Insular variant of poorly differentiated thyroid carcinoma.
OBJECTIVE
To present a case of an insular variant of poorly differentiated thyroid carcinoma (PDTC) and to review the literature related to diagnosis, natural history, and treatment of this unusual form of thyroid cancer.


METHODS
We present the clinical, laboratory, and pathologic findings of the study patient and review English-language literature related to PDTC published between 1970 and the present.


RESULTS
PDTC is a controversial and rare epithelial thyroid cancer, intermediate between differentiated thyroid carcinoma and anaplastic thyroid carcinoma that exhibits increased aggressiveness, propensity to local recurrence, distant metastases, and increased mortality. PDTC warrants aggressive management with total thyroidectomy followed by radioactive iodine ablation and potentially additional therapy for residual or recurrent disease. Some carcinomas do not take up radioactive iodine, and dedifferentiated clones of distant metastases may evolve. It is unclear whether chemotherapy is beneficial. Use of additional imaging modalities, including positron emission tomography, 18-fludeoxyglucose positron emission tomography/computed tomography, 18-fludeoxyglucose positron emission tomography/computed tomography/magnetic resonance imaging, (124)I positron emission tomography/computed tomography, positron emission tomography/magnetic resonance imaging fusion studies, and recombinant human thyrotropin-stimulated radioactive iodine uptake for cancer surveillance are discussed.


CONCLUSIONS
PDTC is an unusual and aggressive form of thyroid cancer. Fine-needle aspiration cytology may not yield sufficient information to specifically diagnose PDTC. Aggressive management with total thyroidectomy and neck dissection followed by high-dose radioactive iodine remnant ablation is standard. Iodine I 131 whole body scanning is often the initial test for tumor surveillance, with other imaging modalities applied as needed.
Fat
Ioana
I
Department of Internal Medicine, Norwalk Hospital, Norwalk, Connecticut 06856, USA.
Kulaga
Mark
M
Dodis
Regina
R
Carling
Tobias
T
Theoharis
Constantine
C
Rennert
Nancy J
NJ
D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D049268:Positron-Emission Tomography; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000601:surgery / Q000628:therapy; D013965:Thyroidectomy
D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18