lambert - eaton myasthenic syndrome ( lems ) is known to be closely associated with small cell lung cancer ( sclc ) in 5060% of patients , and 23% of sclc patients also have lems . it was reported that the symptoms of lems , such as muscle weakness , could be improved by chemotherapy for sclc [ 3 , 4 ] . the agent 3,4-diaminopyridine and intravenous immunoglobulin have been demonstrated to be effective for lems [ 5 , 6 ] . the incidence of lung cancer is thought to be similar in hd patients and non - hd patients . however , the treatment for sclc patients with lems on hd has not been well investigated . here , we report the case of a patient who had sclc with lems and who was receiving hd . a chemotherapy regimen consisting of carboplatin ( cbdca ) and etoposide ( vp-16 ) was effective ; however , hd could not be performed due to the development of severe hypotension . we herein discuss the clinical problems associated with this case and emphasize that physicians should be cautious when treating such patients . he had been examined in the neurology department , and magnetic resonance imaging ( mri ) indicated that both his brain and spine were normal . finally , he was diagnosed as having lems because his serum level of anti - voltage - gated calcium channel antibody was extremely elevated ( more than 23,000 fmol / l ) and electrical stimulation showed waxing of muscle . chest computed tomography ( ct ) showed that the right hilar and mediastinal lymph nodes were enlarged . at first , the patient 's muscle weakness was treated with 3,4-diaminopyridine and intravenous immunoglobulin by his primary physician . lung cancer was suspected based on the above - mentioned phenomena ; thus , the patient was referred to our department . on admission the laboratory data were as follows : aspartate aminotransferase 21 iu / l , alanine aminotransferase 10 iu / l , blood urea nitrogen 30 mg / dl , serum creatinine 7.04 mg / dl , neuron - specific enolase 57.5 ng / ml , and pro - gastrin - releasing peptide 1,107.3 pg / ml . cbdca ( 300 mg / m on day 1 ) and vp-16 ( 50 mg / m on days 1 and 3 ) were administered for 4 cycles , followed by a dose reduction for the further courses . four - hour hd was carried out 1 h after giving the regimen . on day 1 , the patient 's blood pressure became unstable after the administration of the anticancer drugs , with the systolic and diastolic blood pressures measured being 64 and 36 mm hg , respectively . hd could not be performed on day 2 because of continuing hypotension . however , on day 3 , both chemotherapy and hd were administered since his blood pressure completely recovered . the area under the blood concentration - time curve of the patient 's serum carboplatin level was 15 . the concentration of total serum platinum was measured 1 , 2.5 , 24 , 48 and 52 h after chemotherapy administration ( fig . he was given platelet transfusion on days 8 , 10 , 16 and 23 due to thrombocytopenia ( grade 4 ) , and granulocyte colony - stimulating factor was used for febrile neutropenia ( grade 4 , days 1125 ) . his lower extremity muscle weakness dramatically improved to the extent that he was able to kneel down by himself . on day 30 , the mediastinal lymph nodes were decreased in size ( 53% shrinkage ) on ct . on day 31 , both neuron - specific enolase ( 4.3 ng / ml ) and pro - gastrin - releasing peptide levels ( 373.4 pg / ml ) were reduced . however , the patient could not continue the chemotherapy regimen because his general condition deteriorated due to the severe hematological adverse effects of chemotherapy and persistent hypotension . cbdca has been reported to have a favorable profile for the treatment of hd patients because the platinum level in the plasma of hd patients receiving cbdca is much more filterable than is the case with cisplatin . the administered dose of 300 mg / m cbdca was comparable to the dose generally used in patients with normal renal function and seemed to be appropriate for achieving sufficient efficacy in sclc patients [ 8 , 10 ] . relatively high - dose chemotherapy using cbdca and vp-16 for patients with sclc undergoing hd has been reported . therefore , we administered a high dose of cbdca and vp-16 under the informed consent of the patient and the patient 's guardian . however , more patients who were treated with a high dose of cbdca experienced severe adverse effects of chemotherapy than patients on a low dose . although the regimen was effective in the present patient , he could not undergo scheduled hd and experienced severe hematologic adverse effects that prevented the administration of further chemotherapy . lems has previously been reported to induce various symptoms , such as muscle weakness , autonomic dysfunction and cranial nerve symptoms . in addition , it is known that cbdca and vp-16 can cause hypotension [ 12 , 13 , 14 ] . therefore , we concluded that the combination of the high concentration of chemotherapeutic agents and lems caused the severe hypotension that prevented the patient from undergoing hd . in other words , there was a detrimental cycle in which the high concentration of cbdca led to hypotension , preventing the use of hd , which resulted in an inability to remove the excess platinum , maintaining the high serum concentration for a longer time than normal . therefore , physicians should be cautious when using chemotherapy in patients presenting with sclc and combined lems because it can lead to hypotension , which is exacerbated in patients needing hd . we herein reported the first case of a patient with sclc and lems who was treated with cbdca and vp-16 while undergoing hd . as a result of the onset of severe hypotension due to the chemotherapy , the patient could not continue hd , which in turn led to further toxicity . more careful consideration should be given when selecting the treatment regimen and dose for patients with sclc and combined lems with crf .