Primary Histiocytic Sarcoma of the Brain in an African Hedgehog (Atelerix albiventris).

A 2.5-year-old African hedgehog (Atelerix albiventris) with signs of progressive paresis/paralysis for approximately 6 months was diagnosed with 'wobbly hedgehog syndrome' (WHS). Post-mortem examination revealed a primary central nervous system (CNS) histiocytic sarcoma (HS) associated with neurodegenerative changes of the CNS and skeletal muscle atrophy. Grossly, a spherical mass infiltrated the left forebrain and was located between the frontal lobe and thalamus in coronal sections. Microscopically, the neoplastic cells had eccentrically located anisokaryotic nuclei and abundant eosinophilic cytoplasm. Immunohistochemically, they were positive for calcium-binding adapter molecule 1, lysozyme, CD68 and vimentin. Ultrastructurally, the neoplastic cells had varying amounts of bundles and whorls of intermediate filaments and scattered lysosomes. This report represents the first documentation of primary CNS HS in this species. Primary CNS HS should be considered as a differential diagnoses for hedgehogs that present with neurological signs of WHS.