The polymerase chain reaction (PCR) test is useful for diagnosing COVID-19. However, a positive PCR test may persist for several weeks after symptom improvement and make the decision to lift isolation difficult. We investigated factors associated with the duration of positive PCR tests in hospitalized COVID-19 patients. The background of 226 patients who were hospitalized and treated at our hospital between January 1, 2022 and May 8, 2023 was extracted, and factors related to the duration of positive PCR tests were examined. In patients with immunosuppressive conditions such as advanced age, diabetes mellitus, hematologic malignancies, and malignant lymphoma, and those who had undergone B-cell depletion therapy, the duration of positive PCR tests was significantly prolonged. Because long-term viral shedding has been reported in these patients, caution should be exercised when releasing such patients from isolation.

In our study of 109 patients with nontuberculous mycobacterial pulmonary disease (NTM-PD), patients with high chronic obstructive pulmonary disease (COPD) assessment test (CAT) scores ≥10 points) at first visit had higher inflammatory markers and higher rates of smear positivity than patients with low CAT scores. CAT improvement (decrease of ≥2 points) was seen in 18 of 29 patients 6 months after initiating multidrug therapy. Although the rate of culture conversion was significantly lower in patients with high pretreatment CAT scores than in patients with low scores, the CAT improvement rate after treatment was high, and there were many cases in which CAT improved without culture conversion. Assessing health-related quality of life (HRQOL) using CAT could serve as a valuable indicator of treatment efficacy for NTM-PD.

The patient was a woman in her 70s who presented to our hospital with a chief complaint of cough. Contrast-enhanced computed tomography showed a clear vascular shadow and a giant cavity of 5cm in size within low-attenuating consolidation. The lesion removed by open thoracotomy was 14×15×9cm in size, was located near the bronchus, and was covered by a fibrous wall. Mucus production was confirmed, and a diagnosis of invasive mucinous adenocarcinoma (IMA) pT4N0M0, pStage IIIA was made. Although IMA often presents with pneumonia-like findings, it is important to acknowledge that IMA can be associated with a giant cavity.

A 69-year-old male presented with a nodule in the left upper lobe observed on chest computed tomography (CT) scan, and a bronchoscopic biopsy confirmed the diagnosis of lung adenocarcinoma. Contrast-enhanced CT of the chest and abdomen revealed non-enhancing lymphadenopathy in the bilateral supraclavicular regions and intensely enhancing lymphadenopathy in the right inguinal and pelvic regions. PET/CT showed weaker FDG accumulation in the right inguinal and pelvic lymph nodes compared to the supraclavicular lymph nodes. Pathological diagnosis from a biopsy of the right inguinal lymph node confirmed mixed-type Castleman’s disease. When lymphadenopathy associated with malignant tumors cannot be determined as metastatic lesions, it is crucial to actively perform a biopsy.

A 69-year-old woman underwent left lower lobectomy for pStage IA lung adenocarcinoma in the left lower lobe in 20XX-17. She was admitted to our hospital because of carcinoembryonic antigen elevation, gait disorder, and disorientation. Brain magnetic resonance imaging showed high signal along the bilateral cerebral cortex on fluid-attenuated inversion recovery and diffusion-weighted imaging. A slight contrast enhancement on the brain surface was observed in the left frontal lobe on contrast-enhanced T1-weighted imaging, suggesting leptomeningeal metastases. Atypical cells were found on cerebrospinal fluid examination. EGFR deletion 19 was also detected in the cerebrospinal fluid and surgical specimen, and from the above we diagnosed leptomeningeal metastases as a postoperative recurrence of lung adenocarcinoma. After treatment with osimertinib, neurological symptoms improved and carcinoembryonic antigen levels decreased. The magnetic resonance imaging abnormalities also improved. We report this case because we consider it to be an extremely rare instance of leptomeningeal metastases that occurred 17 years after surgery for lung adenocarcinoma.

A 46-year-old female who complained of dyspnea on exertion was diagnosed with mixed connective tissue disease (MCTD) based on interstitial pneumonia on chest computed tomography scan, a positive result for anti-ribonucleoprotein antibodies, and systemic lupus erythematosus-like physical findings such as swelling of the fingers, polyarthritis, and facial erythema. Oral prednisolone (30mg/day) and intravenous cyclophosphamide (500mg/kg body weight) improved both physical symptoms and radiographic findings quickly. However, 10 days after the start of treatment, she developed pyrexia with mild arthralgia and myalgia, and was urgently admitted to the hospital. Pancytopenia and elevated aspartate aminotransferase and lactate dehydrogenase levels were observed, despite no worsening of the interstitial pneumonia. These findings suggested the possibility of macrophage activation syndrome due to uncontrolled MCTD. Methylprednisolone pulse therapy (1,000mg/day) was given, followed by the addition of intravenous cyclophosphamide (500mg/kg body weight) and oral prednisolone (60mg/day). After the treatment, her blood counts recovered, and her fever, arthralgia, and myalgia improved. Early close examination is important when MCTD worsens, as it has a variety of symptoms and can be severe.

A 46-year-old male patient, who was undergoing treatment for erythema and blisters on his legs, developed respiratory failure and lung shadows. He was treated with steroids, and further examination revealed eosinophilic granulomatosis with polyangiitis (EGPA). While tapering steroids, he experienced asymmetric edema, muscle swelling with pain, and neurological disorder, as well as another rise in peripheral eosinophil count. His symptoms improved with a re-increase of steroids. Mepolizumab was administered to allow a reduction in steroid dosage, which was achieved without recurrence of symptoms. It is important to recognize the diverse clinical symptoms of EGPA and to diagnose and treat them accordingly.

A 46-year-old woman diagnosed with ulcerative colitis was started on mesalazine in September 20XX-1 and vedolizumab in October 20XX for induction remission therapy. She presented to our department with cough and dyspnea in December 20XX. Blood tests showed an increased eosinophil count, and chest computed tomography scan showed a pattern of dense and predominantly peripheral confluent consolidation with bronchial translucency. We suspected that she had drug-induced eosinophilic pneumonia caused by vedolizumab. We discontinued vedolizumab and started treatment with prednisolone. After the change in treatment, her pneumonia resolved promptly. We need to consider vedolizumab as a causative agent when drug-induced eosinophilic pneumonia occurs in patients being treated for ischemic bowel disease.

We report a case of severe drug-induced lung injury caused by an everolimus-eluting stent. A 48-year-old man presented with acute myocardial infarction to the Cardiology Department of our hospital. Everolimus-eluting coronary stents were placed in the right coronary and left circumflex coronary arteries. The patient developed pneumonia 10 days post-procedure. Chest radiography revealed bilateral lung field consolidation. Drug-induced lung injury caused by the everolimus-eluting stents was suspected. Corticosteroid therapy and recombinant thrombomodulin were administered, but response to the treatment was poor, resulting in the patient’s death. Everolimus is an antineoplastic agent currently used to coat coronary stents to reduce the rates of restenosis and fatal thrombosis after coronary stent placement. Although pulmonary toxicity related to everolimus-eluting coronary stents is rare, this adverse event may occasionally be lethal. Physicians should, therefore, be aware of this potential issue.