Effects of the tip structure of temporary indwelling catheters on blood recirculation at various blood flow rates and diameters of the mock blood vessel.

AIMS: The aim of the present study was to determine the effects of the tip structure of the catheters used for hemodialysis on blood recirculation at varying blood flow rates and diameters of the mock blood vessel in a well-defined in vitro experimental system, focusing on reverse connection mode. METHODS: A mock circulatory circuit was created with silicon tubing (15 or 20 mm), a circulatory pump, connected through the catheter to dialysis circuit and dialyzer attached to dialysis machine. The tip of the inserted catheter was fixed to the center of the silicone tube, and 3 L of pig blood was poured into the blood side of the dialyzer and the recirculation rates were measured at blood flow rates of 100, 150, and 200 mL/min. Five types of commercially available catheters were used: (A) Argyle™, (B) Gentle Cath™ (Hardness gradient type), (C) Gentle Cath™, (D) Niagara™, and (E) Power-Trialysis®. RESULTS: In the case of reverse connection mode, (1) the recirculation rates were lower in the catheter with a relatively large side hole (catheter C, 17%), catheters with a greater distance between the end hole and side hole (catheters C and D, 25%), and catheter with a symmetrical tip structure (catheter E, 10%) as compared with those in catheters A and B (40% and 25%); (2) increase of the blood flow rate in the dialysis machine was associated with a reduced recirculation rate; and (3) a wider inner diameter of the mock blood vessel and faster flow rate in the vessel were associated with a reduced recirculation rate. CONCLUSION: The lowest recirculation was observed with the catheter with symmetrical holes, which produces a helical blood flow line that does not intersect with the blood streamline flowing out to the blood supply hole.

Successful Radiotherapy of Primary Malignant Peripheral Nerve Sheath Tumor of the Lung.

A 71-year-old man presented with cough and bloody sputum. Computed tomography showed a mass in the lower lobe of the left lung. Histological findings in biopsy tissue revealed a malignant peripheral nerve sheath tumor (MPNST). The patient was diagnosed with primary lung MPNST based on a systemic examination. Although initial chemotherapy treatment with doxorubicin failed to control the disease, radiotherapy considerably shrank the tumor. Primary lung MPNSTs are rare, and there is no established treatment for inoperable cases. This case suggests that radiotherapy is a treatment option for primary lung MPNST.

Serial Cancer Development Three Times in a Patient with Fanconi Anemia.

Fanconi anemia (FA) is characterized clinically by bone marrow failure, congenital malformations, sensitivity to DNA cross-linking agents, and increased risk of malignancy. Hematological cancer is the best-described malignancy in patients with FA, but the susceptibility to the development of solid tumors is also well documented, especially after hematopoietic stem cell transplantation (HSCT). With regard to the development of solid tumors in patients with FA, head and neck, esophageal, and anal squamous cell carcinoma are well known, but reports of lung cancer are extremely rare. Here, we describe an FA patient with a history of HSCT that developed 3 serial cancers - oral, esophageal, and nonsmall cell lung cancer - over a period of 6 years. The third lesion was nonsmall cell lung cancer and its location corresponded closely to the field of irradiation treatment for prior esophageal cancer. The occurrence of lung cancer in patients with FA is uncommon, but FA patients should be screened regularly and serially. Our case also indicated the importance of the irradiated field as a location for subsequent cancer development.

A fulminant case of classical Hodgkin lymphoma: A diagnostic dilemma of Epstein-Barr virus-positive large B-cell neoplasms.

We report a fulminant case of classical Hodgkin lymphoma (CHL). The patient died only approximately 2 months after the onset of subjective symptoms. Autopsy specimens revealed atypical cells resembling Hodgkin and Reed-Sternberg (HRS) cells in a rich inflammatory background in various organs. There were marked, characteristic angiodestructive lesions from infiltrating HRS-like cells and numerous macrophages. The HRS-like cells were infected with Epstein-Barr virus (EBV), immunohistochemically positive for PAX5 and CD30, and negative for CD3, CD20, and ALK. Most B-cell markers other than PAX5 were negative, and the HRS-like cells also expressed cytotoxic molecules. Monoclonal rearrangement of immunoglobulin heavy chain was detected by PCR analysis. According to the 2016 WHO classification, we diagnosed mixed cellularity CHL. However, EBV-positive diffuse large B-cell lymphoma (DLBCL), not otherwise specified and EBV-positive B-cell lymphoma, unclassifiable with features intermediate between DLBCL and CHL were considered as differential diagnoses because both tumors are aggressive EBV-positive large B-cell neoplasms with reactive inflammatory cells and sometimes contains HRS-like cells. The clinical condition of the current case was closer to these two entities than to CHL. A diagnosis of EBV-positive large B-cell neoplasms was difficult because of overlapping morphological and immunohistochemical characteristics, but should be considered for prognosis.