Paraganglioma with unusual presentation in parotid gland: A diagnostic dilemma in fine needle aspiration
The patient was a 56-year-old woman, with a history of unrepaired Tetralogy of Fallot and Eisenmenger's syndrome, who was admitted to our Medical Center with atrial flutter/atrial fibrillation, palpitations, and possible cerebrovascular accident due to the congenital heart disease. Magnetic resonance angiography (MRA) evaluation of the head and neck showed an incidental right parotid gland mass. Subsequent ultrasound of this area showed a 2.0 × 1.5 cm solid tumor located in the deep within the parotid gland, which was presumed to be a pleomorphic adenoma. Ultrasound-guided FNA was then performed by a radiologist. Cytological evaluation of the initial FNA smears showed moderate cellularity consisting of atypical epithelioid cells in disorganized groups, strips, and single cells. The atypical cells showed enlarged nuclei with variably granular chromatin, occasional nucleoli, anisonucleosis, and scant delicate cytoplasm [Figure and ]. Rare salivary gland acinar and ductal cells were noted as small groups in the blood-tinted background. Since the cell block was paucicellular, two of the Papanicolaou-stained slides were re-stained for synaptophysin and keratin by immunohistochemistry (IHC). The positive immunostain of the cells for synaptophysin [] was compatible with a tumor of neuroendocrine origin. The cytokeratin stain showed negative on the re-stained smear. Subsequently, a diagnosis of “atypical cells present, suspicious for neuroendocrine tumor” was rendered.\nOn the basis of diagnosis of neuroendocrine tumor by FNA, a total parotidectomy and neck dissection was performed. During the surgery, the 2.0 cm mass was confirmed to be in the central portion of the deep lobe of the parotid gland. On gross examination, the tumor was a red-pink, firm, well-circumscribed mass, measuring 2.2 × 1.5 × 1.4 cm.\nHistological evaluation of the surgical specimen [] showed epithelioid cells arranged in an alveolar pattern in nests surrounded by capillary networks. These cells showed considerable nuclear atypia, enlargement, and hyperchromasia. The cell cytoplasms varied from pink to clear and often vacuolated. A second type of cell was seen at the periphery of the nests which was more of a spindle shape. No mitoses were identified. The nested (chief) cells were positive for chromogranin and synaptophysin, while negative for keratin and S-100. The spindle cells (sustentacular) at the periphery were positive only for S-100. A final histological diagnosis of PGL was made based on the characteristic morphology and immunohistochemical stains.\nAn incidental metastatic papillary thyroid carcinoma was identified in one of twenty-one dissected lymph nodes. This finding led to a subsequent ultrasound of the thyroid gland which revealed a previously unknown sub-centimeter mass with calcifications suspicious for papillary thyroid carcinoma. Due to the urgent cardiac problem of the patient, the surgical intervention of the thyroid gland was postponed indefinitely.