A case of strongly suspected Lynch syndrome with colorectal neuroendocrine carcinoma.

BACKGROUND: Neuroendocrine cell carcinomas (NEC) of the colon and rectum are uncommon, representing ~ 0.1% of all colorectal carcinomas. They are associated with a much worse prognosis compared to adenocarcinoma of the colon and rectum, as death occurs in approximately half of all patients within 1 year. Lynch syndrome (LS) is the most common cause of inherited colorectal cancer, accounting for 2-4% of newly diagnosed colorectal cancer cases. This case is extremely rare which was strongly suspected LS as the background, and NEC as the histological type of colorectal cancer. CASE PRESENTATION: The patient was a 44-year-old man presenting with vomiting as the main complaint. He had undergone ileocecal resection for cecal cancer at age 29. The diagnosis was obstructive descending colorectal cancer, and colonoscopy revealed tumors in the rectum and sigmoid colon in addition. Due to multiple occurrences of colorectal cancer and its prevalence in the patient's family, LS was suspected. The operation which was a subtotal proctocolectomy was performed. Pathological analysis revealed complete curative resection and the descending colon cancer of the obstructed portion was at the most advanced pathological Stage IIIC in UICC TNM classification, and the tissue type was a NEC. The Ki-67 index was 70%. The results of the microsatellite instability (MSI) test showed high-frequency MSI. The BRAF V600E variant was negative. The immunoexpression of MLH1 was positive, MSH2 was negative, PMS2 was positive, and MSH6 was negative. CONCLUSIONS: Extended surgery is recommended for incipient colorectal cancer in LS cases in order to reliably reduce the risk of developing metachronous colorectal cancer. The survival outcome of surgery alone on digestive tract NECs, even locoregional lesions that are completely resection, is extremely poor. It is currently unclear if digestive tract NECs develop more readily in patients with LS. The accumulation of additional cases is necessary.

Malignant rhabdoid tumours of the small intestine with multiple organ involvement: Case report.

INTRODUCTION AND IMPORTANCE: Malignant rhabdoid tumours (MRTs) were first described as an infrequent variant of Wilms' tumour and have been reported in several organs. The small intestine is a rare site for MRTs. CASE PRESENTATION: A 70-year-old man presented with appetite loss and melena. Haemorrhagic small intestinal tumours, swollen mesenteric and paraaortic lymph nodes, a tumour in the left kidney, and multiple tumours in the lung were found. He underwent partial resection of two haemorrhagic small intestinal tumours classified as MRTs based on the results of a pathological examination. However, melena appeared again on postoperative day 6. We performed another operation and resected approximately 180 cm of the small intestine that contained multiple tumours. All lesions were classified as MRTs. Unfortunately, melena appeared again 4 days after the second operation. He did not want invasive therapy and died from massive melena 2 months after the initial surgery. CLINICAL DISCUSSION: MRTs of the small intestine are uncommon and have an extremely poor prognosis. Although curative resection is an important treatment, cases of metastasis at diagnosis and postoperative early recurrence have been observed, as was the case for the patient described herein. In these cases, effective systemic therapy is necessary. Recently, tumour suppressor genes were shown to be involved in the occurrence of MRT, and new therapies for MRT have been studied. CONCLUSION: We herein conclude effective systemic therapy is necessary for MRTs with multiple organ involvement. The development of new drugs for this disease is ongoing.

Identification of the source of Francisella tularensis infection by multiple-locus variable-number tandem repeat analysis.

Tularemia is a zoonotic disease caused by Francisella tularensis. Most patients in Japan have reportedly acquired such infections through direct contact with infected Japanese hares. We recently encountered a patient who contracted tularemia after skinning and butchering a dead hare. Because the remains of the hare were available, we attempted to determine whether the patient actually contracted infection by handling the carcass. F. tularensis-specific sequences were successfully amplified by PCR from the patient specimens as well as from the remnants of discarded hare carcass. PCR amplification of the ISFtu2 and RD1 regions indicated infection by F. tularensis subsp. holarctica, which was considered as a prevalent strain in Japan. Furthermore, high-resolution multiple-locus variable-number tandem repeat analysis (MLVA) showed that the combination of repeat numbers in sequences from the patient and hare were indistinguishable, thus indicating that the patient had been infected with F. tularensis strain that had also infected the hare. These findings demonstrated that MLVA is a useful epidemiological investigational tool to identify possible sources of certain zoonotic diseases such as tularemia.

Detection of a possible bioterrorism agent, Francisella sp., in a clinical specimen by use of next-generation direct DNA sequencing.

Deep sequencing detected a potential bioterrorism agent, Francisella tularensis, in a human abscess sample (Iwaki-08) of unknown etiology. Identified single-nucleotide variations suggest that the Iwaki-08 case was associated with Francisella tularensis subsp. holarctica (biovar japonica) but not the highly virulent type A (Francisella tularensis subsp. tularensis).