Differential Diagnosis for Atrial Mass and Diarrhea
- Single most likely diagnosis
- Carcinoid syndrome: This condition is characterized by the presence of a neuroendocrine tumor (often in the small intestine) that metastasizes to the liver, producing vasoactive substances like serotonin. These substances can cause diarrhea and lead to the development of cardiac abnormalities, including atrial masses (e.g., carcinoid heart disease). The combination of diarrhea and an atrial mass makes carcinoid syndrome a strong consideration.
- Other Likely diagnoses
- Atrial myxoma with secondary infection or inflammation causing systemic symptoms like diarrhea: Atrial myxomas are the most common type of primary cardiac tumor and can be associated with systemic symptoms due to embolization or production of interleukin-6, leading to fever, weight loss, and possibly gastrointestinal symptoms like diarrhea.
- Metastatic disease to the heart from a gastrointestinal primary cancer: Certain cancers, such as pancreatic or gastric cancer, can metastasize to the heart, forming an atrial mass, and also cause diarrhea due to the primary tumor's location or effects.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Infective endocarditis: Although less common in the atria, infective endocarditis can occur on any valve or cardiac structure, including atrial masses. It can cause systemic symptoms, including diarrhea, due to sepsis or embolic phenomena. Missing this diagnosis could be fatal.
- Lymphoma with cardiac involvement: Lymphoma can involve the heart and cause atrial masses. Systemic symptoms, including diarrhea, can occur due to the lymphoma itself or due to treatment effects.
- Rare diagnoses
- Cardiac sarcoma: These are rare malignant tumors of the heart that can present as an atrial mass. Systemic symptoms, including diarrhea, can occur due to metastasis or tumor effects.
- Atrial thrombus in the setting of hypercoagulable state or atrial fibrillation with systemic embolization causing gastrointestinal symptoms: While not typically considered a "mass" in the traditional sense, an atrial thrombus can form in hypercoagulable states or atrial fibrillation and potentially embolize, causing systemic symptoms including gastrointestinal issues like diarrhea.