Management of patients with skin adnexal carcinomas

Adnexal cancers of the skin constitute a heterogeneous group of malignant tumors with specific pathologic and biological differences. This review aims to provide clinicians with a summary of how to manage the diagnosis, staging, and treatment of cutaneous adnexal cancer patients. In clinical practice, the complexity of this clinical and pathological heterogeneity is partially mitigated by adopting standardized universal classification systems. The WHO classification is used for pathologic diagnosis. Among appendageal skin tumors, it includes four groups of cutaneous adnexal malignancies (apocrine/eccrine differentiation, sebaceous differentiation, follicular differentiation, site-specific appendageal tumors) and seven malignant adnexal tumors of the eyelid. Clinical and pathologic staging should follow the latest AJCC/UICC classification, which includes site-specific systems to be used for these cancers: skin carcinoma of the head and neck, skin carcinoma of the eyelid, anal canal and perianal skin, vulva, penis, breast (for Paget disease), and any other skin carcinoma. The diagnostic hypothesis of genetic syndromes should always be considered for patients diagnosed with an adnexal skin neoplasm, especially when cancers arise in unusual or multiple anatomic sites. The pathologic diagnosis should be performed by expert pathologists, and patients should be referred to high-volume centers. In curative treatments, radical surgery, when feasible, should always be considered the first option for local or regional disease. The opportunity to deliver post-operative treatment should always be discussed at a multidisciplinary level. Patients suffering from advanced disease should be included in clinical studies. Outside trials, the seek for potential druggable targets is advised.