Small-cell anal carcinoma and AIDS: case report and review of the literature

Anal squamous-cell carcinoma has a relatively higher prevalence in HIV-infected individuals than in the general population. In 70% of the cases, it is caused by sexual transmission of the human papillomavirus (HPV). Other anal cancers are rare and have not frequently been described in the setting of HIV infection. In this paper, we report a case of small-cell carcinoma of the anus associated with AIDS. A 45-year-old homosexual man with an 18-year history of HIV infection on triple antiretroviral therapy sought medical attention for anal pain and bloody discharge. He had regularly undergone anal Pap smears and was not found to have any squamous-cell cancer or dysplasia. His general condition was stable, and the WHO performance status was assessed at 1. Scattered lymphadenopathies were present in the cervical, supra-clavicular, and inguinal chains. A nodular hepatomegaly and an exophytic anal mass were discovered. The biopsy of the anal mass showed a small-cell carcinoma. Immunohistochemistry stains supported the diagnosis. The imaging studies confirmed a nearobstructive lesion in the anal canal, metastases in the liver, abdominal, and pelvic lymphadenopathies. There was no lung disease. The CD4 cell count was 23/μl, and the HIV viral load inferior to 50 copies/ml. Because of obstructive abdominal symptoms, the patient received concomitant radiotherapy to the anus and chemotherapy with cisplatin and etoposide, along with antibiotic prophylaxis. Filgrastim was administered with the following three cycles of chemotherapy because of severe neutropenia after the first cycle. The restaging studies showed disease progression especially in the liver, although partial tumor regression was noted in the anal canal. Second-line chemotherapy was proposed, but the patient’s condition rapidly deteriorated with the development of severe cholestasis and hepatic encephalopathy. The icterus was secondary to extensive liver parenchymal involvement by the tumor and, thus, not amenable to stenting. The patient expired without receiving any salvage chemotherapy 6 months after the diagnosis. A review of the literature has shown that small-cell anal tumors are very rare. In a study done in the US veterans population and published by Mabye and collaborators, no small-cell cancer was seen among 204 cases, although adenocarcinomas and melanomas were described in addition to the more common squamous-cell cancers. Likewise, Int J Colorectal Dis (2008) 23:135–136 DOI 10.1007/s00384-007-0283-1