Primary De novo ductal adenocarcinoma of the lacrimal gland

Background: Primary ductal adenocarcinoma of the lacrimal gland is a rare and aggressive malignant epithelial lacrimal gland neoplasm, morphologically and phenotypically resembles salivary duct carcinoma, and both strongly resemble infiltrating ductal carcinoma of breast. Method: Retrospective Chart review of cases of malignant lacrimal gland tumors from 2013 July to 2020 July. Authors describe the clinico radiological, morphological and immunohistochemical features of primary ductal adenocarcinoma (PDA) of lacrimal gland. Extensive review of literature of PDA of lacrimal gland and salivary gland ductal carcinoma has been performed. Results: Retrospective chart review of the last 7 years yielded 22 malignant lacrimal gland neoplasms of which 4 cases demonstrated features of primary ductal adenocarcinoma of lacrimal gland, 2/4 cases showed an evidence of a pre existing pleomorphic adenoma and 2 were found to be de novo ductal adenocarcinomas. PDA of lacrimal gland showed expression of CK7, CK19, AR, HER2, cyclin D1 and were negative for CK5/14, CK 20, ER, PR, PSA, TTF-1, S-100 and SMA. Expression of GCDFP-15 was noted in one case. The presence of multiple events of locoregional recurrences and/or distant metastasis necessitated a multidisciplinary approach. Conclusions: Authors have expressed the need of clinical correlation; thorough tissue sampling and extensive immunohistochemical work up in identification of de novo PDA's and their molecular subtypes. A multi-institutional study might help in formulating the diagnostic criteria, identification of actionable targets, and thus study the role of targeted therapy in this rare and aggressive tumor which may result in better patient outcomes.