langerhans cell histiocytosis ( lch ) is a rare , clinically polymorphous group of disorders , presenting with heterogeneous clinical manifestations and an unpredictable outcome . lch is characterized by proliferation of abnormal and clonal langerhans cells , in one or more organs like skin , bone , lymph nodes , lungs , liver , spleen , and bone marrow . occurrence of lch in adults is rare and is commonly seen in infants and early childhood . the disorder is difficult to diagnose in adults and once diagnosed , the multisystem lch has a poor prognosis . a 26-year - old man , presented with a one - week history of polymorphous eruptions over face , trunk , and extremities , associated with painful sores in the mouth as well as fever . the lesions started around the mouth with greasy scaling , which gradually progressed to involve scalp , neck , trunk , and extremities , including genitals . on general physical examination , jaundice , and inguinal lymphadenopathy were present . on cutaneous examination , multiple skin colored to yellowish papules and pustules were present over the scalp , retro - auricular area , face , neck , trunk , extremities , and genitalia , which were associated with facial edema [ figures 1 and 2 ] . oral mucosa showed multiple vesicles , pustules , and hemorrhagic crusting of lips [ figure 3 ] . scaling with crusting present over face , mimicking seborrheic dermatitis yellow - brown papules with pustules present over chest ulcers present over lips laboratory data showed : hb-16.1 gm / dl ; total leukocyte count ( tlc)-33,600/cu.mm ; neutrophil 54% , lymphocyte 25% , eosinophil 21% ; total bilirubin-5.9 mg / dl ; direct bilirubin-3.5 mg / dl ; serum glutamic oxaloacetic transaminase ( sgot)-179 u / l ; serum glutamic pyruvic transaminase ( sgpt)-269 u / l ; alkaline phosphatase ( alp)-167 u / l ; renal function test- within normal limits . biopsy from the skin , liver , and bone marrow showed dense infiltrate of histiocytes with longitudinal nuclear groove and numerous eosinophils and lymphocytes [ figures 4 and 5 ] . diffuse histiocytic infiltrate , h and e staining , 10 histiocytic infiltrate , h and e staining , 100 with the history , clinical findings , and investigation , the diagnosis of multisystem lch was made . he was given vinblastine and etoposide weekly for 6 weeks with daily prednisolone , followed by maintenance therapy of 12 cycles with same drugs at intervals of 3 weeks and daily 6-mercaptopurine . lichtenstein , in 1953 , coined the term histiocytosis - x to describe a group of disorders ( hand - schuller - christian disease , letterer - siwe disease , and eosinophilic granuloma ) characterized by infiltration of involved tissue with large number of abnormal histiocytes . subsequently , these histiocytes were found to be similar to langerhans cell normally present in the skin , and therefore termed as lch . lch is a clonal neoplastic disorder,[13 ] and its pathogenesis is unknown . whether the infiltrating cells are truly neoplastic or reactive in nature is still a matter of debate . the disease affects young children aged 1 - 4 years , but can occur at any age . the incidence is approximately 2 - 5 per million per year in infants and children and is even rarer in adults . the writing group of histiocytic society ( 1987 ) has recently defined the criteria for diagnosis of langerhans cell histiocytosis . the group proposed three levels of certainty in the diagnosis of lch based on clinical features , histopathology , and immunohistochemistry . the scalp is erythematous with greasy scales , appearing much like seborrheic dermatitis . on the trunk , the lesions are discrete , yellow - brown scaly papules , often showing areas of purpura . ulceration in the flexures , groins , and the perianal area is the common presentation in adults . diabetes insipidus is the most common endocrinal abnormality associated with lch caused by the infiltration of pituitary gland by langerhans cells . histologically , there is a dense dermal infiltrate of langerhans cell , recognized by abundant , amphophilic cytoplasm and round or kidney bean - shaped nucleus . by contrast , 20% of the patients with multisystem involvement have a progressive disease course despite treatment . the prognosis is directly related to the age of onset , numbers of organ involved , and the extent of organ dysfunction . the prognosis of the disease depends on systemic rather than cutaneous involvement . etoposide as a single drug is better than other drugs tested , eg , vinka alkaloid , methotrexate , 6-mp . our patient responded well to the combination therapy of vinblastine , etoposide , and oral corticosteroids .