Paraneoplastic disorders of the CNS are a heterogeneous group of neurological disorders associated with systemic cancer which cannot be attributed to direct effects of the neoplasm. Although there is extensive literature focusing on the neurological manifestations of these disorders, the initial presentation is psychiatric in many instances and discussion in the psychiatric literature is relatively sparse.

1. - To bolster recognition and enhanced characterization of paraneoplastic disorders from within the psychiatric community.

2. - To explore temporal aspects of symptom presentation in relation to biopsy.

3. - To identify how psychoneuroimmunological factors may contribute to the development of paraneoplastic disorders.

We report the case of a 48 year-old female with no past psychiatric history who presented with neuropsychiatric symptoms immediately subsequent to biopsy and inflammatory breast cancer diagnosis. Patient was initially admitted to the psychiatric unit for suspected acute stress reaction, yet eventually diagnosed with paraneoplastic extra-limbic encephalitis.

1. - As early oncologic treatment and immunotherapies improve outcomes, early diagnosis is paramount for both treating the paraneoplastic syndrome and identifying possible underlying malignancy.

2. - Time course of symptom presentation raises the intriguing possibility that perturbation of tumor tissues during biopsy may accelerate the immune response to onconeuronal auto-antigens and inflammation-mediated neuronal injury.

3. - Given the patient's acute stress state, the rapid time course of symptom onset, and known connection between psychological stress and autoimmunity, we propose that the immune system stress-response may additionally contribute to the paraneoplastic syndrome development. This connection warrants further investigation from within the psychoneuroimmunology community.