Hematological findings in an old distressed Dnm2^het mouse. CBC findings in a distressed old female Dnm2^het mouse. One old distressed female Dnm2^het mouse had severe cytopenia (A) and a marked splenomegaly (B). Its BM was entirely effaced by immature myeloid precursors (C). Special stains were performed. Ly6G staining (C) was dramatically reduced. Reticulin staining (D) and Masson’s trichome staining (E) showed early fibrotic changes in the BM of this distress old Dnm2^het mice. Histology slide images were captured using the Aperio AT2 slide scanner at 20X or the CRI Nuance Spectral Imaging microscope, unless specified otherwise.