Single-Cell Transcriptome Analysis Reveals 2 Subtypes of Tumor Cells of Sclerosing Pneumocytoma With Distinct Molecular Features and Clinical Implications.

Pulmonary sclerosing pneumocytoma (PSP) is a rare, distinctive benign lung adenoma of pneumocyte origin. Despite its rarity, the tumor's unique cellular morphology has sparked ongoing debates regarding the origin of its constituent cells. This study aimed to elucidate the molecular features of PSP tumor cells and enhance our understanding of the cellular processes contributing to PSP formation and biological behavior. Tissue samples from PSP and corresponding normal lung tissues (n = 4) were collected. We employed single-cell RNA sequencing and microarray-based spatial transcriptomic analyses to identify cell types and investigate their transcriptomes, with a focus on transcription factors, enriched gene expression, and single-cell trajectory evaluations. Our analysis identified 2 types of tumor cells: mesenchymal-epithelial dual-phenotype (MEDP) cells and a distinct subpopulation of type II alveolar epithelial cells exhibiting characteristics slightly reminiscent of type I alveolar epithelial cells (AT2Cs) corresponding to histologic round stromal cells and surface cuboidal cells, respectively. MEDP cells displayed weak alveolar epithelial differentiation but strong collagen production capabilities, as indicated by the expression of both TTF-1 and vimentin. These cells played a pivotal role in forming the solid and sclerotic areas of PSP. Moreover, MEDP cells exhibited a pronounced propensity for epithelial-mesenchymal transition, suggesting a greater potential for metastasis compared with AT2Cs. The capillary endothelial cells of PSP displayed notable diversity. Overall, this study provides, for the first time, a comprehensive mapping of the single-cell transcriptome profile of PSP. Our findings delineate 2 distinct subtypes of tumor cells, MEDP cells and AT2Cs, each with its own biological characteristics and spatial distribution. A deeper understanding of these cell types promises insights into the histology and biological behaviors of this rare tumor.

Characteristics of Metastatic and Nonmetastatic Pulmonary Sclerosing Pneumocytomas: A Clinicopathological Study of 68 Cases and 15 Reported Metastatic Cases.

To characterize the clinicopathologic features of pulmonary sclerosing pneumocytoma (PSP) and compare these features between the tumors with and without metastasis, 68 cases of PSP (1/68 [1.47%] with metastasis) diagnosed from 2009-2022 in our hospital and 15 previously reported metastasizing cases were studied. There were 54 female patients and 14 male patients, with age ranging from 17 to 72 years and tumor size ranging from 0.1 to 5.5 cm (mean, 1.75 cm). In all, 85.4% of the cases presented with ≥2 patterns, including papillary, sclerotic, solid, and hemorrhagic. Thyroid transcription factor 1, epithelial membrane antigen, CKpan, and CK7 were expressed in surface cells in 100% of the cases and napsin A was expressed in 90% of the cases. Stromal cell expression of these markers occurred in 100%, 93.9%, 13.5%, 13.8%, and 0% of the cases, respectively. Of the 16 PSP cases with metastasis, 8 were female patients and 7 were male patients, with age ranging from 14 to 73 years. The tumor size ranged from 2.5 to 12 cm (mean, 4.85 cm). Forty-five of the cases were negative for BRAF V600E immunostaining and 6 were focally weak positive, in which fluorescent PCR tests showed no detectable mutations. There were significant differences in gender, age, and tumor size between PSP cases with and without metastasis. No BRAF V600E mutation was found in patients with PSP. AKT1 p.E17K mutations were detected in both the primary lung tumor and the lymph node metastatic tumor of our PSP case with lymph node metastasis. In conclusion, PSP is an uncommon pulmonary neoplasm with significant female predilection and has distinct morphologic and immunohistochemical characteristics. The BRAFV600E mutation was not detectable in patients with PSP and thus may not involve in its tumorigenesis. Most PSP tumors are benign, with a minority exhibiting potential for metastasis and malignant behavior.

Analysis of the value of enhanced CT combined with texture analysis in the differential diagnosis of pulmonary sclerosing pneumocytoma and atypical peripheral lung cancer: a feasibility study.

BACKGROUND: As a rare benign lung tumour, pulmonary sclerosing pneumocytoma (PSP) is often misdiagnosed as atypical peripheral lung cancer (APLC) on routine imaging examinations. This study explored the value of enhanced CT combined with texture analysis to differentiate between PSP and APLC. METHODS: Forty-eight patients with PSP and fifty patients with APLC were retrospectively enrolled. The CT image features of the two groups of lesions were analysed, and MaZda software was used to evaluate the texture of CT venous phase thin-layer images. Independent sample t-test, Mann-Whitney U tests or χ2 tests were used to compare between groups. The intra-class correlation coefficient (ICC) was used to analyse the consistency of the selected texture parameters. Spearman correlation analysis was used to evaluate the differences in texture parameters between the two groups. Based on the statistically significant CT image features and CT texture parameters, the independent influencing factors between PSP and APLC were analysed by multivariate logistic regression. Extremely randomized trees (ERT) was used as the classifier to build models, and the models were evaluated by the five-fold cross-validation method. RESULTS: Logistic regression analysis based on CT image features showed that calcification and arterial phase CT values were independent factors for distinguishing PSP from APLC. The results of logistic regression analysis based on CT texture parameters showed that WavEnHL_s-1 and Perc.01% were independent influencing factors to distinguish the two. Compared with the single-factor model (models A and B), the classification accuracy of the model based on image features combined with texture parameters was 0.84 ± 0.04, the AUC was 0.84 ± 0.03, and the sensitivity and specificity were 0.82 ± 0.13 and 0.87 ± 0.12, respectively. CONCLUSION: Enhanced CT combined with texture analysis showed good diagnostic value for distinguishing PSP and APLC, which may contribute to clinical decision-making and prognosis evaluation.

Pulmonary sclerosing pneumocytoma and mortality risk.

BACKGROUND: Surgical resection is usually recommended for the treatment of pulmonary sclerosing pneumocytoma (PSP). However, no comparative study has demonstrated that surgical resection leads to improved outcomes. We aimed to compare all-cause mortality between patients with PSP who underwent surgery or did not and those without PSP. METHODS: Participants aged ≥18 years who had pathologically diagnosed PSP between 2001 to 2018, at 3 hospitals were included. Randomly selected (up to 1:5) age-, sex-, and smoking status-matched controls without PSP who were randomly selected from those who underwent health checkups including chest CT were included. Mortality was compared using Kaplan-Meier estimates and Cox proportional hazards regression models. Literature review of studies reporting PSP was also conducted. RESULTS: This study included 107 patients with PSP (surgery:non-surgery, 80:27) and 520 matched controls. There were no cases of lymph node or distant metastasis, recurrence, or mortality from PSP. No significant difference in all-cause mortality risk was observed between the PSP surgery, PSP non-surgery, and non-PSP groups (log rank test P = 0.78) (PSP surgery vs. non-PSP: adjusted hazards ratio [aHR], 1.80; 95% confidence interval [CI], 0.22-14.6; PSP non-surgery vs. non-PSP: aHR, 0.77; 95% CI, 0.15-3.86; PSP surgery vs. PSP non-surgery: aHR, 2.35; 95% CI, 0.20-28.2). In the literature review, we identified 3469 patients with PSP from 355 studies. Only 1.33% of these patients reported metastasis, recurrence, or death. CONCLUSIONS: All-cause mortality did not differ between patients with PSP and those without, irrespective of undergoing surgery. Our study and the literature review suggest that PSP has less impact on increased mortality risk.

Pulmonary sclerosing pneumocytoma: clinical features and prognosis.

BACKGROUND: Pulmonary sclerosing pneumocytoma is a kind of rare benign pulmonary tumor with potential malignancy. The clinical features, risk factors for prognosis, and optimal treatment have not been identified yet. This study aimed to investigate the clinical features and prognosis of pulmonary sclerosing pneumocytoma. METHODS: We retrospectively performed a review of pulmonary sclerosing pneumocytoma patients in West China Hospital from 2009 to 2019. The basic characteristics, treatment regimens, operation detail, postoperative variables, and follow-up time were recorded for each case. Differences in features between patients undergoing lobectomy and segmentectomy were compared. We also performed a case review and summarized reported clinical features in former studies. RESULTS: Altogether 61 pulmonary sclerosing pneumocytoma patients were retrospectively reviewed. Fifty-six patients were female and 5 were male. The patients' median age was 51 (23-73). Seven (11.48%) patients had smoking history. Twenty tumors were located in the right lung [upper lobe (n = 7), middle (n = 2), and lower (n = 11)] and 41 in the left [upper (n = 12) and lower (n = 29)]. The median tumor size was 2 (0.9-7) cm. Thirty-six (59.02%) patients underwent sublobectomy (segmentectomy or wedge resection) whereas 25 (40.98%) underwent lobectomy. All patients recovered uneventfully, and no perioperative mortality was identified. Sublobectomy showed a trend towards reduced chest tube duration and shorter postoperative hospital stays compared with lobectomy. CONCLUSIONS: The findings showed good prognosis of pulmonary sclerosing pneumocytoma and proved its benign characteristics. Sublobectomy showed advanced efficacy regarding chest tube duration and postoperative hospital stay compared with lobectomy.

Pulmonary Sclerosing Pneumocytoma: A Pre and Intraoperative Diagnostic Challenge. Report of Two Cases and Review of the Literature.

Pulmonary sclerosing pneumocytoma is a rare benign pulmonary tumor of primitive epithelial origin. Because of the unspecific radiological features mimicking malignancies and its histological heterogeneity, the differential diagnosis with adenocarcinoma and carcinoid tumors is still challenging. We report our experience of two cases of sclerosing pneumocytoma, as well as a review of the literature. Immunohistochemical findings showed intense staining of the cuboidal epithelial cells for cytokeratin-pool and TTF-1, with focal positivity for progesterone receptors. Round and spindle cells expressed positivity for vimentin, TTF-1 and focally for the progesterone receptor. Cytologic diagnosis of pulmonary pneumocytoma requires the identification of its dual cell population, made up of abundant stromal cells and fewer surface cells. Since the pre- and intraoperative diagnosis should guide surgical decision making, obtaining a sufficient specimen size to find representative material in the cell block is of paramount importance.

Clinical and histopathological features of pulmonary sclerosing pneumocytoma with dense spindle stromal cells and lymph node metastasis.

AIMS: To determine the clinicopathological features of pulmonary sclerosing pneumocytoma (PSP) with spindle cells and in cases with positive detection of PSP cells in the lymph nodes. METHODS AND RESULTS: This article report the clinical, histological and immunohistochemical features of PSP with dense spindle stromal cells in five patients (including one case with lymph node metastasis) and PSP accompanied by positive nodes in two patients out of 239 cases diagnosed at our institution between 2007 and 2019. The literature on PSP was also reviewed in detail. Six patients were female, and one (with a positive node) was male; their average age was 53 years. Thoracic imaging revealed solid tumours with clear borders and a uniform texture in six patients, but one patient had a lobulated tumour with uneven densities. All tumours were unifocal, and they had an average size of 31 mm. Tumours from five cases were mainly composed of solid regions of diffuse spindle cells rather than polygonal cells. Immunohistochemical staining demonstrated that thyroid transcription factor-1, vimentin, epithelial membrane antigen (weak) and oestrogen receptor (partial) were expressed in spindle cells. The average follow-up time was 31 months. Two of the 234 PSP cases for which adequate data were available had positive nodes (metastasis rate: 0.8%), and one of the five patients with PSP with spindle cells showed lymph node metastasis (metastasis rate: 20%). In addition, stromal cells were found to be predominant at metastatic sites. CONCLUSIONS: Spindle cells are present among the stromal cells of PSP, and not all of them are round cells. PSP patients with spindle cells or male patients may be more prone to metastasis than others.

Pulmonary sclerosing pneumocytoma remains a diagnostic challenge using frozen sections: a clinicopathological analysis of 59 cases.

AIMS: Using intraoperative frozen sections to diagnose pulmonary sclerosing pneumocytoma is always challenging. However, an accurate diagnosis is needed to guide surgical management and prevent unnecessary treatment. The aim of this study was to investigate the most frequently misdiagnosed histological patterns and evaluate the potential diagnostic pitfalls of using frozen sections. METHODS AND RESULTS: We reviewed retrospectively 59 cases of sclerosing pneumocytoma that underwent an intraoperative frozen section examination. All original frozen section slides and permanent section slides were reviewed. The rate of accurate diagnosis using frozen sections was 44.1%, the deferral rate was 15.3% and 10 cases (16.9%) were misdiagnosed as malignancy. A solid-predominant pattern is misdiagnosed more frequently than other growth patterns. We also summarised the five major diagnostic pitfalls, including hypercellularity, glandular spaces, desmoplasia-like sclerosis, cellular atypia and coagulative necrosis. CONCLUSIONS: In addition to evaluating the tumour circumscription and identifying the various growth patterns, we propose that the key to avoiding a misdiagnosis is to recognise the dual-cell populations in a tumour, i.e. cuboidal surface cells and stromal round cells.

Navigating the diagnostic maze: the challenge of sclerosing pneumocytoma in frozen sections.

Pulmonary Sclerosing Pneumocytoma (PSP) represents a rare benign tumor that exhibits a predisposition towards females. Often asymptomatic, its identification usually occurs incidentally through imaging modalities. Histologically, PSP demonstrates features consistent with pneumocytic differentiation and possesses a dual-cell population. However, in rare instances it may demonstrate pleural invasion or lymph node metastasis. Diagnosing PSP through small biopsy or frozen section presents considerable challenges attributed to its heterogeneous growth patterns and striking similarity to well-differentiated pulmonary adenocarcinoma. We report a case of PSP in a 57-year-old female smoker, presenting as a slow-growing 2.5 cm mass that recently exhibited enlargement, as noted on computed tomography (CT) scan. The recommendation for excising the mass prompted the patient to undergo a right robotic-assisted thoracoscopic procedure, which entailed wedge resection of the right lower lobe and an intraoperative consultation. A completion right lower lobectomy was performed, accompanied by lymph node dissection, following a frozen section diagnosis indicating at least adenocarcinoma in situ. The permanent section revealed bland cuboidal cells lining papillary and sclerotic areas, with occasional atypical features such as prominent nucleoli and scattered mitotic figures. Adjacent foci of atypical adenomatous hyperplasia (AAH) were noted. Immunohistochemical (IHC) staining revealed positive Napsin A, keratin AE1/3, and CK7 in surface cells but not in round cells. Both EMA and TTF1 immunostains highlighted surface cells and scattered round cells. Elastic stain highlighted visceral pleural involvement. The combined morphology and immunoprofile supported the diagnosis of PSP. This case underscores the critical importance of accurately diagnosing slow-growing pulmonary nodules, which are increasingly detected by the widespread use of imaging for various medical conditions.

Multiple pulmonary sclerosing pneumocytoma, based on a study of 36 cases worldwide.

To analyze the clinical characteristics and to improve clinicians' understanding of multiple pulmonary sclerosing pneumocytoma (PSP) patients. A total of 36 PSP patients with multiple tumor characteristics were identified from the literature search. They were compared with 43 solitary PSP patients diagnosed and treated in our hospital in the past 5 years. Thus, the pathogenesis, clinical symptoms, diagnosis methods, treatment strategies, and prognosis of pulmonary sclerosing pneumocytoma (PSP) patients with multiple tumors were explored. Patients with multiple PSP are mostly distributed in Asia (88.89%) and are females (83.33%). PSP can be located in any one lobe (19.44%), or grow across ipsilateral lobes (44.44%), or even, bilateral lobes (36.11%). It can be accompanied by metastasis (9.09%) and is prone to misdiagnosis (27.78%). Compared with solitary PSP, the occurrence age of multiple PSP was younger (mean ± standard deviation [SD]: 40.36 ± 18.12: 51.28 ± 12.74 years), but there was no significant difference in sex, tumor size (mean ± SD: 43.54 ± 46.18: 30.56 ± 17.62 mm), or symptoms. Individualized surgical resection is required for treatment, including pneumonectomy (17.65%), lobectomy (23.53%), subpulmonary lobectomy (38.24%), or combined lobectomy (5.88%). Multiple PSP is relatively rare. Surgical resection within a limited time should be the main treatment for such patients. The prognosis of patients with multiple PSP is generally good, but inappropriate diagnosis and treatment plans may lead to poor prognosis.

Pulmonary sclerosing pneumocytoma mimicking a low-grade primary malignancy: A case report.

INTRODUCTION: Pulmonary sclerosing pneumocytoma (PSP) is a rare benign tumor classified as a pulmonary adenoma. It presents as a solitary pulmonary nodule without any specific findings, often posing a diagnostic challenge. We herein present a case of a PSP with a short volume doubling time (VDT) comparable to low-grade pulmonary malignancies. CASE PRESENTATION: A 27-year-old female presented to the emergency department with a fever that had persisted for the past two days. An incidental finding on chest screening computed tomography (CT) revealed a 9 mm pulmonary nodule with a round shape and smooth margin, suggestive of a benign etiology. Follow-up CT one year later revealed an enlarged nodule exhibiting a VDT of 249 days. A thoracoscopic lingulectomy was performed, and the histopathological examination revealed papillary and diffuse proliferation of epithelial-like cells. The epithelial cells were positive for cytokeratin (CKAE1/AE3) and thyroid transcription factor 1 (TTF1), whereas the stromal cells were positive for TTF1 but negative for CKAE1/AE3. Those results were consistent with the diagnosis of a PSP. DISCUSSION: PSPs typically present as incidental pulmonary nodules with no specific findings, often posing a diagnostic challenge. The radiographic features of PSPs have mainly been explored based on the morphological findings and metabolic activity, with limited research on their growth rate, represented by the VDT. CONCLUSION: PSPs may exhibit rapid growth, demonstrating a short VDT similar to that of low-grade pulmonary malignancies. Comprehensive diagnostic testing not based solely on the growth rate for this rare condition is essential.

Pulmonary Sclerosing Pneumocytoma: A Case Revealed During 8-Year of Follow-up with CT imaging.

Pulmonary sclerosing pneumocytoma (PSP) is a rare, benign tumor. Given the challenges of a bronchoscopic diagnosis, surgery is performed during the early stages of the disease. Therefore, little is known about the growth pattern of PSP. This case of PSP was not diagnosed despite bronchoscopy, resulting in lung resection eight years after the anomaly was first identified on computed tomography (CT). This report compares the long-term follow-up of CT and pathological findings and discusses the difficulty in making a diagnosis using a bronchoscopic forceps biopsy to aid in future PSP diagnoses and treatment planning.

Revisiting Pulmonary Sclerosing Pneumocytoma.

Pulmonary sclerosing pneumocytoma (PSP) is a quite rare tumor outside Eastern countries. This rarity, together with a wide histological appearance, makes its correct identification a diagnostic challenge for pathologists under the microscope. Historically, PSP was considered a vascular-derived neoplasm (sclerosing hemangioma), but its immunohistochemical profile clearly supports its epithelial origin. No specific molecular fingerprint has been detected so far. This short narrative revisits the clinical, histological, immunohistochemical, and molecular aspects of this tumor, paying special attention to some controversial points still not well clarified, i.e., clinical aggressiveness and metastatic spread, multifocality, the supposed development of sarcomatoid change in a subset of cases, and tumor associations with lung adenocarcinoma and/or well-differentiated neuroendocrine hyperplasia/tumors. The specific diagnostic difficulties on fine-needle aspiration cytology/biopsy and perioperative frozen sections are also highlighted. Finally, a teaching case of tumor concurrence of lung adenocarcinoma, neuroendocrine lesions, and PSP, paradigmatic of tumor association in this context, is also presented.

A case report on incidentally detected pulmonary sclerosing pneumocytoma: a diagnostic challenge.

Introduction and importance: Pulmonary sclerosing pneumocytoma (PSP) is a rare non-cancerous lung tumor that is usually asymptomatic, but may cause respiratory distress if it becomes large. PSPs are often detected incidentally because of their slow growth, lack of symptoms, characteristic radiographic features, and increased use of imaging studies. Although it is not a malignant tumor, it can mimic malignancy on imaging and histology, leading to misdiagnosis and unnecessary surgery. Case presentation: A 23-year-old asymptomatic female was incidentally diagnosed with PSP during evaluation for a breast fibroadenoma. A chest CT revealed a 3 cm lobulated mass in the left upper lobe. Cytology showed malignant cells with necrotic debris. Immunohistochemistry was positive for TTF-1 and EMA, negative for p63 and AE1/AE3. Histopathology confirmed a well-circumscribed benign neoplasm, consistent with pulmonary sclerosing pneumocytoma. There was no mediastinal lymph node invasion, and the post-surgery prognosis was good. Clinical discussion: PSP is a slow-growing tumor that is often asymptomatic until it reaches a significant size. Owing to their well-circumscribed margins and the presence of calcifications, they are often detected incidentally during imaging studies, such as routine chest radiography or CT scans for unrelated conditions. Although these tumors are often incidental, it is important to diagnose and treat them appropriately to prevent potential complications and malignant transformation. Conclusion: The findings of this study contribute to the existing literature, increase awareness of this rare tumor, and provide insights into its diagnosis, treatment, and follow-up.

Pulmonary sclerosing pneumocytoma containing spindle cells with sarcomatoid features: a case report with literature review.

BACKGROUND: Pulmonary sclerosing pneumocytoma (PSP) is an uncommon benign neoplasm originated from pneumocyte and PSP with malignant transformation is extremely rare. CASE PRESENTATION: We report a case of PSP of a 65-year-old male patient presented as a lobulated mass in the upper lobe of the left lung, in which part of the stromal round cells transformed to spindle cells with sarcomatoid features and showed no specific differentiation. The patient underwent partial lobectomy without further treatment. No recurrence and metastasis was found after eight month's follow up. CONCLUSIONS: To our knowledge, this is the first case of PSP with sarcomatoid malignant transformation devoid of differentiation. Our case adds the evidence in that a subset of PSP bear malignant potential and more studies are needed in order to determine the treatment and prognosis to such patients.

Central and peripheral pulmonary sclerosing pneumocytomas: multi-phase CT study and comparison with Ki-67.

BACKGROUND: This study aimed to evaluate the multi-phase CT findings of central and peripheral pulmonary sclerosing pneumocytomas (PSPs) and compared them with Ki-67 to reveal their neoplastic nature. PATIENTS AND METHODS: Multi-phase CT and clinical data of 33 PSPs (15 central PSPs and 18 peripheral PSPs) were retrospectively analyzed and compared their multi-phase CT features and Ki-67 levels. RESULTS: For quantitative indicators, central PSPs were larger than peripheral PSPs (10.39 ± 3.25 cm3 vs. 4.65 ± 2.61 cm3, P = 0.013), and tumor size was negatively correlated with acceleration index (r = -0.845, P < 0.001). The peak enhancement of central PSPs appeared in the delayed phase, with a longer time to peak enhancement (TTP, 100.81 ± 19.01 s), lower acceleration index (0.63 ± 0.17), progressive enhancement, and higher Ki-67 level. The peak enhancement of peripheral PSPs appeared in the venous phase, with the shorter TTP (62.67 ± 20.96 s, P < 0.001), higher acceleration index (0.99 ± 0.25, P < 0.001), enhancement washout, and lower Ki-67 level. For qualitative indicators, the overlying vessel sign (86.67% vs. 44.44%, P = 0.027), prominent pulmonary artery sign (73.33% vs. 27.78%, P = 0.015), and obstructive inflammation/atelectasis (26.67% vs. 0%, P = 0.033) were more common in central PSPs, while peripheral PSPs were more common with halo sign (38.89% vs. 6.67%, P = 0.046). CONCLUSIONS: The location of PSP is a possible contributing factor to its diverse imaging-pathological findings. The tumor size, multi-phase enhancement, qualitative signs, and Ki-67 were different between central and peripheral PSPs. Combined tumor size, multi-phase findings, and Ki-67 level are helpful to reveal the nature of the borderline tumor.

Magnetic resonance imaging findings of pulmonary sclerosing pneumocytoma: a case report and literature review.

Background: Pulmonary sclerosing pneumocytoma (PSP) is a rare lung tumor that is mostly isolated and commonly reported among middle-aged East Asian women. Recently, Immunohistochemistry (IHC) analysis has suggested that PSP is of primitive epithelial origin, most likely derived from type II alveolar air cells. Patients with PSP are generally asymptomatic and usually detected for other unrelated reasons during routine imaging. Several studies have already investigated the computed tomography (CT) features of PSP and their correlation with pathology. Magnetic resonance imaging (MRI) is a radiation-free imaging technique with important diagnostic value for specific pulmonary nodules. However, very few case reports or studies focus on the MRI findings of PSP. Case report: We reported a case of an asymptomatic 56-year-old female with a solitary, well-defined soft-tissue mass in the lower lobe of the left lung. The mass showed iso-to-high signal intensity (SI) than muscle on T1-weighted image (T1WI) and T2-weighted image (T2WI) and a much higher SI on fat-suppressed T2WI, diffusion-weighted image, and apparent diffusion coefficient image. Contrast-enhanced fat-suppressed T1WI revealed noticeable inhomogeneous progressive enhancement throughout the mass. The mass revealed early enhancement without a significant peak, followed by a plateau pattern on dynamic contrast-enhanced MRI images. The patient underwent left basal segmentectomy via thoracoscopic surgery. Histopathology and IHC results of the surgical specimen confirmed that it was a PSP. We concluded that the MRI findings of PSP might adequately reflect the different components within the tumor and aid clinicians in preoperative diagnosis and assessment. To the best of our knowledge, this is the most comprehensive case report on the MRI findings of PSP. Conclusion: The MRI findings of PSP correspond to its histopathological features. Here, we present a case of PSP with the most comprehensive MRI findings, emphasizing the importance of multiple-sequence MRI in diagnosing PSP.

Giant pulmonary sclerosing pneumocytoma with potentially malignant biological behavior: a case report and literature review.

Background: Pulmonary sclerosing pneumocytoma (PSP) is a rare benign lung tumor which generally presents as a solitary pulmonary nodule in middle-aged females. However, the PSP in some patients exhibits potentially malignant biological behavior, with recurrence and lymphatic or distant metastasis being observed. Case Description: We encountered a case of a 46-year-old female with an inordinately massive tumor 9.5 cm in diameter and a relatively high Ki-67 proliferation rate. Fine needle aspiration (FNA) played a significant but limited role in the preoperative diagnosis: the computed tomography (CT)-guided lung puncture biopsy was consistent with the typical pathology of PSP; however, endobronchial ultrasound-guided transbronchial lung biopsy (EBUS-TBLB) could not provide a definitive diagnosis. The patient ultimately underwent thoracoscopic resection and mediastinal lymph node dissection. Here, we provide a review of the literature on patients with PSP with malignant biological behavior to raise awareness of the malignant potential of PSP and describe our experience to inform future management. Conclusions: PSP lacks specificity in its clinical and radiological characteristics and has complex pathological manifestations. FNA is valuable in the diagnosis and differential diagnosis of PSP but involves the risk of misdiagnosis or missed diagnosis. Additionally, we believe that the accepted benign features of PSP need to be updated and that the potential malignant features of PSP should be carefully monitored. Surgical resection is curative but strict follow-up is crucial.

Clinical Characteristics of Malignant Pulmonary Sclerosing Pneumocytoma Based on a Study of 46 Cases Worldwide.

Objective: To analyze the clinical characteristics of patients with malignant pulmonary sclerosing pneumocytoma (PSP) with metastasis, recurrence, and growth and to improve clinicians' understanding of PSP in patients with malignant tumor characteristics. Methods: A total of 46 PSP patients with malignant tumor characteristics were identified in the literature search and compared with 38 patients with benign PSP diagnosed and treated in our hospital in the past 5 years. We explored the pathogenesis, clinical symptoms, diagnostic methods, treatment strategies and prognosis of PSP patients with malignant tumor. Results: The characteristics of young age (≤41 years old), larger tumor (≥36mm), lymph node metastasis and distribution in East Asians are indicative of PSP with malignant potential. Such patients should undergo segmental resection or lobectomy, combined with necessary lymph node dissection or biopsy. All patients with PSP should have an entire course of follow-up management, because they may have an adverse prognosis such as recurrence, growth, metastasis, and even death. Conclusion: PSP has the potential for malignancy. Anatomical lobectomy or segmental resection combined with lymph node dissection should be performed in PSP with some specific characteristics. Inappropriate diagnosis and treatment may lead to poor prognosis in PSP patients.

An advanced molecular medicine case report of a rare human tumor using genomics, pathomics, and radiomics.

Background: Pulmonary Sclerosing Pneumocytoma (PSP) is a rare tumor of the lung with a low malignant potential that primarily affects females. Initial studies of PSP focused primarily on analyzing features uncovered using conventional X-ray or CT imaging. In recent years, because of the widespread use of next-generation sequencing (NGS), the study of PSP at the molecular-level has emerged. Methods: Analytical approaches involving genomics, radiomics, and pathomics were performed. Genomics studies involved both DNA and RNA analyses. DNA analyses included the patient's tumor and germline tissues and involved targeted panel sequencing and copy number analyses. RNA analyses included tumor and adjacent normal tissues and involved studies covering expressed mutations, differential gene expression, gene fusions and molecular pathways. Radiomics approaches were utilized on clinical imaging studies and pathomics techniques were applied to tumor whole slide images. Results: A comprehensive molecular profiling endeavor involving over 50 genomic analyses corresponding to 16 sequencing datasets of this rare neoplasm of the lung were generated along with detailed radiomic and pathomic analyses to reveal insights into the etiology and molecular behavior of the patient's tumor. Driving mutations (AKT1) and compromised tumor suppression pathways (TP53) were revealed. To ensure the accuracy and reproducibility of this study, a software infrastructure and methodology known as NPARS, which encapsulates NGS and associated data, open-source software libraries and tools including versions, and reporting features for large and complex genomic studies was used. Conclusion: Moving beyond descriptive analyses towards more functional understandings of tumor etiology, behavior, and improved therapeutic predictability requires a spectrum of quantitative molecular medicine approaches and integrations. To-date this is the most comprehensive study of a patient with PSP, which is a rare tumor of the lung. Detailed radiomic, pathomic and genomic molecular profiling approaches were performed to reveal insights regarding the etiology and molecular behavior. In the event of recurrence, a rational therapy plan is proposed based on the uncovered molecular findings.