Uterine Sarcoma Presenting as Hypercapnic Respiratory Failure.

Thyroid cancer is a type of malignancy that is considered to have a low morbidity and an indolent disease course in most patients. Though some of its pathologic variants such as anaplastic carcinoma may present with advanced disease staging, it is important to consider the possibility of metastasis to thyroid which may present like a thyroid primary. Solid organ carcinomas form the bulk of the uncommon metastasis to the thyroid, though sarcomas from various organs also rarely exhibit this activity. Literature demonstrating sound diagnostic criteria for these occurrences is sparse. We present a case of uterine sarcoma with distant metastasis to the thyroid gland that initially presented as hypercapnic respiratory failure. Only an inpatient episode of uterine bleeding prompted our team to explore the potential of a metastatic process. Our diagnosis was made utilizing a multidisciplinary approach that we feel is important for clinicians dealing with metastatic disease to the thyroid. In addition to sound physical exam, and use of appropriate imaging modality, we feel it is essential to utilize a detailed cytohistologic specimen evaluation, immunohistochemistry, and genetic sequencing to effectively work up such patients. Although our patient did not survive her hospital stay, we hope this paper brings greater awareness of this malignancy and acts as a benchmark for diagnosing such an unusual remote primary.