[A Case of Pulmonary Nontuberculous Mycobacterial Infection Accompanied with Intraductal Papillary Mucinous Neoplasm].

An 87-year-old woman presented to the emergency department with left thigh pain, and sciatic nerve pain was diagnosed. A chest CT scan showed bronchiectasis and tree-in buds and an acid-fast stain test of gastric juice was positive; further, M. avium-PCR of sputum and culture results were positive leading to a diagnosis of pulmonary nontuberculous mycobacterial infection(NTM). Abdominal CT showed dilatation of the main pancreatic duct and a multifocal cystic tumor in the pancreatic tail, which was found to be complicated with an intraductal papillary mucinous tumor(IPMN).

Three SARS-CoV-2 PCR-negative cases of COVID-19 diagnosed using isothermal amplification methods.

Coronavirus disease (COVID-19) is a viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 can be detected by polymerase chain reaction (PCR) and isothermal nucleic acid amplification tests, including loop-mediated isothermal amplification (LAMP) and nicking endonuclease amplification reaction (NEAR) tests. Although PCR is the most sensitive and specific method and is generally considered to be the gold standard, it is time-consuming and costly. Isothermal nucleic acid amplification tests have lower sensitivity and specificity than PCR, but are less time-consuming and costly. We encountered three cases of SARS-CoV-2 infection in which the isothermal amplification test was positive but the PCR test was negative on the day of admission; however, the PCR test was positive the next day. These cases showed that some COVID-19 patients can test negative by PCR but positive using isothermal nucleic acid amplification methods. As PCR tests have the possibility of false-negative results, tests that use isothermal amplification methods which can be performed in a shorter time and at a lower cost than PCR tests, may be able to diagnose patients who have false negative PCR results.

Granulomatous-lymphocytic Interstitial Lung Disease Associated with Good's Syndrome That Responded to Immunoglobulin Therapy.

Good's syndrome is associated with thymoma and acquired immunodeficiency. A 54-year-old man visited our hospital with a complaint of cough. Chest imaging revealed diffuse nodular shadows and anterior mediastinal mass. Hypogammaglobulinemia and a decreased B lymphocyte count were found by a laboratory evaluation. The lung nodules markedly regressed after immunoglobulin therapy. The mediastinal mass and remaining nodule were surgically resected and diagnosed as a type AB thymoma and a necrotizing epithelioid granuloma with T lymphocyte-dominant alveolitis, respectively. The overall appearances of these lesions were mostly in line with the spectrum of granulomatous-lymphocytic interstitial lung disease associated with Good's syndrome.