2. Case Report
A 41-year-old female presented to our institution for evaluation of primary hyperparathyroidism. She had a 7-year history of hypercalcemia, with levels up to 11.5 mg/dL (reference range: 8.7 - 10.2 mg/dL) and PTH levels up to 101 pg/mL (reference range: 10 – 73 pg/mL). She has no pertinent family history and is a former smoker (0.25 ppd, 5 pack-years). Initially, she underwent an ultrasound (US) of the neck and99mTc-MIBI single photon emission computed tomography (SPECT) imaging, which failed to identify any suspicious lesions or localizing parathyroid adenomas. Subsequent SPECT/CT (Figure 1 ) and 4-D computed tomography (CT) (Figure 2 ) demonstrated evidence of a 1.3 cm lesion superior to the thyroid at the level of the pyriform sinus on the left side, likely representative of an ectopic or undescended parathyroid adenoma. Given its unusual location patient was preoperatively counseled on the risk of injury to the hypoglossal nerve, marginal mandibular nerve, and the possible need for a second incision for four gland exploration if the candidate lesion was not an adenoma.
On the day of surgery, pre-operative PTH level was 80 pg/mL. In the operating room, an upper transcervical incision was performed to obtain access to the identified site. The subplatysmal flap was raised superiorly and inferiorly to expose the inferior aspect of the submandibular gland. Then the investing fascia was incised just caudal to the submandibular gland, which was retracted superiorly to reveal the posterior belly of the digastric muscle. The digastric muscle was dissected along its anterior face and subsequently retracted superiorly to identify the hypoglossal nerve and the internal jugular vein. A crossing facial vein was encountered that required ligation to gain appropriate access. An enlarged and undescended parathyroid measuring 1.5 x 1.5 cm located deep and slightly inferior to the anterior belly of the digastric muscle, anterior and slightly medial to the carotid artery, was identified and carefully resected (Figure 3, Figure 4 ). 10 minutes following the excision of the adenoma, PTH fell to 16 pg/mL and at 15 minutes post-excision remained stable at 14 pg/mL indicating biochemical cure.