Sebaceous carcinoma: controversies and their evidence for clinical practice.

Sebaceous carcinoma (SC) is a potentially aggressive malignancy of periocular or extraocular skin. It arises sporadically or is associated with Muir-Torre syndrome (MTS). Here, we review three controversial clinical conundra related to the diagnosis and treatment of SC and offer evidence-based recommendations. First, following a diagnosis of SC, deciding which patients to screen for MTS can be challenging. The Mayo MTS Risk Score is a clinical score that incorporates the key cutaneous findings in MTS but relies heavily on personal and family history that may not be available at the time of SC diagnosis, especially in young patients. Young patients, who have extraocular SC and are suspected to have MTS though do not meet criteria by Mayo MTS Risk Score, should have their tumors tested using immunohistochemistry for mismatch repair proteins. Second, sentinel lymph node biopsy (SLNB) is used in periocular SC to evaluate nodal disease. Patient selection is critical for SLNB. Periocular SC stage ≥ T2c (by American Joint Commission on Cancer, 8th edition) may be considered for SLNB given positivity rates over fifteen percent in expert hands. Lastly, treatment of metastatic SC is an area of active investigation. When possible, tumor profiling may be used to select targeted agents. Future research into these three key questions is needed.