Predictive value of hematologic parameters and clinicopathological features of poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma.

PURPOSE: Poorly differentiated thyroid carcinoma (PDTC) and anaplastic thyroid carcinoma (ATC) are rare, aggressive thyroid cancers with poor prognosis. At present, there are a limited number of research reports on PDTC and ATC. The study aimed to analysis the predictive value of hematologic parameters and clinicopathological features of PDTC and ATC. METHODS: This study retrospectively analyzed 67 patients at Tianjin Medical University Cancer Hospital from 2007 to 2019. We analyzed the clinicopathological features and survival outcomes of PDTC and ATC. RESULTS: This study showed that positive D-dimer, a high NLR, and a high PLR were more common in death patients. At the end of follow-up, 22 (32.8%) patients were alive at the time of study and 45 (67.2%) patients died from thyroid carcinoma. Disease-related death rates were 93.8% in ATC and 42.9% in the PDTC group. The median overall survival (OS) was 2.5 (0.3-84) months for patients with ATC, and 56 (3-113) months of PDTC patients. Univariate analysis showed that age at diagnosis and surgery were associations with OS in ATC patients, what's more, age at diagnosis, a high NLR, a high PLR, and positive D-dimer were associations with OS in PDTC patients. Multivariate analysis revealed that age at diagnosis was an independent association with OS in ATC patients. CONCLUSIONS: The hematologic parameters and clinicopathological features may provide predictive value of prognosis for patients with PTDC and ATC.

Thyroid cancer necrosis not evident on imaging: A cautionary case series on poorly differentiated thyroid carcinoma diagnosed only on final pathology.

OBJECTIVE: Poorly-differentiated thyroid cancer (PDTC) is a highly aggressive malignancy which is recently defined and understudied in the radiologic literature. Necrosis is a key histopathologic criterion for the diagnosis of PDTC. We illustrate the current difficulty in accurate identification of histopathologic necrosis on preoperative imaging. METHODS: A series of seven patients with the final diagnosis of PDTC from our institution were identified. Multimodality preoperative imaging was analyzed by two head and neck radiologists. Final pathology reports were queried confirming histopathologic evidence of necrosis. RESULTS: Patients presented with a wide range of preoperative imaging features. A consistent imaging appearance confirming necrosis was not identified. All patients were subsequently upstaged to PDTC following final pathological analysis. CONCLUSION: A lack of definitive evidence of necrosis on preoperative imaging does not exclude the possibility of PDTC. We demonstrate the need for further research to establish a clear methodology for the preoperative diagnosis of PDTC.

Primary high-grade non-anaplastic thyroid carcinoma: a retrospective study of 364 cases.

AIMS: We aimed to study the clinicopathological and molecular features of high-grade non-anaplastic thyroid carcinomas (HGTCs), a carcinoma with a prognosis intermediate between those of well-differentiated carcinoma and anaplastic carcinoma. METHODS AND RESULTS: This study included 364 HGTC patients: 200 patients (54.9%) were diagnosed with poorly differentiated thyroid carcinoma (PDTC), based on the Turin consensus (HGTC-PDTC), and 164 were diagnosed with high-grade features that did not meet the Turin criteria (HGTC-nonPDTC). HGTCs are aggressive: the 3-year, 5-year, 10-year and 20-year disease-specific survival (DSS) rates were 89%, 76%, 60%, and 35%, respectively. Although DSS was similar between HGTC-PDTC and HGTC-nonPDTC patients, HGTC-PDTC was associated with higher rate of radioactive iodine avidity, a higher frequency of RAS mutations, a lower frequency of BRAF V600E mutations and a higher propensity for distant metastasis (DM) than HGTC-nonPDTC. Independent clinicopathological markers of worse outcome were: older age, male sex, extensive necrosis and lack of encapsulation for DSS; older age, male sex and vascular invasion for DM-free survival; and older age, necrosis, positive margins and lymph node metastasis for locoregional recurrence-free survival. The frequencies of BRAF, RAS, TERT, TP53 and PTEN alterations were 28%, 40%, 55%, 11%, and 10%, respectively. TP53, PTEN and TERT were independent molecular markers associated with an unfavourable outcome, independently of clinicopathological parameters. The coexistence of BRAF V600E and TERT promoter mutation increased the risk of DM. CONCLUSIONS: The above data support the classification of HGTC as a single group with two distinct subtypes based on tumour differentiation: HGTC-PDTC and HGTC-nonPDTC.

Expression of T-cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif domains (TIGIT) in anaplastic thyroid carcinoma.

BACKGROUND: Immune checkpoint proteins have not been fully examined in follicular cell-derived thyroid carcinoma and medullary thyroid carcinoma (MTC). Anaplastic thyroid carcinoma (ATC) is one of the most aggressive carcinomas. Even multimodal treatment does not result in favorable clinical outcomes for patients with ATC. Anti-tumor immunity has therefore been highlighted as having therapeutic promise for ATC. METHODS: We examined a novel immune checkpoint receptor, T-cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif domains (TIGIT), in variable thyroid lesions: adenomatous goiter, follicular adenoma, and thyroid carcinoma (TC) using immunohistochemistry (IHC). RESULTS: Our IHC results showed that TIGIT expression was detected in cancer cells of MTC and high-grade TC: poorly differentiated thyroid carcinoma (PDTC) and ATC. Neoplastic cells were positive for TIGIT in four of five MTCs (80.0%), 17 of 31 ATCs (54.8%) and in 3 of 12 PDTCs (25.0%). TIGIT was not detected in any adenomatous goiters, thyroid benign tumors, or differentiated thyroid carcinoma (DTCs). Intriguingly, ATC cells showing pleomorphic/giant cell features were positive for TIGIT, while ATC cells with other cell morphologies lacked the immunoreactivity. Intra-tumoral immune cell was inclined to be enriched in TIGI-positive ATC. Although coexisting papillary thyroid carcinoma (PTC) components demonstrated high-grade microscopic features, neither the PTC nor follicular thyroid carcinoma (FTC) components expressed TIGT in any composite ATCs. CONCLUSION: TIGIT was immunohistochemically found in MTC with high frequency and partially in high-grade TC. TIGIT expression in cancer cells may be beneficial for a potential utility in MTC and a subset of high-grade TC, especially ATC therapy.

Clinicopathological Characteristics and Prognosis of Poorly Differentiated Thyroid Carcinoma Diagnosed According to the Turin Criteria.

OBJECTIVE: Poorly differentiated thyroid carcinoma (PDTC) is the primary cause of death in patients with nonanaplastic follicular cell-derived thyroid carcinoma. We purposed to identify the clinical and pathological characteristics of PDTC and their relationship with prognosis. METHODS: A retrospective analysis was conducted on patients diagnosed with PDTC at our institution from 2010 to 2018. All of their histopathology slides were reviewed by 2 experienced pathologists based on the Turin criteria. Furthermore, information regarding clinical characteristics, pathological characteristics, treatment strategy, and follow-up events were collected. The Kaplan-Meier method was used for survival analysis, while the log-rank test was used to compare survival curves. Then, the Cox proportional hazards model was used to perform univariate and multivariate analyses. RESULTS: Twenty-six patients with PDTC who met the Turin criteria were enrolled in this study. The median follow-up period of the included 26 patients was 76 months, while the 3- and 5-year survival rates were 40% and 18%, respectively. Notably, univariate analysis revealed that tumor size >4 cm (P = .038), extrathyroidal extension (ETE) (P = .020), distant metastases (P = .047), poorly differentiated areas >60% (P = .049), and Ki-67 labeling index >30% (P = .040) were associated with poor prognosis. On the other hand, multivariate analysis identified ETE (P = .007) and distant metastases (P = .031) as independent risk factors for poor prognosis. CONCLUSION: PDTC is a rare carcinoma with high invasiveness and poor prognosis. Patients with ETE or distant metastases may have adverse outcomes.

Inhibition of microRNA-875-5p promotes radioiodine uptake in poorly differentiated thyroid carcinoma cells by upregulating sodium-iodide symporter.

BACKGROUND AND AIM: Poorly differentiated thyroid carcinoma (PDTC) is an endocrine malignancy that is challenging to treat due to its limited radioiodine uptake. microRNAs (miRNAs or miRs) have been shown to be useful in treating many types of tumors, including PDTC. This study aims to evaluate the potential effect of miR-875-5p on the radioiodine uptake of PDTC and to clarify the underlying mechanisms. METHODS: Expression of miR-875-5p and sodium-iodide symporter (NIS) in tissues and cell lines was determined using RT-qPCR. The binding relationship between miR-875-5p and NIS was predicted through in silico analysis and verified by dual-luciferase reporter gene assay. A series of miR-875-5p mimic, miR-875-5p inhibitor, shRNA against NIS, and overexpressed NIS plasmids were introduced into PDTC cells. We then evaluated the cell viability, colony formation, apoptosis, and radioiodine uptake of each PDTC sample via CCK-8 assay, clonogenic assay, flow cytometry, and γ counter, respectively. RESULTS: miR-875-5p was found to be highly expressed, but NIS was poorly expressed in DTC tissues and PDTC cell lines. NIS was verified to be a target gene of miR-875-5p. Upregulation of miR-875-5p was found to induce PDTC cell proliferation, and reduce apoptosis and radioiodine uptake in vitro through down-regulation of NIS. In an in vivo orthotopic model, the enhancement of miR-875-5p led to the reduction of NIS expression and radioiodine uptake in the thyroid tumors. CONCLUSIONS: Altogether, the findings of the current study suggest that down-regulated miR-875-5p expression could promote its target gene NIS to increase radioiodine uptake in PDTC, constituting a preventive strategy against PDTC.

Poorly differentiated thyroid carcinoma.

Poorly differentiated thyroid carcinoma (PDTC) is an aggressive form of follicular cell derived thyroid carcinoma with a prognosis intermediate between the indolent well differentiated thyroid carcinomas and the rapidly growing often fatal anaplastic carcinoma. While all investigators agree on the presence of this entity, there is disagreement in regard to its definition. In 2006, a set of criteria based solely on mitotic index ≥5/10 high power fields and/or tumor necrosis was proposed by a group of researchers from Memorial Sloan Kettering Cancer Center (MSKCC criteria) in New York. A year later, alternative diagnostic criteria of PDTC, so called the Turin proposal, were advocated by an international consensus group. The Turin proposal requires three criteria: 1) solid/trabecular/insular growth pattern; 2) absence of nuclear features of papillary carcinoma; and 3) at least one of the following three features: mitotic index ≥3/10 high power fields (HPFs), necrosis, or convoluted nuclei. In this review, we summarize the histology, diagnostic criteria (Turin proposal and MSKCC criteria) with their pros and cons, the prognostic factors, and molecular profile of PDTC, aiming to provide a practical and compreshensive review of this challenging entity.

Poorly differentiated thyroid carcinoma : An underdiagnosed entity.

Poorly differentiated thyroid carcinomas (PDTCs) are a rare subtype of thyroid carcinomas that are biologically situated between well-differentiated papillary/follicular thyroid carcinomas and anaplastic thyroid carcinomas (ATCs).The diagnosis of conventional as well as oncocytic poorly differentiated thyroid carcinoma is difficult and often missed in daily routine. The current WHO criteria to allow the diagnosis of PDTCs are based on the results of a consensus meeting held in Turin in 2006. Even a minor poorly differentiated component of only 10%of a given carcinoma significantly affects patient prognosis and the oncocytic subtype may even have a worse outcome. Immunohistochemistry is not much help and is mostly used to exclude a medullary thyroid carcinoma with calcitonin and to establish a follicular cell of origin via thyroglobulin staining.Due to the concept of stepwise dedifferentiation, there is a vast overlap of different molecular alterations like BRAF, RAS, CTNNB1, TP53 and others between different thyroid carcinoma subtypes. A distinctive molecular tumor profile is therefore currently not available.PDTCs have a unique miRNA signature, which separates them from other thyroid carcinomas. The average relapse free survival is less than one year and about 50% of patients die of the disease. Modern tyrosine kinase inhibitors offer in conjunction with powerful molecular diagnostic new chances in these difficult to treat carcinomas.

Mutational profiling of poorly differentiated and anaplastic thyroid carcinoma by the use of targeted next-generation sequencing.

AIMS: To characterise the mutational profiles of poorly differentiated thyroid carcinoma (PDTC) and anaplastic thyroid carcinoma (ATC) and to identify markers with potential diagnostic, prognostic and therapeutic significance. METHODS AND RESULTS: Targeted next-generation sequencing with a panel of 18 thyroid carcinoma-related genes was performed on tissue samples from 41 PDTC and 25 ATC patients. Genetic alterations and their correlations with clinicopathological factors, including survival outcomes, were also analysed. Our results showed that ATC had significantly higher mutation rates of BRAF, TP53, TERT and PIK3CA than PDTC (P = 0.005, P = 0.007, P = 0.005, and P = 0.033, respectively). Nine (69%) ATC cases with papillary thyroid carcinoma (PTC) components harboured BRAF mutations, all of which coexisted with a late mutation event (TP53, TERT, or PIK3CA). Nine cases with oncogenic fusion (six RET cases, one NTRK1 case, one ALK case, and one PPARG case) were identified in 41 PDTCs, whereas only one case with oncogenic fusion (NTRK1) was found among 25 ATCs. Moreover, all six cases of RET fusion were found in PDTC with PTC components, accounting for 33%. In PDTC/ATC patients, concurrent TERT and PIK3CA mutations were associated with poor overall survival after adjustment for TNM stage (P = 0.001). CONCLUSIONS: ATC with PTC components is typically characterised by a BRAF mutation with a late mutation event, whereas PDTC with PTC components is more closely correlated with RET fusion. TERT and concurrent PIK3CA mutations predict worse overall survival in PDTC/ATC patients.

[Poorly differentiated thyroid carcinoma : An underdiagnosed entity. German version]. / Gering differenzierte Schilddrüsenkarzinome : Eine unterdiagnostizierte Entität.

Poorly differentiated thyroid carcinomas (PDTCs) are a rare subtype of thyroid carcinomas that are biologically situated between well-differentiated papillary/follicular thyroid carcinomas and anaplastic thyroid carcinomas (ATCs).The diagnosis of conventional as well as oncocytic poorly differentiated thyroid carcinoma is difficult and often missed in daily routine. The current WHO criteria to allow the diagnosis of PDTCs are based on the results of a consensus meeting held in Turin in 2006. Even a minor poorly differentiated component of only 10% of a given carcinoma significantly affects patient prognosis and the oncocytic subtype may even have a worse outcome. Immunohistochemistry is not much help and is mostly used to exclude a medullary thyroid carcinoma with calcitonin and to establish a follicular cell of origin via thyroglobulin staining.Due to the concept of stepwise dedifferentiation, there is a vast overlap of different molecular alterations like BRAF, RAS, CTNNB1, TP53 and others between different thyroid carcinoma subtypes. A distinctive molecular tumor profile is therefore currently not available.PDTCs have a unique miRNA signature, which separates them from other thyroid carcinomas.The average relapse free survival is less than one year and about 50% of patients die of the disease. Modern tyrosine kinase inhibitors offer in conjunction with powerful molecular diagnostic new chances in these difficult to treat carcinomas.

Molecular pathology of thyroid tumours of follicular cells: a review of genetic alterations and their clinicopathological relevance.

Thyroid cancer is the most common endocrine malignancy. Knowledge of the molecular pathology of thyroid tumours originating from follicular cells has greatly advanced in the past several years. Common molecular alterations, such as BRAF p.V600E, RAS point mutations, and fusion oncogenes (RET-PTC being the prototypical example), have been, respectively, associated with conventional papillary carcinoma, follicular-patterned tumours (follicular adenoma, follicular carcinoma, and the follicular variant of papillary carcinoma/non-invasive follicular thyroid neoplasm with papillary-like nuclear features), and with papillary carcinomas from young patients and arising after exposure to ionising radiation, respectively. The remarkable correlation between genotype and phenotype shows how specific, mutually exclusive molecular changes can promote tumour development and initiate a multistep tumorigenic process that is characterised by aberrant activation of mitogen-activated protein kinase and phosphoinositide 3-kinase-PTEN-AKT signalling. Molecular alterations are becoming useful biomarkers for diagnosis and risk stratification, and as potential treatment targets for aggressive forms of thyroid carcinoma. What follows is a review of the principal genetic alterations of thyroid tumours originating from follicular cells and of their clinicopathological relevance.

Utility of monoclonal PAX8 antibody for distinguishing intrathyroid thymic carcinoma from follicular cell-derived thyroid carcinoma.

Follicular cell-derived thyroid carcinomas, including thyroid squamous cell carcinomas (SCCs) and anaplastic carcinomas, are immunoreactive for paired-box gene 8 (PAX8), while non-follicular cell-derived thyroid carcinomas stain negative for the PAX8 antibody. Intrathyroid thymic carcinoma (ITTC) arising from the intrathyroidal ectopic thymus exhibits moderate-to-strong nuclear reactivity for polyclonal PAX8. This is difficult to understand given that PAX8 is not associated with embryonic thymic development. We aimed to determine the diagnostic significance of monoclonal PAX8 antibody in distinguishing ITTCs from follicular cell-derived thyroid carcinomas. Ten ITTCs, 14 poorly differentiated thyroid carcinomas (PDTCs), 14 thyroid SCCs, 7 thymic tissue specimens, 7 thymomas, and 1 thymic carcinoma were analyzed using antibodies against polyclonal and monoclonal PAX8, thyroid transcription factor-1, p63, and CD5. Four ITTCs (40.0%) stained positive for polyclonal PAX8; none stained positive for monoclonal PAX8. All PDTCs and 92.9% of SCCs were immunoreactive for both polyclonal and monoclonal PAX8. All PDTCs, 46.2% of SCCs, and none of the ITTCs were immunoreactive for thyroid transcription factor-1. Eight ITTCs (80.0%), but none of the PDTCs and SCCs, were immunoreactive for CD5. We are the first to show that ITTCs stain negative for monoclonal PAX8. Monoclonal PAX8 is a more reliable marker than polyclonal PAX8 for determining follicular cell origin. We conclude that monoclonal PAX8 is a useful marker for distinguishing ITTCs from PDTCs and SCCs. Monoclonal PAX8 negativity is additional evidence in support of ITTCs not being follicular cell-derived thyroid carcinomas, but having a thymic origin.

[DICER1 mutated, solid/trabecular thyroid papillary carcinoma in an 11-year-old child]. / Carcinome papillaire thyroïdien variante solide/trabéculaire avec mutation DICER1 chez une enfant de 11 ans.

We report the case of an 11-year-old patient diagnosed with a solid variant of papillary thyroid carcinoma. Papillary thyroid carcinoma (PTC) is the most common thyroid cancer, representing 80-90% of all newly diagnosed thyroid cancers. Among the many variants described, solid/trabecular variant of papillary thyroid carcinoma is a rare entity and account for 3% of thyroid cancers. It is more common in children and young adults, and it is seen in higher proportion in post radiation papillary thyroid carcinoma cases. Histologically, solid variant papillary carcinoma is characterized by a predominantly solid, trabecular or insular growth pattern, and the presence of cytological features typical of PTC. Its main differential diagnosis is poorly differentiated thyroid carcinoma. It has a less favorable prognosis than the classical papillary type, with a higher risk of distant metastasis, extrathyroidal extension and lympho-vascular invasion. It is associated with a slightly lower long-term survival in adult cases, but not in children. The management of solid variant PTC includes surgery, associated or not with postoperative radioiodine ablation, according to the aggressiveness criteria. Our patient had a DICER1 somatic mutation. Carriers of germline DICER1 mutations are predisposed to a rare cancer syndrome, the DICER1 syndrome, with a higher risk of numerous tumors and infrequently differentiated thyroid carcinomas.

A rare case of poorly differentiated thyroid carcinoma probably arising from a nodular goiter.

BACKGROUND: Some poorly differentiated thyroid carcinomas (PDTC) arise from pre-existing, well-differentiated carcinomas of follicular cell origin; however, others most likely arise de novo. The case of a PDTC adjacent to a pre-existing nodular goiter is very rare. CASE PRESENTATION: A patient had a PDTC, a widely invasive, cellular tumor with cells that lacked the nuclear features of a papillary thyroid carcinoma. Carcinoma cells were arranged in trabecular, solid, and microfollicular histological patterns and displayed high mitotic activity. A nodule partially encapsulated in a thick fibrous capsule was found adjacent to the PDTC. The nodule was composed of small or dilated follicles, without papillary carcinoma-like nuclear features, that were consistent with a nodular goiter. The PDTC showed a high Ki-67 labeling index and an NRAS gene mutation (codon 61, Q61K). CONCLUSION: These results support our diagnosis of a PDTC, probably arising from a nodular goiter.

FNA diagnosis of poorly differentiated thyroid carcinoma. A review of the recent literature.

Poorly differentiated thyroid carcinoma (PDTC) is a follicular cell-derived tumour that was recognised as a distinct entity by the World Health Organisation in 2004. The natural history and pathological features of PDTC are reported to be intermediate between those of well-differentiated and undifferentiated (anaplastic) thyroid carcinomas. Preoperative identification of PDTC could facilitate better initial patient management in many cases, namely more extensive surgery, without any delay. However, according to some experts, a diagnosis of PDTC can only be rendered on histologic specimens based on criteria recommended in the Turin proposal. Although high-grade features (namely necrosis and mitoses) can be recognised in FNA material, other cytomorphological features have limited value for the preoperative diagnosis of PDTC and specific features for a definitive diagnosis of PDTC have not yet been clearly defined. Here, we review the current status and future prospects for cytological recognition of PDTC; we emphasise the features that should raise suspicion of this rare condition in FNA cytology and provide an update on molecular features and management of PDTC. Despite proposed histological criteria for the diagnosis of PDTC, its recognition on routine thyroid cytology presents a notable challenge. Current and future advances in molecular testing could contribute to the cytological diagnosis of PDTC.

Description and Comparison of the Sonographic Characteristics of Poorly Differentiated Thyroid Carcinoma and Anaplastic Thyroid Carcinoma.

OBJECTIVES: Although poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma account for a substantial portion of the morbidity and mortality associated with thyroid cancer, a chance of a cure exists with aggressive treatment, especially in patients with poorly differentiated thyroid carcinoma. The goal of this study was to evaluate the sonographic characteristics of poorly differentiated thyroid carcinoma and to compare the sonographic findings of poorly differentiated and anaplastic thyroid carcinomas. METHODS: The study included 29 patients with 30 poorly differentiated thyroid carcinomas and 26 patients with 26 anaplastic thyroid carcinomas. Two radiologists retrospectively reviewed sonographic findings. Clinical and sonographic findings were compared between poorly differentiated and anaplastic thyroid carcinomas by univariate and multivariate analyses. RESULTS: In the group of patients with poorly differentiated thyroid carcinoma, the mean age was 53.7 years (range, 14-73 years), and the mean tumor size was 3.6 cm (range, 0.6-10.0 cm). The common sonographic findings of poorly differentiated thyroid carcinoma were heterogeneous echogenicity (93.3%), solitary nodules (80.0%), a circumscribed margin (63.3%), an oval-to-round shape (63.3%), and hypoechogenicity (60.0%). A circumscribed margin (P = .003) and an oval-to-round shape (P = .015) were significantly more frequent in poorly differentiated thyroid carcinoma than in anaplastic thyroid carcinoma. In the multivariate analysis, only the circumscribed margin on sonography was an independent predicting factor for poorly differentiated thyroid carcinoma (odds ratio, 4.642). CONCLUSIONS: Both poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma commonly present as a relatively large malignant mass on sonography; however, poorly differentiated thyroid carcinoma showed a significantly higher incidence of a circumscribed margin and an oval-to-round shape than anaplastic thyroid carcinoma. Knowledge of sonographic characteristics will be useful for differentiation of poorly differentiated and anaplastic thyroid carcinomas.

Fine needle aspiration cytology features of poorly differentiated thyroid carcinoma.

BACKGROUND: Poorly differentiated thyroid carcinoma (PDTC) is an uncommon thyroid malignancy with biological behaviour intermediate between well-differentiated and undifferentiated thyroid carcinoma. The cytological diagnosis of PDTC is often difficult as a result of a lack of well-established cytomorphological features and a considerable degree of morphological overlap with other commoner thyroid neoplasms. OBJECTIVE: To review the cytomorphological features of PDTC with the aim of highlighting salient diagnostic morphological features and differential diagnostic problems. METHODS: Seven cases of histologically proven PDTC with available aspiration cytology smears were reviewed for the presence of distinguishing cytomorphological features. RESULTS: The architectural arrangement of tumour cells was the most important diagnostic parameter. Cellular nests, three-dimensional clusters dyscohesive aggregates and singly dispersed cells in the background were present in all cases. A unique 'garlanded appearance', owing to the peripheral orientation of nuclei within the tumour cell clusters, was noted (71.4%) along with the presence of basement membrane-like material (71.4%). Transgressing vessels (85.7%) and endothelial wrapping of cell clusters (71.4%) were also noted. Interestingly, most cases lacked necrosis and mitotic activity that are included in the histological diagnostic criteria for PDTC. CONCLUSION: Although PDTC has considerable cytomorphological overlap with well-differentiated thyroid tumours, this present study highlights certain cytomorphological features that may suggest the correct pre-operative diagnosis, important for the appropriate management.

Neoadjuvant chemotherapy in 13 patients with locally advanced poorly differentiated thyroid carcinoma based on Turin proposal - a single institution experience.

BACKGROUND: There is a paradigm that chemotherapy is ineffective in thyroid carcinoma. The aim of our study was to find out whether neoadjuvant chemotherapy before thyroid surgery had an effect on the size of primary tumour in patients with poorly differentiated thyroid carcinoma (PDTC) based on Turin proposal. PATIENTS AND METHODS: Altogether, 13 patients (8 women, 5 men; median age 61 years) with PDTC based on Turin proposal were treated with neoadjuvant chemotherapy between 1986 and 2005. Tumour diameter was from 4.5 to 18 cm (median 9 cm). Regional and distant metastases were detected in 6 and 9 patients, respectively. Eight patients had pT4 tumour. RESULTS: Altogether, 29 (range 1-5) cycles of chemotherapy were given. Tumour diameter decreased in all the patients and by more than 30% in 5 patients (= 38%). Two of these five patients had also preoperative external beam irradiation (EBRT). Total thyroidectomy, lobectomy and neck dissection were performed in 10, 3 and 5 cases, respectively. R0 and R1 resection was done in 5 and 8 cases, respectively. Eight patients had postoperative EBRT of the neck and upper mediastinum. The 5-year and 10-year cause-specific survival rates of patients were 66% and 20%, respectively. CONCLUSIONS: After neoadjuvant chemotherapy a partial tumour regression was observed in 38% of patients with PDTC based on Turin proposal.

Poorly Differentiated Thyroid Carcinoma in a 19-Year-Old Young Female Patient: A Case Report.

Poorly differentiated thyroid carcinoma (PDTC) is a rare type of thyroid carcinoma that develops from follicular epithelial cells. In terms of morphology and prognosis, PDTC falls between well-differentiated thyroid carcinoma (WDTC) and anaplastic thyroid carcinoma (ATC). The spectrum of malignant thyroid tumors originating from follicles ranges from the fatal ATC at one end to the indolent WDTC at the other. We present a case of a 19-year-old female patient complaining of swelling on the right side of the neck. Computed tomography revealed a solid cystic lesion within the right lobe of the thyroid gland. The diagnosis of PDTC was made through histopathological examination. In this case, we evaluated the histological characteristics of the right lobe of the thyroid gland and presented a case report of PDTC in a young female.