Macrofollicular Variant of Follicular Thyroid Carcinoma: A Rare Underappreciated Pitfall in the Diagnosis of Thyroid Carcinoma

Background: Follicular-patterned thyroid nodules predominantly composed of macrofollicular structures without nuclear atypia are generally regarded as benign (i.e., hyperplastic nodules or follicular adenomas). In line with this concept, fine-needle aspiration cytology (FNAC) also assigns a benign connotation to the presence of macrofollicular structures, unless thyrocytes present papillary thyroid carcinoma (PTC)-related nuclear features that raise the possibility of a macrofollicular variant of PTC. However, cases showing macrofollicular architecture, capsular invasion, and no PTC features can also be observed. Methods: We describe the clinical, cytological, histological, and molecular genetic features of four cases of encapsulated follicular neoplasms that presented histologically with a predominant (>70%) macrofollicular architecture, but which also showed clear signs of capsular invasion, and thus were classified as macrofollicular variant of follicular thyroid carcinoma (MV-FTC). Results: Cytologically, macrofollicular structures were identified in all cases, leading to a benign FNAC diagnosis in three of the four cases. Due to increasing nodule size, thyroidectomy was performed in all cases. Histology showed focal and limited capsular invasion, without vascular invasion. Next-generation sequencing (custom 394 gene panel) of each tumor compared with matched normal DNA revealed a total of 7 somatic variants, including dual (likely biallelic) mutations in the DICER1 gene in 2 patients. The clinical outcome was excellent in all cases. Conclusions: Similar to the classical minimally invasive follicular thyroid carcinoma, MV-FTC appears to behave indolently. MV-FTC has a high rate of false-negative FNAC results, but MV-FTC is very rare (<0.05% of all thyroidectomies) and apparently has an indolent behavior. Further studies comprising larger series are necessary to better clarify the biology of this diagnostically challenging rare tumor.

Extensive biliary intraepithelial neoplasia (BilIN) and multifocal early intrahepatic cholangiocarcinoma in non-biliary cirrhosis

Biliary intraepithelial neoplasia (BilIN), a preneoplastic condition that may precede invasive intrahepatic cholangiocarcinoma (ICC), has been compared to pancreatic intraepithelial neoplasia (PanIN), a precursor lesion of pancreatic carcinoma. Biliary tract carcinoma development and progression is associated with several gene alterations, but BilIN lesions have yet to be studied in detail by molecular techniques. We describe a case of extensive intrahepatic biliary dysplasia, with lesions ranging from BilIN-1 to BilIN-3 lesions, and multifocal microscopic ICC in hepatitis C virus (HCV)- and alcohol-related cirrhosis. The small ICC foci had remained undetected prior to transplantation. Fluorescence in situ hybridization (FISH) analysis was performed on three foci of BilIN-3 lesions and on three microinvasive ICC foci with a combination of three FISH probes directed against genes frequently altered in pancreatic and biliary tract carcinomas. FISH analysis revealed a CDKNA2 heterozygous deletion in one BilIN-3 focus, and in one non-contiguous ICC focus, although the deletion was just above the chosen threshold. No deletions were detected in the genomic regions encoding TP53 and SMAD4. This report documents for the first time the development of multifocal ICC in the setting of extensive biliary dysplasia in a patient with three risk factors, HCV infection, alcohol abuse, and cirrhosis, and suggests heterogeneous carcinogenesis in ICC and possible involvement of the CDKNA2 gene.

[Treatment of bone metastases with bisphosphonates]

Bone metastasis are very common in many cancers; metastatic bone disease is the most common cause of cancer pain and also of serious complications, which reduce the quality of life of these patients. Management of skeletal cancer involves a multimodality approach who include bisphosphonates, which in association with anti-tumour treatments reduce the apparition of new skeletal-related events (SRE) and prolong the delay to first SRE. They although reduce the pain of bone metastasis. All this facts do the quality of life better.

Anhidrotic ectodermal dysplasia gene region cloned in yeast artificial chromosomes

Anhidrotic ectodermal dysplasia (EDA), an X-chromosomal recessive disorder, is expressed in a few females with chromosomal translocations involving bands Xq12-q13. Using available DNA markers from the region and somatic cell hybrids we mapped the X-chromosomal breakpoints in two such translocations. The breakpoints were further mapped within a yeast artificial chromosome contig constructed by chromosome walking techniques. Genomic DNA markers that map between the two translocation breakpoints were recovered representing putative portions of the EDA gene.