Whole exome sequencing of a patient with metastatic hidradenocarcinoma and review of the literature.

Hidradenocarcinoma is a rare malignancy of the sweat glands with only a few cases reported in literature. The management of these tumors is based on the extent of disease with local disease managed with surgical resection. These can tumors carry a high potential of lymphatic and vascular spread and local and distant metastases are not uncommon. Given the rarity of the tumor and lack of genetic and clinical data about these tumors, there is no consensus on the proper management of metastatic disease. Here in we report the first case of metastatic hidradenocarcinoma with detailed molecular profiling including whole exome sequencing. We identified mutations in multiple genes including two that are potentially targetable: PTCH1 and TCF7L1. Further work is necessary to not only confirm the presence of these mutations but also to confirm the clinical significance.