So-called sclerosing hemangioma of lung: current concept

Characteristics of metastatic and non-metastatic pulmonary sclerosing pneumocytomas

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.

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.

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.

Challenging of frozen diagnoses of small sclerosing pneumocytoma

Aims

An increasing number of small pulmonary nodules are being screened by CT, and an intraoperative diagnosis is necessary for preventing excessive treatment. However, there is limited literature on the frozen diagnosis of small sclerosing pneumocytomas (SPs). In particular, tumours smaller than 1 cm are challenging for pathologists performing intraoperative frozen diagnosis.

Methods

In total, 230 cases of SP were surgically resected between January 2015 and March 2019 at Shanghai Chest Hospital, and of them, 76 cases were smaller than 1 cm. The histology and clinical information of these 76 cases (33.0%, 76/230) were reviewed retrospectively, 54 cases of which were diagnosed intraoperatively, and the pitfalls were summarised. All diagnoses were confirmed on permanent sections and immunohistochemical sections.

Results

Histologically, 78.9% (60/76) of the small SP was dominated by one growth pattern, and solid and papillary growth pattern were the most commonly misdiagnosed circumstances. The rate of intraoperative misdiagnosis of these SP smaller than 1 cm was 11.1% (6/54).

Conclusions

The main reason for misdiagnosis was failure to recognise the dual cell populations and the cellular atypia. Diagnostic clues include the gross morphology, the presence of dual-cell populations and a hypercellular papillary core, foam cell accumulation in glandular spaces and haemorrhage and haemosiderin on the periphery. In spite of awareness of pitfalls some cases may still be essentially impossible to diagnose on frozen section.

68Ga-DOTATATE-avid pulmonary sclerosing pneumocytoma in a man of North African descent: Case report, imaging findings and pathology

Pulmonary sclerosing pneumocytoma (PSP) is a benign tumor originating from primitive respiratory epithelium which tends to present as an asymptomatic solitary lesion in the periphery of the lung. It primarily occurs in women, with a 5:1 ratio of female to male, and in East Asian populations. We describe a rare case of a gallium-68 (⁶⁸Ga)-DOTATATE avid PSP in a middle-aged man of North African ancestry. Contrast-enhanced computed tomography (CT) revealed an enhancing ovoid 2-cm solid lesion within the periphery of the left upper lobe abutting the superior portion of the lateral left ventricular wall. A fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) demonstrated low-level FDG uptake, but a ⁶⁸Ga-DOTATATE PET/CT showed avid tracer uptake, concerning for a carcinoid tumor. The lesion was surgically excised, and the histopathologic analysis revealed the typical morphologic and histochemical markers of a PSP. We conclude that, although rare, PSP can be a differential consideration when evaluating a ⁶⁸Ga-DOTATATE-avid solitary lung nodule concerning for carcinoid tumor, in all genders and in ethnicities other than East Asian.

Pulmonary sclerosing pneumocytoma in an 18-year-old male patient: A case report and literature review

RATIONALE

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign tumor of the lung, mostly presented in Asian middle-aged women. Initially, it was considered as a vascular origin tumor, but then research evidence showed that it was derived from natural epithelial tissue. On imaging, this tumor may be found as a solitary well-circumscribed lung parenchymal lesion, and is often located in juxtapleural or juxtafissural positions. On histopathology, it consists of cuboidal surface cells and stromal round cells, both of which are positive for thyroid transcription factor-1. Here we report a case of a young PSP male patient and review the relevant literature in order to improve our understanding of this disease.

PATIENT CONCERNS

An 18-year-old man was referred to our hospital after accidentally finding a lesion on chest X-ray. Contrast-enhanced computed tomography showed a soft tissue mass with homogeneous enhancement in the left lower lobe posterior segment.

DIAGNOSES

The diagnosis of PSPs was confirmed by histopathological examination.

INTERVENTIONS AND OUTCOMES

The patient underwent a thoracoscopic wedge resection and was followed-up after that. One month later, he had good performance status with no recurrent tumors.

LESSONS

PSP in a young man is really uncommon, and is confused with malignant tumors. A histopathological examination is considered as the diagnostic gold standard for this uncommon tumor. Surgery is the main treatment.

AKT1 internal tandem duplications and point mutations are the genetic hallmarks of sclerosing pneumocytoma

Sclerosing pneumocytoma is a unique benign neoplasm of the lungs. The molecular alterations in sclerosing pneumocytoma are not well understood. In a previous whole-exome sequencing study, recurrent AKT1 point mutation was observed in about half of the cases of sclerosing pneumocytoma. However, in the remaining half, cancer-related mutations have still not been identified. In this study, we first analyzed the raw sequence data from the previous whole-exome sequencing study (PRJNA297066 cohort). Using Genomon-ITDetector, a special software for detection of internal tandem duplications, we identified recurrent internal tandem duplications in the AKT1 gene in 22 of the 44 tumor samples (50%). All the cases positive for AKT1 internal tandem duplications lacked AKT1 point mutations. Next, we performed targeted next-generation sequencing in an independent cohort of sclerosing pneumocytoma from our hospital (VGH-TPE cohort), and again identified recurrent AKT1 internal tandem duplications in 20 of the 40 (50%) tumor samples analyzed. The internal tandem duplications resulted in duplications of 7 to 16 amino acids in a narrow region of the Pleckstrin homology domain of the AKT1 protein. This region contains the interaction interface between the Pleckstrin homology and kinase domains, which is known to play a critical role in the activation of the AKT1 protein. Moreover, we found that AKT1 internal tandem duplications were mutually exclusive of other forms of AKT1 mutations, including point mutations and short indels. Taking all forms of AKT1 mutations together, we detected AKT1 mutations in almost all the sclerosing pneumocytomas in our study (PRJNA297066 cohort: 41 out of 44 cases, 93%; VGH-TPE cohort: 40 out of 40 cases, 100%). Our results suggest that AKT1 mutation is the genetic hallmark of sclerosing pneumocytoma. These results would help in better understanding of the pathogenesis of sclerosing pneumocytoma.

Pulmonary sclerosing pneumocytoma: Cytomorphology and immunoprofile

BACKGROUND

Sclerosing pneumocytoma (SP) is a rare, benign pulmonary neoplasm. To the authors' knowledge, the current study is the first to evaluate the cytomorphology and immunoprofile of SP in a series.

METHODS

A total of 9 fine-needle aspiration cases of SP (7 of which were computed tomography guided and 2 of which were endobronchial ultrasound guided) including histopathology and immunohistochemistry were collected from 5 institutions.

RESULTS

The female-to-male ratio was 3.5:1, and the mean age of the patients was 54 years (range, 27-73 years). All cases presented as lung nodules, with a mean size of 2.2 cm (range, 1.1-5 cm), and were interpreted as atypical on rapid on-site evaluation. The final diagnoses were favor adenocarcinoma (1 case), well-differentiated lung adenocarcinoma (2 cases), low-grade epithelial neoplasm (2 cases), and sclerosing pneumocytoma (4 cases). Samples were moderately cellular, and consisted of round epithelioid cells with clear cell features, columnar cells, and spindle cells. A papillary arrangement with prominent hyalinized fibrovascular cores was the most common architectural pattern, followed by flat sheets and acinar formations. Tumor cells demonstrated mild, focally moderate nuclear pleomorphism with prominent nucleoli, hyperchromasia, nuclear elongation, nuclear overlap, and occasional nuclear inclusions and grooves. The background consisted of foamy macrophages (9 cases), hemosiderin pigment (6 cases), and lymphoid aggregates (3 cases) with no mitoses and/or necrosis. The surface cells and underlying round cells were positive for both thyroid transcription factor 1 and epithelial membrane antigen in all cases, which was the most notable immunohistochemical finding.

CONCLUSIONS

Cytomorphological findings of SP overlap with those of well-differentiated lung adenocarcinoma. Awareness of these cytomorphologic findings and the distinct immunoprofile of the 2 cell types found in SP should prevent a misdiagnosis and aggressive treatment.

Large pulmonary sclerosing pneumocytoma with massive necrosis and vascular invasion: a case report

Pulmonary sclerosing pneumocytoma (PSP) is pathologically classified as an adenoma and behaves in a benign manner. However, some cases of PSP displayed pathologically malignant behavior, such as lymph node metastasis and necrosis. A 64-year-old woman was referred to our hospital complaining of a cough and breathlessness. Histopathological analysis of the resected specimen by left pneumonectomy and lymph node dissection revealed a large PSP measuring 15 × 14 cm in size, with massive necrosis and vascular invasion. This case was the largest ever reported and suggested that clinico-histological presentation of PSP sometimes showed an aggressive phenotype like advanced lung cancer.

Symptomatic pulmonary sclerosing hemangioma: a rare case of a solitary pulmonary nodule in a woman of advanced age

Background

Pulmonary sclerosing hemangioma (PSH) is a rare tumor that usually develops in middle-aged Asian women. PSH has four histological types (hemorrhagic, sclerotic, solid, and papillary) and often grows slowly in a lower lobe of the lung. Preoperative misdiagnosis frequently occurs because of the absence of specific clinical manifestations and imaging findings. Few reports have described PSH in women of advanced age.

Case presentation: A 75-year-old woman presented to our hospital in China with a 5-day history of productive cough and intermittent hemoptysis. Computed tomography indicated bronchiectasis and a large mass in the left inferior lobe of the lung. Treatment of the bronchiectasis provided no symptom relief. The hemoptysis resolved following left lower pulmonary lobectomy, and PSH was pathologically diagnosed following surgery. At the time of this writing (after 6 months of follow-up), the tumor had not recurred, no metastases had been detected, and close follow-up was ongoing.

Conclusions

Both bronchiectasis and PSH can cause hemoptysis. This case demonstrates that PSH should be included as a differential diagnosis of hemoptysis in women of advanced age. For patients with chronic hemoptysis, the diagnosis of PSH should be considered if the therapeutic effect of bronchiectasis is poor.

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.

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.

Pneumocytoma (sclerosing hemangioma), a potential pitfall

Pneumocytoma is an uncommon benign tumor of the lung, derived from primitive respiratory epithelium, with a predilection for middle-aged females. A single, well-circumscribed mass is commonly identified on imaging, necessitating pathologic evaluation for further assessment. Fine-needle aspiration cytology is a minimally invasive and cost-effective method that can be utilized in the diagnosis of these lesions. Yet, distinction of pneumocytoma from other entities such as well-differentiated adenocarcinoma or carcinoid tumor can be quite challenging. Herein, we describe a case initially misdiagnosed as lung adenocarcinoma on FNA that was proven to be pneumocytoma on subsequent resection. This report highlights the importance of recognizing key cytologic features of pneumocytoma, namely the papillary architecture, dual cell population, and the hemorrhagic background with foamy macrophages, among others. An accurate preoperative diagnosis of this entity provides optimal patient management, as conservative surgical excision is curative. Diagn. Cytopathol. 2017;45:744-749. © 2017 Wiley Periodicals, Inc.

Pulmonary Hilar Tumor: An Unusual Presentation of Sclerosing Hemangioma

Pulmonary sclerosing hemangioma is an uncommon benign tumor of the lung; however, on rare occasions it can arise from the pulmonary hilar region. Herein, we report a 53-year-old female patient who presented with a round opacity in the right upper lung field on a radiograph. Chest computed tomography scanning revealed a 3.1 cm mass in the right pulmonary hilum. Thoracoscopic tumor excision was subsequently performed. On pathohistologic study, the tumor was well defined and composed of round stromal cells and surface cells arranged in a papillary, sclerotic, solid, and hemorrhagic pattern. In immunochemical study, the round cells were positive for thyroid transcription factor-1 (TTF-1) and epithelial membrane antigen (EMA) and negative for cytokeratin. The surface cells were positive for TTF-1, EMA, and cytokeratin. Therefore, a final diagnosis of sclerosing hemangioma was confirmed. In conclusion, pulmonary sclerosing hemangioma is uncommon and rare in the pulmonary hilar region. CT scanning is useful to determine its benignity, although imaging features are not specific for a definite differential diagnosis from other pulmonary tumors. Therefore, tissue diagnosis is usually necessary, and pulmonary sclerosing hemangioma should be listed in the differential diagnoses of pulmonary hilar tumors.

Whole-exome sequencing identifies recurrent AKT1 mutations in sclerosing hemangioma of lung

Pulmonary sclerosing hemangioma (PSH) is a benign tumor with two cell populations (epithelial and stromal cells), for which genomic profiles remain unknown. We conducted exome sequencing of 44 PSHs and identified recurrent somatic mutations of AKT1 (43.2%) and β-catenin (4.5%). We used a second subset of 24 PSHs to confirm the high frequency of AKT1 mutations (overall 31/68, 45.6%; p.E17K, 33.8%) and recurrent β-catenin mutations (overall 3 of 68, 4.4%). Of the PSHs without AKT1 mutations, two exhibited AKT1 copy gain. AKT1 mutations existed in both epithelial and stromal cells. In two separate PSHs from one patient, we observed two different AKT1 mutations, indicating they were not disseminated but independent arising tumors. Because the AKT1 mutations were not found to co-occur with β-catenin mutations (or any other known driver alterations) in any of the PSHs studied, we speculate that this may be the single-most common driver alteration to develop PSHs. Our study revealed genomic differences between PSHs and lung adenocarcinomas, including a high rate of AKT1 mutation in PSHs. These genomic features of PSH identified in the present study provide clues to understanding the biology of PSH and for differential genomic diagnosis of lung tumors.

A Comparative Study of Intraoperative Cytology and Frozen Sections of Sclerosing Pneumocytoma

Sclerosing pneumocytoma (SP) is a rare benign neoplasm of the lung. Conservative surgical excision is curative with an excellent prognosis. Preoperative diagnosis of SP can be difficult. Thus, intraoperative frozen sections play a crucial role in guiding surgical management. However, the interpretation of frozen section can be challenging due to freezing artifact. Intraoperative cytology provides a complementary and better morphological detail. In this study, we review and compare the intraoperative cytology and frozen section of 14 cases of SP. SP is characterized by containing 2 cell types: round stromal cells and cuboidal surface cells. The round stromal cells were small with uniform nuclei and inconspicuous nucleoli. The cuboidal surface cells were more differentiated into type II pneumocytes and showed slightly larger in size with intranuclear inclusions. The immunocytochemical double-labeling staining could display 2 distinct population of vimentin-positive round stromal cells and cytokeratin 7-positive cuboidal surface cells. Recognition of the cytological features of SP circumvents the frozen section artifact and is a useful adjunct to the frozen section in leading to the correct diagnosis of SP.

Sclerosing hemangioma: A diagnostic dilemma in fine needle aspiration cytology

Sclerosing hemangioma of the lung is a benign neoplasm with a widely debated histogenesis. It has a polymorphic histomorphology characterized by a biphasic cell population of "surface cells" and "round cells" arranged in four general patterns: Papillary, solid, angiomatous, and sclerotic. This variability in histomorphology makes it difficult to diagnose sclerosing hemangioma by fine needle aspiration (FNA). We present a case of sclerosing hemangioma diagnosed on FNA with immunohistochemistry performed on an accompanied cell block. The clinical presentation, cytomorphology, immunohistochemistry, and differential diagnoses are discussed.

Pulmonary sclerosing pneumocytoma mimicking lung cancer: Case report and review of the literature

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign neoplasm that predominantly affects middle‐aged Asian women. PSP is often asymptomatic and demonstrates a solitary pulmonary nodule on radiologic examination. We report a case of PSP initially misdiagnosed as lung cancer because of strong ¹⁸F‐fluorodeoxyglucose (FDG) uptake revealed by ¹⁸F‐FDG positron emission tomography‐computed tomography scan. After surgery, pathology revealed that the tumor cells were immunopositive for epithelial membrane antigen and thyroid transcription factor‐1. The patient has been followed up without complication or recurrence.

CTNNB1 (β-Catenin)-altered Neoplasia: A Review Focusing on Soft Tissue Neoplasms and Parenchymal Lesions of Uncertain Histogenesis

β-catenin (CTNNB1) is a key regulatory molecule of the Wnt signaling pathway, which is important for tissue homeostasis and regulation of cell proliferation, differentiation, and function. Abnormal stabilization and nuclear accumulation of β-catenin as a consequence of missense mutations or alternative molecular mechanisms occurs at a high frequency in a variety of epithelial cancers. In mesenchymal neoplasia, the role of β-catenin has been traditionally considered limited to desmoid-type fibromatosis. However, the spectrum of β-catenin-driven (β-catenin-altered) neoplasia of mesenchymal origin has been steadily widening to include, in addition to desmoid tumors, a variety of benign and intermediate-biology neoplasms of soft tissue (intranodal palisaded myofibroblastoma), head and neck (juvenile nasopharyngeal angiofibroma and sinonasal hemangiopericytoma/glomangiopericytoma), and ovarian (microcystic stromal tumor) origin. In addition, several old and newly reported distinctive site-specific β-catenin-driven parenchymal neoplasms of uncertain histogenesis have been well characterized in recent studies, including solid-pseudopapillary neoplasm of the pancreas and its recently described ovarian counterpart, sclerosing hemangioma of lung and calcifying nested stromal-epithelial tumor of the liver. This review addresses the most relevant pathobiological and differential diagnostic aspects of β-catenin-altered neoplasms with emphasis on site-specific histologic and biological variations. In addition, the morphologic overlap and analogy as well as distinctness between these uncommon tumors will be presented and discussed. Furthermore, a note is made on association of some of these lesions with hereditary tumor syndromes, in particular with the familial adenomatous polyposis coli.

Sclerosing Pneumocytoma with a Wax-and-Wane Pattern of Growth: A Case Report on Computed Tomography and Magnetic Resonance Imaging Findings and a Literature Review

Sclerosing pneumocytoma (SP) of the lung is a rare benign neoplasm. Here, we describe an unusual presentation of SP with a wax-and-wane pattern of growth in a 47-year-old woman. Tumor diameter decreased over a 3-year follow-up period and then increased on serial follow-up computed tomography scans. The mass showed high signal intensity on both T1- and T2-weighted chest magnetic resonance imaging (MRI) and early enhancement with a plateau on dynamic MRI. We speculate that intratumoral bleeding and resorption processes accounted for the changes in tumor size.

Pulmonary sclerosing pneumocytoma of the lung: CT characteristics in a large series of a tertiary referral center

The purpose of this study is to describe the detailed clinical, chest computed tomography (CT), and F-fluorodeoxyglucose positron emission tomography (FDG PET) characteristics of the tumor boundary for the diagnosis and investigate the outcome of pulmonary sclerosing pneumocytoma (PSP) using confirmed large data of a tertiary referral center. Confirmed 76 patients were included. We evaluated the findings of CT including 4 CT signs, FDG PET, and histopathology. Most patients had a single lesion (92.1%), smooth boundary (65.8%), and oval shape (65.8%) and the mean diameter was 22.7 mm. The CT signs included marginal pseudocapsule (50%), overlying vessel (26.3%), air gap (2.6%), and halo sign (17.1%). A predominantly solid was the most common histopathologic type. The mean maximum standardized uptake value on FDG PET of 17 patients was 1.8 (range, near 0 or normal tissue metabolism ∼2.9). PSP should be considered in middle-aged women whose CT features show incidental nodule(s), commonly with surrounding ground-glass opacity and characteristic CT signs of the tumor boundary, and hypometabolic uptake on FDG PET. Outcome of patients is excellent.

Usefulness of Ki-67 (MIB-1) immunostaining in the diagnosis of pulmonary sclerosing hemangiomas

Pulmonary sclerosing hemangioma (PSH) is an uncommon lung neoplasm with a clinical outcome that is generally benign. However, differentiating PSH from pulmonary carcinoma is sometimes difficult as both lesions share similar histopathologic and immunohistochemical features. In this study, we investigated the usefulness of Ki-67 (MIB-1) immunostaining in the diagnosis of PSH. We compared the staining pattern for Ki-67 (MIB-1) in 29 cases of typical PSH and 79 cases of pulmonary non-small cell carcinoma (NSCLC) using an immunohistochemical method on formalin-fixed paraffin-embedded tissues. In all studied PSH cases, we noted cell membrane and cytoplasmic staining for Ki-67 (MIB-1), but this was not observed in any of the NSCLC cases. The Ki-67 proliferation index was lower in PSH than in the NSCLC cases (mean, 1.1% vs mean, 5.5%; p < 0.001). These findings suggest that cell membrane and cytoplasmic staining for Ki-67 (MIB-1), as well as the Ki-67 proliferation index, may be useful for distinguishing PSH from pulmonary carcinoma.

Treatment of 28 patients with sclerosing hemangioma (SH) of the lung

Background

Sclerosing hemangioma (SH) of the lung is a kind of rare pulmonary tumor. Preoperative diagnosis of this tumor is difficult and it is now generally accepted that SH of the lung is benign lesions and surgical excision alone is curative. Herein, we present our experiences of treating 28 patients with SH.

Methods

The medical records of 28 patients with SH from 1994 to 2010 at the Department of Thoracic Surgery in Beijing Chest Hospital were retrospectively reviewed.

Results

There were 3 male and 25 female patients with sclerosing hemangioma and 50% of the patients were asymptomatic. Preoperatively, all the patients had undergone CT of chest and 5 patients had undergone PET scan but 4 patients were misdiagnosed as malignancy. There was no operative mortality or tumor recurrence despite that three different operative methods were undertaken.

Conclusions

SH has a high incidence in middle-aged women. Most of SH is asymptomatic and the symptoms of SH are not related to the tumor size and distribution. The features of chest CT and PET are not specific. Bilateral or multiple lesions should not exclude the possibility of SH. Complete excision of lesion is a curable treatment method and there is no evidence to verify the need of adjuvant therapy.

Fine-needle aspiration diagnosis of sclerosing hemangioma (pneumocytoma): report of a case and review of the literature

Sclerosing hemangioma (pneumocytoma) is a rare benign lung tumor with uncertain histogenesis but characteristic histology. Reports of the cytopathology of this tumor are even rarer with only a handful of cases in the literature--many of these incorrectly diagnosed by cytology initially. Herein, we describe a case of sclerosing hemangioma diagnosed prima facie by fine-needle aspiration cytology. A cell block preparation with accompanying immunohistochemistry was instrumental in making the diagnosis. A review of the literature is also presented.

[Diagnosis and treatment for pulmonary sclerosing hemangioma]

背景与目的

肺硬化性血管瘤(pulmonary sclerosing hemangioma, PSH)概念的提出迄今只有50余年，是一种少见的肺部良性疾病。PSH临床表现有一定特点，需与肺癌鉴别诊断。本文总结我院48例PSH的临床诊治经验并复习文献，旨在提高对PSH的认识，探讨合理的诊断与治疗手段。

方法

2001年1月-2011年4月共收治PSH 48例，结合文献报道总结分析PSH的发病特点、临床表现、影像学、病理学特点及预后。

结果

全组48例，无症状者27例(56.3%)，肿物大小0.2 cm-7.0 cm，平均2.1 cm，各个肺叶均有发生。合并肺门或纵隔淋巴结肿大者15例(31.3%)。手术47例，其中肺叶部分切除29例(61.7%)，肺叶切除14例(29.8%)，肿物剔除3例(6.4%)，前纵隔肿物切除者1例(2.1%)。47例术后均无复发。CT引导下穿刺活检诊断1例，随访28个月未见肿瘤进展。

结论

PSH术前定性诊断困难，手术既是确诊手段又是有效的治疗手段，该病预后良好。

Pulmonary sclerosing hemangioma: pitfalls in management

Pulmonary sclerosing hemangioma is a rare benign tumor for which surgical excision is curative with an excellent prognosis. It often mimics malignancy, making it a diagnostic and management challenge. We reviewed the clinical, radiological, and histopathological characteristics as well as the surgical management of our patients to assess the potential pitfalls in management. All 19 patients who underwent surgical biopsy between January 1999 and December 2009 with a final histopathological diagnosis of pulmonary sclerosing hemangioma were reviewed retrospectively. The median age was 48 years, 89.5% were female, 89.5% were Chinese, and 68.4% were asymptomatic. There were no specific diagnostic radiological characteristics; 1 of 3 patients who underwent combined positron-emission and computed tomography had a false-positive result. Preoperative attempts at establishing a diagnosis were successful in 20% of patients who had invasive procedures. Intraoperative frozen-section evaluation for pulmonary sclerosing hemangioma had an error rate of 25% and a deferred rate of 31%, resulting in nearly half of our patients undergoing unnecessary extensive surgical procedures. We hope to heighten awareness of this diagnosis, thereby increasing the index of suspicion and minimizing errors in diagnosis.