A Singular Case of Intracranial Sinus Histiocytosis without Massive Lymphadenopathy: Isolated Rosai-Dorfman Disease of the Hypothalamus.

BACKGROUND: Sinus histiocytosis with massive lymphadenopathy (also known as Rosai-Dorfman disease [RDD]) is a benign but chronic cervical lymphadenopathy associated with systemic inflammation. Although extranodal manifestations of RDD have been described, isolated central nervous system (CNS) involvement is exceedingly rare. CASE DESCRIPTION: We present the case of a 66-year-old woman who presented with 3 weeks of intermittent headaches, diplopia, and increasing confusion who was found on work-up to have isolated hypothalamic RDD, evidenced by a dense admixture of large histiocytic cells admixed with numerous small mature lymphocytes and some scattered plasma cells and neutrophils on stereotactic brain biopsy. Over 19 months of follow-up, neurologic examination continues to reveal stable bilateral partial abducens nerve palsies without diplopia, and a new gradual onset short-term memory loss. Interim treatment for the histiocytic lesion consisted of 10 cycles of external-beam radiation therapy along with high-dose steroids. The patient currently experiences minimal functional loss from treatment of her intracranial sinus histiocytosis, with a Karnofsky performance status of 80, and she remains without any disease involvement outside of the CNS. CONCLUSION: Because misdiagnosis of a hypothalamic contrast-enhancing lesion could potentially lead to therapeutic mismanagement and poor outcomes, it is important to consider RDD in the differential diagnosis.

Differential loss of synaptic proteins in Alzheimer's disease: implications for synaptic dysfunction.

The objective of our research was to determine synaptic protein levels in brain specimens from AD subjects and age-matched control subjects. Further, to determine whether presynaptic or postsynaptic compartments of neurons are preferentially affected in AD patients, we studied 3 presynaptic vesicle proteins (synaptotagmin, synaptophysin, and Rab 3A), 2 synaptic membrane proteins (Gap 43 and synaptobrevin), and 2 postsynaptic proteins (neurogranin and synaptopodin) in specimens from AD and age-matched control brains. Two brain regions--the frontal and parietal cortices--were assessed for protein levels by immunoblotting analysis. We found a loss of both presynaptic vesicle proteins and postsynaptic proteins in all brain specimens from AD patients compared to those from age-matched control subjects. Further, we found that the loss of synaptic proteins was more severe in the frontal cortex brain specimens than in the parietal cortex brain specimens from the AD subjects compared to those from the control subjects, suggesting that the frontal brain may be critical for synaptic function in AD. Using immunohistochemistry techniques, we also determined the distribution pattern of all synaptic proteins in both the frontal and parietal cortices brain specimens from control subjects. Of the 7 synaptic proteins studied, the presynaptic proteins synaptophysin and rab 3A and the postsynaptic protein synaptopodin were the most down-regulated. Our study suggests that postsynaptic proteins and presynaptic proteins are important for synaptic function and may be related to cognitive impairments in AD.