PIK3CA mutations associated with a poor postoperative prognosis in patients with pulmonary pleomorphic carcinoma: a retrospective cohort study.

BACKGROUND: Pulmonary pleomorphic carcinoma (PPC) is a rare type of non-small cell lung cancer characterized by high malignancy and a poor prognosis. PPC is associated with a high frequency of postoperative relapse, and shows resistance to chemotherapy. The high malignancy of cancers is associated with genomic instability, which is related to mutations of tumor suppressor genes, such as tumor protein p53 (TP53) and ataxia-telangiectasia mutated (ATM). In addition, signaling pathways involving the oncogenes such as phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) and epidermal growth factor receptor (EGFR) are associated with resistance to chemotherapy. However, the association of PPC with these gene mutations remains unknown. We investigated the impact of TP53, ATM, PIK3CA, and EGFR mutations on the postoperative prognosis of PPC. METHODS: Fifty-five patients with PPC who underwent complete resection were studied. A gene mutation analysis was performed using next-generation sequencing. Postoperative overall survival of patients with gene mutations was evaluated using a multivariable Cox proportional hazards model in which the explanatory variables were the presence of each gene mutation, and the confounding factors were pathological stage and age. The robustness of the results was evaluated by a sensitivity analysis. RESULTS: The frequencies of pathogenic mutations in TP53, ATM, PIK3CA, and EGFR were 47, 0, 7, and 9%, respectively. A multivariable analysis adjusted for pathological stage and age showed a significant difference for only PIK3CA mutations. The hazard ratio (HR) for overall survival in cases with pathogenic mutations of PIK3CA for wild type or non-pathogenic mutations was 4.5 (95% confidence interval [CI] 1.1-18.8). Likewise, sensitivity analyses adjusted for pathological stage and sex (HR, 7.5; 95% CI 1.7-32.4) and for age and sex (HR, 5.4; 95% CI 1.4-21.7) resulted in similar findings. Although three patients with pathogenic mutations of PIK3CA that recurred postoperatively were treated by chemotherapy or immunotherapy, they survived for less than 2 years. CONCLUSIONS: The postoperative prognosis of PPC with PIK3CA pathogenic mutations is particularly poor. Pathogenic mutations of PIK3CA may be a postoperative prognostic marker. Inhibition of signaling pathways associated with PIK3CA mutations may also be a target for chemotherapy after relapse of PPC.

High programmed death ligand 1 expression in carcinomatous components predicts a poor prognosis in pulmonary pleomorphic carcinoma.

PURPOSE: This study reviewed the clinicopathological characteristics and programmed death ligand 1 (PD-L1) expression of 46 patients with pulmonary pleomorphic carcinoma to better understand its clinical behavior and factors affecting the survival. METHODS: Data of patients with pulmonary pleomorphic carcinomas resected in our institution were retrospectively reviewed. The tumors were classified as carcinomatous or sarcomatous according to the tissue components. Pathological characteristics were evaluated on hematoxylin and eosin-stained sections. The percentages of tumor cells with membrane staining for PD-L1 in carcinomatous and sarcomatous components were determined. RESULTS: We reviewed data of 46 patients (41 males, 5 females; median age 70.5 years old, range 36-83 years old). Most patients with pulmonary pleomorphic carcinoma expressed PD-L1 (80.4%), and the proportion of PD-L1 expression in tumor cells was significantly higher in sarcomatous components than in carcinomatous components. In univariable analyses, high p-stage (III), necrosis on pathological findings, and high PD-L1 expression in carcinomatous components (≥ 50%) were poor prognostic factors for the overall survival. In multivariable analyses, high PD-L1 expression in carcinomatous components was significantly associated with a poor prognosis after surgery. CONCLUSIONS: High PD-L1 expression in carcinomatous components was significantly associated with a poor prognosis after surgery.

Pulmonary Pleomorphic Carcinoma Harboring EGFR Mutation Successfully Treated with Osimertinib: A Case Report.

Pulmonary pleomorphic carcinoma (PPC) is well-known for its aggressive nature that is usually resistant to platinum-based chemotherapy. On the other hand, the efficacy of an immune checkpoint inhibitor-based regimen in PPC has been elucidated. PPCs harboring epidermal growth factor receptor (EGFR) mutations are extremely rare, and the efficacy of EGFR-tyrosine kinase inhibitors in PPC is limited compared to their efficacy in EGFR-mutated adenocarcinoma. A 43-year-old female patient presenting with a lung mass with multiple brain metastases, carcinomatous pericarditis, and multiple bone metastases was referred to our department. Transbronchial biopsy confirmed the diagnosis of PPC harboring an EGFR mutation with exon 19 deletion. Subsequently, she was treated with osimertinib, a third-generation EGFR-tyrosine kinase inhibitor, which resulted in partial response with shrinkage of the primary lesion and brain metastases. This partial response remained durable for 11 months with an ongoing regimen. The current case suggests that osimertinib would show promising effects as a first-line treatment for PPCs harboring EGFR mutations, as well as a reasonable sequence of therapy followed by immune checkpoint inhibitor-based regimens.

Programmed death-ligand 1 (PD-L1) expression in pleomorphic carcinoma of the lung.

BACKGROUND AND OBJECTIVES: Pulmonary pleomorphic carcinoma (PPC) is a rare and aggressive subtype of lung cancer. Programmed cell death-ligand 1 (PD-L1) expression may be induced in a variety of malignant tumors, but its prognostic implication in PPC remains unclear. METHODS: Twenty-six patients with surgically resected PPC were retrospectively reviewed. Immuno-histochemical staining was used to detect PD-L1 expression, and PD-L1 status was classified into "high" or "low" according to the percentage of tumor cells (TCs) expressing PD-L1 (tumor proportion score, TPS). RESULTS: PD-L1 expression was positive in 20 (76.9%) patients at the cut-off TPS value of 1%. A receiver-operating characteristic (ROC) analysis showed that the optimal cut-off value was 15% for prediction of cancer-specific death with the area under ROC curve of 0.701 (P = 0.107). High PD-L1 expression was associated with a favorable overall survival (88.9% vs 37.5% at 5 years; P =.046) as well as a favorable cancer-specific (100% vs 45.9% at 5 years; P =.012). A multivariate analysis indicated a trend toward a favorable prognosis associated with high PD-L1 expression (hazard ratio [HR], 0.254 [95% confidence interval, 0.054-1.200]; P = 0.084). CONCLUSIONS: PD-L1 expression was positive in most PPC cases, and high PD-L1 expression may predict a favorable prognosis in resected PPC.

EGFR and KRAS mutations in pulmonary pleomorphic carcinoma and their correlation with clinicopathologic features.

AIM OF THE STUDY: Pulmonary pleomorphic carcinoma (PPC) of the lung is a subset of poorly differentiated non-small cell lung cancers (NSCLCs). Because of its rarity, information on epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene (KRAS) mutations is controversial and sparse. The aim was to investigate the two key oncogenes' characteristics and their correlation with clinical variables. MATERIAL AND METHODS: We retrospectively screened 110 paraffin-embedded surgically resected specimens from patients with PPC. Of these, follow-up information was available for 48 patients. We then successfully analyzed 70 PPC samples and examined EGFR and KRAS mutation status by direct sequencing. The findings were correlated with a control group of patients with other NSCLCs. RESULTS: In our department, PPC comprised about 1.57% of surgical resected cases (110/6990). 37.4% of patients smoked. EGFR mutations were detected in 11 cases (15.7%), with a significantly higher frequency in women than men (p = 0.011). KRAS mutations were detected in 10 cases (14.3%) and were more often found at age 65 or older (p = 0.02). Of interest, in PPC, all KRAS mutations occurred in never smokers. Also, most never smokers have transversion mutations (G→T) in PPCs and other NSCLCs. CONCLUSIONS: Our results demonstrated a similar EGFR and KRAS mutation rate in Chinese PPC patients. EGFR tyrosine kinase inhibitors may be a treatment option for PPCs with EGFR mutations. Of note, EGFR mutations in PPC were commonly identified in women; therefore women should be high-priority candidates for mutation screening.

A rare case of allergic bronchopulmonary mycosis complicating pulmonary pleomorphic carcinoma.

A 72-year-old man with productive cough and wheezing was referred to our institution for a growing mass shadow and central bronchiectasis in the right lower lobe on computed tomography. Based on the symptoms, elevated Aspergillus-specific immunoglobulin E levels, and radiological findings, allergic bronchopulmonary mycosis (ABPM) was suspected according to the Japanese clinical diagnostic criteria. The patient refused bronchoscopic examination, and oral prednisolone (0.5 mg/kg/day) improved the symptoms; however, the mass shadow continued to grow. Subsequently, bronchoscopy revealed mucus plugs and an endobronchial tumour with a whitish surface. The tumour was surgically resected, and the pathological diagnosis was a coexistence of ABPM and pulmonary pleomorphic carcinoma. To the best of our knowledge, this is the first case of ABPM developing at the site of pulmonary pleomorphic carcinoma. Careful bronchoscopic examinations and histopathological evaluations of the surgical specimen led to a prompt and accurate diagnosis.

Pulmonary pleomorphic carcinoma arising in mixed squamous and glandular papilloma: A case report.

Solitary pulmonary papillomas (SPPs) are rare lung neoplasms. Histologically, SPP is classified into three subtypes, and mixed squamous and glandular papilloma (MP) is the rarest subtype. Although SPPs are considered benign tumors, there have been several reports on the synchronous malignant transformation in SPPs. An 82-year-old asymptomatic man was referred to our hospital for further examination of a 2.2 cm-sized left lung tumor. Pathology of bronchoscopic specimens showed the possibility of pulmonary papilloma but did not reveal any malignancy. The patient complained of bloody sputum during the eighth month after the initial visit. The size of the lesion had increased to 4.3 cm. These data suggested the existence of malignancy, and the patient underwent an operation. Histologically, the tumor was composed of fibrovascular cores and papillomatous fronds lined by pseudostratified columnar cells and mucin-filled goblet cells. Keratinizing squamous epithelium was also observed. Overall, the diagnosis of MP was obtained by fundamental histology. In addition, a solid part beneath mild atypical squamous epithelia, which was composed of malignant-appearing squamous cells and spindle-shaped atypical cells, was observed. The spindle portion was positive for cytokeratin AE1/AE3 and vimentin, and focally positive for alpha-smooth muscle actin (αSMA). The final diagnosis was pulmonary pleomorphic carcinoma (PPC) arising in the MP. Only two cases have been reported for atypical spindle tumor cells that are found in MP or bronchiolar adenoma/ciliated muconodular papillary tumor (BA/CMPT), which has histologically similar features to MP. This is the second case report of PPC arising in MP.

Pulmonary pleomorphic carcinoma treated with PD-1 inhibitor: Two case reports.

Pulmonary polymorphic carcinoma (PPC) is a rare and poorly differentiated form of non-small cell lung cancer (NSCLC), accounting for just approximately 0.1% to 0.4% of all NSCLC cases. Historically, the conventional treatments for PPC have been linked to a grim prognosis. However, with the advent of immune checkpoint inhibitors (ICIs), including PD-1 inhibitors, for the management of NSCLC, our center has witnessed encouraging outcomes in two PPC patients who underwent PD-1 inhibitor therapy. The first patient was a 70-year-old male who initially came to our attention after the discovery of a lung mass during a routine physical examination. A lung biopsy confirmed the diagnosis of PPC, and further complications included brain metastasis. Surgical intervention was conducted for the brain metastases, while PD-1 inhibitor therapy was employed for the lung tumors. The second patient was a 60-year-old male who was admitted with a history of persistent coughing and hemoptysis, which led to the diagnosis of a left lung tumor. Subsequent postoperative pathology revealed pulmonary adenocarcinoma coexisting with PPC. However, 2 months later, distant metastases were detected during a follow-up examination. The patient encountered difficulty in tolerating the adverse effects of chemotherapy, prompting the initiation of PD-1 inhibitor treatment. Notably, both patients underwent one cycle of PD-1 inhibitor therapy without encountering significant adverse reactions, and their responses proved to be promising during re-examinations. These findings suggest that surgery combined with immunotherapy PD-1 inhibitor therapy may represent an effective approach for the treatment of PPC.

Metastatic pulmonary pleomorphic carcinoma involving the jejunum: a case report and review of the literature.

We present a case report of a pulmonary pleomorphic carcinoma that metastasized to the jejunum in an 80-year-old woman. The patient was admitted to the hospital with symptomatic anemia and melena that had been ongoing for several months. In 2021, non-small cell carcinoma was diagnosed by fine-needle aspiration. In 2022, a computed tomography (CT) scan revealed an enormous mass in the small bowel. The tumor was resected and showed pleomorphic neoplastic cells with giant and spindle cell morphology. These neoplastic cells were positive for thyroid transcription factor 1 (TTF1). Next-generation sequencing of the secondary tumor revealed 97% genomic similarities to the lung tumor and high expression of programmed cell death ligand 1 (PD-L1). The patient may benefit from immune checkpoint therapy.

A case of pulmonary pleomorphic carcinoma associated with cystic airspace.

Lung cancer associated with a cystic airspace is frequently misdiagnosed or overlooked. Adenocarcinoma, followed by squamous cell carcinoma, is the most typical histologic type of lung cancer connected to a cystic airspace. Here we present the rare case of lung pleomorphic carcinoma associated with a cystic airspace. We encountered a 74-year-old Japanese man diagnosed by computed tomography (CT) as having a nodule outside a cystic airspace in the lung. Several previous CT images showed that the cystic airspace preceded the nodule. Postsurgery, pathology indicated a diagnosis of pleomorphic carcinoma. Since pulmonary pleomorphic carcinomas pursue an aggressive clinical course, their early detection may contribute to an improved prognosis. Our case demonstrated that pleomorphic carcinoma can arise with cystic airspaces. For early diagnosis of those aggressive lung cancers, chest physicians should carefully examine the walls of cystic airspaces on CT.

Asbestos Exposure and Development of Pulmonary Pleomorphic Carcinoma in a Non-smoker: A Rare Non-small Cell Lung Cancer.

Pulmonary pleomorphic carcinoma (PPC) is a subtype of non-small cell lung cancer that is extremely rare and carries a poor prognosis due to its inadequate response to treatment. Patients that present with PPC often exhibit similar symptoms of other malignancies of the lung, making it hard for clinicians to distinguish between each type. However, cytology and gene mutation testing are two approaches that can aid physicians in an accurate and definitive diagnosis. We present a case of an 88-year-old male patient with a diagnosis of pulmonary pleomorphic carcinoma after experiencing recurrent sanguineous pleural effusions. The patient had no smoking history but did have a history of asbestos exposure and pulmonary fibrosis. The patient underwent thoracotomy with pleurodesis and analysis of the surgical pleural biopsy specimen stained positive for markers indicative of PPC. The pathology report was also consistent with the associated cell morphology. Lung cancer is the leading cause of mortality due to cancer in the United States, and exposure to certain substances contributes to the development of these poorly treatable lung malignancies. Smoking and asbestos exposure are well known to act synergistically with each other as risk factors in developing these lung malignancies. In addition to clinical suspicion, screening for these risk factors with laboratory values and imaging is important to diagnose these rare cases of lung malignancies.

A case of pulmonary pleomorphic carcinoma with preexisting interstitial pneumonia successfully treated with pembrolizumab.

Pulmonary pleomorphic carcinoma is often refractory to chemotherapy and follows an aggressive clinical course. Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced lung cancer, and a few cases with pleomorphic carcinoma have been reported to show tumor shrinkage after therapy with ICIs. When treating patients with ICIs, patient selection is essential, and monitoring and management of immune-related adverse events, including pneumonitis, are needed. We herein report a case of pulmonary pleomorphic carcinoma with preexisting interstitial pneumonia treated with pembrolizumab, antiprogrammed cell death 1 antibody. Our report highlights important considerations necessary when treating advanced pleomorphic carcinoma patients complicated with interstitial pneumonia. We also review the literature regarding the use of ICIs in such patients.

Pulmonary pleomorphic carcinoma metastasizing to the anterior mandibular gingiva: A case report and literature review.

INTRODUCTION AND IMPORTANCE: Pulmonary pleomorphic carcinoma (PPC) is a rare subtype of non-small cell lung cancer. No standard therapy has been established for advanced disease, which results in poor prognosis. Some cases of PPC metastasizing to mandibular gingiva have been reported, and the involved site in these reports is all unilateral mandible. CASE PRESENTATION: We report a case of PPC metastasizing to the anterior mandibular gingiva in a 68-year-old man. The patient was referred to our hospital with tumor bleeding and difficulty with intake. One month before, he had been diagnosed as PPC. The size of oral tumor was 28 × 25 mm, and we performed surgical resection. Although there was no recurrence of oral lesion, he died of systemic metastases after 3 months since the surgery. CLINICAL DISCUSSION: The prognosis of patients with metastatic tumor in oral region is poor. Radical treatment for oral lesion is often difficult due to the existence of other metastasis or the refractory, in particular cases with high grade malignancies such as PPC. On the other hand, because of the development of cancer treatment and the arrival of super-aging society, the number of patients with metastatic tumor in oral region has been expected to increase in future. CONCLUSION: PPC metastasizing to the gingiva of mandibular symphysis is extremely rare. If there are possibilities to improve the prognosis or quality of life, radical or palliative treatment for metastatic tumor in oral region should be performed.

Robust response of pulmonary pleomorphic carcinoma to pembrolizumab and sequential radiotherapy: A case report.

Pulmonary pleomorphic carcinoma (PPC) is a rare type of non-small cell lung cancer (NSCLC) with a more aggressive clinical course and a worse outcome than other types of NSCLC. Pembrolizumab, a monoclonal antibody targeting programmed cell death-1 (PD-1), has been approved as the first-line treatment for advanced NSCLC with robust PD-L1 expression in at least 50% of tumour cells, without epidermal growth factor receptor gene (EGFR) mutations or anaplastic lymphoma kinase gene (ALK) rearrangement. Here, we report the case of an 81-year-old man with multiple comorbidities who was diagnosed with PPC and showed a robust response to pembrolizumab followed by radiation therapy without adverse effects. In the absence of randomized clinical trials for PPCs, our case report demonstrates the potential application of pembrolizumab and radiation therapy for the treatment of PPCs.

Expectoration of tonsillar metastasis of pulmonary pleomorphic carcinoma after pseudoprogression: A case report.

Pulmonary pleomorphic carcinoma is a rare malignant tumor that grows rapidly and has a poor prognosis. Although no effective treatments have so far been established, immune checkpoint inhibitors (ICIs) have shown clinical improvement in some cases of pleomorphic carcinoma. However, pseudoprogression is a major concern for treatment of this carcinoma using ICIs. Here, we report the case of a 61-year-old man who was diagnosed with large cell carcinoma of the lung with brain metastases. Systemic chemotherapy comprising carboplatin and pemetrexed was administered as a first-line therapy; however, disease progression was observed. A tonsillar lesion grew rapidly after the administration of nivolumab as a second-line therapy. Tracheostomy was planned to avoid suffocation, but the patient naturally expectorated the tumor. Pathological examination revealed that it was a palatine tonsillar metastasis of pulmonary pleomorphic carcinoma with infiltration of CD8+/CD4- lymphocytes and necrosis. The primary lesion expanded after nivolumab administration and shrank with no additional nivolumab administration. We therefore concluded that pseudoprogression caused expectoration of the tonsillar metastasis. Hence, ICIs can cause serious adverse events due to pseudoprogression.

Prognostic impact of the tumor immune microenvironment in pulmonary pleomorphic carcinoma.

INTRODUCTION: Pulmonary pleomorphic carcinoma (PC) is a rare non-small cell lung carcinoma (NSCLC) and is characterized by sarcomatoid and NSCLC components. This study aimed to characterize the association between immune microenvironmental factors and clinicopathological characteristics of PC. METHODS: Eighty consecutive PC patients who had undergone complete surgical resection were enrolled. We calculated the immunohistochemical staining scores for E-cadherin, vimentin, programmed death ligand 1 (PD-L1), and carbonic anhydrase IX in cancer cells and counted the numbers of CD204-positive tumor-associated macrophages (TAMs) and Foxp3-, CD8-, and CD20-positive tumor-infiltrating lymphocytes (TILs). We also examined the association between these scores and the prognostic outcomes. RESULTS: The staining score for PD-L1 in cancer cells and the number of CD204-positive TAMs in the sarcomatoid component were significantly higher than those in the NSCLC component; E-cadherin score in the sarcomatoid component was significantly lower. Patients with high PD-L1 expression in the NSCLC component had significantly longer overall survival (OS) and recurrence-free survival (RFS) than those with low PD-L1 expression in the NSCLC component (OS: p = 0.001, RFS: p = 0.038). Multivariate analysis revealed that high PD-L1 expression in the NSCLC component was an independent favorable prognostic factor for OS (p = 0.018), whereas high PD-L1 expression in the sarcomatoid component was not. The number of CD8-positive TILs was significantly higher in the high PD-L1 expression group than in the low expression group (NSCLC components: p < 0.001). CONCLUSION: High PD-L1 expression in the NSCLC component may be associated with a favorable prognostic value in pulmonary PC.

Two different patients with pulmonary pleomorphic carcinoma response to PD-1 inhibitor plus anlotinib.

Pulmonary pleomorphic carcinoma (PPC) is a rare and highly malignant subtype of non-small-cell lung cancer (NSCLC), and chemotherapy and radiotherapy are insensitive. Some clinical trials have shown that targetable driver gene mutations, such as EGFR, ALK or BRAF, have rarely been detected in PPC patients, but the incidence of MET exon 14 mutations is more frequent. For these patients with driver gene mutations, corresponding molecular targeted therapy may be valid. In addition, limited cases have suggested that immunotherapy may be effective for PPC without sensitising EGFR or ALK alterations, but the efficacy in patients with other driver mutations remains unclear. Herein, we reported two PPC patients with different targetable gene mutations who both responded dramatically to the PD-1 inhibitor camrelizumab combined with the oral anti-angiogenic drug anlotinib: one harbouring a BRAF V600E mutation with positive PD-L1 expression, few tumour-infiltrating lymphocytes (TILs) and abundant tumour blood vessels; and the other exhibiting a MET exon 14 skipping mutation with PD-L1 overexpression, scattered TILs and abundant tumour blood vessels. Our findings suggest that PD-1 inhibitor combined with anlotinib may be a potential treatment for PPC patients, and abundant tumour vessels should be investigated as a possible therapeutic biomarker.

Case report: Postoperative abdominal recurrence of pulmonary pleomorphic carcinoma showed a dramatic response to S-1 after pembrolizumab.

The patient was an 80-year-old woman with combined pulmonary fibrosis and emphysema. She was diagnosed with pulmonary pleomorphic carcinoma in the right upper lobe, which relapsed 18 months after the operation. Computed tomography showed a mass in contact with the posterior wall of the lower part of the stomach. The patient was treated with two cycles of pembrolizumab, but the disease progressed. She was treated with S-1 as second-line therapy, resulting in tumor-shrinking after two cycles. Progression was not observed over the next twelve months. We report a rare case involving S-1 after immune checkpoint inhibitor treatment.

Significant therapeutic effectiveness of durvalumab after chemoradiotherapy for a patient with post-operative recurrent pulmonary pleomorphic carcinoma.

Pulmonary pleomorphic carcinoma (PPC) is a poorly differentiated non-small cell lung cancer. Because of its rarity, no standard therapy has been established for advanced disease. We herein report on a 62-year-old man with recurrent post-operative PPC, for whom durvalumab after chemoradiotherapy was effective. He was referred to our hospital because of an abnormal shadow in the right upper lung on chest X-ray. After surgical resection was performed, the imaging and histopathological findings revealed PPC (T4N0M0, stage IIIA) with elevated expression of programmed cell death-ligand 1 (PD-L1). A metastasis was found in the left hemithorax 22 months later, and chemoradiotherapy consisting of 60 Gy of radiation and cisplatin plus tegafur/gimeracil/oteracil potassium was administered. Durvalumab was then begun as consolidation therapy. The efficacy of the treatments has continued for longer than 10 months. This case suggests that multidisciplinary treatment with chemoradiotherapy and consolidation immunotherapy may improve the prognosis of locally advanced PPC.

A case of hyperprogressive disease following atezolizumab therapy for pulmonary pleomorphic carcinoma with epidermal growth factor receptor mutation.

A 66-year old man with non-smoking history was diagnosed with pulmonary pleomorphic carcinoma of the right lower lobe. The carcinoma metastasized to the brain, lungs, pleura, and mediastinal lymph nodes. It was positive for epidermal growth factor receptor (EGFR) L858R mutation, and tumor cells highly expressed programmed death-ligand 1(PD-L1). Atezolizumab was initiated as the fourth treatment. After three days, he developed cardiac tamponade and immediately underwent pericardial drainage. Computed tomography showed bilateral ground-glass opacity (GGO), significant worsening of multiple lung metastases, and increased size of metastatic lesions. Newly developed metastasis was noted in the lung, and the patient's respiratory condition rapidly deteriorated. He died of respiratory failure on day 13 after atezolizumab administration. The autopsy showed widespread metastasis in all lobes of the bilateral lungs, cardiac tamponade due to carcinomatous pericarditis, carcinomatous lymphangiopathy, and multiple lung metastases, which were thought to be comprehensively the cause of death. These symptoms suggested hyperprogressive disease (HPD). Hence, we report the first case of HPD following atezolizumab therapy for pulmonary pleomorphic carcinoma with EGFR mutation.