P3040 - One Lesion at a “Thyme:” Oligometastatic Thymoma to the Liver

Mohammed Abusuliman, MD¹, Taher Jamali, MD², Amr Abusuliman, MD³, Faisal Nimri, MD², Sheema Rehman, DO², Tariq Hammad, MD², Robert Pompa, MD^1
1Henry Ford Health, Detroit, MI; ²Henry Ford Hospital, Detroit, MI; ³Tanta University, Qutour, Al Gharbiyah, Egypt

Introduction: Thymomas are rare slowly growing tumors that can infiltrate directly through contiguity. They account for 40% of all mediastinal masses, resulting from neoplastic transformation of thymus epithelial cells. They mostly affect the surrounding structures via direct invasion. Extra-thoracic metastasis of thymomas is exceedingly rare, and the exact incidence is not known. Available literature revealed a total of 50 cases of extra-thoracic metastasis of thymoma. Of these have been 18 cases with liver metastasis,10 with simultaneous liver and other organs metastasis, and only 8 with solely liver metastasis. We herein report the first endoscopic ultrasound (EUS)-guided biopsy of metastatic thymoma solely to the liver.

Case Description/Methods: An 89-year-old male presented to his primary physician with urinary retention. Computed tomography (CT) scan incidentally noted a 6.8 x 5.2 cm heterogeneous mass in the aortopulmonary window suspicious for primary mediastinal malignancy or metastatic disease and an indeterminate 1.9 cm lesion in the left hepatic lobe. Abdominal Magnetic resonance imaging confirmed a 1.9 cm lesion in the left hepatic lobe concerning malignancy (Figure 1-B). The mediastinal mass was biopsied, and pathology showed features consistent with Thymoma type B2.

Gastroenterology team were consulted for an endoscopic ultrasound-guided biopsy of the liver lesion. The lesion appeared hypoechoic, heterogenous, and solid with well-defined borders, 16 mm ×20 mm in diameter (Figure 1-A). Pathology findings were consistent with metastatic thymoma. PET-CT confirmed a hypermetabolic anterior mediastinal mass and segment III liver mass consistent with metastatic thymoma. Radiation therapy was recommended as the patient was a poor candidate for surgery or chemotherapy given his advanced age and comorbidities.

Discussion: Extra-thoracic dissemination of thymomas is an extremely rare occurrence of these already rare tumors (Table 1). EUS-guided liver biopsy is a useful tool for diagnosis and easy access to metastatic lesions in the liver, and also morphologically characterize the lesion, avoiding more invasive diagnostic methods.



Disclosures:


Mohammed Abusuliman, MD¹, Taher Jamali, MD², Amr Abusuliman, MD³, Faisal Nimri, MD², Sheema Rehman, DO², Tariq Hammad, MD², Robert Pompa, MD¹. P3040 - One Lesion at a “Thyme:” Oligometastatic Thymoma to the Liver, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.