The association between Hashimoto thyroiditis (HT) and papillary thyroid carcinoma (PTC) is well known but few reports have described the morphological features of HT-associated PTC.1,2 Di Pasquale et al.3 described a peculiar histological pattern of HT-associated PTC consisting of anastomosing spaces lined with cells having the characteristic nuclear features of PTC. The authors named this HT-associated variant of PTC as angiomatoid and emphasized that these cases may be missed if the cells lining the spaces are not examined at high magnification. 3 We describe the fine needle aspiration (FNA) cytological and histological findings n a case of HT-associated PTC in its angiomatoid variant, in which the diagnosis of PTC was more straightforward on cytology than histology. A 16-year- ld girl complained of diffuse enlargement of the neck. Clinical examination showed a generalized enlargement and increased hardness of the thyroid. Serological data showed high levels of anti-thyroglobulin, anti-thyreoproxidase antibodiesand increased thyroid-stimulating hormone (TSH)levels that were indicative of a HT with subclinical hypothyroidism. An ultrasonography (US) showed the gland to have irregular borders, diffuse micronodulation and hyperechoic bands in both lobes. Moreover, an irregular, 12-mm-sized hypoechoic nodule was detected at the base of the right lobe; no cervical lymph nodes were detected. An US-guided, FNA of the nodule was performed. The Diff-Quik stained smears were highly cellular; follicular cells were organized in very large overlapping groups with a branching appearance. In some monolayered groups, the cells showed plentiful squamoid cytoplasm (Figure 1a); the nuclei were irregular in size and shape, with granular coarse chromatin and inconspicuous nucleoli. Grooves and cytoplasmic intranuclear inclusions were detected (Figure 1a, inset). The background was haemorrhagic, with some lymphoid cells and tangles intermingled with follicular cells; colloid was absent. The cytological diagnosis was PTC in a background of HT. The patient underwent a total thyroidectomy. The gland on the cut section was solid and showed a greyreddish colour, with accentuated lobulation. In the right lobe a haemorrhagic, ill-defined 12-mm nodule was detected. The histological sections showed the classic features of HT, with lymphoid follicles and Hurthle cell metaplasia. The nodule appeared as a haemorrhagic, poorly defined area, and consisted of irregular, spaces, fibrotic bands and inflammatory cells lacking papillary or follicular structures (Figure 1b). The spaces ranged from a roundish to stag-horn pattern and were lined with flat or cuboidal epithelial cells (Figure 1c). Follicular cells showed plentiful cytoplasm, irregular nuclei, sometimes empty, with grooves and cytoplasmic intranuclear inclusions (Figure 1c, inset); these cells were positive for thyroglobulin and thyroid transcription factor-1 (TTF-1) on immunohistochemistry. Because of the coexistence of the classic nuclear features of PTC and the histological features described above, a diagnosis of HT-associated PTC in its angiomatoid variant was made. There is clinical and pathological evidence of a relationship between HT and PTC ranging between some cytological features and RET-PTC rearrangement. 1 Some studies report that over 90% of thyroids with HT express RET ⁄ PTC1 and RET ⁄ PTC3 oncogenes.4 Nevertheless, few reports have described the morphological features of HT-associated PTC.
Histological and fine needle aspiration cytological features of Hashimoto thyroditis-associated 'angiomatoid' papillary thyroid carcinoma.
ZEPPA, Pio
2012-01-01
Abstract
The association between Hashimoto thyroiditis (HT) and papillary thyroid carcinoma (PTC) is well known but few reports have described the morphological features of HT-associated PTC.1,2 Di Pasquale et al.3 described a peculiar histological pattern of HT-associated PTC consisting of anastomosing spaces lined with cells having the characteristic nuclear features of PTC. The authors named this HT-associated variant of PTC as angiomatoid and emphasized that these cases may be missed if the cells lining the spaces are not examined at high magnification. 3 We describe the fine needle aspiration (FNA) cytological and histological findings n a case of HT-associated PTC in its angiomatoid variant, in which the diagnosis of PTC was more straightforward on cytology than histology. A 16-year- ld girl complained of diffuse enlargement of the neck. Clinical examination showed a generalized enlargement and increased hardness of the thyroid. Serological data showed high levels of anti-thyroglobulin, anti-thyreoproxidase antibodiesand increased thyroid-stimulating hormone (TSH)levels that were indicative of a HT with subclinical hypothyroidism. An ultrasonography (US) showed the gland to have irregular borders, diffuse micronodulation and hyperechoic bands in both lobes. Moreover, an irregular, 12-mm-sized hypoechoic nodule was detected at the base of the right lobe; no cervical lymph nodes were detected. An US-guided, FNA of the nodule was performed. The Diff-Quik stained smears were highly cellular; follicular cells were organized in very large overlapping groups with a branching appearance. In some monolayered groups, the cells showed plentiful squamoid cytoplasm (Figure 1a); the nuclei were irregular in size and shape, with granular coarse chromatin and inconspicuous nucleoli. Grooves and cytoplasmic intranuclear inclusions were detected (Figure 1a, inset). The background was haemorrhagic, with some lymphoid cells and tangles intermingled with follicular cells; colloid was absent. The cytological diagnosis was PTC in a background of HT. The patient underwent a total thyroidectomy. The gland on the cut section was solid and showed a greyreddish colour, with accentuated lobulation. In the right lobe a haemorrhagic, ill-defined 12-mm nodule was detected. The histological sections showed the classic features of HT, with lymphoid follicles and Hurthle cell metaplasia. The nodule appeared as a haemorrhagic, poorly defined area, and consisted of irregular, spaces, fibrotic bands and inflammatory cells lacking papillary or follicular structures (Figure 1b). The spaces ranged from a roundish to stag-horn pattern and were lined with flat or cuboidal epithelial cells (Figure 1c). Follicular cells showed plentiful cytoplasm, irregular nuclei, sometimes empty, with grooves and cytoplasmic intranuclear inclusions (Figure 1c, inset); these cells were positive for thyroglobulin and thyroid transcription factor-1 (TTF-1) on immunohistochemistry. Because of the coexistence of the classic nuclear features of PTC and the histological features described above, a diagnosis of HT-associated PTC in its angiomatoid variant was made. There is clinical and pathological evidence of a relationship between HT and PTC ranging between some cytological features and RET-PTC rearrangement. 1 Some studies report that over 90% of thyroids with HT express RET ⁄ PTC1 and RET ⁄ PTC3 oncogenes.4 Nevertheless, few reports have described the morphological features of HT-associated PTC.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
