Poorly differentiated ('insular') carcinoma of the thyroid.
Three cases of unusual poorly differentiated ('insular') carcinoma of the thyroid gland are presented. These three thyroid carcinomas were large; the tumors from patients 1 and 3 were encapsulated, and that from patient 2 showed invasive growth. Microscopically the tumors were characterized by well-defined solid nests (insulae), which were composed of rather small and uniform tumor cells with round to oval nuclei. Formation of small and colloid-containing follicles was associated with these nests to varying degrees. The tumors of patients 1 and 3 were composed entirely of insular components, but that of patient 2 was associated with small areas of well-differentiated follicular carcinoma. The metastatic tumors of patients 1 and 2 were essentially similar to the primary with small foci of follicular carcinoma. Patient 1 is alive with local and mediastinal node recurrences, but patient 2 died of the disease with local recurrences and metastases to lungs, bones and skin. Patient 3 had no recurrences and died of unrelated disease 5 years after surgery. The present study indicates that insular carcinomas have characteristic histologic features and a less favorable prognosis, confirming the findings of previous studies.
Mizukami
Y
Y
Pathology Section, Kanazawa University Hospital, Japan.
Nonomura
A
A
Michigishi
T
T
Noguchi
M
M
Ohmura
K
K
Nakamura
S
S
Hoso
M
M
D018263:Adenocarcinoma, Follicular / Q000473:pathology; D000293:Adolescent; D001707:Biopsy, Needle; D002277:Carcinoma / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000473:pathology*