a 42-year - old woman diagnosed with stage iv nsclc ( adenocarcinoma ) was admitted to our hospital in august 2013 and given an ap regimen ( pemetrexed 500 mg / m on day 1 , cisplatin 75 mg / m on days 1 to 3 , repeated every 3 weeks ) as initial chemotherapy on august 2nd , 2013 . several days later , her egfr genetic test results demonstrated an exon 19 mutation ( l747-t751>p ) ; thus , she started taking gefitinib ( 250 mg once daily ) on august 15th . on august 23th , which was 21 days after ap chemotherapy and 8 days after gefitinib treatment , the patient suddenly developed a widespread eruption including acne - like rash on the face , erythema papules on the trunk and limbs , oral ulcer , and conjunctivitis ( figure 1a and 1b ) , followed by a fever of 39c . the rash gradually increased and aggravated , accompanied with blisters , pruritus , and ulceration . gefitinib was immediately stopped , and imipenem , amikacin , and fluconazole were administered intravenously as prophylaxis , and diphenhydramine and loratadine were given as an anti - allergy treatment . on the 13th day , the patient 's condition deteriorated further with a fever of 42c , fused mucocutaneous rash as well as diffuse vesicles and bullae ( figure 1c and 1d ) , which coalesced and then sloughed , presenting a scalded appearance . a positive nikolsky sign was present on her back and feet ( figure 1e and 1f ) . after consulting dermatology doctors , the patient was diagnosed with ten and transferred to the dermatology department at the second affiliated hospital of sun yat - sen university for further treatment . routine laboratory testing showed a white blood cell ( wbc ) count of 6.26  10/l [ reference value : ( 3.69 - 9.16 )  10/l ] , neutrophil ( neu ) proportion of 73.1% ( reference : 50%-70% ) , and c - reactive protein ( crp ) level of 16.36 mg / l ( reference : 0 - 8.2 mg / l ) ; both the mycoplasma pneumoniae igm antibody and mac strains were negative . no suspicious fungus was found in the oral swab examination , nor did bacteria grow in the skin secretion culture . immunosuppressive treatment was started with 100 mg methylprednisolone ( daily injection ) for 9 days and intravenous immunoglobulin ( 20 g / day ) for 5 days , followed by 10 g / day for 5 days , accompanied with imipenem and teicoplanin for anti - infection and other supportive treatment . this treatment led to a recurrence of the rash and the mucosal lesions , reepithelization of the denuded skin ( figure 2 ) , and improvement of the patient 's general condition within 40 days . a chest computed tomography ( ct ) scan and brain magnetic resonance imaging ( mri ) showed partial remission after treatment . the combination of ap and gefitinib was suspended ; accordingly , the patient began treatment with icotinib ( another egfr - tki made in china ) after recovery , without exfoliative dermatitis or other similar toxicities . stable disease was later achieved . on the 8th day after gefitinib treatment , diffuse erythema papules were observed on the trunk ( a ) and palms ( b ) ; on the 13th day , fused skin rash and diffuse vesicles and bullae ( c ) as well as erosive lip mucosa ( d ) were observed ; on the 16th day , fused and sloughed systematic herpes ( e ) and plantar blister ( f ) were observed . the systematic rash gradually crusted and desquamated ( a and b ) ; reepithelization of the denuded skin and ultimate healing were observed ( c - e ) . most ten cases result from hypersensitive reaction to drugs , and sulfonamides , pyrazolones , barbiturates , and antiepileptics are the most frequent triggers . ten usually occurs between 7 days to 8 weeks after drug administration . upon readministration of the implicated drugs ten is a t - cell  mediated disease with cd8 t cells acting as the major mediator of keratinocyte death . drug - induced cd8 t - cell activation is highly specific for particular human leukocyte antigen ( hla ) allotypes , placing certain populations at a greater risk of developing ten . granulysin is the main mediator of apoptosis , and soluble fas ligand ( sfasl ) , tumor necrosis factor - alpha ( tnf- ) , and granzyme b / perforin are important in the pathogenesis of ten . put forward that the clinical features of ten include ( 1 ) constitutional symptoms such as fever , malaise , anorexia , and pharyngitis ; ( 2 ) erythematous , dusky , violaceous macules , morbilliform , or atypical targetoid macules starting on the trunk and spreading distally , confluence on the face , trunk , and elsewhere [ the skin lesion area of ten is greater than that of stevens - johnson syndrome ( sjs ) ] ; ( 3 ) manifests in flaccid bullae , epidermal sloughing , and necrosis with gray hue ; ( 4 ) exfoliation of the epidermis involving 10% of body surface area for sjs , 10%-30% for sjs / ten overlap , and > 30% for ten ; ( 5 ) oral , genital , and ocular mucositis in nearly all patients ; ( 6 ) tender skin and painful mucosal erosions ; ( 7 ) positive nikolsky sign ; ( 8) positive asboe - hansen sign ; ( 9 ) systemic symptoms always present in sjs / ten overlap and ten ; and ( 10 ) respiratory tract epithelial involvement in 25% of patients with ten . histological features were described as follows : ( 1 ) full thickness epidermal necrosis ; ( 2 ) subepidermal split , lymphocytic infiltrate at the dermoepidermal junction , cd4 t cells in the dermis , and cd8 t cells in the epidermis ; and ( 3 ) endothelial apoptosis . for mild and early stage ten , the main differential diagnoses includes sjs , acute generalized exanthematous pustulosis ( agep ) , erythema multiforme major ( emm ) , staphylococcal scalded skin syndrome ( ssss ) , drug - induced linear immunoglobulin a ( iga ) dermatosis , acute graft versus host disease ( gvhd ) , and a generalized morbilliform drug eruption , among other conditions , . our patient 's clinical characteristics were consistent with the above criteria except items ( 8) and ( 10 ) . because the patient 's exfoliation was almost systemic , sjs and emm were excluded ; ssss were excluded due to negative blood and rash cultures for bacteria and fungus as well as the presence of conjunctiva and oral mucosa damage . in addition , the patient 's rash mainly appeared as blisters and bullae due to erythema in the beginning stage , without pustules . therefore , the patient was diagnosed with ten according to typical clinical features . after treatment with glucocorticoids combined with immunoglobulin , her condition gradually improved , which verified the diagnosis of ten . however , there also exists some deficiency in the diagnosis of this case , primarily the lack of mucocutaneous biopsy and immunologic examination to aid in the diagnosis . an effec - tive treatment requires early diagnosis , immediate discontinuation of the causative drugs , and supportive and specific treatment . recently , the systematic application of glucocorticoids has been the major therapeutic regimen , and glucocorticoids combined with immunoglobulin can quickly control symptoms and shorten hospitalization time and is especially suitable for patients with concurrent infection . because this case of ten occurred after ap and gefitinib sequential combination treatment , it is difficult to determine which drug was responsible for this toxicity . thus far , there has been no report of ten induced by cisplatin , whereas there has only been one case of sjs related to bleomycin - cisplatin combination treatment and another case of exfoliative dermatitis associated with cyclophosphamide - cisplatin combination treatment . to the best of our knowledge , 4 cases of ten due to pemetrexed have been reported thus far : 1 due to pemetrexed alone , 1 related to pemetrexed plus carboplatin , and the other 2 related to pemetrexed plus cisplatin . the mucocutaneous disorder occurs between 2 days after the first cycle and 15 days after the second cycle of drug administration . although our patient received gefitinib after ap chemotherapy , ten occurred at the expected time and the patient did not develop mucocutaneous disorder after readministration of another egfr - tki , which supports pemetrexed as the initiator . although there is no report of egfr - tki - induced ten thus far , gefitinib could not be ruled out for the cause of this case as egfr - tkis alter keratinocyte proliferation , differentiation , migration , and attachment , and cutaneous toxicity occurs in more than 50% of patients . meanwhile , ten occurring after 8 days of gefitinib administration has also increased the suspicion of gefitinib as the initiator . another possible mechanism may be the synergistic effect on dermal toxicity for pemetrexed and gefitinib combination therapy . the basic skin toxicity of egfr - tkis may facilitate the occurrence of ten induced by pemetrexed . meanwhile , is there any possibility for the enhancement of egfr - tki - induced mucocutaneous disorder based on the alternation of folic acid metabolism of epithelial cells by pemetrexed ? it is still unknown . in summary , we report this case with the intent to further understand the potential rare mucocutaneous adverse effects of ap with gefitinib combination therapy . this case report also warns of the possibility of gefitinib as a potential initiator agent of ten .