the head and neck regions are common sites where intra - dermal or subcutaneous firm nodules of 0.5 - 3 cm are found .
although its histological findings are well - described , the radiological features of chondroid syringoma have been reported in only few cases .
a 59-year - old man presented with a painless mass on the anterior aspect of the upper thigh with a slow enlargement over the past 5 years [ figure 1 ] .
dermatological examination showed a relatively firm , mobile 5  3 cm nodule covered by normal skin .
laboratory studies including complete blood count , erythrocyte sedimentation rate ( esr ) , urine analysis , aspartate aminotransferase ( ast ) , alanine aminotransferase ( alt ) , blood urea , creatinine were normal .
sonographic examination revealed mixed , echogenic solid mass measuring approximately 4.5  3  2 cm . on doppler ultrasound ,
magnetic resonance images ( mri ) revealed a 4.7  2.9  2.2 cm , well - circumscribed , lobular mass that showed heterogeneous enhancement predominantly in the peripheral portion of the mass after intravenous contrast administration [ figure 2 ] .
diffusion - weighted imaging ( dwi ) showed areas of increased signal intensity that were indicative of a highly cellular tumor [ figure 3 ] . according to the mri findings , we considered benign subcutaneous lipomatous tumors with cystic and solid components such as angiolipoma or fibrolipoma or well - circumscribed low - grade soft tissue liposarcoma without surrounding tissue extension in our differential diagnosis . because the vascularity of the lesion and heterogeneous pattern with contrast enhancement on mri examination , we excluded lipoma . relatively firm , 5  3 cm , lipoma - like mass covered by normal skin post - contrast
axial fat - saturated t1-weighted images show well - circumscribed , lobular mass with heterogeneous enhancement diffusion - weighted imaging ( b : 800 ) signs of increased restriction in diffusion , a finding indicative of a highly cellular tumor we decided to perform trucut biopsy .
histopathological examination revealed a group of cells , which have eosinophilic cytoplasm and regular small nuclei , exhibited epithelial - like pattern in the myxoid stroma .
however , as adipocytes were variable in size and focally showed a lipoblast - like appearance , some tumor areas were reminiscent of a well - differentiated lipoma - like liposarcoma [ figure 4 ] .
microscopic examination shows a focal area of lipoblast - like appearance in the myxoid background ( h and e , 10 ) the patient underwent surgical excision of the mass .
there were foreign body reactions against the epidermoid cysts within the tumor and surrounding tissue .
epidermoid cysts were seen ( h and e , 5 ) epithelial nests and tubuloalveolar structures in a chondromyxoid stroma .
the head and neck regions are common sites ; less commonly , axillary region , hand , foot , abdomen , penis , vulva , scrotum can be involved .
chondroid syringoma usually presents as a solitary , asymptomatic , intracutaneous or subcutaneous nodule , mainly seen in middle - aged or older males .
the size is usually between 0.5 and 3 cm , but it may be very large .
most chondroid syringomas are benign with a slow progression over years . in our case ,
malignant lesions are usually larger than 3 cm , but benign one measuring 10 cm is also reported .
histologically , a wide variety of structures may be found in chondroid syringoma of skin .
eccrine types have multiple small syringoid elements and are rich in mucin . in the apocrine type ,
in our case , there was abundant lipomatous stroma that made diagnostic difficulty in radiological imaging and histopathological examination .
previous case reports have described the mr imaging findings of benign and malignant chondroid syringomas.[79 ] although the mr imaging appearance of chondroid syringoma is relatively non - specific , mr imaging generally may allow characterization of the origin of tissue components in the tumor and depiction of the extent and relationships of the lesion to adjacent structures . in our case ,
the signal intensity characteristics of the lesion ( heterogeneous lesion of mixed fat and fluid - like intensity ) , while not specific for chondroid syringoma , allowed for some analysis of the consistency of the tumor .
the benign neoplasms of the subcutaneous tissue that may have similar appearances with our case include superficial lipoma and variants of lipoma ( angiolipoma , myolipoma , spindle - cell and pleomorphic lipoma , chondroid lipoma , and hibernoma ) . although subcutaneous in location , superficial lipoma consists entirely of fat , unlike our lesion . variants of lipoma are commonly heterogeneous and include more than one type of tissue , which may be fat , muscle , chondroid matrix , vascular elements , or myxoid tissue with calcification and hemorrhage . due to the presence of vascular channels on doppler examination ,
the malignant tumors that may bear similar characteristics with mixed tumor of the skin include well - differentiated liposarcoma , myxoid liposarcoma , extraskeletal myxoid chondrosarcoma , myxofibrosarcoma , and malignant peripheral nerve sheath tumors .
after tru - cut biopsy , we considered many of the above entities in the differential diagnosis .
there were no cytologic atypia , increased mitotic figures , tumor necrosis , or infiltrative margins , thus excluding malignant chondroid syringoma .
the mixed fat and fluid - like signal intensity lesion of skin is somewhat of a diagnostic enigma due to its non - specific imaging and histologic presentation .
clearly a soft tissue lesion of mixed fat and fluid - like signal intensity , as in this case , while not pathognomonic for chondroid syringoma , allows for a limited differential diagnosis .
as this case shows , chondroid syringoma should be included in the differential diagnosis of a slowly growing , nodular heterogeneous mass in the skin or subcutaneous tissue .
1 . diffusion - weighted imaging , which showed signal intensity changes indicative of a highly cellular tumor in this case , is not routinely done in chondroid syringoma .
to our knowledge , this is the first case of chondroid syringoma mimicking low - grade liposarcoma reported in the literature .
 chondroid syringoma , or mixed tumor of skin , is a relatively rare , usually benign sweat gland tumor , most often seen in the head - and - neck region . 
 rare malignant examples have been reported , commonly involving the extremities . 
 we report here a case radiologically mimicking a malignant neoplasm , but histologically - proven benign subcutaneous chondroid syringoma , arising in the anterior aspect of the upper thigh of a 59-year - old male . 
Introduction
Case Report
Discussion