Cytopathology of insular carcinoma of the thyroid

Abstract

BACKGROUND Insular carcinoma of the thyroid (ICT) first was reported in 1984. To the authors' knowledge, few cytology reports have been published since that time. The authors describe the cytologic features of six tissue‐proven ICTs and propose criteria that suggest its diagnosis. METHODS Four cases were thyroid fine‐needle aspiration (FNA) samples. Two cases were FNAs of metastases. All cases were found to be classic ICT on examination of primary or metastatic surgical specimens. RESULTS Three cases originally were diagnosed as carcinoma, including two FNAs of metastatic sites and one thyroid FNA. Two additional thyroid FNAs were diagnosed as suspicious for malignancy, favor follicular neoplasm. One case was termed a neoplasm, favor follicular type. Smears showed high cellularity and scanty colloid. Three cases were found to contain some microfollicles. One case showed a few papillae. Necrosis and mitosis were rare. Cells were round with pale, poorly defined cytoplasm. Nuclei were round and monomorphic with finely granular chromatin, mild hyperchromasia, smooth nuclear membranes, and small nucleoli. Nuclear grooves and inclusions were rare. CONCLUSIONS Three cases were diagnosed as suspicious for follicular neoplasm, the main differential diagnosis of ICT. Both tumors exhibited high cellularity and scanty colloid. However, ICT showed a predominance of single cells whereas follicular neoplasms reveal microfollicles with more nuclear atypia. There is cytologic overlap between these two neoplasms. Papillary thyroid carcinoma should be distinguished from ICT easily because the latter usually does not reveal the classic cytologic features associated with the former. ICT should be considered in the differential diagnosis of follicular neoplasms. Features favoring ICT are predominance of single cells, small loose nests of cells with few microfollicles, and little nuclear atypia. Cancer (Cancer Cytopathol) 1999;87:196–202. © 1999 American Cancer Society.

A review of thyroid cancer with intermediate differentiation

“…The nuclear to cytoplasmic ratio is high and nuclear overlapping is a prominent feature. Nuclear grooves and intranuclear inclusions are not frequently seen [71,73,74].…”

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.…”

Das insuläre Schilddrüsencarcinom – ein differenziertes Schilddrüsencarcinom mit schlechter Prognose

“…Das Überwiegen von Patientinnen gilt auch für andere Schilddrüsencarcinomtypen [30]. Bei Kindern und Adolescenten sind insuläre Schilddrüsencarcinome Einzelfälle [14,15,22,32,41,42]. Das mittlere Alter dieser Form ist grundsätzlich höher als bei den gut differenzierten Schilddrüsencarcinomen [8,37], in unserem Patientengut war es 52 Jahre und schwankte in den gröûeren Untersuchungen zwischen 49 und 56 Jahren [3,5,9,32,37,42,43].…”

“…Fernmetastasen, zumeist klinisch asymptomatisch, sind bei der Erstdiagnose in ca. Die in der Literatur vertretenen Auffassungen zur Möglichkeit der Diagnosesicherung durch präoperative Feinnadelbiopsie sind kontrovers [3,14,23,25,26,31,41]. Die in der Literatur vertretenen Auffassungen zur Möglichkeit der Diagnosesicherung durch präoperative Feinnadelbiopsie sind kontrovers [3,14,23,25,26,31,41].…”

“…Schilddrüsencarcinome enthalten oft Anteile unterschiedlicher cyto-und histologischer Differenzierung [14,30,34]. Deshalb wurde untersucht, welche Relevanz ein prozentual unterschiedlicher Anteil insulärer Differenzierung hat: die Gröûe des Carcinoms [3,39], das Stadium [3], das Auftreten regionaler oder Fernmetastasen [3,43] und auch das Überleben [3,9,43] scheinen nicht mit dem prozentualen Anteil einer insulären Differenzierung assoziiert zu sein.…”