Endocrine Abstracts

Background: Neck ultrasonography (USG) is an important imaging tool in the postoperative follow-up of papillary thyroid carcinoma (PTC). Sarcoidosis is an inflammatory disease characterized by non-caseating granulomas with involvement in various organs and lymph nodes. Herein, a case with atypical lymph nodes detected on neck USG during routine follow-up for PTC and diagnosed with sarcoidosis will be presented.

Case presentation: A 52-year-old female patient, diagnosed with PTC 7 years ago, applied to our clinic for follow-up. The pathology after total thyroidectomy was compatible with classical-type PTC which was multicentric, bilateral, and had the largest diameter of 22 mm. No residual focus or metastatic lymphadenopathy (LAP) was detected in the patient’s 1-year follow-up whole-body iodine scan, who received postoperative 100 millicuries of radioactive iodine therapy. The patient, who has not had regular follow-up for the last 2 years, had TSH: 0.21 uIU/ml (reference range (RR):0.35-4.94), thyroglobulin (Tg): <0.01 ng/ml (RR:3.68-64.15) and anti-thyroglobulin (a-Tg): 1.14 IU/ml (RR<4.11) under 125 mg levothyroxine replacement. On neck USG, conglomerate, hypoechoic lymphadenopathies with no echogenic hilum were observed at bilateral cervical levels 3 and 4, the largest of which had a longitudinal dimension of 23 mm. Leukopenia (WBC: 2.92 10³/ul (RR:4.0-10.5), neutrophil: 1.65 10³/ul (RR:1.5-6.6), lymphocyte: 0.92 10³/ul (RR:1.5-3.5)) and hypercalcemia (Ca: 10.8 mg/dl (RR:8.5-10.4)) were also detected in her laboratory tests. Considering hematological malignancies, thoracoabdominal computed tomography (CT) examination was performed. Multiple conglomerated LAPs, the largest of which was paratracheal, measuring 27x25 mm, were observed in the mediastinum, and multiple paraaortic and intraaortocaval LAPs were observed in the retroperitoneal area in thoracoabdominal CT. Her right supraclavicular lymph node was excised and histopathological examination revealed non-caseating granulomas that tended to coalesce. The patient was diagnosed with sarcoidosis, as her serum angiotensin-converting enzyme (ACE) level was found to be high along with the present histopathological findings. The patient, who was in remission in terms of PTC, was planned to continue follow-up by reducing the levothyroxine dose replacement to 100 mg.

Conclusions: The coexistence of PTC and sarcoidosis has been reported as rare case reports. Sarcoid lesions can easily be confused with PTC metastases due to their involvement in both neck lymph nodes and lungs. The current case highlights that granulomatous diseases such as sarcoidosis should also be included in the differential diagnosis if pathological LAP with an advanced hypoechoic, conglomerate appearance is detected in a PTC follow-up patient with no increase in Tg levels.