An unusual case of Cowden syndrome associated with ganglioneuromatous polyposis

A novel mutation in PTEN in anaplastic thyroid carcinoma: A case report

Anaplastic thyroid cancer (ATC) is a rare disease with a poor prognosis and accounts for a high proportion of thyroid cancer deaths. The present study reported on a 56-year-old male patient with ATC and examined the clinical manifestations, pathological features, differential diagnosis and genetic mutations. Immunohistochemical analysis showed positivity for vimentin, Ki-67 and cytokeratin in the tumor specimen. In addition, pathological mitotic figures of tumor cells and intra-lymph node metastasis were observed. Genetic analysis revealed the presence of a novel mutation (c.388C>T, p.R130X) in exon 5 of the phosphatase and tensin homolog (PTEN) gene, which was first detected in ATC. Gene conservation analysis showed that R130 is a highly conserved amino acid. Protein structure model predictions implied that p.R130X mutation results in a severe defect of the C2 domain and the TAD domain of PTEN, which may be a reason for the high malignancy of the tumor. The present case report highlights a novel mutation of PTEN in ATC, which expands the molecular spectrum of PTEN and further underlines the importance of PTEN.

Colonic Ganglioneuroma: A Combined Single-Institution Experience and Review of the Literature of Forty-Three Patients

Ganglioneuromas (GNs) are rare, benign tumors composed of ganglion cells, nerve fibers, and glial cells. Three types of colonic GN lesions exist: polypoid GNs, ganglioneuromatous polyposis, and diffuse ganglioneuromatosis. Less than 100 cases of GN are documented in the literature. A 10-year retrospective search of the pathology database at our institution identified eight cases of colonic GNs. All cases were incidental. Seven of the eight cases presented with colonoscopy findings of small sessile polyps (ranging between 0.1 and 0.7 cm) treated with polypectomy, whereas one case showed a 4 cm partially circumferential and partially obstructing mass in the ascending colon, treated with right hemicolectomy. Almost two-thirds of the cases (5/8) demonstrated associated diverticulosis. All cases were positive for S100 protein and Synaptophysin via immunohistochemistry (IHC). No syndromic association was identified in any of the cases. We also conducted a comprehensive review using PubMed to identify cases of colonic GN reported in the literature. In total, 173 studies were retrieved, among which 36 articles met our inclusion criteria (35 patients and 3 cases on animals). We conclude that while most GNs are incidental and solitary small sessile lesions, many can be diffuse and associated with syndromes. In these cases, the tumor can result in bowel obstruction simulating adenocarcinoma.

Colorectal polyposis as a clue to the diagnosis of Cowden syndrome: Report of two cases and literature review

Cowden Syndrome (CS) is an autosomal dominant disorder characterized by hamartomatous growth in several organs and by an increased risk of malignancies, which makes its recognition essential to undertake risk reduction measures. Although the involvement of gastrointestinal tract is extremely common, awareness of this entity among gastroenterologists appears limited. We report on two unrelated patients: a 46-year-old male and a 38-year-old woman, who were referred to the Genetic Clinic because of the endoscopic finding of multiple colorectal polyps. Despite both displayed striking clinical (and, in the first case, familial) manifestations of Cowden Syndrome (PTEN Hamartoma Tumor Syndrome-PHTS), they had not been recognized before. Diagnosis of PHTS was confirmed by the detection of causative PTEN variants. Pathological examination of the polyps showed multiple histology types: hyperplastic, juvenile, serrated and lymphoid. Hyperplastic polyps analyzed from both patients failed to show BRAF V600E and KRAS codon 12/13 mutations, which provides evidence against their potential to evolve to colorectal cancer through the serrated pathway. We then reviewed the literature on gastrointestinal polyps detected in patients with Cowden Syndrome, in order to provide a comprehensive scenario of presentations: among a total of 568 patients reported in the literature, 91.7 % presented with colon polyps, with 63.0 % having two or more different histological types of polyps; besides, 58.5 % had extra-colonic polyps (located either in stomach and/or in small intestine). Finding multiple polyps with mixed and/or unusual histology should alert gastroenterologists and pathologists about the possible diagnosis of Cowden Syndrome and prompt the search for other manifestations of this condition in the patient.

Next-generation panel sequencing identifies NF1 germline mutations in three patients with pheochromocytoma but no clinical diagnosis of neurofibromatosis type 1

OBJECTIVE

Our objective was to improve molecular diagnostics in patients with hereditary pheochromocytoma and paraganglioma (PPGL) by using next-generation sequencing (NGS) multi-gene panel analysis. Derived from this study, we here present three cases that were diagnosed with NF1 germline mutations but did not have a prior clinical diagnosis of neurofibromatosis type 1 (NF1).

DESIGN

We performed genetic analysis of known tumor predisposition genes, including NF1, using a multi-gene NGS enrichment-based panel applied to a total of 1029 PPGL patients. We did not exclude genes known to cause clinically defined syndromes such as NF1 based on missing phenotypic expression as is commonly practiced.

METHODS

Genetic analysis was performed using NGS (TruSight Cancer Panel/customized panel by Illumina) for analyzing patients' blood and tumor samples. Validation was carried out by Sanger sequencing.

RESULTS

Within our cohort, three patients, who were identified to carry pathogenic NF1 germline mutations, attracted attention, since none of the patients had a clinical suspicion of NF1 and one of them was initially suspected to have MEN2A syndrome due to co-occurrence of a medullary thyroid carcinoma. In these cases, one splice site, one stop and one frameshift mutation in NF1 were identified.

CONCLUSIONS

Since phenotypical presentation of NF1 is highly variable, we suggest analysis of the NF1 gene also in PPGL patients who do not meet diagnostic NF1 criteria. Co-occurrence of medullary thyroid carcinoma and PPGL was found to be a clinical decoy in NF1 diagnostics. These observations underline the value of multi-gene panel NGS for PPGL patients.