Elsevier

Mayo Clinic Proceedings

Volume 78, Issue 11, November 2003, Pages 1363-1368
Mayo Clinic Proceedings

Original Article
Clinical, Magnetic Resonance Imaging, and Electroencephalographic Findings in Paraneoplastic Limbic Encephalitis

https://doi.org/10.4065/78.11.1363Get rights and content

Objective

To analyze clinical presentation of and paraclinical test abnormalities in patients with paraneoplastic limbic encephalitis (PLE).

Patients and Methods

We retrospectively reviewed 24 patients seen at the Mayo Clinic in Rochester, Minn, between 1985 and 2002 in whom PLE was suspected. Patients were identified on the basis of clinical history and presence of cancer. Data were reviewed from magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis, electroencephalography (EEG), and paraneoplastic serologic studies.

Results

Common manifestations were cognitive dysfunction (92%), seizures (58%), and psychiatric symptoms (50%); 13 patients had small cell lung carcinoma; 11 had other malignancies. Paraneoplastic neuronal autoantibodies were found in 14 (64%) of 22 patients tested. Electroencephalography showed focal or generalized slowing and/ or epileptiform activity, maximal in the temporal regions, in all 22 patients tested. Magnetic resonance imaging revealed increased T2 signal involving one or both temporal lobes in 15 (83%) of 18 patients. Cerebrospinal fluid test results were abnormal in 18 (78%) of 23 patients tested. Clinical or radiographic evidence of extralimbic involvement was documented in 12 (55%) of 22 patients. No abnormality on EEG, MRI, or CSF analysis correlated with a specific cancer type or with a specific paraneoplastic autoantibody.

Conclusions

In patients with suspected PLE, EEG is invaluable for confirming cerebral dysfunction. Magnetic resonance imaging can show unequivocal involvement of temporolimbic structures and helps exclude other diagnoses. When EEG and cranial MRI are both normal, PLE is unlikely. Comprehensive testing for paraneoplastic neuronal nuclear, cytoplasmic, and ion channel autoantibodies is an important part of the evaluation, but negative results do not rule out PLE.

Section snippets

Clinical Material

We used the Mayo Clinic medical records linkage system to identify 24 patients (seen at the Mayo Clinic in Rochester, Minn, between 1985 and 2002) in whom PLE was suspected. The study was approved by the Mayo Foundation Institutional Review Board. Paraneoplastic limbic encephalitis was defined as cognitive changes, seizures, or psychiatric symptoms having a subacute onset (during a period <6 months) and accompanied by histological confirmation of malignancy. Cases were excluded if another

Clinical Features

We identified 24 patients with PLE (Table 1); 2 patients were reported previously.15, 16 The median age was 61 years (range, 23-72 years). Thirteen patients had histologically proven SCLC; the other 11 had other types of cancer (3 breast adenocarcinoma, 2 thymoma, 1 testicular embryonal cell carcinoma, 1 testicular seminoma, 1 renal cell carcinoma, 1 lung carcinoid tumor, 1 lung adenocarcinoma, and 1 lung squamous cell carcinoma). In most patients (18/24), neurologic symptoms preceded the

Discussion

Laboratory investigations play an important role in the evaluation of suspected PLE. This diagnosis should be suspected in any patient with subacute onset of cognitive impairment, particularly when associated with seizures. However, clinical seizures are not a constant feature, and PLE also must be considered in the differential diagnosis of patients with a subacute psychiatric presentation. Our findings are similar to those reported in previous studies of PLE,4, 17 but our study has several

Conclusions

The identification of limbic dysfunction without definable cause should suggest the possibility of PLE and lead to a search for occult malignancy. Investigations should be performed to confirm cerebral dysfunction, show involvement of temporolimbic structures, and exclude meningoencephalitis due to infectious or carcinomatous processes. The EEG is invariably abnormal, reflecting the presence of cerebral dysfunction predominantly involving the temporal regions. Detection of epileptiform

REFERENCES (23)

  • CF Lucchinetti et al.

    Paraneoplastic and oncologic profiles of patients seropositive for type 1 antineuronal nuclear autoantibodies

    Neurology

    (1998)
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    1

    Dr Lawn is now with the Royal Perth Hospital, Perth, Australia.

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