Cutaneous Metastases of Solid Tumors: Demographic, Clinical, and Survival Characteristics

Background: Cutaneous metastasis (CM), while uncommon, is usually an indicator of poor prognosis. With cancer patients living longer, the incidence of CM has increased, which justifies its analysis. Objectives: The objective of this study was to carry out a descriptive study of CM diagnosed for 18 years in a dermatology department of a tertiary care hospital and to assess the epidemiological, clinical, and histological variables that condition them, as well as data on their survival and prognosis. Methods: We performed a descriptive study of cases of CM diagnosed over 18 years in the dermatology department of a tertiary referral hospital analyzing the following variables: patient age and sex, site of primary neoplasm, pathochronology, survival time, histological findings, immunohistochemical markers, the anatomical area affected, the clinical appearance of the metastasis, therapeutic plan, and existence of metastases in other regions. We checked normal distribution using the Kolmogorov-Smirnov test and then compared the quantitative variables using the Student's t-test (unpaired samples), Mann-Whitney test (non-normal distribution), analysis of variance (ANOVA; for more than two groups), and categorical variables using the chi-square or Fisher’s exact test. Results: We included 37 cases (20 men and 17 women), of whom 32 had died. The mean age was 62 ± 15 years. CM detection was defined early in 8% of cases, synchronous in 32%, and metachronous in 60%. The most frequent primary tumor sites were lungs (24%), breasts (21%), and bladders (11%). Most metastases were solitary. The most frequent locations for CM were the scalp, trunk, armpits, and groin. Most lesions had a nodular presentation (81%). Squamous cell carcinoma and adenocarcinoma showed the same frequency in lung cancer CM. Breast cancer leading to CM was the most common invasive ductal carcinoma. The most aggressive cases, with the worst survival, originated in lung neoplasms. Therapeutic management for most patients involved surgery in combination with other procedures. The only difference detected between the lung and breast cancer CM was the predominance of lung tumors in men (89%) and breast tumors in women compared with metastases from other sites; breast cancer CM manifested more frequently as plaques and less frequently as nodules (p < 0.05) and was less frequently associated with multisystemic metastasis. In lung cancer CM, time from tumor diagnosis to CM occurrence was shorter (p < 0.01) and multisystemic metastasis was more frequent than in CM of other tumors. Conclusions: CM tends to affect patients aged above 60 years and arises predominantly from lung cancer in men and breast cancer in women. The most typical locations are the chest and scalp, and the appearance is usually nodular. Survival after CM detection is low, particularly in lung cancer CM.