Langerhans cell histiocytosis is a rare proliferative disorder

Over the last 30 years, there have been approximately 49 case reports of tumors composed of both malignant epithelial and malignant melanocytic populations. Herein, we present four additional cases of combined tumors that consist of two phenotypically distinct but intermingled populations of malignant cells. Each tumor was composed of an invasive melanoma closely associated with either a basal cell carcinoma or a squamous cell carcinoma. We review all previous case reports in the English literature and attempt to clarify the terminology and summarize what is currently known about these unique tumors.

Background As life expectancy of HIV-infected persons increases, cancers have become an important cause of morbidity and mortality. Although cutaneous neoplasms are the most common malignancies in the general population, little data exist among HIV-positive persons especially regarding the impact of HIV-specific factors. Methods We evaluated the incidence rates and factors associated with the development of cutaneous malignancies among HIV-infected persons by examining prospectively collected data from a large HIV Natural History Study composed of 4,490 persons (1986 to 2006). Poisson regression and Cox proportional hazards models were performed. Results Six percent (n=254) of HIV-infected persons developed a cutaneous malignancy during 33,760 person-years of follow-up (mean 7.5 years). Since the advent of highly active antiretroviral therapy (HAART), incidence rates of cutaneous non-AIDS defining cancers (NADCs), in particular basal cell carcinoma, have exceeded rates of cutaneous AIDS-defining cancers such as Kaposi’s sarcoma. Factors associated with the development of cutaneous NADCs in the multivariate models included increasing age (hazard ratio (HR) 2.1; 95% CI 1.7–2.6) and race. Compared to white/non-Hispanic race, African Americans (HR 0.03, 95% CI 0.01–0.14) and other races (HR 0.14, 95% CI 0.03, 0.57) had a lower risk of cutaneous NADCs. There were no significant associations between cutaneous NADCs and time-updated CD4 counts, HIV RNA levels, or HAART receipt. Conclusions NADCs are now the most common cutaneous malignancies among HIV-infected persons. Cutaneous NADCs do not appear to be significantly associated with immune function or HAART, but rather are related to traditional factors, such as aging and skin color.

Although dendritic, melanin-containing melanocytes can be seen in a variety of epithelial neoplasms, only 0.01% to 7% of all squamous cell carcinomas (SCC) are pigmented. Furthermore, most reported cases have occurred in the oral and ocular mucosa, with relatively few cases reported to originate in the skin. Herein we report a case of a 61-year-old Caucasian male who presented with a large blue-black nodule on his left cheek, clinically suspicious for a melanoma; however, histological evaluation revealed an acantholytic pigmented squamous cell carcinoma. Previous cases are reviewed and the clinical and histological differential diagnoses are discussed.