A Case of Mediastinal Carcinosarcoma With Beta-HCG Production and KRAS Mutation

Carcinosarcomas of mediastinum are rare and only few well-documented cases are available in the literature. We report a detailed description of mediastinal carcinosarcoma with unique clinical manifestations and immunohistochemical and molecular profiles. A 44-year-old female with an enlarging anterior mediastinal mass was found to have a positive pregnancy test. Thoracoscopic biopsy revealed that the mass represented a carcinosarcoma with adenocarcinoma and chondrosarcoma components. The tumor focally expressed beta-HCG by immunohistochemistry and had KRAS G12A missense mutation by next generation sequencing. The case documents a rare presentation of carcinosarcoma within the mediastinum with uncommon paraneoplastic syndrome and genetic profile. Awareness of these unusual clinical and pathological manifestations of the tumor will help in reaching correct diagnosis and proper management of such patients.

Automated summary

In this article, we report a rare case of mediastinal carcinosarcoma with unique clinical manifestations and immunohistochemical and molecular profiles. The patient, a 44-year-old female, presented with an enlarging anterior mediastinal mass and a positive pregnancy test. The thoracoscopic biopsy revealed a carcinosarcoma with adenocarcinoma and chondrosarcoma components. The tumor showed focal expression of beta-HCG and had a KRAS G12A missense mutation. This case highlights the importance of recognizing the uncommon clinical and pathological manifestations of mediastinal carcinosarcoma in order to ensure accurate diagnosis and proper management.