Sclerosing Pneumocytoma with Lymph Node Metastasis

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.

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.

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.

Completion lower lobectomy after basal segmentectomy for pulmonary sclerosing pneumocytoma with lymph node metastasis

A 20-year-old man was referred to our hospital because of a tumor in his left lung. Chest computed tomography showed a 35-mm nodule in the left lower lung lobe. Bronchoscopic examination and cryobiopsy were performed, which revealed suspicion for sclerosing pneumocytoma. We performed basal segmentectomy, and intraoperative-frozen pathological examination revealed no metastases in the segmental lymph nodes. However, the postoperative pathological diagnosis revealed metastasis in these nodes. We performed additional resection of segment 6 (completion lower lobectomy) and hilar and mediastinal lymph node dissection 2 weeks after the first surgery. The postoperative course was favorable, and the patient was discharged 13 days after the second surgery. Pathological examination of the additional resected specimens revealed lymph node metastases in the interlobar and mediastinal lymph nodes. Pulmonary sclerosing pneumocytoma with lymph node metastasis is extremely rare, and its prognosis is unclear. Recurrence has been reported rarely, and long-term follow-up is required.

Case Report and Literature Review: Pulmonary Sclerosing Pneumocytoma With Multiple Metastases Harboring AKT1 E17K Somatic Mutation and TP53 C176Y Germline Mutation

Pulmonary Sclerosing Pneumocytoma (PSP) is considered as a benign tumor, although a few cases have been reported to have multiple lesions, recurrence, and even regional lymph nodes (LNs) metastasis. Here, we report a case of PSP with atypical histologic features and malignant biological behavior, and explore its molecular genetic changes. The 23-year-old male showed a 6.5-cm pulmonary nodule in the right middle lobe (RML) and enlarged media stinal LNs. He underwent thoracoscopic RML lobectomy, systematic LNs dissection, and mediastinal lymphadenectomy. The metastases to the cervical LNs and liver were detected in a short period and then resected. Postoperative pathological examination confirmed the diagnosis of PSP in all the lesions, based on the histological characteristics and immune phenotypes. Furthermore, whole-exome sequencing identified both AKT1 E17K somatic mutation and TP53 C176Y germline mutation in this case. Thus, we presented an extremely rare case of atypical PSP with rapid recurrence and multiply metastases, which can easily be misdiagnosed as primary lung cancer. In addition, PSP-specific AKT1 E17K somatic E17K somatic mutation accompanied with TP53 C176Y germline mutation may contribute to the malignant clinical course of this tumor.

A case of pulmonary sclerosing pneumocytoma diagnosed preoperatively using transbronchial cryobiopsy

Background

The preoperative diagnosis of pulmonary sclerosing pneumocytoma (PSP) is complicated since PSP has several histological structural patterns in the same neoplasm; hence, it is sometimes pathologically misdiagnosed as adenocarcinoma or carcinoid. In recent years, with the prevalence of transbronchial cryobiopsy (TBLC), we are able to obtain larger specimens than previously. However, to date, there have been no reports describing PSP diagnosed using TBLC.

Case reports

A 43-year-old man was referred to our hospital for an abnormal lesion in the left lung discovered on routine health examination. A computed tomography scan of the chest revealed a 14-mm heterogeneous round nodule with surrounding ground-glass opacity in the left lower lobe. The tumor size increased to 18 mm in three weeks, and he developed bloody sputum. TBLC was performed using radial endobronchial ultrasonography and fluoroscopy. An occlusion balloon and prophylactic epinephrine were used to prevent severe bleeding. Histologically, epithelioid cells with solid proliferation, various papillary lesions, and hemosiderin-laden histiocytes were observed. Immunohistochemical staining revealed the histiocytes positive for thyroid transcription factor-1 and vimentin, and the type II pneumocyte-like-cells positive for cytokeratin 7. The tumor was preoperatively diagnosed as a PSP; the patient underwent left basal segmentectomy and consequently, a final diagnosed of PSP was formulated.

Conclusion

We report the first case of PSP preoperatively diagnosed using TBLC. Therefore, cryobiopsy could be beneficial in the preoperative diagnosis of PSP.

Pulmonary sclerosing pneumocytoma masquerading adenocarcinoma with co-existing BRAF V600E and PTEN mutation

We report a case of a massive primary sclerosing pneumocytoma (PSP) involving the right lower lobe adhering esophagus with small synchronous PSP on the superior segment of the left lower lobe with concurrent mutation for B-RAF proto-oncogene, serine/threonine kinase (BRAF V600E), and phosphatase and tensin homolog (PTEN) gene in a young female. She underwent right lower lobectomy and mediastinal lymph node dissection under single lung ventilation with tumor-free margins on diagnosis-based findings of preoperative computed tomography-guided biopsy and positron emission tomography. Histopathology was suggestive of PSP-papillary variant with concurrent mutation of BRAF V600E and PTEN genes. Post-operative follow-up at four weeks was uneventful. She has to undergo wedge resection for the contralateral disease after six weeks following recovery from the first surgery.

Sclerosing Pneumocytoma: A Host for a Typical Carcinoid With Pleural Metastasis-A Wolf in Sheep`s Clothing

Sclerosing pneumocytoma (SP) is a rare primary lung tumor. Typical carcinoids (TCs) count for 2% of lung malignancies. A description of a combined neoplasm of SP with a nodal and pleural metastasized TC has, to our knowledge, never been published. A 57-year-old actively smoking woman received a diagnosis of a lesion in the left lower lobe via a screening CT scan for rheumatoid arthritis. A fluorodeoxyglucose-PET scan confirmed a 21 × 26 × 16 mm (standardized uptake maximum value, 3.0), well-circumscribed round lesion with calcification, which was thought to be most probably benign. No mediastinal lymph node enlargement or fluorodeoxyglucose uptake was detected. The results of routine laboratory tests, respiratory function tests, and physical examination were unremarkable. In diagnostic thoracoscopy pleural, diaphragmatic, and pericardial lesions were discovered and biopsied in addition to a wedge resection. After diagnosis of a pleural metastasized TC mixed with SP, radical resection and systemic lymph node dissection were performed. The patient is in remission after 36 months of follow-up.

Analysis of the F-18 FDG PET/CT features of pulmonary sclerosing pneumocytoma

PURPOSE

This retrospective study aimed to analyzed the F-18 fluorodeoxyglucose PET/computed tomography (F-18 FDG PET/CT) features of pulmonary sclerosing pneumocytoma (PSP) to improve the understanding and preoperative diagnostic efficacy of this rare disorder.

METHODS

FDG PET/CT images from 11 patients with 22 lesions (including one patient with 12 lesions) proven PSP in our hospital were reviewed. We summarized the PET/CT features of PSP and analyzed the correlation between FDG uptake and tumor size.

RESULTS

PET/CT imaging revealed all tumors located in each lobe of the two lungs randomly. All 22 tumors were round or oval nodules; 15 had smooth margins, six were lobulated, six were calcified, and one had a ground-glass halo sign. The mean diameter of these tumors was 19.2 ± 7.8 mm (range: 8-34 mm); the mean maximum standardized uptake value (SUVmax) was 2.8 ± 1.3 (range: 1.1-7.4). Sixteen of the lesions exhibited mild to moderate FDG uptake (mean SUVmax 2.3 ± 0.6), and six of the lesions exhibited intense FDG uptake (mean SUVmax 4.3 ± 1.6). A positive correlation was observed between FDG uptake and tumor size (P <0.05).

CONCLUSION

Single round or ovoid soft-tissue lesions with smooth margins, and mild to moderate FDG uptake on PET/CT images in middle-aged females, suggest a possible diagnosis of PSP. For some atypical cases with intense FDG uptake, a diagnosis of PSP also can be considered. A statistically significant positive correlation was found between SUVmax and PSP lesion size in our study.

Correlation Between Pulmonary Sclerosing Pneumocytoma Features and MSCT Imaging Manifestations in 34 Patients: Implications for Precision Medicine

Objective: To identify and analyze the multi-slice computed tomography (MSCT) imaging manifestations and clinicopathological features of PSP to improve the preoperative and intraoperative diagnosis of the disease. Method: This was a retrospective study conducted on the imaging and clinicopathological data of the PSP patients treated in two major hospitals in China from October 2001 to December 2019. The locations of lung lesions, clinical symptoms, surgical complications, MSCT imaging features, and the corresponding relationship with clinicopathological features were assessed. Then, a new diagnostic approach was defined and used to train imaging and pathological doctors (experimental group). Then, the diagnostic accuracy of the experimental group was evaluated in preoperative and intraoperative diagnosis of PSP. Results: Thirty-four PSP cases were analyzed (mean: 51.42; range: 39-69 years old). The peripheral type was more common, while 92% of the lesions located in the middle lobe of the right lung and the lower lobe of bilateral lungs. The shortest lesion edge-pleura distance ranged 0 to 30 mm and 46% of the lesions (16/34) were attached to the pleura, 62% (21/34) located at 0-5 mm, 92% (31/34) within 20 mm from the pleura. Diameters of the lesions ranged 8.58 to 68.41 mm, while most of them were 20-40 mm. All lesions showed enhancement, and 97% (33/34) were unevenly enhanced. PSP volume was negatively correlated with the total degree of enhancement (r = -0.587, p < 0.01), and the volume difference between the obvious enhancement zone and the slight enhancement zone (r = -0.795, p < 0.01). Welt vessel sign was observed in 61.7% (21/34) of cases, and none of welt vessels entered into the lesions. Vascular-like enhancement area inside the lesion showed no significant correlation with the welt vessels outside the lesion, and no case showed entrance of bronchus into the lesion. The trained experimental group showed significantly greater diagnostic accuracy than the control group. In particular, the accuracy rate of intraoperative frozen section diagnosis was 60% higher in the experimental group than the control group. Conclusion: PSP has characteristic imaging manifestations, which can be utilized to improve the preoperative and intraoperative diagnostic coincidence rate of PSP.

[Analysis of Clinical Characteristics of 35 Cases of Pulmonary Sclerosing Pneumocytoma]

BACKGROUND

Pulmonary sclerosing pneumocytoma (PSP) is rare benign lung tumor which usually develops in middle-aged women without typical clinical and imaging findings. PSP consists of two basic cell types (surface cubic epithelial cells and round mesenchymal cells) and four histological types (hemorrhagic, sclerotic, solid and papillary). It grows slowly, but it can metastasize to distant organs. The pathology before surgery is easily misdiagnosed. This study aims to improve clinicians' understanding of PSP by discussing the clinical characteristics of the disease.

METHODS

This represents a retrospective study of thirty-five patients diagnosed with pulmonary sclerosing pneumocytoma by pathological examination from January 2011 to December 2019.

RESULTS

A total of 35 patients in this study, 12 cases were male and 23 cases were female, the average age is 51 years old. 7 cases were discovered accidentally by physical examination or routine chest computed tomography (CT), and 28 cases were found due to symptoms such as cough, sputum, hemoptysis and chest pain. The imaging changes is mainly featured with isolated or clear circular or round-like single nodule and lump in the lungs. In this group, 12 cases underwent percutaneous lung biopsy, only 7 cases were diagnosed with PSP. A total of 28 patients underwent surgery, 24 cases underwent rapid frozen pathological biopsy, only 5 cases diagnosed with PSP. Postoperative pathological examination results shows that 1 case was diagnosed with keratotic squamous cell carcinoma with partial PSP, and the rest were diagnosed with PSP. The surgical and non-surgical patients were followed up for 1 to 8 years after discharge, and the overall recovery was good. The patients were no recurrence and metastasis on chest CT review.

CONCLUSIONS

PSP is a clinically rare benign lung tumor, which is more common in middle-aged women. The clinical manifestations and imaging features are lack of significance. Percutaneous lung puncture pathological examination and intraoperative rapid frozen pathological sections often leads to misdiagnosis. Final diagnosis relies on postoperative pathological work-up for most cases.

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.

First report of pulmonary sclerosing pneomucytoma with malignant transformation in both cuboidal surface cells and stromal round cells: a case report

BACKGROUND

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign tumor. Although lymph node metastasis has been reported, it is still considered benign. No malignant transformation has been reported. This is the first case of malignant transformation of both cuboidal surface cells and stromal round cells.

CASE PRESENTATION

A 64-year-old male had been complaining of intermittent hemoptysis several times per day for eight months. Chest computed tomography scan showed parenchymal infiltration with cystic lesion in the right lower lobe accompanied by enlarged right hilar lymph nodes. Lobectomy and systemic lymph node dissection was performed. On grossly pathological examination, the lesion was 50 mm from the bronchial stump. It was a mixture of both cystic and solid components and 30 mm * 20 mm in size with unclear border. Microscopically, the cuboidal surface cells transformed to adenocarcinoma. The stromal round cells also had a malignant transformation. The Ki-67 proliferation index in malignant cuboidal surface cells and stromal round cells were 70 and 55%, respectively. Furthermore, E-cadherin was negative in primary tumor but positive in metastatic lymph node, which suggested that the mesenchymal to epithelial transition may play an important role in lymph node metastasis.

CONCLUSIONS

To our knowledge, we present the first case of malignant transformation of both cuboidal surface cells and stromal round cells in PSP. The process of mesenchymal to epithelial transition may play an important role in lymph node metastasis.

Pulmonary sclerosing pneumocytoma demonstrating intratumoral hematoma

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign neoplasm of the lung that shows a slow growing pattern. Corresponding contrast-enhancements on chest computed tomography (CT) vary widely in both patterns and degrees. However, gross intratumoral radiolucencies, attributable to cyst formation, necrosis, or intratumoral hematoma, were rarely reported in PSP cases. We herein report on a case involving a 61-year-old Japanese women with PSP demonstrating CT-defined intratumoral radiolucency. A chest CT scan revealed a solitary and well-circumscribed nodule that showed a substantial growth over a 7-year period. The tumor was composed of a solid portion visualized with contrast-enhancement and a central radiolucency on a chest CT scan. A positron emission tomography scan revealed high uptake of fluorodeoxyglucose on the solid portion of the tumor, but the radiolucent portion showed negative uptake. The examination of a tumor specimen obtained by a percutaneous core needle biopsy aided in determining a pathological diagnosis of PSP, and the patient subsequently received a right lower lobectomy of the lung. The portion of central radiolucency on the CT scan corresponding to the surgical specimen was pathologically proven to be gross hematoma.

Ectopic ACTH Syndrome With Association of Multiple Pulmonary Sclerosing Pneumocytomas and Multiple Carcinoid Tumorlets

We present the case of multiple sclerosing pneumocytomas (SPs) associated with ACTH-secreting carcinoid tumorlets responsible for an ectopic Cushing syndrome (ECS). SP is a rare benign tumor originating from pulmonary epithelial cells. An 18-year-old male presented with shortness of breath and right-sided chest pain after exercise. Chest radiograph indicated right pneumothorax and bilateral lung nodules. CT imaging showed innumerable bilateral hypodense pulmonary nodules and a wedge resection gave the definitive diagnosis of SP with associated carcinoid tumorlets. Two years later, he presented with severe back pain in context of thoracic vertebral compression fracture. He had central fat accumulation, violaceous striae, proximal muscle weakness, hypertension, and diabetes. MRI of the pituitary gland showed a 7-mm adenoma. Inferior petrosal sinus sampling with no central-to-periphery gradient suggested an ectopic origin of ACTH, which was confirmed by ACTH expression in a subset of tumorlet cells in the lung lesions. The patient was started on ketoconazole and subsequently underwent a bilateral adrenalectomy. During follow-up, CT scans showed no growth of the lesions, except for the most recent CT scan, in which an increase in the size of the largest nodule was described. Ten years after the diagnosis, the patient remains asymptomatic of his pulmonary lesions. This article provides a case of ECS in the setting of multiple SP with associated carcinoid tumorlets.

Sclerosing pneumocytoma mixed with a typical carcinoid tumor: A case report and review of literature

RATIONALE

Sclerosing pneumocytoma accompanied with other type of tumor in one patient is very rare. Here, we report a case of a sclerosing pneumocytoma mixed with a typical carcinoid tumor in a same neoplasm.

PATIENT CONCERNS

A 55-year-old woman incidentally detected a space-occupying lesion of right lung in routine health examination. The patient was asymptomatic and there were no positive findings in routine laboratory examination, physical examination, and pulmonary function test. Computed tomography revealed a solitary round mass in the middle lobe of the right lung.

DIAGNOSIS

The lesion was diagnosed as a sclerosing pneumocytoma accompanied with a typical carcinoid tumor of the right lung.

INTERVENTION

The patient underwent thoracoscopic lobectomy in our hospital.

OUTCOMES

The postoperative course was uneventful.

LESSONS

This case is rare and noteworthy for a lesion containing two different types of neoplasms, which may cause diagnostic difficulties.

Sclerosing Pneumocytoma: A Ten-Year Experience at a Western Balkan University Hospital

Background and objective: Sclerosing pneumocytoma is a rare, benign tumor of the lung that represents a diagnostic challenge due to the diversity of pathohistological findings. The aim of this study was to present a 10-year experience with sclerosing pneumocytoma of a large center for the diagnosis and treatment of pulmonary diseases, and to emphasize differential diagnostic dilemmas as a potential source of errors. Material and Methods: This represents a retrospective study of six patients diagnosed and treated with sclerosing pneumocytoma in the 10-year period. The study analyzed various parameters, which are: Sex, age, symptoms, size and localization of the tumor, and its gross and histological features. Results: Sclerosing pneumocytoma was more frequently diagnosed in females (83.34%). The patients ranged in age from 38 to 61. Most of the patients (66.66%) were asymptomatic. Two patients underwent a video-assisted thoracoscopic surgery, two patients had a video-assisted minithoracotomy, and two patients underwent a thoracotomy in order to remove the tumor. The tumor was localized in the left lower lobe, in the right upper lobe, and in the right lower lobe in 50%, 33.34%, and 16.66% of patients, respectively. The tumor size ranged from 1 to 2.5 cm. A pathohistological examination of all six cases reported that all four major histological patterns were found in tissue sections: solid, papillary, sclerosing, and hemorrhagic. In all six cases, an immunohistochemical analysis showed positive expression of TTF-1 and panCK in surface epithelial cells, and TTF-1 positivity and panCK negativity in round stromal cells. Conclusions: Sclerosing pneumocytoma is a strictly histological diagnosis supported by clinical and radiological findings and corresponding immunohistochemical methods. Lung pathologists should always keep this tumor in mind, since its spectrum of differential diagnosis is wide, and therefore it can be an important diagnostic pitfall.

Sclerosing pneumocytoma with metastasis to the mediastinal and regional lymph nodes

Sclerosing pneumocytoma (SP) is an uncommon benign tumor, and metastasis of SP has been rarely reported. Here, we report the case of a 26-year-old woman with surgically confirmed SP. The tumor diameter was 40 mm, and metastasis to mediastinal and regional lymph nodes was observed. Immunohistochemically, both surface and round cells were positive for epithelial membrane antigen, thyroid transcription factor 1, and vimentin. Only surface cells expressed creatine kinase, carcinoembryonic antigen, napsin A, and cytokeratin 7, and only round cells expressed progesterone receptor. Ki-67 was detected in ~3% of cells, and the rate of weak positive p53 staining was 3%. Both cell types were negative for chromogranin A, synaptophysin, CD3, and CK20. Multiple metastases in a young SP patient are very rare, and potential mechanisms of metastasis may be related to epithelial-mesenchymal transformation.

Analysis of the clinical differentiation of pulmonary sclerosing pneumocytoma and lung cancer

Background

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign lung tumor. This study investigated the diagnostic experience of PSP and lung cancer.

Methods

This study is a retrospective study. We observed the locations of lung lesions, imaging form and clinical symptoms, and recorded the surgical complications through comparing patients with PSP and lung cancer.

Results

From December 2012 to February 2017, 187 PSP cases and 197 lung cancer cases were collected. PSP was commonly found in women (88.2%), often occurred in the left lower lobe (32.6%), and was associated with a lesion size of 10-20 mm (48.7%). PSP patients presented with cough, sputum, chest pain, and most patients had a single lesion, which could showed no clear boundary. Most PSP patients exhibited no enlargement of mediastinal lymph nodes, had no involvement of the blood vessels, and had low computed tomography (CT) values (low Hounsfield units). Lung cancers were more commonly found in men (69.0%), with the lesions scattered throughout all lobes of the lung. Cases with a tumor size >30 mm accounted for 76.2% of patients. Lung cancer patients also presented systemic symptoms, and the tumors were found to have unclear boundaries. Moreover, patients presented with enlarged mediastinal lymph nodes, high CT values, and heterogeneous internal tumor texture.

Conclusions

This study showed that PSP was rare and difficult to differentiate from lung cancer. PSP was often found in 40-70-year-old non-smoking women and most patients presented with cough and sputum. Patients often had a single lesion, which was commonly located in the left lower lobe and could have unclear boundaries. The majority of patients exhibited no enlargement of mediastinal lymph nodes and had low CT values. Therefore, our results can provide some basis for the differential diagnosis of PSP and lung cancer.