Case Reports in Oncology最新文献

{"title":"Pembrolizumab plus Lenvatinib for Postoperative Recurrent <i>TFEB</i>-Amplified Renal Cell Carcinoma: A Case Report.","authors":"Shunya Ishikawa, Hiromichi Katayama, Juntaro Koyama, Takuro Goto, Tomonori Sato, Yohei Satake, Takuma Sato, Yoshihide Kawasaki, Naoki Kawamorita, Hirofumi Watanabe, Fumiyoshi Kojima, Akihiro Ito","doi":"10.1159/000552853","DOIUrl":"10.1159/000552853","url":null,"abstract":"<p><strong>Introduction: </strong>Transcription factor EB (<i>TFEB</i>)-amplified renal cell carcinoma (RCC) is a molecularly defined subtype, newly recognized in the 2022 World Health Organization classification. Diagnosis is challenging because conventional morphologic and immunohistochemical findings are often insufficient, and confirmation typically requires fluorescence in situ hybridization (FISH) or RNA sequencing. This entity is extremely rare and has been associated with an unfavorable prognosis. No standard systemic therapy has been established.</p><p><strong>Case presentation: </strong>A 67-year-old man presented with gross hematuria and was diagnosed with left RCC with a renal vein tumor thrombus (cT3aN0M0). He underwent radical nephrectomy. Histopathology showed proliferation of atypical cells with pale eosinophilic or clear cytoplasm, while immunohistochemical findings were inconclusive. Partial positivity for Melan-A prompted further evaluation. FISH analysis confirmed <i>TFEB</i> amplification, establishing the diagnosis of <i>TFEB</i>-amplified RCC. No recurrence was detected 3 months postoperatively; however, intra-abdominal recurrence developed at 6 months. Given the non-clear cell histology and poor-risk classification according to the International Metastatic Renal Cell Carcinoma Database Consortium criteria, pembrolizumab plus lenvatinib was initiated. Comprehensive genomic profiling revealed a high tumor mutational burden and amplification of vascular endothelial growth factor A (<i>VEGFA</i>) and other genes located in the 6p21 region, supporting the molecular diagnosis. Partial response was achieved 2 months posttreatment, with a complete response confirmed 1 year later. The patient remains on combination therapy with pembrolizumab and lenvatinib, with dose adjustment of lenvatinib.</p><p><strong>Conclusion: </strong>Pembrolizumab plus lenvatinib demonstrated clinical efficacy in postoperative recurrent <i>TFEB</i>-amplified RCC. Combination therapy incorporating immune checkpoint inhibition and VEGF-targeted treatment may represent a therapeutic option for this entity.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"989-997"},"PeriodicalIF":0.7,"publicationDate":"2026-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13399957/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148583713","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":"Chronic Cavitary Pulmonary Metastases Mimicking Infection in Epithelioid Sarcoma: A Case Report.","authors":"Yudai Murayama, Makoto Abe, Hirokazu Ideta, Rumi Nakagawa, Koichi Inoue, Eisuke Miura, Kaoru Hirabayashi, Takehiko Yamaguchi, Hiroyuki Kawashima, Kazutaka Kikuta","doi":"10.1159/000552335","DOIUrl":"10.1159/000552335","url":null,"abstract":"<p><strong>Introduction: </strong>Epithelioid sarcoma is a rare soft tissue malignancy with a high propensity for local recurrence and distant metastasis, usually to the lungs. Pulmonary metastases typically appear as solid nodules, whereas cavitary pulmonary metastases are exceptionally rare and may closely mimic infectious lung disease.</p><p><strong>Case presentation: </strong>Herein, we report the case of a woman diagnosed with epithelioid sarcoma of the foot at 26 years of age. She developed slowly progressive cavitary pulmonary lesions more than a decade after initial treatment. During long-term follow-up without adjuvant therapy, small pulmonary nodules gradually evolved into cavitary lesions, raising strong suspicion for tuberculosis or fungal infection rather than metastatic disease. Video-assisted thoracic surgery was performed for definitive diagnosis and treatment, and histopathological examination confirmed metastatic epithelioid sarcoma.</p><p><strong>Conclusion: </strong>This case underscores the fact that epithelioid sarcoma can present as a chronic cavitary pulmonary disease that mimics infection. Clinicians should consider metastatic disease in the differential diagnoses of cavitary lung lesions in patients with a history of this malignancy.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"978-983"},"PeriodicalIF":0.7,"publicationDate":"2026-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13399961/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148583733","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":"Diffuse Amelanotic Choroidal Melanoma Mimicking Mushrooming Melanocytic Melanoma and Choroidal Metastasis in a Patient with Dual Primary Malignancies: A Case Report.","authors":"Jose Cijin Puthussery, Matthew C Hagen, Christopher D Riemann, Zeynep Gursel","doi":"10.1159/000552701","DOIUrl":"10.1159/000552701","url":null,"abstract":"<p><strong>Introduction: </strong>Choroidal melanoma is the most common primary intraocular malignancy in adults, whereas ocular metastases are the most frequent overall intraocular tumors. Diffuse amelanotic choroidal melanomas are rare and may mimic metastatic lesions, particularly in patients with known systemic malignancies. Optic nerve invasion is an uncommon but clinically significant feature of advanced melanoma.</p><p><strong>Case presentation: </strong>We report an 82-year-old male with a history of recurrent cutaneous melanoma and stage III rectal carcinoma who presented with progressive vision loss in the right eye. Fundus examination revealed a peripapillary elevated hemorrhagic mass and a flat tan choroidal lesion. Multimodal imaging suggested a differential diagnosis of choroidal metastasis versus melanoma. Intraocular biopsy confirmed diffuse amelanotic choroidal melanoma. Enucleation revealed mixed cell-type melanoma with optic nerve invasion and extrascleral extension. The patient later developed systemic metastasis from the ocular melanoma.</p><p><strong>Conclusion: </strong>Diffuse amelanotic choroidal melanoma can closely mimic metastatic disease, especially in patients with known primary cancers. Intraocular biopsy remains essential for definitive diagnosis in ambiguous cases and guides appropriate oncologic management.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"998-1004"},"PeriodicalIF":0.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13399952/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148583698","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":"Tumor-Related Pericardial and Myocardial Infiltration in Diffuse Large B-Cell Lymphoma Presenting as an ST-Elevation Myocardial Infarction Mimic: A Case Report.","authors":"Zhandos Burkitbayev, Ainur Bilmakhanbetova, Aliya Omarbek, Kulshat Aidarbekova, Assel Zhumabekova, Aigerim Tanyrbergenova, Bairam Kochiev, Alexandr Kolesnev","doi":"10.1159/000550935","DOIUrl":"10.1159/000550935","url":null,"abstract":"<p><strong>Background: </strong>Cardiac involvement in diffuse large B-cell lymphoma (DLBCL) is rare and often underrecognized. Concurrent pericardial and myocardial infiltration can mimic acute myocardial infarction on electrocardiography, posing diagnostic challenges.</p><p><strong>Case presentation: </strong>We present a 64-year-old female with biopsy-confirmed DLBCL who developed acute respiratory symptoms and electrocardiographic changes mimicking ST-elevation myocardial infarction (STEMI). Multimodal imaging revealed a large pericardial effusion, myocardial infiltration, and no obstructive coronary disease. Despite chemotherapy and supportive care, the patient succumbed to cardiopulmonary failure.</p><p><strong>Conclusion: </strong>This case highlights a rare manifestation of lymphoma-associated cardio-infiltration presenting as STEMI mimic. Early multidisciplinary evaluation is essential to differentiate pseudo-infarction syndromes and prevent unnecessary invasive interventions.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"758-766"},"PeriodicalIF":0.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13282105/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148293481","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":"Olfactory Groove Meningioma Detected 10 Months after Cranial Radiotherapy in a Metastatic Ewing Sarcoma Survivor: A Case Report.","authors":"Ahmad M Al Malla, Ahmad Al-Bitar, Anas Bitar, Maher Saifo","doi":"10.1159/000552787","DOIUrl":"10.1159/000552787","url":null,"abstract":"<p><strong>Introduction: </strong>Secondary intracranial neoplasms are a well-recognized late complication of cranial radiotherapy. Among these, meningiomas are the most frequently reported radiation-associated tumors. However, olfactory groove meningiomas (OGMs) are uncommon, and their development after cranial irradiation with a very short latency remains exceptionally rare.</p><p><strong>Case presentation: </strong>A 38-year-old woman with Ewing sarcoma of the right thigh and brain metastases underwent multimodal treatment of surgical resection, VDC-IE chemotherapy, and subsequent cranial radiotherapy (54 Gy in 27 fractions). Retrospective review of pre-radiotherapy brain MRI showed no lesion in the olfactory groove region. Ten months after completing treatment, she presented with progressive headache, recurrent vomiting, and generalized seizures. Brain CT and MRI revealed a well-circumscribed, homogeneously enhancing extra-axial mass centered at the olfactory groove, with dural attachment and compression of the frontal lobes. Gross-total microsurgical resection was achieved through a right-sided pterional craniotomy. Histopathological examination confirmed a WHO grade I meningioma with diffuse SSTR2A expression, focal epithelial membrane antigen positivity, and a Ki-67 labeling index of 2%-3%. Immunohistochemistry was negative for CD99 and FLI1, excluding metastatic Ewing sarcoma. The postoperative course was uneventful, and follow-up imaging at 1 year showed no evidence of recurrence.</p><p><strong>Conclusion: </strong>This case highlights a rare early-onset OGM arising after cranial radiotherapy in a metastatic Ewing sarcoma survivor. Although the unusually short latency interval precludes definitive causal attribution, the temporal association, absence of a preexisting lesion on pre-radiotherapy imaging, and distinct histopathological profile support consideration of a radiation-associated origin. Long-term neuro-oncologic surveillance remains essential in patients treated with cranial irradiation.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"969-977"},"PeriodicalIF":0.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13395415/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148577060","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":"Efficacy of Pazopanib for a Patient with <i>FGFR1</i>-Amplified Breast Cancer: A Case Report.","authors":"Yurina Ochiai, Saori Hayashi, Emiko Hiraoka, Takafumi Morisaki, Yoshiki Otsubo, Chiaki Nakahara, Yo Sato, Kimihisa Mizoguchi, Yuichi Hisamatsu, Mamoru Ito, Eishi Baba, Natsuko Okita, Makoto Kubo","doi":"10.1159/000552744","DOIUrl":"10.1159/000552744","url":null,"abstract":"<p><strong>Introduction: </strong>Fibroblast growth factor receptor 1 (<i>FGFR1</i>) amplification is associated with endocrine therapy resistance and a poor prognosis in hormone receptor-positive breast cancer. However, effective therapeutic options for <i>FGFR1</i> amplification remain limited. We report a patient with metastatic breast cancer who was treated with pazopanib for <i>FGFR1</i> amplification in the BELIEVE trial.</p><p><strong>Case presentation: </strong>A 71-year-old woman was diagnosed with bilateral luminal-HER2 type breast cancer (pT2N1M0) 18 years previously, and underwent bilateral mastectomy and axillary lymph nodes dissection followed by adjuvant therapy. She had no family history. She developed bone and liver metastases 4 years after the operation and her condition became worse, despite multiple lines of endocrine and cytotoxic therapies. She was treated with pazopanib under the trial because comprehensive genomic profiling showed <i>FGFR1</i> amplification. After 3 months, computed tomography demonstrated necrosis and shrinkage of liver metastases, consistent with a partial response. Serum tumor markers (CEA and CA15-3) showed a sustained decline, reaching their lowest levels at approximately 5 months, consistent with radiologic response. Treatment was continued for 8 months until tumor markers increased and imaging revealed disease progression. Adverse events were manageable.</p><p><strong>Conclusion: </strong>Pazopanib is likely to have a clinical benefit for patients with <i>FGFR1</i>-amplified breast cancer using genomic profiling in personalized oncology at the early stage of metastasis.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"1029-1034"},"PeriodicalIF":0.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13412246/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148618434","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":"Long-Segment Malignant Tracheal Stenosis from Recurrent Medullary Thyroid Carcinoma Successfully Palliated with a Covered Self-Expanding Metallic Stent: A Case Report.","authors":"Mohammad Alaa Aldakak, Yousef Al Jabban, Mohammad Shbat, Mohammad Ali Makki, Ahmed Nabhan, Bassam Darwish","doi":"10.1159/000552789","DOIUrl":"10.1159/000552789","url":null,"abstract":"<p><strong>Background: </strong>Medullary thyroid carcinoma (MTC) may rarely cause malignant central airway obstruction (MCAO) through locoregional tracheal invasion, requiring urgent multidisciplinary management. In unresectable thyroid cancer-related MCAO, interventional bronchoscopy with airway stenting can provide rapid restoration of airway patency and symptomatic palliation.</p><p><strong>Case presentation: </strong>A 58-year-old nonsmoking woman with a history of MTC treated with total thyroidectomy and adjuvant radiotherapy presented with progressive exertional dyspnea, productive cough, intermittent mild stridor, and recurrent respiratory infections. She was tachycardic and tachypneic but maintained oxygen saturation on room air. Physical examination revealed a firm, fixed mass in the thyroid bed region. Laboratory investigations showed mild anemia and thrombocytosis. Computed tomography demonstrated approximately 5 cm of tracheal involvement with critical luminal narrowing, consistent with malignant tracheal stenosis from suspected locoregional recurrence. Tracheal biopsy revealed high-grade carcinoma considered clinically compatible with recurrence, although immunohistochemistry and RET mutation testing were unavailable. The disease was deemed unresectable due to local invasion involving the trachea and carotid sheath. Because systemic targeted therapy was not locally available, urgent airway palliation was prioritized. A covered self-expanding metallic tracheobronchial stent was placed successfully across the stenotic segment, resulting in meaningful improvement in breathing and phonation.</p><p><strong>Conclusion: </strong>Covered metallic airway stenting is an effective palliative option for long-segment unresectable malignant tracheal stenosis caused by recurrent MTC, particularly when systemic targeted therapy is unavailable and rapid airway stabilization is required.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"926-932"},"PeriodicalIF":0.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13363140/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148435164","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":"Sustained Disease Control of High-Risk Metastatic Renal Epithelioid Angiomyolipoma through Multimodal Treatment Including Repeated Thoracic Resection and Systemic Therapy: A Case Report.","authors":"Seiji Omura, Jun Hagiuda, Naoko Izawa, Aya Sasaki, Ken Nakagawa, Keisuke Eguchi","doi":"10.1159/000552721","DOIUrl":"10.1159/000552721","url":null,"abstract":"<p><strong>Introduction: </strong>Renal epithelioid angiomyolipoma (EAML) is a rare perivascular epithelioid cell tumor with malignant potential. Radiologic distinction from renal cell carcinoma (RCC) may be difficult in fat-poor cases, and standardized treatment strategies for metastatic disease have not been established.</p><p><strong>Case presentation: </strong>A woman in her 30 s presented with a palpable right abdominal mass and anorexia. Contrast-enhanced computed tomography showed an 18-cm heterogeneous right renal mass and a 25-mm liver lesion suspicious for metastasis, without pulmonary metastasis at diagnosis. The pretreatment clinical stage was cT2bN0M1, stage IV. Imaging findings strongly suggested clear cell RCC, and the lesion was managed as presumed metastatic clear cell RCC. The International Metastatic RCC Database Consortium risk category was poor risk. Nivolumab plus cabozantinib was initiated without pretreatment biopsy. At Month 3, the primary tumor showed partial response and the liver lesion remained stable; however, cabozantinib became difficult to continue because of adverse effects, and right nephrectomy was performed in a setting analogous to deferred cytoreductive nephrectomy. Histopathology established renal EAML with pT2b disease, necrosis, mitotic count ≥2, atypical mitoses, severe nuclear atypia, smooth muscle actin negativity, and Ki-67 ≥ 10%, fulfilling six of seven adverse prognostic factors and indicating high-risk disease. Everolimus induced partial response of a new lung metastasis. Subsequent liver and bilateral lung metastases were managed with systemic therapy and staged thoracoscopic resections. Later, isolated subcarinal mediastinal lymph node progression was treated by thoracoscopic resection. The patient remains recurrence-free for 8 months on everolimus.</p><p><strong>Conclusion: </strong>Metastatic renal EAML lacks a standardized treatment strategy. This case suggests that durable disease control may be achievable in selected high-risk patients through individualized multimodal treatment integrating systemic therapy with repeated local treatment for thoracic oligoprogressive lesions.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"918-925"},"PeriodicalIF":0.7,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13363133/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148435258","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":"Disguised Within: Ectopic Intrathyroidal Parathyroid - A Case Report.","authors":"Chun He, Zhaofei Zeng, Yun Peng, Xianhua Zhuo","doi":"10.1159/000552718","DOIUrl":"10.1159/000552718","url":null,"abstract":"<p><strong>Introduction: </strong>Secondary hyperparathyroidism is prevalent among individuals with chronic kidney failure and is frequently associated with the occurrence of one or more instances of parathyroid hyperplasia. The presence of ectopic parathyroid glands poses significant challenges for the diagnosis and management of affected patients. Intra-adenomatous ectopic parathyroid glands are exceedingly rare, and their preoperative diagnosis using conventional methods is challenging.</p><p><strong>Case presentation: </strong>In this paper, we present a case of a 32-year-old male patient who underwent surgical treatment for secondary hyperparathyroidism. During the operation, an ectopic intrathyroidal parathyroid adenoma was found to mimicked a thyroid nodule. We analyzed the clinical characteristics of these patients and proposed precautions and treatment plans by a comprehensive literature review and analysis.</p><p><strong>Conclusion: </strong>The findings offer valuable insights for the diagnosis and treatment of similar cases and aim to enhance clinicians' understanding of this condition.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"911-917"},"PeriodicalIF":0.7,"publicationDate":"2026-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13363137/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148435119","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":"Thyroid Dysfunction Induced by Pembrolizumab: Five Case Reports.","authors":"Tingting Zhang, Jing Li, Junru Cai, Xiang Li, Lu Lin","doi":"10.1159/000552474","DOIUrl":"10.1159/000552474","url":null,"abstract":"<p><strong>Introduction: </strong>Although pembrolizumab, as a programmed cell death receptor-1 (PD-1) inhibitor, has revolutionized cancer therapy, it is frequently accompanied by immune-related adverse events. Thyroid dysfunction represents a common irAE, yet its clinical trajectory, optimal management approaches, and long-term outcomes remain incompletely characterized.</p><p><strong>Case presentation: </strong>We conducted a retrospective analysis of 5 cancer patients who developed thyroid dysfunction following pembrolizumab therapy. All patients ultimately progressed to hypothyroidism, manifesting heterogeneous patterns: biphasic thyroid dysfunction, persistent hypothyroidism, and delayed presentation after treatment cessation. Patients with baseline positivity for thyroid antibodies (thyroglobulin/thyroid peroxidase antibodies) and elevated thyrotropin levels demonstrated higher susceptibility to severe hypothyroidism. Longitudinal follow-up revealed that thyroid function achieved stabilization following early initiation of hormone replacement therapy, whereas delayed intervention was associated with increased requirements for hormone dose titration.</p><p><strong>Conclusion: </strong>Thyroid dysfunction induced by pembrolizumab is characterized by diverse clinical manifestations and heterogeneous timing of onset. Combination regimens and baseline thyroid status may be significantly associated with its course. Re-treatment risk assessment and dynamic monitoring during therapy should be strengthened in clinical practice as early intervention may improve patient outcomes.</p>","PeriodicalId":9625,"journal":{"name":"Case Reports in Oncology","volume":"19 1","pages":"933-942"},"PeriodicalIF":0.7,"publicationDate":"2026-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13363141/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148435256","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}