Insular thyroid carcinoma: a retrospective clinicopathologic study.
BACKGROUND
Poorly differentiated carcinoma is a rare epithelial tumor that falls between well-differentiated thyroid carcinoma and anaplastic thyroid carcinoma in terms of morphologic appearance and biologic behavior. An insular variant was characterized in 1983. Further study of this neoplasm is warranted owing to its high aggressiveness, propensity to local recurrence and distant metastases, and high associated mortality. Since insular thyroid carcinoma may have varied presentations, treatment should be individualized.


OBJECTIVE
To describe the experience of a major tertiary medical center with insular thyroid carcinoma over a 7-year period.


METHODS
The study sample consisted of 17 patients with poorly differentiated thyroid cancer, insular variant, who were treated and followed at the Department of Otolaryngology, Head and Neck Surgery of Rabin Medical Center, Israel, in 1992-2009. The medical files were reviewed for background data, clinicopathologic features, treatment, and outcome.


RESULTS
The study group included 10 men and 7 women with a mean age of 63 years (range 16-78). Initial treatment was total thyroidectomy, in a single session (n=9) or two sessions (n=8), followed by radioiodine ablation. In addition, five patients received postoperative external beam radiation and one patient received chemotherapy. Nine patients had extrathyroidal extension, seven had vascular invasion, and four had multifocal disease. Distant metastases were present in four patients. Follow-up ranged from 6 months to 12 years. At present, 11 patients are alive and well. Five died of disease, and one died of another cause.


CONCLUSIONS
Insular thyroid carcinoma is aggressive and difficult to treat. Surgery remains the mainstay of treatment, though multimodality therapy is usually required.
Department of Otolaryngology, Head and Neck Surgery, Rabin Medical Center, Petach Tikva, Israel. royhod@gmail.com
Roy
R
Hod
Gideon
G
Bachar
Yulia
Y
Sternov
Jacob
J
Shvero
D000293:Adolescent; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007557:Israel; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D065646:Thyroid Carcinoma, Anaplastic; D013964:Thyroid Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D013965:Thyroidectomy / Q000379:methods; D055815:Young Adult