Analysis of expression, epigenetic, and genetic changes of HNF1B in 130 kidney tumours.

Hepatocyte nuclear factor 1 beta (HNF1B) is a transcription factor which plays a crucial role in nephronogenesis, and its germline mutations have been associated with kidney developmental disorders. However, the effects of HNF1B somatic exonic mutations and its role in the pathogenesis of kidney tumours has not yet been elucidated. Depending on the type of the tumour HNF1B may act as a tumour suppressor or oncogene, although the exact mechanism by which HNF1B participates in the process of cancerogenesis is unknown.

HNF1B, EZH2 and ECI2 in prostate carcinoma. Molecular, immunohistochemical and clinico-pathological study.

Hepatocyte nuclear factor 1 beta (HNF1B) is a tissue specific transcription factor, which seems to play an important role in the carcinogenesis of several tumors. In our study we focused on analyzing HNF1B in prostate carcinoma (PC) and adenomyomatous hyperplasia (AH), as well as its possible relation to the upstream gene EZH2 and downstream gene ECI2. The results of our study showed that on an immunohistochemical level, the expression of HNF1B was low in PC, did not differ between PC and AH, and did not correlate with any clinical outcomes.

A Clinicopathological Study of 29 Spitzoid Melanocytic Lesions With ALK Fusions, Including Novel Fusion Variants, Accompanied by Fluorescence In Situ Hybridization Analysis for Chromosomal Copy Number Changes, and Both TERT Promoter and Next-Generation Sequencing Mutation Analysis.

ALK-fused spitzoid neoplasms represent a distinctive group of melanocytic lesions. To date, few studies addressed genetic and chromosomal alterations in these lesions beyond the ALK rearrangements. Our objective was to study genetic alterations, including ALK gene fusions, telomerase reverse transcriptase promoter (TERT-p) mutations, chromosomal copy number changes, and mutations in other genes.

Solitary fibrous tumors of the head and neck region revisited: a single-institution study of 20 cases and review of the literature.

A solitary fibrous tumor (SFT) is a rare, NAB2-STAT6 fusion gene-associated mesenchymal neoplasm. It most commonly arises in the pleural site, but it can occur at many other sites, and rarely also in the head and neck (H&N) region. STFs may show many growth patterns and therefore can be easily mistaken for other more common H&N spindle cell or epithelial lesions.

Inflammatory leiomyosarcoma shows frequent co-expression of smooth and skeletal muscle markers supporting a primitive myogenic phenotype: a report of 9 cases with a proposal for reclassification as low-grade inflammatory myogenic tumor.

Inflammatory leiomyosarcoma (ILMS) is a very rare soft tissue tumor that usually follows an indolent clinical course, but long-term follow-up studies are lacking. Recent publications primarily focused on its genetic profile characterized by a near haploid genome. One study also showed these tumors to have upregulation of genes known to be crucial for skeletal muscle differentiation.

Papillary fibroelastoma on pulmonary valve - Valve-sparing surgery of a cardiac tumor in a rare location.

We present images of a papillary fibroelastoma on a pulmonary valve - echocardiography, intraoperative images, macroscopic and microscopic images of the tumor in this uncommon location.

Spitz Tumors With ROS1 Fusions: A Clinicopathological Study of 6 Cases, Including FISH for Chromosomal Copy Number Alterations and Mutation Analysis Using Next-Generation Sequencing.

Spitz tumors represent a heterogeneous group of melanocytic neoplasms with a spectrum of biological behavior ranging from benign (Spitz nevus) to malignant (spitzoid melanoma). Prediction of the behavior of these lesions based on their histological presentation is not always possible. Recently, mutually exclusive activating kinase fusions, involving ALK, NTRK1, NTRK3, RET, MET, ROS1, and BRAF, have been found in a subset of spitzoid lesions.

Mummified Cells are a Common Finding in Cutaneous Hodgkin Lymphoma and Can Be Used as a Diagnostic Clue.

Specific cutaneous involvement in Hodgkin lymphoma is rare. In cutaneous lesions, the diagnosis is usually based on the recognition of diagnostic Reed-Sternberg cells and its variants. In nodal Hodgkin lymphoma, so-called mummified cells (cells with condensed cytoplasm and pyknotic eosinophilic or basophilic nuclei) are often seen.

Spindle Cell Predominant Trichodiscoma or Spindle Cell Lipoma With Adnexal Induction? A Study of 25 Cases, Revealing a Subset of Cases With RB1 Heterozygous Deletion in the Spindle Cell Stroma.

In our routine and consultative pathology practices, we have noticed that a relatively high proportion of spindle cell predominant trichodiscomas demonstrate a remarkable stromal admixture of adipose tissue, which along with spindle cells, prominent collagen bundles and myxoid change closely resembles spindle cell lipoma (SCL). To clarify their possible relationship to SCL, 25 cases of trichodiscoma and fibrofolliculoma with stromal "lipomatous metaplasia" were collected and examined using immunohistochemical stains [CD34 and retinoblastoma-1 (RB1) protein] and fluorescence in situ hybridization (RB1 deletion). The patients ranged in age from 35 to 81 years (median 64 years).

Results of morphological screening for Lynch syndrome during the period 2013-2016.

The introduction of a screening system for Lynch syndrome in pathology laboratories in Plzen yielded 24 diagnoses of Lynch syndrome during the period of 2013-2016, 20 of them presenting with colorectal cancer. In 8 of those 24 cases germline mutations of MMR genes, previously not recognized as pathogenic with certainty, were detected. Although the frequency of Lynch syndrome in patients with colorectal cancer was only 0.

Tenosynovitis With Psammomatous Calcifications: A Distinctive Trauma-Associated Subtype of Idiopathic Calcifying Tenosynovitis With a Predilection for the Distal extremities of Middle-Aged Women-A Report of 23 Cases.

The term "idiopathic calcifying tenosynovitis" (ICT) refers to a clinically and radiologically defined syndrome of pain and tendinous calcifications, most often involving the shoulder joint. A distinctive subset of ICT cases, termed "tenosynovitis with psammomatous calcifications" (TPC), occurs in the distal extremities and shows characteristic morphology, in particular psammomatous calcifications. As only 14 cases have been reported to date, TPC remains poorly recognized by both pathologists and clinicians.

Dysplastic Lipoma: A Distinctive Atypical Lipomatous Neoplasm With Anisocytosis, Focal Nuclear Atypia, p53 Overexpression, and a Lack of MDM2 Gene Amplification by FISH; A Report of 66 Cases Demonstrating Occasional Multifocality and a Rare Association With Retinoblastoma.

In our routine and consultative pathology practices, we have repeatedly encountered an unusual subcutaneous fatty tumor with notable anisocytosis, single-cell fat necrosis, and patchy, often mild, adipocytic nuclear atypia. Because of the focal atypia, consultative cases have most often been received with concern for a diagnosis of atypical lipomatous tumor. Similar tumors have been described in small series under the designations "subcutaneous minimally atypical lipomatous tumors" and "anisometric cell lipoma.

EWSR1-SMAD3-rearranged Fibroblastic Tumor: An Emerging Entity in an Increasingly More Complex Group of Fibroblastic/Myofibroblastic Neoplasms.

Three cases of superficial acral fibroblastic spindle cell neoplasms with EWSR1-SMAD3 fusion have been recently reported. Their differential diagnosis is broad, primarily comprising rare tumors from the fibroblastic/myofibroblastic category. The aim of this report is to present 4 new cases of this entity and to discuss the appropriate differential diagnosis.

Small Subset of Adenoid Cystic Carcinoma of the Skin Is Associated With Alterations of the MYBL1 Gene Similar to Their Extracutaneous Counterparts.

Adenoid cystic carcinoma (ACC) of the skin is a rare malignant neoplasm histologically identical to homonymous tumors in other organs. Cutaneous ACC has been found to harbor MYB gene activations, either through MYB chromosomal abnormalities or by generation of the MYB-NFIB fusion. In salivary gland ACC, in addition to the MYB gene, alterations in MYBL1, the gene closely related to MYB, have been reported.

Dedifferentiated liposarcoma composed predominantly of rhabdoid/epithelioid cells: a frequently misdiagnosed highly aggressive variant.

Dedifferentiated liposarcoma is one of the most common sarcoma types in adults with a predilection for the retroperitoneum. We have recently encountered 6 cases of DDL composed predominantly of rounded, rhabdoid or epithelioid cells mimicking rhabdoid melanoma, epithelioid rhabdomyosarcoma or undifferentiated carcinoma. Patients were 5 males and one female aged 64 to 81 years (median, 68).

Primary signet ring stromal tumor of the testis: a study of 13 cases indicating their phenotypic and genotypic analogy to pancreatic solid pseudopapillary neoplasm.

Primary signet ring stromal tumor of the testis (PSRSTT) is an extremely rare tumor described only twice in the literature. Pancreatic-analogue solid pseudopapillary neoplasm (SPN) of the testis is a recently reported entity with morphological overlap with PSRSTT. We reviewed our files to find all cases of PSRSTT to better characterize this entity.

Phosphaturic Mesenchymal Tumors: Clinicopathologic, Immunohistochemical and Molecular Analysis of 22 Cases Expanding their Morphologic and Immunophenotypic Spectrum.

Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm of uncertain histogenesis that has been linked to tumor-induced osteomalacia (TIO) since 1959. The neoplastic cells produce increased amount of FGF23 which results in TIO via uncontrolled renal loss of phosphate (phosphaturia), and consequently diminished bone mineralization. To date, ∼300 cases have been reported.

Lipoblasts in spindle cell and pleomorphic lipomas: a close scrutiny.

The presence and frequency of lipoblasts (LPB) in spindle cell lipomas (SCL) and pleomorphic lipomas (PL) has never been studied in detail on a histologically, immunohistochemically and molecular genetically validated set of tumors. The authors investigated this feature by reviewing 91 cases of SCL and 38 PL. When more than 3 unequivocal LPB were found, the case was regarded as positive for the presence of LPB.

Basal Cell Carcinoma With Matrical Differentiation: Clinicopathologic, Immunohistochemical, and Molecular Biological Study of 22 Cases.

Basal cell carcinoma (BCC) with matrical differentiation is a fairly rare neoplasm, with about 30 cases documented mainly as isolated case reports. We studied a series of this neoplasm, including cases with an atypical matrical component, a hitherto unreported feature. Lesions coded as BCC with matrical differentiation were reviewed; 22 cases were included.

Differentiated squamous intraepithelial lesion (dSIL)-like changes in the epidermis overlying anogenital melanocytic nevi: A diagnostic pitfall.

Background: Differentiated squamous intraepithelial lesion (dSIL) is morphologically and immunohistochemically analogous in the whole anogenital region. dSIL is a premalignant lesion frequently misinterpreted histopathologically as a benign dermatosis. The authors describe a peculiar change in the basal cell layer of the epidermis/epithelium overlying anogenital melanocytic nevi that may histopathologically imitate dSIL.

Cutaneous Sebaceous Lesions in a Patient With MUTYH-Associated Polyposis Mimicking Muir-Torre Syndrome.

A 76-year-old white male with a history of adenocarcinoma of the rectosigmoideum and multiple colonic polyps removed at the age of 38 and 39 years by an abdominoperitoneal amputation and total colectomy, respectively, presented with multiple whitish and yellowish papules on the face and a verrucous lesion on the trunk. The lesions were surgically removed during the next 3 years and a total of 13 lesions were investigated histologically. The diagnoses included 11 sebaceous adenomas, 1 low-grade sebaceous carcinoma, and 1 squamous cell carcinoma.

Superficial acral fibromyxoma: clinicopathological, immunohistochemical, and molecular study of 11 cases highlighting frequent Rb1 loss/deletions.

Superficial acral fibromyxoma (SAF) is an uncommon benign dermal mesenchymal lesion of adults with predilection for acral sites, in particular the nail region. To date, less than 300 cases have been reported. SAFs consistently express CD34, but other diagnostic markers or specific genetic alterations have not been established yet.

Multivacuolated mucin-filled cells: a unique cell characteristic of plexiform neurofibroma. A report of 11 cases.

The authors present 11 cases of plexiform neurofibroma (PN) that featured a very characteristic type of cell appearing as multivacuolated mucin-filled cells (MMFC). The 11 cases were obtained after reviewing 109 cases of PN. Six out of 10 patients showed clinical features of neurofibromatosis type 1.

Follicular dendritic cell sarcoma: clinicopathologic study of 15 cases with emphasis on novel expression of MDM2, somatostatin receptor 2A, and PD-L1.

Follicular dendritic cell sarcoma (FDCS) is a rare low-grade neoplasm with the phenotype of FDC cells. This rare sarcoma has been well known for being mistaken for a variety of neoplasms (mainly meningioma), particularly at extranodal sites. Diagnosis of FDCS mainly relies on characteristic histologic appearance supplemented by immunohistochemistry and electron microscopy.

Littoral cell angioma of the spleen: a study of 25 cases with confirmation of frequent association with visceral malignancies.

Aims: Littoral cell angioma (LCA) is a rare primary splenic tumour that is frequently associated with internal malignancies. Immunohistochemistry can demonstrate a distinct hybrid endothelial-histiocytic phenotype of littoral cells, and is a helpful adjunct for making the correct diagnosis. The aims of this study were to present a series of 25 LCAs, with an emphasis on the frequent association of the neoplasm with visceral malignancies, and to provide a detailed immunohistochemical analysis by employing new markers.