Langerhans’ Cell Histiocytosis Masquerading as Metastatic Papillary Thyroid Cancer on F-18 FDG PET/CT: Diagnostic Dilemma Solved by PET/CT-Guided Biopsy

• Published in: Nuclear medicine and molecular imaging Vol. 52; no. 5; pp. 394 - 397
• Main Authors: Malik, Dharmender, Kumar, Rajender, Mittal, Bhagwant Rai, Parkash, Gaurav, Bal, Amanjit, Bhattacharya, Anish
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2018; Springer Nature B.V; 대한핵의학회
• Subjects: Ablation; Cancer; Cardiology; Computed tomography; Diagnostic systems; Fluorine isotopes; Imaging; Interesting Image; Iodine; Lesions; Medicine; Medicine & Public Health; Nuclear Medicine; Oncology; Orthopedics; Radioisotopes; Radiology; Thyroid cancer; 방사선과학; Papillary thyroid cancer; Langerhans’ cell histiocytosis; PET/CT-guided biopsy; F-FDG PET/CT; Anti-thyroglobulin level; 18F-FDG PET/CT
• ISSN: 1869-3474; 1869-3482
• DOI: 10.1007/s13139-018-0536-7

We present a case of papillary thyroid cancer (post-thyroidectomy status) on regular treatment with suppressive Levothyroxine therapy. On follow-up at 6 months after radioactive iodine ablation for remnant thyroid tissue, her thyroglobulin, and anti-thyroglobulin levels were 0.06 ng/ml and 670 IU/ml, respectively. Low-dose whole-body I-131 scan was negative. To look for the cause of isolated increased anti-thyroglobulin level, a whole-body 18 F-FDG PET/CT was done which revealed multiple FDG-avid lytic skeletal lesions suggestive of metastases. For confirmation of diagnosis, 18 F-FDG PET/CT-guided metabolic biopsy was done, which revealed Langerhans’ cell histiocytosis on histopathological examination.