Littoral cell angioma presenting as metastatic thyroid carcinoma to the spleen

Papillary thyroid carcinoma (PTC) commonly metastasizes to cervical lymph nodes. Distant metastases are unusual with the lungs most frequently involved. Well-differentiated thyroid carcinoma very rarely presents with metastases to the spleen. This is the case of a 25-year-old man with a history of PTC (1.4 cm primary; no capsular invasion and negative lymph node metastases). One year after initial surgery, recurrent disease was found in multiple neck nodes by central neck dissection. Whole body scan (WBS) following a therapeutic ablation dose of 150 mCi I¹³¹ revealed mediastinal metastases. Computerized axial tomography (CT) of the chest one year later showed no gross mediastinal or pulmonary disease. However, multiple large splenic lesions were incidentally noted. Evaluation by ultrasound (US) showed lesions to be solid echogenic masses without remarkable Doppler characteristics to suggest vascular tumors. US-guided percutaneous fine-needle aspiration biopsy (FNAB) of one lesion was nondiagnostic. After withdrawal from Levothyroxine, serum TSH was > 100 mU/L with a thyroglobulin of 9.4 ng/mL and negative anti-thyroglobulin antibodies. Diagnostic WBS revealed faint splenic uptake but was otherwise unremarkable. Following treatment with 192 mCi I¹³¹, WBS demonstrated increased activity in the mediastinum as well as in the spleen suggesting mediastinal and splenic metastases. Contrast CT of the abdomen showed multiple low-attenuated heterogeneously enhancing splenic masses, normal liver and no intra-abdominal lymphadenopathy. The largest mass (4.5 × 3.5 cm) was exophytic and in close proximity to the splenic capsule. Despite the serum thyroglobulin of only 9.4 ng/mL, the finding of I¹³¹ accumulation within solid splenic masses led to a preoperative diagnosis of thyroid carcinoma metastases. To establish the diagnosis and to remove the risk for splenic rupture, a laparoscopic splenectomy was performed. Histopathologic analysis showed large littoral cell angiomas (LCA). False-positive radioiodine scintigraphy in the setting of PTC involving a vertebral hemangioma has been reported. To our knowledge, this is the first case that describes multiple angiomas mimicking metastatic thyroid carcinoma to the spleen. In one-third of all cases reported, LCA co-exists with various visceral organ cancers or malignant lymphoma. This is the first report of an association between LCA and thyroid carcinoma.