Abstract Introduction: Human immunodeficiency virus (HIV) infection has been shown to directly and indirectly affect breast tissue. HIV-related breast conditions vary by geographic region and may include infection, benign breast enlargement from gynecomastia or lipomastia, and neoplasia. The aim of this study was to describe the spectrum of HIV-related breast disease encountered at a community teaching hospital, and identify factors associated with these breast conditions.Methods: A retrospective review was performed of HIV positive patients with a breast related encounter seen at our institution over a 9 year time period (1998-2007). Data was collected regarding patient demographics, HIV status (risk category, duration of HIV infection, CD4 cell count, HIV viral load), comorbid disease, and medications including antiretroviral therapy (ART). Breast events (encounters) were analyzed according to breast disease category (cancer, atypia, infection, benign), clinical findings, diagnostic procedure performed, pathology, imaging, treatment and outcome. Data was analyzed using descriptive statistics. Univariate and multiple logistic regression was conducted for significance of factors in the development of breast cancer, infection or gynecomastia.Results: A total of 46 individuals were included with a median age of 47 years (range 24-64 years) and male:female ratio of 1:3. In the study population, 48% were Hispanic, 35% African American, and 17% Caucasian. HIV acquisition risk categories were heterosexual in 59%, intravenous drug users in 35%, and one man with gynecomastia was homosexual. The mean duration of HIV infection was 7 years prior to presentation with a breast condition, during which time 46% had an AIDS defining illness. The median CD4 cell count was 437 cells/mm3 (range 2 to ≥ 500) when their breast condition was diagnosed. Categories of breast disease identified were benign conditions (59%), infection (17%), cancer (22%), and atypia (2%; 1 patient had atypical ductal hyperplasia). Patients with breast infection had a lower median CD4 count (241 cells/mm3) than patients with breast cancer (442 cells/mm3) or benign conditions (496 cells/mm3). Most (78%) patients received combination ART. ART of all drug classes was associated with gynecomastia (n=8), including one man with concomitant lipohypertrophy and hyperlipidemia. Infections included abscesses (n=6), mastitis (n=1) and cutaneous molluscum contagiosum (n=1). Breast cancer included patients with invasive ductal carcinoma (n=7), ductal carcinoma in situ (n=2), and 1 liposarcoma. Five (11%) patients died, only one from breast disease.Conclusion: These data indicate that increased longevity in patients with chronic HIV infection may be associated with the development of benign, neoplastic and infectious breast conditions in both men and women. Breast disease does not appear to be related to HIV immunosuppression, with the possible exception of bacterial infection. Gynecomastia in men appears to be linked to antiretroviral therapy, including the fat maldistribution syndrome. A broad spectrum of breast disease should be anticipated as HIV infected persons are living longer with effective antiretroviral therapy. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2076.