpathogenic strain of SHIV, further attenuated by deletion of the vpu gene and inoculated orally into adult macaques, had effectively prevented AIDS following vaginal inoculation with pathogenic SHIV(KU). Examination of lymph nodes from the animals at 18 weeks postchallenge had shown that all six animals were persistently infected with challenge virus. We report here on a 2-year follow-up study on the nature of the persistent infections in these animals. DNA of the vaccine virus was present in the lymph nodes at all time points tested, as far as 135 weeks postchallenge. In contrast, the DNA of SHIV(KU) became undetectable in one animal by week 55 and in three others by week 63. These four macaques have remained negative for SHIV(KU) DNA as far as the last time point examined at week 135. Quantification of the total viral DNA concentration in lymph nodes during the observation period showed a steady decline. All animals developed neutralizing antibody and cytotoxic-T-lymphocyte responses to SHIV(KU) that persisted throughout the observation period. Vaccine-like viruses were isolated from two animals, and a SHIV(KU)-like virus was isolated from one of the two macaques that remained positive for SHIV(KU) DNA. There was no evidence of recombination between the vaccine and the challenge viruses. Thus, immunization with the live vaccine not only prevented disease but also contributed to the steady decline in the virus burdens in the animals.