langerhans cell histiocytosis ( lch ) is a disease characterized by the proliferation of langerhans cells , which are dendritic cells that express cd1a and s100 and contain birbeck granules . lch has a complex relationship with malignant neoplasms ; however , the association is rare and has been the subject of isolated case reports . the literature contains several reports of cases in which malignant lymphoma follows lch , but fewer cases in which lch follows malignant lymphoma [ 1 - 5 ] . here , we describe a case of lch followed by hodgkin 's lymphoma ( hl ) and discuss the association between lch and hl . a 22-year - old man with lower back pain of one month in duration was referred to our institution . a bone scan , computed tomography ( ct ) scan and magnetic resonance imaging ( mri ) suggested tuberculous spondylitis on the thoracic and lumbar spine . an excisional biopsy of the osteolytic t2 spinal lesion showed extensive intramedullary proliferation of histiocytic cells with folded nuclei , numerous eosinophils , phagocytic histiocytes , and fibroblasts ( fig . immunostaining assays for cd1a and s100 were strongly positive in histiocytes with folded nuclei , suggesting lch . whole body positron emission tomography ( pet ; f - fluorodeoxyglucose , f - fdg ) revealed other lesions in the sternum and left sacral ala . the multiple lesions of the spine , sternum , and sacrum were treated with involved - field radiotherapy . subsequent fdg - pet scans revealed that the original lesions had completely disappeared , but that new hypermetabolic lesions had appeared in the subcarinal lymph node , left hilar lymph node , and left ischium . we determined that lch had become systemic and the patient was treated with a combination of various chemotherapeutic agents in six cycles of cyclophosphamide , doxorubicin , vincristine , and prednisolone ( chop ) . the extracted lymph node was smooth and measured 4.6  3.7  1.5 cm ( fig . microscopic examination at a magnification of  100 showed a broad sclerotic fibrous band dividing the lymph node into multiple nodules containing large , scattered , and atypical cells ( fig . further examination at a higher magnification showed that the atypical cells were either mononucleated or binucleated , with prominent nucleoli and abundant cytoplasm ( fig . immunostaining revealed cd1a - positive langerhans cells in the residual histiocytes within the sclerotic bands , and large , atypical , cd30 ( ki-1)-positive cells (  400 ) . fdg - pet imaging and ct scans of the patient 's thorax , abdomen , and pelvis revealed involvement of the right lung , right level ii cervical lymph nodes , t12 , l5 , right 3rd rib anterior arc , right ischium , and right ilium . the patient received three cycles of eshap ( methylprednisolone , etoposide , cisplatin , and cytosine arabinoside ) chemotherapy , followed by high - dose chemotherapy ( busulfan , etoposide , and cyclophosphamide ) and autologous stem cell transplantation ( asct ) . ten months after asct , the patient reported no further symptoms of the disease , and fdg - pet scans were negative for hypermetabolic lesions . langerhans cells are non - pigmented , bone marrow - derived dendritic cells . as such , they function as antigen - presenting cells that are vital to the epidermal component of the immune system . langerhans cells share certain properties with monocytes and macrophages , but differ from other histiocytes in that they are cd1a - positive , with pale clefted nuclei , abundant pale eosinophilic cytoplasm , and birbeck granules . their most striking histological feature , which is absent from hl , is the presence of eosinophils . in contrast , hl has histologically distinct reed - sternberg cells that are not present in lch . lch manifests clinically in various ways , ranging from solitary bone lesions to polysystemic disease . the condition is occasionally fatal and is classified as a dendritic disorder by the world health organization classification of 1997 . lch resembles a malignant disease due to its progressive and/or invasive growth and dissemination . depending on the clinical course and classification , lch can be treated with many different therapeutic strategies , including benign neglect and observation , local treatment , immunomodulation , irradiation , chemotherapy , and allogenic stem cell transplantation . for progressive multisystemic disease , various combinations of three- or four - agent chemotherapy regimens are used to treat higher risk lymphoma . until recently , coincidental lch and hl were reported more often than could be expected on a case - by - case basis . in particular , egeler et al .   studied 39 patients with lch and malignant neoplasia , and found an association between the two conditions . that report suggested that lch is associated with lymphoma , wherein the timing and unifocal involvement suggest a reactive process . burns et al .   speculated that malignant lymphoma may directly or indirectly stimulate the proliferation of lch . presented a case of sequential discordant malignant lymphoma and suggested a degree of interdependence between the development of lch and malignant lymphoma . in the present case , we found no histological evidence to explain the coincidental lch and hl . however , many reports of an association between lch and hl exist in the literature . in some cases , histological examination revealed lymphoid cells and langerhans cells in the same lymph node . furthermore , the year - long interval between the development of lch and hl suggests an association between the two diseases that is unrelated to chemotherapy or radiation treatments . such an association may involve a malignant change or modulation of the monocyte - histiocyte system . for example , langerhans cells may themselves be premalignant , or may provide an immunologic environment conducive to the development , growth , and promotion of malignant cells . in conclusion , we describe a case in which lch developed after hl . the significance of this association should be further explored in future studies , especially in regard to the clinical aspects of the disease course and management . in addition , the mechanism underlying the association between lch and hl must be elucidated .
a 22-year - old man was referred to our institution due to lower back pain and was diagnosed with langerhans cell histiocytosis of the thoracic and lumbar spine . 
 the patient achieved complete remission with radiotherapy and chemotherapy . 
 one year later , right cervical lymphadenopathy was observed and hodgkin 's lymphoma was confirmed on biopsy . 
 the patient was treated with chemotherapy and autologous stem cell transplantation , and experienced no further symptoms . 
 further , no evidence of recurrence was observed on follow - up imaging . 
 this report discusses the association between langerhans cell histiocytosis and hodgkin 's lymphoma .