human infection comes from eating undercooked meat , especially the snake or frog , or ingesting water contaminated with infected cyclops . clinical manifestations are diverse , including non - specific discomfort , vague pain , palpable mass , headach , or even no symptoms . most infection is presented with lumps in soft tissues , such as subcutaneous tissues or muscles in healthy adults [ 2 - 4 ] . in some cases , it is developed among immune - compromised patients , including aids patients , renal allograft recipients and patients with advanced solid tumors [ 5 - 8 ] . herein , we report a case of human sparganosis manifested overtly and mimicking myeloid sarcoma in a patient undergone allogeneic hematopoietic stem cell transplantation ( hsct ) for treatment of myelodysplastic syndrome ( mds ) . a 56-year old male visited our out - patient clinic for pancytopenia . bone marrow biopsy and karyotype analysis showed myelodysplastic feature with 14% blast count and normal karyotype , indicating mds , refractory anemia with excessive blast . he received 4 cycles of decitabine treatment during searching for matched unrelated donor , and partial response was shown . allogeneic peripheral hsct with myeloablative conditioning regimen consisting of busulphan and cyclophosphamide was performed from a hla full - matched unrelated donor . however , at day 5 post - hsct , 5 cm - sized hard and movable mass in the left scrotum and multiple palpable lymph nodes was detected at the left inguinal area . pelvic magnetic resonance imaging and computed tomography were done and it was suspected initially as a myeloid sarcoma in the subcutaneous fat layer of the left scrotum and pathologic lymphadenopathy at the left inguinal area ( fig . gun biopsy was done on the left scrotal mass to avoid bleeding due to thrombocytopenia after hsct . the result of the gun biopsy was inflamation of fibrovascular soft tissues with extensive interstitial eosinophilic infiltrations without evidence of malignancy . subsequently , igg antibody tests for paragonimiasis , cysticercosis , sparganosis , and clonorchiasis were done , and the results were positive for sparganosis and negative for all others . we re - evaluated the patient 's past history and found out that he had swam in the river and ate raw fish , cow liver , and pork meat frequently when he was young . for a next step , the cut surface of the biopsied specimen showed a cyst filled with whitish and myxoid tissues , measuring 2.00.6 cm ( fig . the biopsy result was severe acute and chronic inflammation and fibrosis with a sparganum worm ( fig . he was discharged after complete wound healing and stabilization of the post - hsct condition . most sparganosis cases present as lumps in subcutaneous tissues or intermuscular fascia , which are non - tender and sometimes resolve spontaneously . therefore , the diagnosis is often made incidentally by an imaging study or surgical biopsy in many cases . because of late diagnosis , the sparganum worm is presumed to have lived many years , and even a 10-year survived sparganum was reported . the final diagnosis is done by the surgical biopsy proving the presence of the worm . however , immunodiagnosis is also recommended to establish a preoperative diagnosis when soft tissue tumors are detected in patients living in endemic areas . sometimes , mass - like lesions of sparganosis are confused as solid tumors or other benign diseases , such as varicose vein , whereas there have been no reported cases mimicking myeloid sarcoma [ 8 - 11 ] . in our case , the left inguinal movable mass was initially suspected as a myeloid sarcoma , which is the extramedullary manifestation of acute leukemia , by initial imaging techniques . however , the positive anti - sparganum igg antibody test after a gun - biopsy suggested sparganosis rather than malignancy . there were few reports of sparganosis developed in immune - compromised patients , including malignancy , aids , and renal allograft recipients [ 5 - 7 ] . in our case , the immunosuppressive condition of transplantation might have brought out the hidden clinical presentation of the pre - existing sparganum infection . however , the causality between this condition and the development of sparganosis is unclear because the time of mass development from transplantation was too short , and the possibility of sustained sparganosis before transplantation also existed . this case suggests that physicians have to give an effort to exclude sparganosis with careful diagnostic approaches , including a detailed history taking , serologic test for parasites , optimal image techniques , and tissue obtainment when they face mass - forming lesions in patients under these clinical situations .
we report here a case of inguinal sparganosis , initially regarded as myeloid sarcoma , diagnosed in a patient undergone allogeneic hematopoietic transplantation ( hsct ) . 
 a 56-year - old male patient having myelodysplastic syndrome was treated with allogeneic hsct after myeloablative conditioning regimen . at day 5 post - hsct , 
 the patient complained of a painless palpable mass on the left scrotum and inguinal area . 
 pelvic magnetic resonance imaging and computed tomography revealed suspected myeloid sarcoma . 
 gun - biopsy was performed , and the result revealed eosinophilic infiltrations without malignancy . 
 subsequent serologic igg antibody test was positive for sparganum . 
 excisional biopsy as a therapeutic diagnosis was done , and the diagnosis of sparganosis was confirmed eventually . 
 this is the first report of sparganosis after allogeneic hsct mimicking myeloid sarcoma , giving a lesson that the physicians have to consider the possibility of sparganosis in this clinical situation and perform adequate diagnostic and therapeutic approaches .