Background: Paraneoplastic encephalomyelitis (PEM) is a well characterized, and typically irreversible, paraneoplastic syndrome, usually associated with small cell lung cancer or other malignancy. We describe a case of a young woman with a benign ovarian teratoma who presented with a reversible PEM. Case report: A 24-year-old woman presented with a three week history of memory impairment, unusual behavior, personality changes, auditory hallucinations, hypersomnolence and binocular diplopia. On admission she was disoriented and inattentive with impaired short term memory. Small doses of lorazepam (1 mg), given for episodic agitation, repeatedly induced multidirectional bilateral nystagmus and a skew deviation, but her neurological examination was otherwise normal. A left-sided pelvic mass was palpable. Brain MRI pre-and post-gadolinium was normal. There was a mild CSF pleocytosis and an EEG showed minimal bilateral background activity irregularities. There were no other laboratory abnormalities. Two weeks after admission, she clinically deteriorated developing central respiratory failure and a flaccid paraplegia. Repeat MRI showed an area of increased T2 weighted signal in the medulla and three similar areas in the spinal cord. Following removal of her tumor, treatment with high dose corticosteroids and intravenous immunoglobulin, she ultimately made a full recovery. Pathology revealed the tumor to be a benign ovarian cystic teratoma. Conclusions: This is the first report of a reversible PEM seen in association with a benign tumor, in this case a mature ovarian teratoma. Presumably, an immune response directed against neural elements of the teratoma crossreacted with normal brain, brainstem and spinal cord antigens to cause neurologic symptoms. Tumor removal was followed by neurologic recovery. R É S U M É : Encéphalomyélite paranéoplasique réversible associée à un tératome bénin de l'ovaire . I n t r o d u c t i o n :L' e n c é p h a l o m y é l i t e paranéoplasique (EMP) est un syndrome paranéoplasique réversible bien caractérisé, habituellement associé à un cancer du poumon à petites cellules ou à un autre type de cancer. Nous décrivons le cas d'une jeune femme porteuse d'un tératome bénin de l'ovaire et qui a présenté une EMPréversible. Présentation clinique: Une jeune femme de 24 ans a consulté pour un problème de mémoire évoluant depuis 3 semaines, un comportement inhabituel, des changements de la personnalité, des hallucinations auditives, de la somnolence et de la diplopie binoculaire. À l'admission, elle était désorientée et inattentive et présentait un déficit de la mémoire à court terme. De petites doses de lorazépam (1mg), administré pour contrôler une agitation épisodique, ont induit à plusieurs reprises un nystagmus bilatéral multidirectionnel et une disjonction des mouvements du regard. Son examen neurologique demeurait par ailleurs normal. La palpation de l'abdomen a révélé une masse pelvienne gauche. L'IRM cérébrale pré et post-gadolinium était normale. Il existait une pléiocytose légè...

Objective: Some features of attention-deficit/hyperactivity disorder (ADHD) may resemble those of mild cognitive impairment (MCI) in older adults, contributing to diagnostic uncertainty in individuals seeking assessment in memory clinics. We systematically compared cognition and brain structure in ADHD and MCI to clarify the extent of overlap and identify potential features unique to each. Method: Older adults from a Cognitive Neurology clinic (40 ADHD, 29 MCI, 37 controls) underwent neuropsychological assessment. A subsample ( n = 80) underwent structural neuroimaging. Results: Memory was impaired in both patient groups, but reflected a storage deficit in MCI (supported by relatively smaller hippocampi) and an encoding deficit in ADHD (supported by frontal lobe thinning). Both groups displayed normal executive functioning. Semantic retrieval was uniquely impaired in MCI. Conclusion: Although ADHD has been proposed as a dementia risk factor or prodrome, we propose it is rather a pathophysiologically-unique phenotypic mimic acting via overlap in memory and executive performance.

Background: Attention deficit/hyperactivity disorder (ADHD) is increasingly being recognized in adults and older adults. Some of its behavioral features (e.g., distractibility, forgetfulness, impulsivity) may resemble those of mild cognitive impairment (MCI), which contributes to diagnostic uncertainty in later life. The present study aimed to systematically compare ADHD and MCI on measures of cognition and structural neuroimaging to clarify the extent of their overlap (i.e., cognitive features of ADHD that are most likely to be taken for signs of MCI) and identify potential features unique to each disorder (i.e., that may be used to guide diagnostic impressions). Methods: One hundred and six adults aged 50 years or above were recruited from a Cognitive Neurology clinic (40 ADHD, 29 MCI and 37 controls) completed a comprehensive neuropsychological battery. A subsample (n=80) underwent structural neuroimaging.Results: Memory was impaired in both patient groups, but reflected a storage deficit in MCI (supported by imaging findings of reduced hippocampal volumes) and an encoding deficit in ADHD (supported by frontal-lobe cortical thinning). Both groups performed normally on executive measures. Semantic retrieval was uniquely impaired in MCI.Conclusions: Behavioral and structural imaging features strongly suggest that ADHD and MCI are similar manifestations of separate pathophysiological processes. Although ADHD has been proposed as a risk factor or prodromal stage of neurodegeneration, we propose it is rather acting as a phenotypic mimic of MCI via overlap in memory and executive performance.