Malignant Paraganglioma: A Case Diagnosed by Fine-Needle Aspiration

Abstract

The prevalence of malignant paragangliomas is approximately 10% and is defined by the presence of metastases. Differential diagnosis includes hepatic tumors, alveolar soft part sarcoma, melanoma, glomus tumors, vascular neoplasms, and primary or metastatic carcinomas with endocrine or nonendocrine phenotype. Increasingly, fine-needle aspiration (FNA) is being used to evaluate primary and potential metastatic lesions. We describe a recent case of metastatic paraganglioma diagnosed by FNA and review the relevant clinicopathologic features of this rare entity. A 41-year-old man with a medical history of hypertension was admitted with left-sided numbness and weakness for 3 days. A 5.7-cm mass was found on the right anterior chest with destruction of the anterior portion of the sixth rib. An FNA with core biopsies was obtained. CT of abdomen/pelvis showed multiple nodules along the spinal ganglion chain representing primary paraganglioma. Pathologic material was obtained, including 6 slides (3 Diff-Quik and 3 Papanicolaou stains) and 6 fragmented red-tan needle cores. Immunostains for CD56, synaptophysin, chromogranin, vimentin, CK7, CK20, AE1/AE3, CD10, CD34, and CAM5.2 were performed using standard techniques. Cytologic examination demonstrated irregular clusters of tumor cells in an organoid-like pattern with eosinophilic, finely granular cytoplasm and irregularly shaped nuclei with finely stippled, densely clumped chromatin. Vascular tracts were noted. Tumor cells were negative for keratin and positive for CD56, synaptophysin, chromogranin, and vimentin. S-100 highlighted sustentacular cells. The microscopic and immunohistochemical findings along with the radiographic features were consistent with metastatic malignant paraganglioma. Malignant paraganglioma is a rare entity with a 40% to 72% 5-year survival. Patients with increased (>5 cm) primary tumor size or with primary tumors located in the mediastinum or infradiaphragmatic para-aortic area are at increased risk for malignancy. Our case demonstrates that patients can be reliably diagnosed using a combination of cytology, immunohistochemistry, clinical history, and imaging.