Gastrointestinal involvement is an unusual presentation for mitochondrial disorders with only 21 reported cases. More typical findings of mitochondrial myopathies are progressive ptosis, ophthalmoplegia and proximal muscle weakness in young patients. All these findings can be found on an internists thorough physical exam, as this case illustrates.`I CAN'T TIE MY SHOES. '' ADENOCARCINOMA OF THE LUNG AND PARANEOPLASTIC ANTIBODY ENCEPHALOPATHY: FOLLOW UP 2 YEARS LATER. K.S. Jorn 1 ; 1 Mayo Community Internal Medicine, Jacksonville, FL (Tracking ID #74452) LEARNING OBJECTIVES: 1. To describe symptoms that may be seen in primary care that should prompt evaluation for paraneoplastic limbic encephalopathy 2. To describe the clinical course of and paraneoplastic antibody levels in this patient over time 3. To present the concept that paraneoplastic antibody levels may not be cost-effective for surveillance after cancer is treated, but additonal study is needed. CASE INFORMATION: A 47 yo nurse presented for primary care in May 2000 after recovering from a massive pulmonary embolus in February 2000. Previous medical history was significant only for tobacco abuse and history of depression and anxiety, stable with medical therapy. Evaluation for causes of the embolus revealed only a 1cm coin lesion in her right lung, stable on follow-up CT through June 2001. In Fall-Winter of 2000, the patient, co-workers, and her supervisors noted a decline in the patient's concentrating ability and documentation efficiency. An accusation of diversion of narcotics triggered severe depression and anxiety in December 2000. The patient was receiving medical and psychological therapy for depression and anxiety when apraxic symptoms such as inability to tie her shoes, loss of direction sense, fecal and urinary incontinence, and absence-seizure type episodes were noted in the spring of 2001. She was felt to have symptoms of limbic encephalopathy. A paraneoplastic antibody panel revealed an elevated P/Q calcium channel antibody. Thoracotomy with removal of the coin lesion July 2001 revealed it to be bronchoalveolar cell carcinoma. Patient's cognitive function has gradually improved to near-normal levels. Though the elevated P/Q antibody led to her cancer diagnosis, the antibody levels have not paralleled her clinical course. IMPLICATIONS/DISCUSSION: Neurologic paraneoplastic antibody syndromes are more typically associated with small cell lung carcinoma and often involve brain stem, cerebellar, or neuromuscular junction dysfunction. There is little literature to guide the follow-up use of paraneoplastic antibody testing after cancer has been treated. This unusual case is characterized by cognitive dysfunction in the presence of lung adenocarcinoma and suggests that follow-up paraneoplastic antibody testing does not add much to clinical assessment after treatment of cancer. Additional studies are needed to determine if there is prognostic information to be gained by surveillance with paraneoplastic antibody testing.