항문도관 암종

초록

Anal duct carcinoma, also known as anal gland carcinoma or adenocarcinoma of the anal canal, is an unusual anal cancer that accounts for approximately 0.1% of all gastrointestinal cancers. The tissues of origination are the glands of the anal duct. The features that differentiate this tumor from the usual rectal adenocarcinoma are prominent ductal structures, abundant mucin production with organized mucinous pools, and infiltration into the perirectal soft tissue. Delays in diagnosis most likely account for the poor prognosis associated with this cancer. We experienced a case of anal duct carcinoma, clinically presented as a buttock lesion. The patient was a 62 year old male who had a past history of a hemorrhoid for the past 40 years and anal fistula for 10 years. He took fistulectomy operation two times. One year ago, pain, redness, and heating sensation were developed in both buttock area. At that time, CT scan revealed multiple abscess in perirectal, perianal, retrovesical and subcutaneous fat of both buttocks with fluid collection. Multiple enlargement of lymph nodes were present in internal and external iliac chain. He underwent an incision and drainage and colostomy of transverse colon. Although antibiotics therapy, the lesion didn't subside and the MRI revealed multiseptated cystic lesions involving pelvic cavity, perineum and presacral space. Incision and darainage were performed, again. Histologically, the lesion was composed of a low grade mucinous tumor that forms large amount of colloid, suppurative exudate, and granulation tissue. The mucus-producing columnar epithelium showed very mild cytologic atypia, but they were positive for carcinoembryonic antigen and showed p53 overexpression. Overlying benign squamous mucosa was present. The presence of mucin in granulation tissue or free in the histologic section should alert the pathologist and clinician to the possibility of an underlying mucinous carcinoma.