SAT197 A Rare Case Of Infected Parathyroid Cyst Associated With Hyperparathyroidism

Disclosure: B. Ataallah: None. M. Al Tameemi: None. P.R. Orlander: None. Introduction: Parathyroid cysts are considered rare lesions compromising 1-5 % of neck masses. Clinical pictures can range from asymptomatic to symptoms and signs of hyperparathyroidism, and it may lead to compressive symptoms as well. Infection of the parathyroid cyst is not reported in literature. We are presenting a patient with parathyroid cyst and was found to be infected with E-coli. Case presentation: A 59-year-old woman presented with neck swelling and ear pain. She was initially diagnosed with otitis externa and was treated with antibiotics. Her neck swelling worsens over a brief period with associated ear drainage and shortness of breath. Computed tomography (CT) scan of the neck revealed a large cystic lesion up to 10 cm in largest diameter in the region of the thyroid gland with inflammatory changes extending to the prevertebral soft tissues. CT scan of the chest showed a mass effect on the trachea and adjacent structures with possible hemorrhage. Eventually the patient was intubated. Laboratory evaluation revealed parathyroid hormone (PTH) at 455 pg/ml, corrected calcium of 11.3 mg/dl, Ionized calcium of 1.41 mMol/L, and phosphorus at 3.0 mg/dl. Aspiration of the cyst was done prior to surgery and the culture grew E-coli. She started on antibiotics, and eventually underwent a total thyroidectomy with excision of the parathyroid cyst and adenoma. Pathology showed a ruptured cyst with marked inflammation and granulation tissue with hypercellular left superior parathyroid gland. Postoperatively, corrected calcium dropped to 10.1mg/dl and PTH to 38.5 pg/ml. Discussion: Parathyroid cyst (PC) is a relatively rare neck or mediastinal lesion, representing less than 0.5% of parathyroid gland disorders. Most PCs are nonfunctional, but some may produce excess parathyroid hormone or can cause local compressive symptoms like dyspnea, dysphagia, or hoarseness of voice, depending on the size and location of the lesion. There are no distinct clinical or radiological features to differentiate parathyroid cysts, and that makes preoperative diagnosis challenging, and most cases are diagnosed during surgery or postoperatively. Aspiration and fluid analysis can confirm the diagnosis preoperatively, and the treatment can be achieved either by cyst aspiration for small lesions with less than 2.5 cm in diameter, through sclerosing agent injection, or by surgical resection. In this patient, the culture of the aspirated parathyroid cyst surprisingly grew E coli. It is unusual to have an infection with E coli in the neck tissues or the surrounding structures, and it is unknown whether the cyst infection is related to the ear infection that our patient has. Parathyroid cyst infection is not reported in literature reviews, and it is important to consider fluid analysis and culture to confirm the diagnosis preoperatively and to rule out cyst infection Presentation: Saturday, June 17, 2023