Respiratory Medicine Case Reports最新文献

{"title":"Chronic streptococcal pneumonia presenting as a chest wall mass: An unusual case of malakoplakia","authors":"Ali Husam Al Zuwayny,&nbsp;Meghana Muppuri,&nbsp;Abiramy Karunanathan,&nbsp;David Kim,&nbsp;Jessie Saverimuttu","doi":"10.1016/j.rmcr.2026.102520","DOIUrl":"10.1016/j.rmcr.2026.102520","url":null,"abstract":"<div><h3>Introduction</h3><div>Malakoplakia is a rare disorder of defective macrophage bactericidal function associated with gram-negative organisms. Pulmonary involvement is uncommon, and association with <em>Streptococcus pneumoniae</em> is exceedingly rare, often mimicking thoracic malignancy.</div></div><div><h3>Case</h3><div>72-year-old man with a 50-pack-year smoking history and chronic alcohol use presented with cough, dyspnea, fever, weight loss and a tender left chest wall mass. Computed tomography demonstrated a 10.9 × 6.2 cm mass traversing multiple tissue planes with mediastinal lymphadenopathy raising concern for malignancy. Cultures grew <em>Streptococcus pneumoniae.</em> Lung biopsy revealed Periodic Acid–Schiff positive macrophages with chronic inflammatory infiltrate and histiocytes without evidence of malignancy, confirming pulmonary malakoplakia. He received ceftriaxone followed by amoxicillin-clavulanate alongside surgical debridement, achieving clinical improvement. Re-biopsy confirmed the absence of malignancy.</div></div><div><h3>Conclusion</h3><div>This case illustrates the importance of correlating a detailed, potentially suspicious history with an appropriate and comprehensive microbiologic, surgical, radiographic, and histopathological evaluation process, which leads to a maximally effective intervention.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"64 ","pages":"Article 102520"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149161384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acute respiratory failure from organophosphate poisoning: Early intervention and holistic care in a resource-limited setting","authors":"Gudisa Bereda","doi":"10.1016/j.rmcr.2026.102524","DOIUrl":"10.1016/j.rmcr.2026.102524","url":null,"abstract":"<div><div>Acute respiratory failure due to organophosphate (OP) poisoning is a life-threatening emergency caused by acetylcholinesterase inhibition and subsequent cholinergic overstimulation. The author reports a 36-year-old male who intentionally ingested 50% malathion and presented with blurred vision, excessive salivation, muscle fasciculations, altered consciousness, and acute respiratory distress. His laboratory tests showed reduced cholinesterase levels, and chest imaging showed mild bilateral infiltrates without evidence of aspiration pneumonia. Immediate management included securing the airway with mechanical ventilation and administering atropine according to the patient's clinical response. Pralidoxime was administered, and appropriate intravenous fluid resuscitation was provided for hypotension. Close monitoring allowed early differentiation between his primary respiratory failure due to OP toxicity and potential secondary complications. He was discharged on day nine after making a full recovery. This case highlights the critical importance of rapid recognition, early airway stabilization, and timely antidote administration in managing acute respiratory failure resulting from OP poisoning.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"64 ","pages":"Article 102524"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149212487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oronasal fistula following spontaneous exfoliation of a maxillary third molar in a patient receiving concurrent CPAP therapy: a case report","authors":"Atsushi-Doksa Lee,&nbsp;Yuto Takada,&nbsp;Yuko Kinoshita,&nbsp;Takeshi Shimoide,&nbsp;Sanae Iwasaki,&nbsp;Akifumi Enomoto","doi":"10.1016/j.rmcr.2026.102386","DOIUrl":"10.1016/j.rmcr.2026.102386","url":null,"abstract":"<div><h3>Background</h3><div>Continuous positive airway pressure (CPAP) therapy is the first-line treatment for obstructive sleep apnea (OSA) and is generally considered safe. The reported adverse effects, such as nasal dryness, congestion, and mask-related discomfort, are usually mild and localized. Severe structural complications involving the oral or nasal cavities are exceedingly rare.</div></div><div><h3>Case presentation</h3><div>A 59-year-old man with severe OSA, successfully managed with nasal CPAP therapy for four years, presented with air leakage during CPAP use and nasal regurgitation of fluids while drinking. Two months prior to presentation, spontaneous exfoliation of the left maxillary third molar had occurred, suggesting underlying odontogenic and maxillary pathology. Subsequently, an oronasal fistula developed. Computed tomography revealed a fistulous tract extending from the nasal floor to the posterior maxillary region, accompanied by localized bone defects. Conservative management was unsuccessful, and surgical closure using a local mucoperiosteal flap was performed. Complete symptom resolution was achieved, and CPAP therapy was successfully resumed without recurrence during follow-up.</div></div><div><h3>Conclusion</h3><div>This case describes a rare occurrence of an oronasal fistula as a potential complication following spontaneous exfoliation of a maxillary third molar in a patient receiving concurrent long-term CPAP therapy. While underlying odontogenic and maxillary pathology was considered the primary structural vulnerability, sustained positive airway pressure may have acted as a perpetuating or aggravating factor by interfering with normal wound healing. Clinicians managing patients with long-term CPAP therapy should be aware of potential interactions between positive airway pressure and pre-existing dental or maxillary conditions, underscoring the importance of interdisciplinary collaboration.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"60 ","pages":"Article 102386"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biot's respiratory pattern under mechanical ventilation: Two case reports and literature review","authors":"Hugo Arturo Tirapé-Castro ,&nbsp;Lía Cristina Cajamarca-Sacta ,&nbsp;Fernando Martínez-Arias ,&nbsp;Angélica María Solís-Manzano ,&nbsp;Pablo Gabriel Cevallos Morejón ,&nbsp;Andrés Ruiz-Flores","doi":"10.1016/j.rmcr.2026.102403","DOIUrl":"10.1016/j.rmcr.2026.102403","url":null,"abstract":"<div><h3>Background</h3><div>Biot's breathing, first described in 1876, remains an underrecognized yet clinically relevant marker of pontomedullary dysfunction. In mechanically ventilated patients, its identification through ventilator waveforms provides an objective correlate of central respiratory control failure.</div></div><div><h3>Case presentation</h3><div>We report two elderly female patients admitted to the intensive care unit for acute neurological deterioration, both requiring invasive mechanical ventilation initially delivered in controlled mandatory modes. After sedation withdrawal and transition to spontaneous ventilation, irregular clusters of breaths interspersed with apneic pauses were observed, consistent with Biot's respiratory pattern. In Case 1, neuroimaging showed a large hemispheric ischemic stroke without radiological evidence of brainstem involvement, suggesting a secondary or functional Biot-like pattern. In Case 2, brain MRI confirmed caudal brainstem ischemic involvement, correlating with the classic bulbar form of Biot's breathing. Both patients evolved with poor neurological outcomes.</div></div><div><h3>Conclusion</h3><div>Mechanical ventilation enables objective documentation of Biot's breathing, transforming a historically clinical sign into a quantifiable physiological marker. Early recognition contributes to prognostic assessment and improves understanding of central respiratory control failure.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"61 ","pages":"Article 102403"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147554011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A rare case report of acute respiratory distress syndrome secondary to pulmonary tuberculosis: Review of radiographic findings of pulmonary tuberculosis to enhance diagnosis accuracy","authors":"Kittipadh Boonyavarakul ,&nbsp;Theerawut Wongjeeraphat ,&nbsp;Thitiwat Sriprasart ,&nbsp;Vorakamol Phoophiboon","doi":"10.1016/j.rmcr.2026.102429","DOIUrl":"10.1016/j.rmcr.2026.102429","url":null,"abstract":"<div><h3>Background</h3><div>Tuberculosis (TB) remains a global health concern, with pulmonary involvement accounting for most cases. Acute respiratory distress syndrome (ARDS) is a rare but severe complication of pulmonary TB. We report a rare case of pulmonary TB complicated by ARDS and provide a comprehensive review of characteristic chest imaging findings of pulmonary TB.</div></div><div><h3>Clinical presentations</h3><div>A previously healthy 47-year-old man, presented with acute worsening hypoxemia following 2-week fever, night sweat, productive cough, dyspnea, and weight loss. On emergency room admission, he was tachypneic (respiratory rate 30 breaths/minute, oxygen saturation 80% on room air). Sputum acid-fast bacilli smear, polymerase chain reaction (PCR) and subsequent culture confirmed <em>Mycobacterium tuberculosis</em>. Chest X-ray showed diffuse, reticulonodular infiltrations with multiple cavities at both upper lobes. Chest computerized tomography revealed diffuse, tree-in-bud, centrilobular nodules with areas of consolidation, consistent with active infectious tuberculosis. Despite early anti-TB regimen, the patient developed ARDS with subsequent spontaneous pneumothorax from a ruptured cavity, requiring intensive care unit admission with lung-protective ventilation, prone positioning and chest drain. After 4 weeks of mechanical ventilation and a 2-month hospital stay, he was successfully extubated and discharged without the need of supplemental oxygen.</div></div><div><h3>Conclusions</h3><div>This case highlights ARDS secondary to pulmonary TB, an uncommon and highly complicated manifestations of pulmonary TB. Recognition of clinical manifestations combined with radiographic findings including patterns and lesion distribution can facilitate a more robust diagnosis and prompt patient isolation.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"61 ","pages":"Article 102429"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147859027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Delayed-onset portopulmonary hypertension following liver transplantation with near hemodynamic normalization on triple therapy","authors":"Maie Abdullah ,&nbsp;Stephen Roche ,&nbsp;John Mwangi ,&nbsp;Liam Arnold","doi":"10.1016/j.rmcr.2026.102439","DOIUrl":"10.1016/j.rmcr.2026.102439","url":null,"abstract":"<div><div>Portopulmonary hypertension (PoPH) is a distinct subtype of pulmonary arterial hypertension (PAH) occurring in the setting of portal hypertension. Although liver transplantation (LT) may relieve portal pressure, pulmonary vascular remodeling can persist or, rarely, develop de novo after transplantation, posing diagnostic and therapeutic challenges.</div><div>Delayed-onset PoPH after LT remains poorly characterized, with limited data to guide recognition and management.</div><div>We describe a case of a 67-year-old male who developed severe PoPH three years after orthotopic LT for end-stage liver disease secondary to alcohol use and metabolic dysfunction– associated steatotic liver disease (MASLD). He presented with hypoxic respiratory failure, dyspnea, and volume overload. Echocardiography and right-heart catheterization (RHC) confirmed severe precapillary pulmonary hypertension. Combination therapy with intravenous epoprostenol, macitentan, and sildenafil resulted in marked hemodynamic and clinical improvement. He was subsequently transitioned from intravenous epoprostenol to oral selexipag and has maintained near-normal pulmonary pressures for two years. This case highlights delayed post-LT PoPH and demonstrates that even late-presenting disease may achieve substantial hemodynamic improvement with aggressive, guideline-directed PAH therapy.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"62 ","pages":"Article 102439"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148231666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Xanthomatous pleuritis in a child with recurrent pneumonia and patent ductus arteriosus: A rare pediatric case report and literature review","authors":"Seyedeh Zalfa Modarresi,&nbsp;Atossa Madanipour,&nbsp;Fariba Binesh,&nbsp;Somayeh Talaeepour,&nbsp;Mahla Towhidifar","doi":"10.1016/j.rmcr.2026.102445","DOIUrl":"10.1016/j.rmcr.2026.102445","url":null,"abstract":"<div><h3>Background</h3><div>Xanthomatous pleuritis is an exceptionally rare benign inflammatory condition characterized by aggregates of lipid-laden macrophages within the pleura. To the best of our knowledge, only three adult cases have been reported worldwide, associated with chronic pleural inflammation or infection. Pediatric pleural xanthomas are exceedingly uncommon, and xanthomatous pleuritis has not been previously reported in a child.</div></div><div><h3>Case presentation</h3><div>We report a 3.5-year-old girl with recurrent pneumonia, chronic respiratory symptoms, and Failure to Thrive (FTT). Chest X ray (CXR) revealed cardiomegaly and subpleural nodules, followed by high resolution Computed Tomography scan (CT scan) showing patchy right-sided consolidation, mild pleural thickening, subpleural nodules and loculated effusion. Diagnostic thoracentesis was performed; however, only a minimal amount of loculated fluid was obtained.</div><div>CT-guided biopsy of a pleural-based nodule demonstrated numerous lipid-laden (foamy) macrophages with scattered multinucleated histiocytes, without granuloma or malignancy, supporting the diagnosis of xanthomatous pleuritis.</div><div>Further evaluations for tuberculosis, cystic fibrosis, and primary immunodeficiency were negative. Echocardiography identified a patent ductus arteriosus (PDA). The child improved clinically with intravenous (IV) broad-spectrum antibiotics and then after Amoxicillin-Clavulanate therapy. She later underwent successful PDA closure.</div></div><div><h3>Conclusion</h3><div>To the best of our knowledge, this case represents the first pediatric case with xanthomatous pleuritis described in the literature and emphasizes the importance of histopathologic evaluation in children with unexplained recurrent pulmonary disease.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"62 ","pages":"Article 102445"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13316216/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148363840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pulmonary coexistence of immunoglobulin light chain amyloidosis and light chain deposition disease: A case report","authors":"Yasushi Murakami,&nbsp;Makoto Goshima,&nbsp;Mitsuki Tanimoto,&nbsp;Naoto Kobayashi,&nbsp;Atsushi Sumida,&nbsp;Reo Kondo,&nbsp;Shoichi Mori,&nbsp;Ayami Kiriyama,&nbsp;Hideki Murakami,&nbsp;Kai Miyazaki,&nbsp;Yukako Shintani-Domoto","doi":"10.1016/j.rmcr.2026.102457","DOIUrl":"10.1016/j.rmcr.2026.102457","url":null,"abstract":"<div><div>We report the case of a 73-year-old woman with diffuse pulmonary cysts and multiple nodules incidentally detected during the follow-up for chronic liver disease. High-resolution computed tomography revealed numerous thin-walled cysts, predominantly in the lower lobes, with randomly distributed nodules. Pathological evaluation of the surgical lung biopsy specimens revealed nodular deposits of eosinophilic, amorphous material with peribronchiolar lymphoplasmacytic inflammation and identified pulmonary mucosa-associated lymphoid tissue lymphoma. Congo red staining revealed coexisting positive and negative foci within a single nodule, whereas immunohistochemistry showed kappa (κ) light chain positivity in both. Laser microdissection with liquid chromatography-tandem mass spectrometry identified a κ light chain dominant signature with amyloid signature proteins in the Congo red-positive region, consistent with immunoglobulin light chain amyloidosis (AL) κ-type, and abundant κ light chain peptides without amyloid signature proteins in the Congo red-negative region, consistent with non-amyloid κ light chain deposition. Systemic evaluation revealed no extrapulmonary amyloid or light-chain deposition, whereas Sjögren disease was confirmed by serological testing and minor salivary gland histology. The patient was managed conservatively with surveillance and remained clinically and radiographically stable without disease progression for approximately 1 year. Pulmonary AL and light-chain deposition are rare lung disorders, and pathologically proven pulmonary coexistence is rare. This case may help delineate the clinicopathological features of pulmonary monoclonal light chain deposition disorders.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"63 ","pages":"Article 102457"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13351146/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148425819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Primary poorly differentiated enteric-type adenocarcinoma of the thymus with characteristic intracytoplasmic vacuoles on cytology","authors":"Mitsuhiro Tachibana ,&nbsp;Takayoshi Hirota ,&nbsp;Masahiro Uehara ,&nbsp;Kei Tsukamoto ,&nbsp;Rei Ishikawa ,&nbsp;Takashi Tsuchida","doi":"10.1016/j.rmcr.2025.102361","DOIUrl":"10.1016/j.rmcr.2025.102361","url":null,"abstract":"<div><div>Primary thymic enteric-type adenocarcinomas are exceedingly rare. This rare case highlights the significance of intracytoplasmic vacuoles (ICVs) as a cytologic marker for primary enteric-type adenocarcinoma of the thymus. We present a case of a 62-year-old Japanese man who experienced progressive dyspnea for two months. Chest computed tomography (CT) revealed a 66 × 65 × 50-mm irregular mass in the right anterior mediastinum. Both CT-guided biopsy and needle-washing cytology were performed. Papanicolaou-stained specimens showed atypical cells with a high nuclear-cytoplasmic (N/C) ratio, bare nuclei on a hemorrhagic background, and small nucleoli with mild nuclear atypia, lacking glandular, luminal, or papillary structures. Giemsa-stained specimens revealed ICVs. Histological examination showed atypical cells arranged in solid nests. Immunohistochemical profiling showed CEA (+), CD5 (+), cytokeratin (CK) 7 (+), CK20 (+), adipophilin (+), CDX2 (−), TTF-1(−), p40 (−), and CD117 (KIT) (−). On the final diagnosis was poorly differentiated enteric-type adenocarcinoma, classified as cT3N2M0, cStage IVb. After neoadjuvant chemotherapy, the patient underwent surgical resection at Hamamatsu University Hospital in Japan. Postoperative findings revealed poorly differentiated adenocarcinoma with treatment-induced changes, measuring 60 × 50 × 40 mm, and classified as ypT3N0M0, with lymphovascular invasion. Despite adjuvant chemoradiotherapy, metastases developed 26 months postoperatively. The ICVs are immunoreactive for adipophilin and are therefore considered to represent lipid vacuoles. Identifying tumor cells with ICVs in cytology specimens and immunocytochemistry for CK7, CK20, CD5, p40, CDX2, MUC2, KIT, adipophilin, and CEA may be useful for diagnosis.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"59 ","pages":"Article 102361"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cavitary pulmonary metastasis from renal pelvic urothelial carcinoma with pathological evidence of bronchiolar obstruction supporting a check-valve mechanism: a case report","authors":"Kei Nakano ,&nbsp;Tomoki Nakagawa ,&nbsp;Haruka Kishi ,&nbsp;Shota Fujino ,&nbsp;Takashi Ishihara ,&nbsp;Masaya Ohara ,&nbsp;Kazuhiro Matsuo ,&nbsp;Tomoki Higeta ,&nbsp;Kie Maita ,&nbsp;Hirohito Kobayashi ,&nbsp;Masatoshi Yamada ,&nbsp;Ryota Masuda","doi":"10.1016/j.rmcr.2026.102431","DOIUrl":"10.1016/j.rmcr.2026.102431","url":null,"abstract":"<div><div>Approximately 4% of metastatic lung tumors exhibit cavitation. Cavitary pulmonary metastases arising from urothelial carcinoma are rare. Renal pelvic cancer accounts for only 3%–5% of all urothelial carcinomas; cavitary pulmonary metastasis from renal pelvic cancer is rare. This report describes pulmonary metastasis from renal pelvic cancer with cavitation. A man in his 50s underwent laparoscopic left nephroureterectomy with hilar lymph node dissection for left renal pelvic cancer 2 years earlier. During follow-up, chest computed tomography (CT) revealed a gradually enlarging lesion with internal cavitation in the right lower lobe. Chest CT demonstrated a 17-mm cavitary nodule in segment 7 of the right lung, enlarged from 4 mm over 1 year. Cavitation was evident even when the lesion was small; tumor diameter and cavity size also increased. The cavity wall remained thin, measuring 1.5 mm in most areas, up to 4 mm, without progressive thickening. Given the rarity of cavitary metastasis from renal pelvic cancer, a surgical biopsy was performed. Thoracoscopic wedge resection revealed a nodular lesion with a grayish-white cavity. Immunohistochemical staining demonstrated GATA3 positivity, confirming pulmonary metastasis. Microscopically, the tumor proliferated while destroying the lung architecture, with small tumor cell clusters within the alveolar spaces. Tumor extension into a bronchiole lacking cartilage resulted in partial luminal obstruction. Here, radiological progression and pathological findings supported cavity formation via a check-valve mechanism. This case provides radiological and pathological evidence supporting a check-valve mechanism of cavitation in pulmonary metastasis and contributes to the differential diagnosis of thin-walled cavitary pulmonary nodules.</div></div>","PeriodicalId":51565,"journal":{"name":"Respiratory Medicine Case Reports","volume":"62 ","pages":"Article 102431"},"PeriodicalIF":0.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147946681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}