Cytopathology of insular carcinoma of the thyroid

Abstract

Four pure insular carcinomas (IC) and one IC with focal anaplastic carcinoma (AC) of the thyroid with cytologic evaluation by fine-needle aspiration (FNA) were reviewed. The needle aspirates from the four pure ICs revealed abundant monomorphic follicular cells present singly, in small, loose aggregates, and in cohesive trabecular and acinar clusters. Tumor cells showed fragile, ill-defined, granular cytoplasm and oval nuclei with conspicuous or inconspicuous nucleoli. The case of IC with focal AC yielded, in addition to the follicular cells as seen in the FNA of the 4 cases of pure IC, large pleomorphic malignant cells with prominent nucleoli that were characteristic for an AC, giant-cell type. No intact insulae of tumor cells were identified in any of the 5 cases. Thus, a thyroid IC may be suspected if abundant cohesive and dyshesive monomorphic follicular cells are present in the tumor FNA. However, a firm diagnosis of thyroid IC can only be made by histologic examination of the excised tumor.

Cytologic features of insular carcinoma of the thyroid: A case report

“…These consist of retrospective reviews after the histologic diagnosis has been made from the thyroidectomy specimen. [3][4][5][6] The remaining publications consist of single case reports, [7][8][9][10][11][12][13][14][15][16][17][18][19][20] and none of these authors claims to have made the diagnosis of insular carcinoma from the aspirate. We report a case, diagnosed as moderately differentiated papillary carcinoma on FNA, subsequently diagnosed as insular carcinoma upon resection.…”

Fine Needle Aspiration of Poorly Differentiated Oxyphilic (Hürthle Cell) Thyroid Carcinoma

“…[6][7][8] Extreme cellularity of smears, to a degree that would be considered unusual for classic follicular neoplasms and many papillary carcinomas, seems to be the common denominator in these reports. The predominance of single, monomorphic cells with fewer atypical features, paucity of classic microfollicles, absence of central colloid cores in the few microfollicles that may be seen, occasional intact insulae and deposits of necrotic debris are other features that favor a diagnosis of poorly differentiated carcinoma over a follicular neoplasm.…”

Update in Thyroid Fine Needle Aspiration

“…PDTC has an aggressive clinical behavior intermediate between that of WDTCs and undifferentiated (anaplastic) thyroid carcinomas [32][33][34][35][36] While PDTC represents an extremely important clinical entity, few studies have examined its cytologic features, and aspirates of PDTC represent a diagnostic challenge for the cytopathologist. One of the first cytological descriptions of PDTCs was a report of 6 cases by Pietribiasi et al [37][38][39][40][41]. In addition to these series, a limited number of published case reports are also available, but only a few FNAB cases have prospectively recognized the tumors as PDTC.…”