Discrete T-lymphocytic leptomeningitis of the ventral medullary surface in a case of Sudden Unexpected Infant Death

The Authors report the case of a 4 month old female infant dying suddenly and unexpectedly. At post-mortem examination, nothing significant was found, except a focal T-lymphocytic brainstem leptomeningitis, involving the ventral medullary surface (VMS) particularly coincidental with the pyramids, with involvement of the outer layer of the nucleus arcuatus (NARC). Moreover, the NARC itself presented, on serial sections, interdigitated subdivisions. To the present authors' best knowledge, no case has been recordered in the literature, as yet, exhibiting VMS inflammation, evidently acquired (likely viral) in nature, associated to a NARC developmental defect, altogether bespeaking for the etio-pathogenic importance of such a combined pathology of the central chemosensitive field among the long debated mechanisms of SIDS.