Tumors with poroid features: a clinicopathologic analysis of 25 cases

LI Ying-feng; LI Xiao-qiang; YU Min; SUN Jing; SONG Meng-yuan; LIU An-qi

doi:10.3969/j.issn.1007-8096.2017.03.004

Abstract：Objective To explore the clinical and pathological features,diagnosis and differential diagnosis of benign and malignant poroid tumor.Methods Clinical characteristics and pathological morphology were analyzed in 19 cases of eccrine poroma (EP) and 6 cases of eccrine porocarcinoma (EPC),with immunohistochemical staining (6 cases),and review of the relevant literature.Results Tumors with poroid features occurred at similar site,first commonly in the lower limb,second trunk and head face,and there was significant age difference.It was easily misdiagnosed as pigment nevus,hemangioma,squamous cell carcinoma or seborrheic keratosis etc.EP microscopically by hyperplasia of basal cell and cuboidal cells with ductal differentiation,occasionally cyst formation,and visible focal necrosis and mitotic activity;EPC microscopically showed the tumor cells were significantly high atypia or mitotic activity and/or interstitial infiltrates.Immunohistochemical staining showed P53 positive tumor cells were positive about 10％-90％,Ki67 positive rate was about 10％-80％,but P16 (-);in the tumor cells of ductal structure CEA and EMA were positive,and SMA was positive for interstitial vascular smooth muscle.Conclusions In the umor with poroid features correct diagnosis relies mainly on histopathology observation;tumor cell atypia and/or invasive growth is the main basis of EPC diagnosis.Immunohistochemical staining is auxiliary in the differential diagnosis;focal high mitotic activity,tumor cell necrosis and P53 positive tumor cell are not independent diagnosis index of EPC.Rapid growth in a short period of time in an EP with longer history,spontaneous bleeding or itching,surface ulcers or multiple nodules suggests malignant transformation risk.