Rapid and aggressive recurrence of pulmonary sarcomatoid carcinoma after curative resection: a case report.

Background
Pulmonary sarcomatoid carcinoma (PSC) represents a rare and highly aggressive histological variant of non-small cell lung cancer, accounting for approximately 0.1⎯0.4% of all primary lung malignancies [1]. Characterized by the presence of both epithelial and mesenchymal components, PSC has an exceptionally poor prognosis, with a median overall survival ranging from 8⎯22 months, even after complete surgical resection [2, 3]. The rarity of this entity, combined with its histological heterogeneity and propensity for extensive necrosis, hinders its diagnosis and optimal treatment planning.
Recent advances in molecular profiling have revealed that compared with conventional non-small cell lung cancer subtypes, PSC has distinct biological characteristics. Notably, patients with PSC have significantly higher rates of PD-L1 expression, with 65.9⎯71.7% of patients showing PD-L1 expression ≥ 50%, suggesting that these tumours are potentially excellent candidates for immune checkpoint inhibitor therapy [4, 5]. Compared with conventional chemotherapy, immunotherapy has demonstrated superior efficacy in patients with PSC, with objective response rates ranging from 38⎯45.6%, and significantly improved survival outcomes in patients with high PD-L1 expression.
However, the management of PSC faces significant challenges in health care systems with limited access to immunotherapy. In Korea, insurance restrictions prevent the utilization of immune checkpoint inhibitors for patients with PSC, despite compelling evidence supporting their efficacy. This limitation forces treatment with conventional chemotherapy approaches, which have markedly inferior outcomes than immunotherapy-based regimens do. The therapeutic implications of these access restrictions remain poorly characterized in the literature, particularly regarding their impact on patient outcomes and clinical decision-making.
The aggressive biological behaviour of PSC, characterized by rapid progression and early recurrence even after complete resection, demands immediate and optimal therapeutic intervention. Understanding the clinical implications of treatment delays and limited therapeutic access is crucial for improving outcomes in this devastating disease. We report a case of PSC with exceptionally early recurrence following complete resection, highlighting the challenges of managing this aggressive malignancy within the constraints of the Korean health care system.

Case presentation
A 41-year-old male (188 cm, 82 kg) presented to the emergency department with dyspnoea and fever. Initial vital signs revealed a body temperature of 38.9 °C and a heart rate of 135 beats per minute. Chest radiography revealed lobar atelectasis of the right lower lobe (RLL) with blunting of the cardiophrenic angle (Fig. 1A). Low-dose computed tomography (CT) of the chest revealed an approximately 10 cm heterogeneously attenuated mass in the RLL, accompanied by a small pleural effusion in the right hemithorax (Fig. 1B).

The patient reported a three-month history of progressive dyspnoea, persistent cough, intermittent fever, haemoptysis, and significant weight loss (9 kg). His medical history revealed a malignant peripheral nerve sheath tumour of the left shoulder treated 10 years previously, which had remained in remission, and chronic kidney disease secondary to the prior chemoradiation therapy. However, the patient was subsequently lost to follow-up after alternative acupuncture therapy was chosen over conventional oncologic surveillance.
Contrast-enhanced magnetic resonance imaging (MRI) of the chest revealed a well-defined 11 × 10 × 8 cm mass with heterogeneous intermediate signal intensity on both T1- and T2-weighted images, along with a substantial volume of nonspecific pleural effusion in the right hemithorax (Fig. 1C). Positron emission tomography-computed tomography (PET-CT) revealed a hypermetabolic tumour in the RLL with a maximum standardized uptake value (SUVmax) of 23.4, which is consistent with malignancy. Bronchoscopic biopsy confirmed malignancy with extensive necrosis, suggesting poorly differentiated carcinoma. However, extensive necrosis prevented definitive histologic classification and precluded confirmation of a specific treatment strategy.
On the basis of these findings, a multidisciplinary team initially recommended surgery for pleural exploration and tissue acquisition. However, given the patient’s persistent symptoms and explicit request for tumour removal, the decision was made to proceed with complete surgical excision. Therefore, the procedure was performed four weeks after the initial presentation. During surgery, the mass demonstrated severe adherence to the parietal pleura, mediastinum, and diaphragm, with extension to the bifurcation of the right middle lobe (RML) and RLL bronchi. Following extensive adhesiolysis and parietal pleurectomy, bilobectomy of the RML and RLL was performed with systematic mediastinal lymph node dissection. No definitive evidence of pleural metastasis was observed intraoperatively. The postoperative course was uncomplicated, with chest tubes removed on postoperative days 3 and 6, and the patient was discharged on postoperative day 8.
Comprehensive pathologic examination confirmed a diagnosis of sarcomatoid carcinoma measuring 12.5 × 9.5 × 9.0 cm (Fig. 2). The tumour had invaded the visceral pleural surface (PL2) and demonstrated lymphovascular invasion, spread through air spaces (STAS), and extensive necrosis. The resection margins were negative for tumour involvement, confirming the success of R0 resection. No metastases were identified in any of the examined lymph nodes, resulting in a final pathological stage of pT4N0M0 according to the AJCC 9th edition staging system. Pathologic molecular analysis revealed exceptionally high PD-L1 expression, with 22C3 pharmDx staining positive in 80% of tumour cells, 40% SP263 expression, and 20% SP142 level II tumour cells (TCs), with 0% immune cell (IC) staining. Genetic mutation analysis revealed no actionable driver mutations, including EGFR, KRAS, ROS1 gene fusion, or BRAF V600E mutations. ALK (D5F3) and Pan-TRK (EPR17341) immunostaining was also negative. Immunohistochemical analysis demonstrated focal and weak positivity for MOC-31 and cytokeratin (CK), supporting epithelial differentiation.

A postoperative multidisciplinary team meeting recommended adjuvant systemic chemotherapy followed by sequential radiation therapy. However, the patient declined all adjuvant therapy and was subsequently lost to follow-up. During this period, the patient pursued alternative acupuncture therapy. Two months after surgery, the patient returned to the outpatient clinic with complaints of a rapidly growing mass on the right chest wall. Upon surgical excision of this chest wall lesion, it was found to communicate directly with the pleural cavity. Pathologic examination confirmed a 2.3 × 2.0 × 1.7 cm sarcomatoid carcinoma, which was consistent with recurrent disease. Follow-up contrast-enhanced chest MRI revealed multiple masses and nodules throughout the right pleural cavity, with the largest mass measuring 16 cm and demonstrating internal haemorrhagic necrosis (Fig. 3). The patient subsequently initiated systemic chemotherapy with the ICE regimen (ifosfamide, carboplatin, and etoposide).

Discussion
Pulmonary sarcomatoid carcinoma (PSC) represents one of the most clinically aggressive and diagnostically challenging variants of non-small cell lung cancer ans is characterized by consistently poor outcomes across all stages of disease [1]. The rarity and histological heterogeneity of PSC hinders its diagnosis, particularly when initial biopsy samples contain extensive necrosis or insufficient viable tissue, as in our case. Definitive diagnosis often requires surgical resection and comprehensive immunophenotyping, which underscore the importance of obtaining adequate tissue for both diagnostic and prognostic evaluation [6].
This case demonstrates several exceptional characteristics that distinguish it from typical PSC presentations reported in the literature. Most notably, the extraordinarily rapid recurrence within two months post-surgery represents one of the earliest documented recurrences following complete resection in contemporary series. While median disease-free survival following R0 resection typically ranges from 4⎯6 months, recurrence within 8 weeks is exceptionally rare and indicates the highly aggressive biological nature of this tumour subtype [2, 3]. The severity of recurrence was equally remarkable, with the development of a 16 cm pleural mass accompanied by haemorrhagic necrosis despite the absence of traditional high-risk features such as nodal involvement or positive margins. Additionally, the exceptionally high PD-L1 expression (80% by 22C3 pharmDx) places this tumour in the highest expression category, representing a potentially favourable biomarker profile that could not be leveraged therapeutically owing to health care system limitations [7].
Recent large-scale institutional studies provide important information for understanding PSC outcomes and place our case within the broader clinical landscape. A comprehensive single-institution series demonstrated median overall survival of 22.0 months for the entire PSC cohort, with 1-, 3-, and 5-year survival rates of 59.9%, 40.1%, and 36.1%, respectively [3]. Compared with non-surgical patients, patients who underwent surgical resection achieved significantly improved outcomes (median survival 23.0 vs. 11.0 months, p = 0.016), emphasizing the critical importance of complete resection when technically feasible [3]. However, even after complete resection, PSC maintains its aggressive biological behaviour, with independent risk factors for recurrence including a preoperative systemic immune-inflammation index (SII >430.8) and the presence of histologic necrosis⎯both of which are present in our case [3]. The rapid progression observed in our patient aligns with reports documenting the propensity for early micrometastatic spread, even in the absence of detectable nodal involvement at the time of resection [2].
Compared with that of conventional chemotherapy, the therapeutic landscape of PSC has been revolutionized by emerging evidence demonstrating the superior efficacy of immunotherapy. Large institutional cohorts from major cancer centres have shown that 65.9⎯71.7% of PSC patients exhibit PD-L1 expression ≥ 50%, with objective response rates of 38⎯45.6% to immune checkpoint inhibitors [4, 5]. In patients treated with immune checkpoint inhibitors, the median progression-free survival ranged from 5.4⎯5.83 months with the median overall survival extending to 11.7⎯33.4 months, depending on the institutional cohort [4, 5]. Comparative analyses demonstrated the marked superiority of immunotherapy over chemotherapy in advanced PSCs, with first-line immunotherapy-based regimens leading to a median progression-free survival of 7.2 months and a median overall survival of 13.7 months, compared with chemotherapy, with a median progression-free survival of 2.1 months and a median overall survival of 3.6 months [8]. Immunotherapy was an independent favourable prognostic factor with hazard ratios of 0.22 for progression-free survival and 0.27 for overall survival [8].
However, the management of PSCs in Korea faces unique and significant challenges related to health care coverage limitations that fundamentally impact therapeutic decision-making and patient outcomes. Despite compelling international evidence supporting the superior efficacy of immune checkpoint inhibitors in treating PSC, these agents remain inaccessible because of insurance restrictions within the Korean health care system. This limitation is particularly significant given that the majority of PSC patients exhibit high PD-L1 expression, potentially qualifying them for immunotherapy in other health care systems [4, 5]. The exceptionally high PD-L1 expression observed in our patient would typically predict a favourable response to checkpoint inhibitors on the basis of international experience, but the inability to access these agents in Korea necessitates the use of conventional chemotherapy approaches, which results in markedly inferior outcomes [4, 5, 8]. This creates a substantial therapeutic disadvantage for Korean PSC patients compared with international standards of care, potentially resulting in worse outcomes because of limited access to optimal therapeutic interventions.
The patient’s refusal of adjuvant therapy, combined with the inability to access immunotherapy due to insurance restrictions, represented a significant missed therapeutic opportunity that likely contributed to the aggressive clinical course observed. In this constrained therapeutic environment, the ICE regimen (ifosfamide, carboplatin, and etoposide) administered after recurrence represents a reasonable salvage approach within available options. However, platinum-based chemotherapy typically yields modest outcomes in patients with PSC, and the absence of immunotherapy access likely contributes to the poor disease control observed. This rapid progression despite chemotherapy treatment reflects both the inherent aggressiveness of PSC and the limitations of available therapeutic options within the Korean health care framework.
In addition to single-agent approaches, emerging combination strategies show promise for the international management of PSCs. Case reports describe exceptional responses to pembrolizumab combined with anlotinib in patients with high PD-L1 expression and tumour mutational burden, with some patients achieving overall survival exceeding 45 months. Additionally, neoadjuvant immunochemotherapy has demonstrated the potential to convert unresectable stage III PSC to resectable disease with a pathological complete response. These advances highlight the therapeutic potential that remains inaccessible to Korean patients because of coverage restrictions.
This case highlights several critical principles for PSC management within the Korean health care context. Given the propensity for early recurrence and limited therapeutic options, intensive postoperative surveillance should be initiated within 4⎯6 weeks post-surgery rather than following conventional 3-month intervals, as early detection of recurrent disease may provide the best opportunity for intervention with available therapies [2, 3]. The importance of achieving complete surgical resection cannot be overstated when downstream therapeutic options are restricted and requires careful preoperative staging and multidisciplinary planning to maximize the likelihood of R0 resection [3]. The narrow therapeutic window and aggressive biological behaviour of PSCs expedited decision-making and treatment initiation under the constraints of available options [1]. Comprehensive patient education regarding the aggressive nature of PSC and the critical importance of treatment compliance becomes essential when therapeutic options are limited, with patients needing to understand the urgency of following recommended surveillance schedules and the importance of prompt evaluation of concerning symptoms.
The management challenges illustrated by this case highlight broader health care policy considerations regarding access to emerging therapies. The compelling evidence for immunotherapy superiority in patients with PSC, combined with the potential for significantly improved outcomes in patients with favourable biomarker profiles, suggests that current insurance restrictions may substantially impact patient survival [4, 5, 8]. Future health care policy discussions should consider the cost-effectiveness of providing access to immunotherapy for highly selected PSC patients with high PD-L1 expression, as the potential for improved outcomes in this aggressive disease may justify expanded coverage considerations [4, 5].

Conclusions
Pulmonary sarcomatoid carcinoma (PSC) represents one of the most biologically aggressive subtypes of non-small cell lung cancer, with an exceptionally high likelihood of rapid recurrence despite complete surgical resection. This case demonstrates the extraordinary aggressiveness of PSC, with recurrence occurring within two months post-surgery despite R0 resection and node-negative disease, representing one of the earliest recurrences documented in the contemporary literature. Management challenges are compounded in the Korean health care system, where insurance restrictions limit access to immunotherapy despite compelling evidence demonstrating superior efficacy compared with conventional chemotherapy.
In health care systems with limited immunotherapy access, PSC management must focus on optimizing surgical approaches and implementing intensive postoperative surveillance strategies. Complete surgical resection becomes even more critical when downstream therapeutic options are restricted, and early detection of recurrent disease through accelerated surveillance schedules may provide the best opportunity for intervention with available therapies. The narrow therapeutic window and aggressive biological behaviour of PSCs underscore the critical importance of multidisciplinary care coordination, optimal surgical techniques, and comprehensive patient education regarding the urgency of treatment compliance and surveillance adherence.
This case highlights the need for ongoing health care policy discussions regarding expanded access to immunotherapy for PSC patients with favourable biomarker profiles, as current restrictions may significantly impact outcomes in this devastating disease. Future improvements in PSC management may depend not only on continued therapeutic advances but also on health care system adaptations that ensure equitable access to effective treatments for all patients facing this aggressive malignancy.