Poorly differentiated thyroid carcinoma (PDTC) is a rare malignancy with higher mortality than well-differentiated thyroid carcinoma. The histological diagnosis can be difficult as well as the therapy. Improved diagnosis and new targeted therapies require knowledge of DNA sequence changes in cancer-relevant genes. The TruSeq Amplicon Cancer Panel was used to screen cancer genomes from 25 PDTC patients for somatic single-nucleotide variants in 48 genes known to represent mutational hotspots. A total of 4490 variants were found in 23 tissue samples of PDTC. Ninety-eight percent (4392) of these variants did not meet the inclusion criteria, while 98 potentially pathogenic or pathogenic variants remained after filtering. These variants were distributed over 33 genes and were all present in a heterozygous state. Five tissue samples harboured not a single variant. Predominantly, variants in P53 (43% of tissue samples) were identified, while less frequently, variants in APC, ERBB4, FLT3, KIT, SMAD4 and BRAF (each in 17% of tissue samples) as well as ATM, EGFR and FBXW7 (each in 13% of tissue samples) were observed. This study identified new potential genetic targets for further research in PDTC. Of particular interest are four observed ERBB4 (alias HER4) variants, which have not been connected to this type of thyroid carcinoma so far. In addition, APC and SMAD4 mutations have not been reported in this subtype of cancer either. In contrast to other reports, we did not find CTNNB1 variants.

Diagnosis of adenocarcinoma in the liver is a frequent scenario in routine pathology and has a critical impact on clinical decision-making. However, rendering a correct diagnosis can be challenging and often requires the integration of clinical, radiological, and immunohistochemical information. We present a deep learning model (HEPNET) to distinguish intrahepatic cholangiocarcinoma (iCCA) from colorectal liver metastasis (CRM) as the most frequent primary and secondary forms of liver adenocarcinoma with clinical-grade accuracy using hematoxylin and eosin-stained whole-slide images. HEPNET was trained on 714 589 image tiles from 456 patients who were randomly selected in a stratified manner from a pool of 571 patients who underwent surgical resection or biopsy at Heidelberg University Hospital. Model performance was evaluated on a hold-out internal test set comprising 115 patients and externally validated on 159 patients recruited at Mainz University Hospital. On the hold-out internal test set, HEPNET achieved an area under the receiver operating characteristic curve (AUROC) of 0.994 (95% CI 0.989-1.000) and an accuracy of 96.522% (95% CI 94.521-98.694%) at the patient level. Validation on the external test set yielded an AUROC of 0.997 (95% CI 0.995-1.000), corresponding to an accuracy of 98.113% (95% CI 96.907-100.000%). HEPNET surpassed the performance of six pathology experts with different levels of experience in a reader study of 50 patients (P=.0005), boosted the performance of resident pathologists to the level of senior pathologists, and reduced potential downstream analyses. Here, we provide a ready-to-use tool with a clinical-grade performance that may facilitate routine pathology by rendering a definitive diagnosis and guiding ancillary testing. The incorporation of HEPNET into pathology laboratories may optimize the diagnostic workflow, complemented by test-related labor and cost savings.

(1) Background: Intrahepatic cholangiocarcinoma (ICC) is a rare malignancy. Besides tumor, nodal, and metastatic status, the UICC TNM classification describes further parameters such as lymphangio- (L0/L1), vascular (V0/V1/V2), and perineural invasion (Pn0/Pn1). The aim of this study was to analyze the influence of these parameters on recurrence and survival. (2) Methods: All surgical explorations for patients with ICC between January 2008 and June 2018 were collected and further analyzed in our institutional database. Statistical analyses focused on perineural, lymphangio-, and vascular invasion examined histologically and their influence on tumor recurrence and survival. (3) Results: Of 210 patients who underwent surgical exploration, 150 underwent curative-intended resection. Perineural invasion was present in 41, lymphangioinvasion in 21, and vascular invasion in 37 patients (V1 n = 34, V2 n = 3). Presence of P1, V+ and L1 was significantly associated with positivity of each other of these factors (p < 0.001, each). None of the three parameters showed direct influence on tumor recurrence in general, but perineural invasion influenced extrahepatic recurrence significantly (p = 0.019). Whereas lymphangio and vascular invasion was neither associated with overall nor recurrence-free survival, perineural invasion was significantly associated with a poor 1-, 3- and 5-year overall survival (OS) of 80%, 35%, and 23% for Pn0 versus 75%, 23%, and 0% for Pn1 (p = 0.027). Concerning recurrence-free survival (RFS), Pn0 showed a 1-, 3- and 5-year RFS of 42%, 18%, and 16% versus 28%, 11%, and 0% for Pn1, but no significance was reached (p = 0.091). (4) Conclusions: Whereas lymphangio- and vascular invasion showed no significant influence in several analyses, the presence of perineural invasion was associated with a significantly higher risk of extrahepatic tumor recurrence and worse overall survival.

Background: Intrahepatic cholangiocarcinoma (iCCA) accounts for about 10% of primary liver cancer. Surgery is the only potentially curative treatment. We report on our current series of 229 consecutive hepatic resections for iCCA, which is one of the largest Western single-center series published so far. Methods: Between January 2008 to December 2020, a total of 286 patients underwent 307 surgical explorations for intended liver resection of iCCA at our department. Data were analyzed with regard to (1) preoperative treatment of tumor, (2) operative details, (3) perioperative morbidity and mortality, (4) histopathology, (5) outcome measured by tumor recurrence, treatment of recurrence and survival and (6) prognostic factors for overall and disease-free survival. Results: the resectability rate was 74.6% (229/307). In total, 202 primary liver resections, 21 repeated, 5 re-repeated, and 1 re-re-repeated liver resections were performed. In primary liver resections there were 77% (155/202) major hepatectomies. In 39/202 (20%) of patients additional hepatic wedge resections and in 87/202 (43%) patients additional 119 other surgical procedures were performed next to hepatectomy. Surgical radicality in first liver resections was 166 R0-, 33 R1- and 1 R2-resection. Following the first liver resection, the calculated 1-, 3- and 5-year-survival is 80%, 39%, and 22% with a median survival of 25.8 months. Until the completion of data acquisition, tumors recurred in 123/202 (60.9%) patients after a median of 7.5 months (range 1–87.2 months) after resection. A multivariate cox regression revealed tumor size (p < 0.001), T stage (p < 0.001) and N stage (p = 0.003) as independent predictors for overall survival. N stage (p = 0.040), preoperative therapy (p = 0.005), T stage (p = 0.004), tumor size (p = 0.002) and M stage (p = 0.001) were independent predictors for recurrence-free survival. Conclusions: For complete surgical removal, often extended liver resection in combination with complex vascular or biliary reconstruction is required. However, despite aggressive surgery, tumor recurrence is frequent and long-term oncological results are poor. This indicated that surgery alone is unlikely to make great strides in improving prognosis of patients with iCCA, instead clearly suggesting that liver resection should be incorporated in multimodal treatment concepts.

Mediastinal tumours represent a heterogeneous group of entities derived from the manifold structures located in or adjacent to the mediastinum. Due to the occurrence of some of these tumours in characteristic mediastinal compartments, an anatomical subdivision of the mediastinum in the prevascular (anterior), visceral (middle), and paravertebral (posterior) is helpful for the differential diagnosis. Benign anterior mediastinal tumours linked to an enlargement of the thymic gland mainly consist of thymic cysts and several types of thymic hyperplasia: true thymic hyperplasia, rebound hyperplasia, lymphofollicular hyperplasia, and so‐called thymic hyperplasia with lymphoepithelial sialadenitis (LESA)‐like features. Mature teratomas, ectopic (para)thyroid tissue, and benign thymic tumours such as thymolipoma or thymofibrolipoma represent further typical tumours of the anterior mediastinum. Pericardial, bronchogenic, or oesophageal duplication cysts predominate in the middle mediastinum, whereas neurogenic tumours and myelolipomas are characteristic findings in the posterior compartment. Vascular tumours, lipomas, adenomatoid tumours, Castleman disease, or mediastinitis are further examples of less frequent tumours or tumorous lesions affecting the mediastinum. This review focuses on benign mediastinal lesions with an emphasis on benign tumours of the thymus. Besides histology, characteristic epidemiological and clinical aspects prerequisite for the correct diagnosis and patient management are discussed.

Intrahepatic cholangiocarcinomas (iCCAs) may be subdivided into large and small duct types that differ in etiology, molecular alterations, therapy, and prognosis. Therefore, the optimal iCCA subtyping is crucial for the best possible patient outcome. In our study, we analyzed 148 small and 84 large duct iCCAs regarding their clinical, radiological, histological, and immunohistochemical features. Only 8% of small duct iCCAs, but 27% of large duct iCCAs, presented with initial jaundice. Ductal tumor growth pattern and biliary obstruction were significant radiological findings in 33% and 48% of large duct iCCAs, respectively. Biliary epithelial neoplasia and intraductal papillary neoplasms of the bile duct were detected exclusively in large duct type iCCAs. Other distinctive histological features were mucin formation and periductal-infiltrating growth pattern. Immunohistochemical staining against CK20, CA19-9, EMA, CD56, N-cadherin, and CRP could help distinguish between the subtypes. To summarize, correct subtyping of iCCA requires an interplay of several factors. While the diagnosis of a precursor lesion, evidence of mucin, or a periductal-infiltrating growth pattern indicates the diagnosis of a large duct type, in their absence, several other criteria of diagnosis need to be combined.