Early evolutionary divergence between papillary and anaplastic thyroid cancers.

Background: Papillary thyroid cancer (PTC) is the most common thyroid carcinoma and exhibits an almost uniformly good prognosis, while anaplastic thyroid cancer (ATC) is less frequent and is one of the most aggressive cancers usually resistant to conventional treatment. Current hypothesis posits that ATC derives from PTC through the progressive acquisition of a discrete number of genomic alterations and implies that the mutational landscape of ATC resembles that of PTC. However, the clinical behaviour of ATC and PTC is radically different. We decided to address the disconnection between the clinical behaviour of ATC and PTC and the proposed model of the progressive development of ATC from PTC. Patients and methods: We carried out exome sequencing of DNA from 14 ATC specimens including three cases of concomitant ATC and PTC as well as their corresponding normal DNA from 14 patients. The sequencing results were validated using droplet digital PCR. We carried out immunohistochemistry and immunofluorescence studies of the concomitant ATC and PTC cases. In addition, we integrated our sequencing results with the existing TCGA data. Results: Most of the somatic mutations identified in the ATC component differed from the ones in PTC in the cases of concomitant ATC and PTC. The trunks of the phylogenetic trees representing the somatic mutations were short with long branches. In one case of concomitant PTC and ATC specimens, we observed an infiltration of PTC cells within the ATC component. Moreover, we integrated our results with data obtained from TCGA and observed that the most frequent mutations found in ATC presented high cancer cell fraction values and were significantly different from the PTC ones. Conclusion: ATC diverge from PTC early in tumour development and both tumour types evolve independently. Our work allows the understanding of the relationship between ATC and PTC facilitating the clinical management of these malignancies.

High incidence of large deletions in the PMS2 gene in Spanish Lynch syndrome families.

Lynch syndrome (LS) is caused by germline mutations in one of the four mismatch repair (MMR) genes. Defects in this pathway lead to microsatellite instability (MSI) in DNA tumors, which constitutes the molecular hallmark of this disease. Selection of patients for genetic testing in LS is usually based on fulfillment of diagnostic clinical criteria (i.e. Amsterdam criteria or the revised Bethesda guidelines). However, following these criteria PMS2 mutations have probably been underestimated as their penetrances appear to be lower than those of the other MMR genes. The use of universal MMR study-based strategies, using MSI testing and immunohistochemical (IHC) staining, is being one proposed alternative. Besides, germline mutation detection in PMS2 is complicated by the presence of highly homologous pseudogenes. Nevertheless, specific amplification of PMS2 by long-range polymerase chain reaction (PCR) and the improvement of the analysis of large deletions/duplications by multiplex ligation-dependent probe amplification (MLPA) overcome this difficulty. By using both approaches, we analyzed 19 PMS2-suspected carriers who have been selected by clinical or universal strategies and found five large deletions and one frameshift mutation in PMS2 in six patients (31%). Owing to the high incidence of large deletions found in our cohort, we recommend MLPA analysis as the first-line method for searching germline mutations in PMS2.

Histopathological Features of Pendred Syndrome Thyroids Align with Differences in the Expression of Thyroid-Specific Markers, Apical Iodide Transporters, and Ciliogenesis Process.

Pendred syndrome (PDS) is an autosomal recessive disorder caused by mutations in the gene that encodes pendrin. Pendred thyroid tissue is supposedly altered by the absence of functional pendrin, but it is still unknown whether other iodide exchangers could compensate for the loss of the protein. Moreover, we have recently described that primary cilium, a conserved structure present at the apical surface of normal follicular cells, suffers different alterations in functional thyroid diseases. We aimed (1) to better understand the histopathological changes experienced by PDS thyroids, (2) to analyze the expression of different thyroid-specific genes and alternative iodide transporters and, finally, (3) to determine whether those changes may alter the morphological pattern of primary cilia in follicular cells. Thyroid samples from a series of four PDS patients were analyzed by immunohistochemistry, double immunofluorescence, and morphometry to evaluate changes in primary cilia frequency and length. We found thyroid follicular nodular disease in all PDS thyroids, frequently in association with follicular adenomas. There were only slight changes in the expression of thyroid-specific markers. Although no positivity for pendrin was found, cytoplasmic immunostaining for ANO-1, CLC-5, and CFTR was stronger in diffuse hyperplastic areas when compared to areas with highly cellular follicular nodules (HCFNs). HCFNs and follicular adenomas always showed diminished ciliary frequency and length. Our results suggest a direct relationship between the absence of functional pendrin and the loss of the normal thyroid architecture in PDS patients, which was also accompanied by differences in the expression of specific immunohistochemical markers and altered ciliogenesis. The present data may help the pathologist in screening for PDS.

Exome sequencing of early-onset patients supports genetic heterogeneity in colorectal cancer.

Colorectal cancer (CRC) is a complex disease that can be caused by a spectrum of genetic variants ranging from low to high penetrance changes, that interact with the environment to determine which individuals will develop the disease. In this study, we sequenced 20 early-onset CRC patients to discover novel genetic variants that could be linked to the prompt disease development. Eight genes, CHAD, CHD1L, ERCC6, IGTB7, PTPN13, SPATA20, TDG and TGS1, were selected and re-sequenced in a further 304 early onset CRC patients to search for rare, high-impact variants. Although we found a recurring truncating variant in the TDG gene shared by two independent patients, the results obtained did not help consolidate any of the candidates as promising CRC predisposing genes. However, we found that potential risk alleles in our extended list of candidate variants have a tendency to appear at higher numbers in younger cases. This supports the idea that CRC onset may be oligogenic in nature and may show molecular heterogeneity. Further, larger and robust studies are thus needed to unravel the genetics behind early-onset CRC development, coupled with novel functional analyses and omic approaches that may offer complementary insight.

EWSR1 rearrangement is a frequent event in papillary thyroid carcinoma and in carcinoma of the thyroid with Ewing family tumor elements (CEFTE).

Carcinomas of the thyroid with Ewing family tumor element (CEFTEs) are small-cell thyroid tumors with epithelial differentiation that disclose p63 expression and EWSR1-FLI1 rearrangement, carry a favorable prognosis and may co-exist with papillary thyroid carcinoma (PTC) foci. Two histogenetic hypotheses have been advanced regarding the origin of CEFTEs: arising in PTCs or in solid cell nests (SCN). A total of 3 CEFTEs, 54 PTCs, and 10 SCNs were reviewed, and fluorescence in situ hybridization (FISH) technique was performed in all cases to search for the presence of EWSR1 rearrangements. The three CEFTEs disclosed the EWSR1-FLI1 rearrangement both in the small cell and in the PTC component. Out of the 54 PTC cases, 28 (51.9%) were positive, 20 (37.0%) were negative, and 6 (11.1%) were inconclusive for EWSR1 rearrangement; in two of the positive PTC cases, the EWSR1-FLI1 rearrangement was detected. Classic PTC disclosed more often the EWSR1 rearrangement than other PTC variants (p = 0.031). PTCs with EWSR1 rearrangement disclosed a lower percentage of nuclei with EWSR1 polysomy than those without EWSR1 rearrangement (p = 0.001). Out of the 10 SCNs, 7 (70.0%) were negative and 3 (30.0%) were inconclusive for the EWSR1 rearrangement. Monosomic nuclei were more frequent (mean of 44.3%) in SCNs than in PTCs (p < 0.001). The presence of the EWSR1-FLI1 rearrangement in PTC component of all studied CEFTEs and the existence of the EWSR1 rearrangement in some PTCs favor the origin of CEFTE from PTC. The high frequency of EWSR1 rearrangements in PTC may represent a new diagnostic marker of these tumors.

Rewiring of the apoptotic TGF-ß-SMAD/NFκB pathway through an oncogenic function of p27 in human papillary thyroid cancer.

Papillary thyroid carcinoma (PTC), the most frequent thyroid cancer, is characterized by low proliferation but no apoptosis, presenting frequent lymph-node metastasis. Papillary thyroid carcinoma overexpress transforming growth factor-beta (TGF-ß). In human cells, TGF-ß has two opposing actions: antitumoral through pro-apoptotic and cytostatic activities, and pro-tumoral promoting growth and metastasis. The switch converting TGF-ß from a tumor-suppressor to tumor-promoter has not been identified. In the current study, we have quantified a parallel upregulation of TGF-ß and nuclear p27, a CDK2 inhibitor, in samples from PTC. We established primary cultures from follicular epithelium in human homeostatic conditions (h7H medium). TGF-ß-dependent cytostasis occurred in normal and cancer cells through p15/CDKN2B induction. However, TGF-ß induced apoptosis in normal and benign but not in carcinoma cultures. In normal thyroid cells, TGF-ß/SMAD repressed the p27/CDKN1B gene, activating CDK2-dependent SMAD3 phosphorylation to induce p50 NFκB-dependent BAX upregulation and apoptosis. In thyroid cancer cells, oncogene activation prevented TGF-ß/SMAD-dependent p27 repression, and CDK2/SMAD3 phosphorylation, leading to p65 NFκB upregulation which repressed BAX, induced cyclin D1 and promoted TGF-ß-dependent growth. In PTC samples from patients, upregulation of TGF-ß, p27, p65 and cyclin D1 mRNA were significantly correlated, while the expression of the isoform BAX-ß, exclusively transcribed in apoptotic cells, was negatively correlated. Additionally, combined ERK and p65 NFκB inhibitors reduced p27 expression and potentiated apoptosis in thyroid cancer cells while not affecting survival in normal thyroid cells. Our results therefore suggest that the oncoprotein p27 reorganizes the effects of TGF-ß in thyroid cancer, explaining the slow proliferation but lack of apoptosis and metastatic behavior of PTC.

Breast tumor resembling the tall cell variant of papillary thyroid carcinoma: a case report.

The breast tumor resembling the tall cell variant of papillary thyroid carcinoma is a very unusual mammary carcinoma whose histologic and predominant nuclear features mimic a papillary thyroid carcinoma. We report the case of a 64-year-old woman who presented with a palpable nodule in the right breast. Fine needle aspiration disclosed abundant cellularity with isolated cells, sheets, and papillary formations of epithelial cells with nuclear grooves. Histologically, the neoplastic cells were arranged in a solid to papillary architecture, with follicular-like and cribriform areas. The cells were columnar to cuboidal with eosinophilic cytoplasm, clear chromatin, nuclear grooves, and occasional nuclear pseudoinclusions. Tumor cells were positive for cytokeratins, alpha and beta-estrogen receptors, progesterone receptor, androgen receptor, CEA, and bcl-2. We searched for BRAF mutations with negative results. Recognizing the cytologic and histologic characteristics of these peculiar mammary tumors that mimic thyroid carcinomas can avoid unnecessary clinical investigations.

Cell-cycle-associated markers and clinical outcome in human epithelial cancers: a tissue microarray study.

The development and progression of epithelial cancers are the result of an imbalance in signals promoting and inhibiting cellular proliferation and apoptosis. The aim of this study is to evaluate the expression of cell-cycle and apoptosis regulators and correlate them with clinical outcome in the most frequent carcinomas, in order to establish common prognostic biomarkers independent of cancer origin. Using tissue microarrays (TMAs), we have analysed the immuno-expression of Ki-67, Bcl-2, Bax, cyclin D1, cyclin D3, CDK1, CDK2, CDK6, p16, p21, and p27 in a series of 205 carcinomas of the large bowel, breast, lung and prostate (80, 73, 37 and 15 cases, respectively). By univariate analysis, positivity for p27, p16 and Bcl-2 was associated with better overall survival (P<0.0135, P<0.0442 and P<0.0001, respectively). The risk of mortality was 2.3-fold greater in patients without Bcl-2 expression. TMA immunohistochemical analysis identified a subset of epithelial cancers with overlapping alterations in cell-cycle checkpoints, apoptosis regulators and tumour suppressor pathways. We found that in most common epithelial cancers, regardless of origin, Bcl-2 appears to be the key biological factor influencing clinical behaviour.

Primary anaplastic large cell lymphoma of the central nervous system.

Central nervous system (CNS) involvement is extremely rare in anaplastic large cell lymphoma (ALCL), and in children only isolated cases have been reported, mainly as secondary CNS involvement. A case of fatal primary ALCL of the brain in a 13-year-old white boy is reported. Magnetic resonance imaging of the brain showed decreased absorption in T1- and T2-weighted image showed a hyperintense signal in the right parietal lobe and 2 masses in the right frontal lobe. A frontal lobe biopsy showed a pleomorphic neoplasm diffusely infiltrating the brain parenchyma and composed of large cells with bizarre, often polylobated or horseshoe-shaped nuclei. Immunohistochemical stains showed diffuse strong positivity for CD30, anaplastic lymphoma kinase protein (ALK-1), p80, leucocyte common antigen, CD45RO (UCHL1), and focal staining for epithelial membrane antigen. Immunostainings for cytokeratins, monocyte-macrophage, and B-cell markers were negative. Epstein-Barr virus latent membrane protein was not detected. To the best of our knowledge, there is only 1 case of primary ALCL of the brain in childhood previously reported in the literature. Before the biopsy, both cases were clinically misdiagnosed as mycobacterial CNS infection. Therefore, primary ALCL should also be included in the differential diagnosis when a mycobacterial CNS infection is suspected in pediatric patients; a careful cytological evaluation of the cerebrospinal fluid or cerebral biopsy are essential for an accurate diagnosis.

Solid cell nests of the thyroid: light microscopy and immunohistochemical profile.

The morphological, histochemical, and immunohistochemical findings of seven cases of solid cell nests (SCNs) of the thyroid are described. Light microscopy showed two cell types forming the SCNs, which we refer to as "main cells" and "C cells." In all cases "mixed thyroid follicles" (a unique structure lined by follicular epithelium and epidermoidlike cells) were observed in which the histochemical study confirmed the presence of intraluminal acid mucins. Adult adipose tissue and cartilage were found in one case and foci of cartilage were observed in another case in association with the SCN. Immunohistochemical studies showed positivity of "main cells" for carcinoembryonic antigen (CEA), high- and low-molecular weight keratins, neurotensin, and somatostatin. "C cells" were positive for calcitonin, calcitonin gene-related peptide (CGRP), and chromogranin. The two cell types in SCNs were consistently negative for thyroglobulin. Neuron-specific enolase (NSE)-positive cells were found in the vicinity of the SCN. The unusual association of adipose tissue and cartilage as well as the results of the extended immunohistochemical study in this series provides further support to the belief that SCNs and "mixed thyroid follicles" represent remnants of the ultimobranchial body and should be considered normal components of the thyroid gland.

Solitary fibrous tumor of the thyroid.

A case of solitary fibrous tumor (SFT) of the thyroid in a 43-year-old woman with a multinodular goiter is reported. This is the first case of SFT described in the thyroid. On histologic, immunohistochemical, and ultrastructural examination, the tumor was identical to SFT of the pleura and other organs. Despite its rarity, SFT should be included in the differential diagnosis of spindle-cell tumors of the thyroid, along with anaplastic carcinoma, spindle-cell medullary carcinoma, and several types of mesenchymal tumors.

Somatic but not germline mutation of the APC gene in a case of cribriform-morular variant of papillary thyroid carcinoma.

We report a case of cribriform-morular variant (C-MV) of papillary thyroid carcinoma (PTC) in a 27-year-old woman. In addition to conventional cytologic features of typical PTC, the fine-needle aspirate showed numerous epithelial cells with abundant, eosinophilic, very elongated cytoplasm. Microscopically, the tumor was encapsulated and highly cellular and exhibited a mixture of cribriform, follicular, papillary, trabecular, solid, and spindle cell patterns of growth, with morular foci showing peculiar nuclear clearing (biotin-rich nuclei). The cells were cuboidal or tall, with frequent nuclear pseudostratification and abundant eosinophilic cytoplasm. The nuclei were usually hyperchromatic, with grooving, pallor, and pseudoinclusions. Angioinvasion and foci of capsular invasion were observed. Immunohistochemically, the neoplastic cells showed reactivity for thyroglobulin, epithelial membrane antigen, low- and high-molecular-weight cytokeratins, vimentin, neuron-specific enolase, CD15, estrogen and progesterone receptors, and bcl-2 protein. Molecular genetic analysis of the APC gene revealed a mutation in exon 15 at codon 1309 in tumoral tissue but not in peripheral lymphocytes. These findings support a relationship between the morphologic pattern of the C-MV of PTC and the APC gene and the existence of this variant as a sporadic counterpart of familial adenomatous polyposis-associated thyroid carcinoma.

Intrathyroid salivary gland-type tissue in multinodular goiter.

We report a case of intrathyroid salivary gland tissue in a 66-year-old Caucasian female with multinodular goiter. Lobules of well differentiated seromucinous salivary glands were found in close relationship with cartilage and fat, and intimately associated with normal thyroid follicles and solid cell nests (SCN) of the thyroid gland. This is the first report of non-neoplastic intrathyroid salivary gland tissue. We conclude that this heterotopic tissue probably arises from the SCN as ultimobranchial vestigial structures.

Intra-alveolar granulocytic sarcoma developing after tooth extraction.

Granulocytic sarcoma (GS) is a malignant tumour composed of poorly differentiated myeloid cells forming in an extramedullary site. It is generally associated with acute leukaemia, particularly the myelocytic type. Its appearance in patients with chronic myeloid leukaemia is exceptional. GS can appear in multiple locations with the oral cavity being rarely involved. A mandibular GS detected in a patient with chronic myeloid leukaemia 10 days after a tooth extraction is reported. The pathogenesis (by metastatic cells or migration through the Haversian canals) of the tumour is discussed.

Papillary and mucoepidermoid carcinoma of the thyroid with anaplastic transformation: a case report with histologic and immunohistochemical findings that support a provocative histogenetic hypothesis.

A unique thyroid tumor in a 62-year-old woman is reported. Foci of papillary carcinoma (PC), mucoepidermoid carcinoma (MEC) and undifferentiated carcinoma (UC) were found in the surgical specimen. Acid mucosubstances were observed in the two histologically differentiated areas of the neoplasia. The PC showed immunoreactivity for thyroglobulin, and both PC and MEC foci were positive for high-molecular-weight keratins. Papillary carcinoma, MEC and UC were stained with antibodies against keratin CAM 5.2, vimentin, S-100 protein and neuron-specific enolase. No immunoreactivity was found for calcitonin, calcitonin-gene-related peptide, chromogranin, keratin 1, carcinoembryonic antigen and p53 suppressor gene. The diagnosis of this peculiar carcinoma of the thyroid exhibiting papillary and mucoepidermoid features together with undifferentiated (anaplastic) areas, reinforces the existence of a close relationship between papillary carcinoma and mucoepidermoid carcinoma, and supports the importance that ultimobranchial multipotential stem cells may have in the histogenesis of thyroid carcinomas.

Apocrine carcinoma with signet ring cells and histiocytoid features. A potentially confusing axillary tumor.

A case of carcinoma of the axillary apocrine gland in a 42-year-old man is reported. The cytomorphic features of this tumor on fine-needle aspiration closely resemble invasive lobular carcinoma of the breast. Both in situ, and invasive apocrine gland carcinoma were present within the excision specimen, and metastatic tumor was found in the axillary lymph nodes. On histologic, immunohistochemical and ultrastructural examination, the tumor was similar to invasive lobular carcinoma of the breast. The tumor cells analyzed by cytometry displayed a diploid pattern. Serial sections of the whole resected specimen failed to reveal breast parenchyma. To the best of our knowledge, this is the first case presented in axilla of an unusual variant of carcinoma of the skin, very similar or identical to six other cases located on the eyelids. The descriptive term "apocrine carcinoma with signet ring cells and histiocytoid features" is proposed in order to emphasize that these tumors are easily confused with benign conditions, mammary cancer and other metastatic carcinomas.

Immunohistochemical detection of parathyroid hormone-related protein in a cutaneous squamous cell carcinoma causing humoral hypercalcemia of malignancy.

Humoral hypercalcemia of malignancy is a cancer-related hypercalcemia caused by production of humoral factors by malignant cells in patients without bone metastases. Squamous cell carcinomas are the tumors most frequently associated with humoral hypercalcemia of malignancy, and parathyroid hormone-related protein is the main humoral factor implicated. In spite of the fact that normal keratinocytes produce parathyroid hormone-related protein, it is highly unusual for patients with squamous cell carcinomas of the skin to present with humoral hypercalcemia of malignancy. We present a well-documented case of cutaneous squamous cell carcinoma complicated by hypercalcemia in a patient with high levels of plasma parathyroid hormone-related protein and immunohistochemical evidence of high parathyroid hormone-related protein production by the tumoral cells.