Primary Sarcomatoid Carcinoma of the Lung: Radiometabolic (18F-FDG PET/CT) Findings and Correlation with Clinico-Pathological and Survival Results

Pulmonary sarcomatoid carcinoma: A rare case report, diagnostic dilemma and review of literature

RATIONALE

Pulmonary sarcomatoid carcinoma (PSC), a rare tumor, comprises 0.1% to 0.4% of all malignant lung tumors. Given the rarity of PSC, its clinical course, therapeutic guidelines, and patient outcomes remain largely unknown. Therefore, it is imperative to alert clinicians to this extremely rare and instructive early-onset cancer.

PATIENT CONCERNS

This report describes a 28-year-old woman with PSC, who was initially misdiagnosed with Whipple's disease. A conclusive diagnosis of PSC was made following careful clinical examination, imaging, and histopathological evaluation of the patient's biopsy sample. Radiological imaging revealed multiple nodules and mass formations in the left upper lobe of the patient's lung, with the largest measuring of 5.4 × 3.2 cm.

DIAGNOSIS

Histopathological examination indicated the presence of a malignant neoplasm associated with necrosis suggestive of sarcoma, which was pathologically staged as cT4N1M1.

INTERVENTIONS AND OUTCOMES

A regimen of doxorubicin and ifosfamide was administered therapeutically, resulting in a stable disease state.

LESSONS

The rarity and tumor origin challenge the diagnosis, which emphasizes the imperative role of histological examination, immunohistochemistry, and flow cytometry in achieving an accurate diagnosis. This report summarizes the existing publications to provide a comprehensive overview of PSC, including its clinical manifestations, radiographic imaging, pathologic features, diagnostic challenges, treatment strategies, and prognosis, and aims to improve the understanding of PSC.

18F-FDG PET/CT imaging in pulmonary sarcomatoid carcinoma

Background

Pulmonary sarcomatoid carcinoma (PSC) is a rare highly aggressive and poorly differentiated non-small cell carcinoma, and little is known about the information on the usefulness of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT). We investigated the clinical and 18F-FDG PET/CT features of PSC.

Methods

We retrospectively analyzed 25 consecutive PSC patients who had undergone 18F-FDG PET/CT. Demographic data, PET/CT findings before treatment, pathological features, and prognosis in these patients were investigated to define correlates between maximal standard uptake value (SUVmax) and clinicopathological parameters.

Results

From March 2017 to January 2023, twenty-five eligible patients with PSC were identified. There were 23 (92%) men, aged 68.5 ± 8.5 (range 56-90) years. Eighteen (72%) patients had a frequent smoking history. The mean size of PSCs was 59.3 ± 18.6 (range 29-97) mm, and 23 (92%) PSCs were Stage IV tumors. 20 (80%) lesions were located in the upper lung and 19 (76%) cases belonged to the peripheral type. Necrotic foci appeared in 21(84%) tumors. 11 (44%) PSCs invaded the pleura. All PSCs were FDG avid, and the mean of SUVmax was 11.8 ± 5.3 (range 4.8-25.5). Metastases were found on PET/CT in 24(96%) patients. The SUVmax of the lesions ≥ 5cm was higher than that of the lesions < 5cm (p=0.004), and the SUVmax of lesions with TTF-1 expression was higher than those of lesions without TTF-1 expression (p=0.009). All of the 25 primary lesions were considered malignant and confirmative, probable, and possible diagnosis of PSC was made in 2 (8%), 4 (16%), and 5(20%) patients, respectively on PET/CT. PSC was not considered in 14 (56%) patients, in PET/CT. The survival of patients with surgery didn't demonstrate a significantly good prognosis as compared with those without surgery (p=0.675).

Conclusion

All PSCs had obvious FDG avidity. Although imaging diagnosis is still difficult, combined clinical and imaging features more than 40% of primary lesions were considered for the possibility of PSC in our group. Early histopathological diagnosis is necessary to help develop a reasonable regimen.

Significant response of pulmonary sarcomatoid carcinoma with obstructive atelectasis to treatment with the PD-1 inhibitor camrelizumab combined with transbronchial cryoablation: A case report and literature review

Pulmonary sarcomatoid carcinoma (PSC) is a rare subtype of non-small cell lung cancer with high malignancy and poor prognosis. Chemotherapy or radiotherapy do not usually provide satisfactory results in patients with PSC, especially in those with advanced-stage cancer. Targeted therapy and immunotherapy are more precise therapies that may be effective in the treatment of PSC; however, further research is needed. Here, we present a case of stage III PSC with obstructive atelectasis, which is more challenging and hinders treatment. Treatment with the PD-1 inhibitor camrelizumab and transbronchial cryoablation showed significant clinical efficacy. This type of combined treatment has not been reported previously for PSC. Thus, this case may provide a valuable reference for future clinical practice and research.

Prognostic value of PET parameters in patients with pleomorphic lung cancer: Results from a single institution

OBJECTIVES

Pleomorphic lung carcinoma (PLC) is a rare histotype of non-small cell lung cancer (NSCLC) characterized by aggressive clinical course, poor response to therapy and poor prognosis. Therefore, aim of our study is to analyze with 18F-FDG PET/CT a subset of patients affected by PLC to evaluate their metabolic characteristics in terms of SUVmax, MTV and TLG, in order to correlate them with overall survival (OS) and disease-free survival (DFS).

MATERIAL AND METHODS

We retrospectively analyzed 49 consecutive patients with histologically defined PLC occurred to our Institution between 2003 and 2014. All patients underwent F18-FDG PET-CT before surgery and primary tumor was automatically segmented using an isocontour threshold method. SUV threshold for tumor segmentation was defined as the 41 % of lesion SUVmax. Total volume of the segmented VOI (MTV, centimeters cubed) and average SUV (SUVavg, grams per milliliter) in the segmented VOI were measured.

RESULTS

In our population men were significantly more affected than women (42:7). According to Youden criteria, SUVmax, MTV41 and TLG41 best cut-off values to predict 2-year mortality were, 18.95, 27.89 and 290.45, respectively, with TLG41 showing best specificity (85 %) and positive predictive value (82.4 %). As concerning 2-year recurrence, SUVmax, MTV41 and TLG41 best cut-off values were 10.08, 27.89 and 134.85, with SUVmax showing best sensitivity (96.7 %) and negative predictive value (85.7 %). ROC curves confirmed that SUVmax, MTV41 and TLG41 were equally accurate to predict 2-year mortality and 2-year recurrence in our population.

CONCLUSION

Metabolic biomarkers such as SUVmax, MTV and TLG can be used as a prognostic index for disease progression, recurrence and death in patients with PLC, independently from other clinical/pathological prognostic elements.

Pleomorphic carcinoma of the lung: Prognostic models of semantic, radiomics and combined features from CT and PET/CT in 85 patients

Introduction

To demonstrate semantic, radiomics, and the combined risk models related to the prognoses of pulmonary pleomorphic carcinomas (PCs).

Methods

We included 85 patients (M:F = 71:14; age, 35–88 [mean, 63 years]) whose imaging features were divided into training (n = 60) and test (n = 25) sets. Nineteen semantic and 142 radiomics features related to tumors were computed. Semantic risk score (SRS) model was built using the Cox-least absolute shrinkage and selection operator (LASSO) approach. Radiomics risk score (RRS) from CT and PET features and combined risk score (CRS) adopting both semantic and radiomics features were also constructed. Risk groups were stratified by the median of the risk scores of the training set. Survival analysis was conducted with the Kaplan-Meier plots.

Results

Of 85 PCs, adenocarcinoma was the most common epithelial component found in 63 (73 %) tumors. In SRS model, four features were stratified into high- and low-risk groups (HR, 4.119; concordance index ([C-index], 0.664) in the test set. In RRS model, five features helped improve the stratification (HR, 3.716; C-index, 0.591) and in CRS model, three features helped perform the best stratification (HR, 4.795; C-index, 0.617). The two significant features of CRS models were the SUVmax and the histogram feature of energy ([CT Firstorder Energy]).

Conclusion

In PCs of the lungs, the combined model leveraging semantic and radiomics features provides a better prognosis compared to using semantic and radiomics features separately. The high SUVmax of solid portion (CT Firstorder Energy) of tumors is associated with poor prognosis in lung PCs.

Pulmonary sarcomatoid carcinoma: progress, treatment and expectations

Pulmonary sarcomatoid carcinoma (PSC) is a unique, highly invasive pulmonary malignancy with a poor prognosis, representing 0.1-0.4% of all malignant lung tumors. Because of its highly aggressive character and propensity for frequent metastasis, PSC shows low response rates to traditional treatments such as chemotherapy, radiotherapy, and neoadjuvant therapy. In recent years, considerable progress has been made in gene sequencing, targeted therapies, and immunotherapies. One of the most promising treatment approaches is the selection of mono-targeted or multi-targeted drugs according to tumor gene-mutation sites, such as epidermal growth factor receptor or vascular endothelial growth factor receptor 2 (EGFR/VEGFR2), anaplastic lymphoma kinase (ALK), and others. Another approach is the activation of therapeutic anti-tumor immunity via pathways including programmed cell-death protein-1/programmed cell-death ligand-1 (PD-1/PD-L1), which has been used in individual cases. In this review, we will introduce the clinicopathologic features, molecular typing, and traditional treatments. We will also review the biological characteristics and the latest therapies for PSC. These novel therapies show promise in the management of PSC, and the outcomes of investigative trials will hopefully reveal a variety of treatment options for patients with PSC.

18 F-FDG PET/CT imaging of small intestinal metastasis from pulmonary sarcomatoid carcinoma: Brief report and review of the literature

We herein report two cases of small intestinal metastasis from pulmonary sarcomatoid carcinoma (PSC) detected by ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG PET/CT). We reviewed the literature on ¹⁸F‐FDG PET/CT features in gastrointestinal metastasis of PSC patients since 1992, and further analyzed the imaging features. According to the literature review, 23 eligible cases were identified from eight studies, and no cases underwent ¹⁸F‐FDG PET/CT imaging. In this study, clinical and PET/CT imaging data of two patients are reported. In our cases, clinical and the CT images of lung masses were not typical, but the uptake of ¹⁸F‐FDG was remarkably high, with SUVmax exceeding 30. Small intestinal metastases may not be related to obstruction, or even the local intestinal cavity may be dilated. Therefore, in PSC patients with mild or without abdominal symptoms, ¹⁸F‐FDG PET/CT imaging could identify intestinal metastasis at a relatively early stage and may be used to determine the preferred biopsy site, or early intervention by surgery.

Key points

¹⁸F‐FDG PET/CT imaging of small intestinal metastasis of PSC has not been previously reported in the literature and here we report the ¹⁸F‐FDG PET/CT features of two cases.

The uptake of ¹⁸F‐FDG was remarkably high in both the primary tumor and metastatic intestinal lesion. ¹⁸F‐FDG PET/CT imaging may therefore be used to determine the preferred biopsy site or early intervention by surgery.

Pulmonary Sarcomatoid Carcinoma: Experience From SEER Database and Shanghai Pulmonary Hospital

BACKGROUND

Pulmonary sarcomatoid carcinoma (PSC) is a rare type of lung cancer. This study aimed to explore the appropriate treatment for PSC.

METHODS

Two cohorts were used: patients from the Surveillance, Epidemiology, and End Results (SEER) database (1988 to 2014) and Shanghai resident patients at Shanghai Pulmonary Hospital (2009 to 2019) in China. Cox regression analysis was applied to identify prognostic factors for progression-free survival and overall survival (OS). Interaction assessments were performed using likelihood ratio tests to examine relationships between adjuvant chemotherapy and other baseline characteristics.

RESULTS

In the SEER cohort, 1640 patients with PSC were identified, with a median survival and a 5-year OS rate of 7 months (95% confidence interval (CI), 6 to 8 months) and 19.5%, respectively. Multivariable Cox analysis of surgically treated patients revealed that adjuvant chemotherapy was significantly associated with better survival (hazard ratio, 0.78; 95% CI, 0.62 to 0.98), and the benefit was more pronounced in T3 to T4 stage (P = .04) and N-positive patients (P < .01). In the Shanghai Pulmonary Hospital cohort (n = 175), the median progression-free survival and OS were 8 months (95% CI, 7 to 12 months) and 12 months (95% CI, 10 to 18 months), respectively, with a 5-year OS rate of 25.1%. Similarly, the survival benefit of adjuvant chemotherapy was confirmed in patients with surgical resection (hazard ratio, 0.50; 95% CI, 0.31 to 0.81), but this benefit was restricted to patients who were younger (age <63 years; P = .02) and had a higher body mass index (>25 kg/m²; P < .01) by interaction assessments. The disease control rate after chemotherapy was 58.62%, and the disease control rate after targeted therapy was 57.14%.

CONCLUSIONS

Adjuvant chemotherapy should be recommended for patients with surgically treated PSC, especially for patients with advanced-stage cancer, younger age, or higher body mass index.

Approaches to Tumor Classification in Pulmonary Sarcomatoid Carcinoma

Pulmonary sarcomatoid carcinoma (PSC) is a heterogeneous category of primary lung cancer accounting from 0.3% to 3% of all primary lung malignancies. According to the most recent 2015 World Health Organization (WHO) classification, PSC includes several different variants of malignant epithelial tumors (carcinomas) histologically mimicking sarcomas showing or entirely lacking a conventional component of non-small cell lung cancer (NSCLC). Thus, this rare subheading of lung neoplasms includes pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, pulmonary blastoma, and carcinosarcoma. A diagnosis of PSC may be suspected on small biopsy or cytology, but commonly requires a surgical resection to reach a conclusive definition. The majority of patients with PSC consists of elderly, smoking men with a large, peripheral mass characterized by well-defined margins. However, presentation with a central, polypoid endobronchial lesion is well-documented, particularly in pleomorphic carcinoma and carcinosarcoma showing a squamous cell carcinoma component. As expected, PSC may pose diagnostic problems and immunohistochemistry is largely used when pathologists deal these tumors in routine practice. Indeed, PSC tends to overexpress molecules associated with the epithelial-to-mesenchymal transition, such as vimentin, but the panel of immunostains also includes epithelial markers (cytokeratins, EMA), TTF-1, p40 and negative markers (e.g., melanocytic, mesothelial and sarcoma-related primary antibodies). Although rare, PSC has increased their interest among oncologist community for different reasons: a. identification of the epithelial-to-mesenchymal phenomenon as a major mechanism of secondary resistance to tyrosine kinase inhibitors; b. over-expression of PD-L1 and effective treatment with immunotherapy; c. identification of c-MET exon 14 skipping mutation representing an effective target to crizotinib and other specific inhibitors. In this review, the feasibility of the diagnosis of PSC, its differential diagnosis and novel molecular findings characterizing this group of lung tumor are discussed.

[Current Status of Diagnosis and Treatment of Pulmonary Sarcomatoid Carcinoma]

Pulmonary sarcomatoid carcinoma (PSC) is a rare, poorly differentiated, subtype of non-small cell lung carcinoma (NSCLC) and constitutes approximately 0.1% to 0.5% of all lung malignancies. PSC can be divided into five subtypes based on the 2015 World Health Organization (WHO) classification of lung tumors: pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pulmonary blastoma. Some imaging characteristics can be found for PSC although no special symptoms. The accurate pathological diagnosis of PSC can be a significant challenge, which depends on pathology and immunohistochemistry. PSC should be managed similar to other NSCLC, surgical resection is the standard management for early stage cases, moreover, multimodal treatment should be considered. However, PSC is insensitive to radiotherapy and chemotherapy, and has high rate of local and metastatic recurrence and poor prognosis. With the development of molecular pathology, targeted therapy and immunotherapy may have broad prospects.
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Pulmonary Sarcomatoid Carcinomas: A Review

Pulmonary sarcomatoid carcinomas belong to a group of neoplasms that remain incompletely understood. They are rare tumors of the bronchopulmonary system that incorporate a wide range of neoplasms that by definition contain a sarcomatoid component characterized by spindle or giant cells. Such classification has led to a heterogenous tumor category that includes neoplasms with different clinical, morphologic, and prognostic features. To date, the histopathologic diagnosis of pulmonary sarcomatoid carcinomas does not require the use of ancillary testing and is based on light microscopic criteria alone. However, with recent advances in immunohistochemical and molecular methods, it is becoming increasingly clear that pulmonary sarcomatoid carcinomas represent poorly differentiated or "dedifferentiated" variants of conventional non-small cell carcinomas with similar immunophenotype and molecular signatures. This review summarizes the latest insights and concepts of these unusual tumors and outlines future directions with emphasis on tumor classification and patient management.