Sebaceous carcinoma in situ as a diagnostic entity. Case report and review of the literature.

The concept of carcinoma in situ was first introduced by Broders in 1932 [1] and has been accepted as a well-established notion and diagnostic category in many organs and systems. However, sebaceous carcinoma in situ (SCIS) has not yet been recognized as a concept and diagnostic entity in general pathology or dermatopathology. Such lesions have been commonly misinterpreted as either a benign neoplasm or sebaceous carcinoma. Tumors that do not necessarily arise in pre-existing sebaceous glands are usually invasive at the time of diagnosis, and like their ocular counterparts, can exhibit pagetoid intraepidermal spread. Cases of purely in- situ extraocular sebaceous carcinoma are extremely rare and yet controversial until now.Recognizing sebaceous carcinoma in situ as a valid concept and diagnostic entity that will certainly help to avoid misinterpretation and subsequently under or over treatment of such lesions.In this article, we provide a case report presentation with histopathological examination and a critical review of the literature.