The psuedo-Chediak-Higashi anomaly: an unusual staining pattern in an Indian child with acute myeloid leukemia.

The authors describe the psuedo-Chediak-Higashi anomaly in a 12-year-old boy with acute myeloid leukemia (AML-M2). There were large purple granules in the blasts, promyelocytes, and myelocytes. Instead of the previously described patterns, the authors observed a unique rim pattern staining of the granules in both the May-Grunwald-Giemsa and the myeloperoxidase stains. Moreover, many of the granules had central vacuoles with strong myeloperoxidase positivity at the periphery. The bone marrow had a much higher positivity for these mega-granules as compared to the peripheral blood. On remission, these granules were no longer seen. To the best of the authors' knowledge, this pattern of staining has not been previously reported in the literature.