The aim of this study is to collect sebaceous carcinomas from the Fondazione Policlinico Gemelli retrospectively and prospectively, to analyse them morphologically and immunopathologically and to correlate them with molecular genetic aspects. This study will help to clarify and develop a more effective multidisciplinary diagnostic-therapeutic pathway.

The purpose of this research is to prospectively and retrospectively collect sebaceous carcinomas from the Fondazione Policlinico Gemelli, examine them immunopathologically and morphologically, and establish a correlation between these characteristics and molecular genetic factors. Conducting this research will contribute to the elucidation and advancement of a multidisciplinary therapeutic-diagnostic pathway. The study will utilise surgical specimens, irrespective of the disease stage, that have been formalin-fixed and paraffin-embedded. These specimens were previously collected for clinical practise at the Ocular Oncology of Fondazione Policlinico A. Gemelli IRCCS The informed consent of the patients regarding the use of these specimens for research purposes was obtained beforehand.Each specimen will be subjected to a comprehensive microscopic examination, followed by precise subclassification in accordance with the WHO classification and immunophenotypic characterization. An exhaustive collection of conventionally standardised histopathological prognostic attributes for sebaceous carcinomas will be compiled. Following this, tissue samples are sent for single and/or multiple IHC. Tumour tissues will be subjected to automated digital quantification in conjunction with multiparametric cell line evaluation. Integrating IHC with digital automation of analysis.Exome sequencing will be performed on DNA extracted from paraffin-embedded sections in order to detect variants that are specific to tumours.

For each tumour, three to nine sections (10 micrometres in thickness) will be utilised as the DNA source. Following the identification and separation of tumour tissue from normal tissue by the pathologist, the two DNAs will be sequenced independently. A comparison will be made between variants derived from tumour and normal tissue, with contrasting results. Anticipated outcomes include 1) somatic or tumor-specific variants, which are non-existent in healthy tissue, and 2) variants that are lost during the evolution of the tumour as a result of segmental chromosomal deletion or other mechanisms that induce heterozygosity loss. During the project's prospective phase, newly developed tumours will be preserved. Furthermore, this resource will facilitate methylome analysis, which is in addition to exome analysis.

Inclusion Criteria:

• Age 18 years or older;
• Diagnosis of sebaceous Ca of the ocular adnexa
• Ability to obtain formalin-fixed and paraffin-embedded primary and/or metastatic tumour tissue (FFPE) and healthy tissue
• Availability of primary and/or metastatic tumour tissue in paraffin-embedded or OCT (prospective part) and healthy tissue
• Written informed consent for use of data for research purposes.

Exclusion Criteria:

• Age < 18 years;
• Lack of sufficient clinical data on selected patients.
• Lack of tumor and/or metastatic tissue in kerosene or OCT.
• Refusal to give informed consent to data processing for research purposes.