eccrine poroma is a benign neoplasm of the sweat glands originating from the intraepidermal eccrine duct.1 ) this unusual tumor is known to arise in bare skin areas , such as the sole of the foot .
recently it was revealed that it could occur in more various skin region.2 ) but only few cases have been reported in the head and neck area .
a 54-year - old female presented with a gradually increasing mass on the auricle for one year . on physical examination , there was a soft , protruding , and purple - colored , solitary mass , 1.01.0 cm in size on the retroauricular surface of the left auricle ( fig .
the patient reported serous discharge but there was no pain nor tenderness . with an impression of an atypical nevus or a melanoma
histopathological findings revealed that broad anasto - mosing bands extended from the epidermis to dermis with multifocal fibrovascular cores and irregular duct - like structures ( fig .
there were also tightly packed small uniform cells with central round to oval nuclei , prominent nucleoli , and occasional clear cytoplasm ( fig .
we did not find any necrosis , nuclear atypia , or mitosis in the specimen .
after complete excision , the patient has been followed up without any recurrence for more than 6 months .
eccrine poroma was first described by goldman , et al.2 ) in 1956 as a neoplasm composed of cells that are analogous to cells in the walls of eccrine sweat pores .
it is composed of poroid cells and cuticular cells that have much eosinophilic cytoplasm , similar to eccrine ductal cuticles.1 ) vacuolizations in the intracytoplasmic and intercellular areas are characteristic histological features , resembling the formation of eccrine ducts.1 ) this tumor is occurred in bare areas of skin such as the sole of the foot .
goldman , et al.2 ) reported that the most common sites were soles of feet ( 65% ) followed by the hands ( 10% ) .
only one case of the ear ( external auditory canal ) has been previously reported , and only three cases reported in the postauricular scalp skin , not on the auricle worldwide . among seven cases reported in the korean literature ,
the scalp was the most common site.3,4,5,6 ) moore , et al.7 ) compared patients with poroma in the head and neck area with lesions occurred in extremities .
lesions of the head and neck were mostly asymptomatic mass , but some patients with poroma in the extremities complained symptoms such as pain or discharge . and more pigmented lesions were noted in the head and neck , compared with mass of the extremities . in our case ,
histopathological diagnosis is crucial because eccrine poroma should be differentiated from basal cell carcinoma and seborrheic keratosis.3 ) poroma seems to have more organoid appearance than basal cell carcinoma . also , poroma has fewer epithelial cells compared to the seborrheic keratosis of the sweat duct .
it has been found that about 18% of poromas transform to procarcinoma.8 ) in a case of reported malignancy , it causes multiple cutaneous metastases leading to death.4 ) porocarcinoma shows more exphytic and ulcerative appearance than eccrine poroma .
when the eccrine poroma develop into malignancy , it shows spontaneous bleeding , ulceration , sudden itching sense or pain , and rapid growth in a short period.8 ) so early detection , complete excision and close follow up are important in the management of the tumor .
 eccrine poroma is described as a benign neoplasm originating from the intraepidermal eccrine duct of sweat glands . 
 this tumor is known to arise in bare skin areas , but more rarely appeared in head and neck region . a 54-year - old female presented with a mass on the retroauricular aspect of the left auricle . 
 there was a soft , protruding , and purple - colored , solitary mass of about 1.01.0 cm in size . 
 after authors performed an excisional biopsy , eccrine poroma was confirmed histopathologically . 
 thus , we report a rare case of eccrine poroma of the ear with the review of literature . 
Introduction
Case Report
Discussion