Pulmonary sclerosing hemangioma consistently expresses thyroid transcription factor-1 (TTF-1): a new clue to its histogenesis

Proteomic analysis of pulmonary sclerosing hemangioma

Sclerosing hemangioma (SH) is a rare benign pulmonary tumor derived from the primitive respiratory epithelium. However, the pathogenesis of SH has not yet been clear. Surfactant protein, thyroid transcription factor-1, epithelial membrane antigen, cytokeratin, and vimentin have been identified in SH by immunohistochemistry and electron microscopy. To identify proteins specifically regulated in SH, 2-D PAGE was performed using SH and paired normal tissues. Ten selected differentially expressed protein spots were identified by PMF, MALDI-TOF-MS, and database searching. Apolipoprotein A-1, antizyme inhibitor, heat shock 27-kDa protein 1, and antioxidant proteins, such as peroxiredoxin II (Prx II) and GST, were identified among the down-regulated proteins in SH. Western blot and immunohistochemistry confirmed reduced expressions of Prx II and GST in SH versus normal lung tissue. This study is the first report on the reduced expressions of Prx II and GST in SH.

Pulmonary sclerosing hemangioma with metastasis to the mediastinal lymph node

During a routine health care evaluation, an abnormal shadow was detected in the chest roentgenogram of a 35-year-old man. Chest computed tomography scanning showed a nodule, approximately 3 cm in diameter, in the left S6 pulmonary segment with surrounding infiltration. Bronchoscopy revealed obstruction of the left B6c bronchus by a tumor, for which biopsy was done but no definitive histologic diagnosis could be made. Then, left lower lobectomy was performed, and the tumor was diagnosed as a pulmonary sclerosing hemangioma. A mediastinal lymph node (no. 7) showed some metastatic tumor cells. As lymph node metastasis from pulmonary sclerosing hemangioma is very rare, we herein report the details of our case.

Expression Patterns of Markers for Type II Pneumocytes in Pulmonary Sclerosing Hemangiomas and Fetal Lung Tissues

Context.—Although the histogenesis of sclerosing hemangioma is currently not well understood, the tumor has been characterized by its 2 histologically different types of cells, namely, surface and polygonal cells.

Objective.—To elucidate the origin of these cells, we analyzed samples from 15 cases of sclerosing hemangioma and 15 specimens of fetal lung tissue.

Design.—We immunostained specimens from 15 cases of sclerosing hemangioma and 15 samples of fetal lung tissue using antibodies against thyroid transcription factor 1, MUC1, Thomsen-Friedenreich antigen, and CD44v6, known as markers for type II pneumocytes, and a panel of antibodies against cytokeratin, epithelial membrane antigen, synaptophysin, CD56, estrogen receptor, and progesterone receptor.

Results.—In fetal lung tissue, MUC1 and thyroid transcription factor 1 were expressed throughout all developmental stages of airway epithelium, whereas Thomsen-Friedenreich antigen and CD44v6 were expressed by type II pneumocytes of saccular and alveolar origin. Thomsen-Friedenreich antigen was expressed in the bronchial bud of the pseudoglandular stage. MUC1, thyroid transcription factor 1, and epithelial membrane antigen were observed in both surface and polygonal cells of sclerosing hemangioma. Only the surface cells in all cases of sclerosing hemangioma showed positivity for cytokeratin and CD44v6. Thomsen-Friedenreich antigen was expressed in the surface cells of 11 of 15 cases of sclerosing hemangioma. Epithelial membrane antigen was expressed in both types of tumor cells, whereas cytokeratin was not detected on polygonal cells, but was reactive with surface cells.

Conclusions.—Our results suggest that the 2 types of cells in sclerosing hemangioma may derive from a common precursor cell through divergent differentiation toward the type II pneumocyte during tumorigenesis.

["Pneumocytoma" or "sclerosing hemangioma": histogenetic aspects of a rare tumor of the lung]

Aspects of histogenesis and nomenclature of so called "sclerosing hemangioma" of the lung (WHO 1999) are discussed and compared with immunohistochemical findings in eight examined operation specimen. The lesion is characterised by the presence of typical surface cells, which can be related to type II pneumocytes. Progesterone-receptor positive stromal cells may derive from primitive mesenchymal cells. Endothelial proveniance of tumor cells could not be confirmed by immunohistochemistry. Therefore, this rare usually benign pulmonary neoplasm should be entitled "pneumocytoma" analogous to the suggestion of several other authors.

Loss of heterozygosity patterns of sclerosing hemangioma of the lung and bronchioloalveolar carcinoma indicate a similar molecular pathogenesis

CONTEXT

The histogenesis and origin of sclerosing hemangioma (SH) of lung were uncertain for many years. Many immunohistochemical, ultrastructural, and recent molecular studies support the hypothesis that SH is a neoplasm originating from the cells of the terminal lobular unit, similar to the nonmucinous variant of bronchioloalveolar carcinoma (BAC). Most cases of SH are benign, but they can metastasize to the regional lymph nodes.

OBJECTIVE

To compare the patterns of allelic loss of tumor suppressor genes in SH and BAC by microdissection-based genotypic analysis.

DESIGN

Microdissection-based loss of heterozygosity analysis of 9 cases of SH and 14 cases of BAC, using a panel of 7 polymorphic microsatellite markers located on 1p, 5q, 9p, 10q, and 17p. Microsatellite marker and chromosomal arm-based fractional allelic loss (FAL) were calculated in each case.

RESULTS

Our results showed similar patterns of allelic loss between the 2 groups of tumors on an individual case basis. Chromosomal arms 5q and 10q showed frequent allelic loss in SH (66.7% and 62.5%, respectively), whereas in BAC, chromosomal arm 17p (52.6%) was frequently affected. A statistically significant difference in allelic loss between SH and BAC was located only on chromosomal arm 5q (P =.04). Microsatellite marker D5S615 was significantly more frequently affected in SH than in BAC (66.7% vs 28.6%; P =.04).

CONCLUSION

Our molecular data support the hypothesis of common origin of SH and BAC. A putative tumor suppressor gene that might play a role in tumorigenesis of SH may be located on the chromosomal arm 5q.

The utility and limitation of thyroid transcription factor-1 protein in primary and metastatic pulmonary neoplasms

Thyroid transcription factor-1 (TTF-1) is a tissue-specific transcription factor expressed in the thyroid and lung. The clinical utility and limitation of TTF-1 in primary or metastatic carcinomas of the lung have not been previously studied in detail. We examined TTF-1 expression in 510 primary lung and 107 metastatic neoplasms. TTF-1 was detectable in 4/99 (4%) squamous cell carcinomas, 169/176 (96%) solitary adenocarcinomas, 34/34 (100%) multifocal adenocarcinomas, 1/1 (100%) signet ring cell carcinoma, 16/20 (80%) mucinous adenocarcinomas, 23/23 (100%) nonmucinous bronchioloalveolar carcinomas, 19/36 (53%) small cell carcinomas, and 39/44 (89%) sclerosing hemangioma. TTF-1 was absent in all eight carcinoids, three atypical carcinoids, 23 pleomorphic carcinomas, 25 lymphoepithelioma-like carcinomas, the sarcomatous component of one pseudomesotheliomatous carcinoma, and one mesothelioma. In four combined small cell carcinomas and 12 adenosquamous carcinomas, TTF-1 expression was only demonstrated in the adenocarcinoma component. There were 78 TTF-1 non-immunoreactive metastatic cases from 22 livers, 20 colorectums, 10 breasts, six nasopharynx, four larynx, four ovaries, three salivary glands, three esophagus, two adrenal glands, two kidneys, one bile duct, and one endometrium. TTF-1 was also detected in all 10 cervical lymph nodes, seven brain, and 6/7 (86%) bony tissues of 24 patients with metastatic carcinomas of unknown primary site, but it was absent in 125 patients with metastatic carcinomas other than lung origin in cervical lymph nodes, brain, and bony tissues. These results indicate the clinical usefulness and limitation in certain primary and metastatic lung neoplasms.

Sixteen cases of sclerosing hemangioma of the lung including unusual presentations

Sclerosing hemangiomas (SH) of the lung are uncommon tumors and are thought to be benign. However, the biologic behavior of this tumor has not yet been characterized adequately. The clinicopathologic features were reviewed and analyzed for 16 cases of SH. The age of the patients ranged from 37 to 73 yr (mean 50.6 yr). There were fifteen female and one male patient. The SH located at the intraparenchyme in 14 cases, the interlobar fissure in one case and the visceral pleura in one case. The size of SH ranged from 0.3 cm to 8 cm (mean 2.6 cm). There were five unusual presentations of SH including a case having two SH with multiple nodules of atypical adenomatous hyperplasia in the same lobe, a case showing adenocarcinoma-like area within the SH, a case showing one peribronchial lymph node metastasis (N1 nodal stage) with location of interlobar major fissure, a case showing alveolar adenoma-like area within the SH, and one case with a large visceral pleural-based pedunculated mass presenting as mediastinal mass. All patients were alive and well without recurrence at the last follow up. Here, we reviewed previously published literatures and discussed the histogenesis of SH.

Immunohistochemical and ultrastructural markers suggest different origins for cuboidal and polygonal cells in pulmonary sclerosing hemangioma

We report the morphological characteristics of 30 cases of sclerosing hemangioma (SH) of the lung and explore the histological origin of the major cells in these tumors. In addition to routine light and electron microscopy, immunohistochemistry was performed by using 12 monoclonal primary and 5 polyclonal primary antibodies. These included surfactant protein B (SP-B), thyroid transcription factor-1 (TTF-1), mast cell trypsin, CD68, epithelial antigen markers (high molecular weight cytokeratin, low molecular weight cytokeratin [CK-L], epithelial membrane antigen [EMA], cancer embryonic antigen), mesothelial antigen, neuroendocrine markers (neuron-specific enolase [NSE], chromogranin A, synaptophysin, calcitonin, adrenocorticotropic hormone, human growth hormone [hHG]), vimentin, and CD34. Surface cuboidal cells have short microvilli and have lamellar bodies in their cytoplasm. They can sometimes merge into multinuclear giant cells. Immunohistochemical results showed that these cells are strongly positive for SP-B, TTF-1, CK-L, EMA, and cancer embryonic antigen, whereas polygonal cells, previously also described as round or pale cells, were strongly positive for vimentin and TTF-1, and positive or weakly positive for 2 to 3 kinds of neuroendocrine markers. Sparse neuroendocrine granules and abundant microfilaments were observed in their cytoplasm. Some cell clusters in the solid regions were positive for SP-B and EMA. Mast cells existed sparsely in almost every field. Both cuboidal and polygonal cells were negative to CD34 and mesothelial antigen staining. We conclude that cuboidal cells of SH originate from reactive proliferating type II pneumocytes, which can fuse into multinuclear giant cells. Polygonal cells, as true tumor cells, likely originate from multipotential primitive respiratory epithelium and possess the capability for multipotential differentiation. The antibodies of SP-B, TTF-1, vimentin, and CK-L are very helpful to diagnosis and differential diagnosis of SH.

Type-II pneumocyte differentiation in pulmonary sclerosing hemangioma: ultrastructural differentiation and immunohistochemical distribution of lineage-specific transcription factors (TTF-1, HNF-3 alpha, and HNF-3 beta) and surfactant proteins

Sclerosing hemangioma (PSH) is a rare pulmonary tumor, in which two types of tumor cells could be histologically discerned--surface and stromal tumor cells. Nine tumor-tissue specimens from six female Japanese patients were studied, focusing on the distribution of several transcription factors related to lung epithelial development and surfactant proteins and comparing the ultrastructural features of the tumor cells. The immunohistochemical analysis revealed that the surfactant proteins of surfactant apoprotein A, surfactant protein B, and prosurfactant protein C were distributed in many of the surface-lining cells and in a small number of stromal-tumor cells. In addition, the nuclei of the tumor cells stained positive for thyroid transcription factor 1 (TTF)-1, hepatocyte nuclear factor (HNF)-3 alpha, and HNF-3 beta. In situ hybridization staining for TTF-1 showed similar positive signals. Ultrastructurally, two types of tumor cells showed similar features, but stromal tumor cells lost the definitive apico-lateral differentiation compared with the surface tumor cells and showed restricted surface differentiation between the adjacent tumor cells, forming small lumina accompanied by microvilli and occasional multi-vesicle or multi-lamellar bodies. Conclusively, the real tumoral population being undifferentiated stromal cells, the lining cells are fully differentiated type-II pneumonocytes. PSH is a proliferation of rather fetal type-II pneumonocytes (pneumocytoma or pneumoblastoma?).

Prognostic significance of thyroid transcription factor-1 expression in both early-stage conventional adenocarcinoma and bronchioloalveolar carcinoma of the lung

Thyroid transcription factor 1 (TTF-1) is a diagnostic immunohistochemical marker for primary pulmonary neoplasms, but its utility as a prognostic marker is not well established. Surgical specimens from 100 cases of pulmonary adenocarcinoma were retrieved from the hospital computer system, including 50 cases of conventional adenocarcinoma (CA) and 50 cases of bronchioloalveolar adenocarcinoma (BAC) (32 nonmucinous type and 18 mucinous type). Representative sections were immunostained for TTF-1. Positive immunohistochemical study was correlated with other prognostic parameters. In the CA group, strong or moderate TTF-1 expression was seen in 30 of 50 (60%) patients and was associated with significantly better survival compared with those patients having weak staining (7 cases; 14%) or negative staining (13 cases; 26%) (P <0.01; log-rank test). Spearman and Pearson's correlation showed no significant correlation between TTF-1 expression and tumor grade, size, recurrence, or vascular invasion; therefore, TTF-1 was considered an independent predictor of survival. In the BAC group, TTF-1 was strongly expressed in 34 of 50 cases (68%) and was negative in 16 of 50 cases (32%), including 14 mucinous BACs. Although TTF-1 immunoreactivity was not statistically associated with good survival in BAC patients, those patients with strong immunohistochemical expression showed a trend toward longer survival. Our results indicate that TTF-1 positivity is an independent predictor of better survival, especially in patients with CA. Mucinous and nonmucinous BACs exhibit disparate staining patterns with TTF-1, with nonmucinous BAC demonstrating greater positivity. Although nonmucinous BAC patients showing strong positive staining had longer survival, the difference was not statistically significant, which is probably related to the overall good survival of patients with early-stage BAC.

Cystic sclerosing haemangioma of the lung

AIMS

To present three cases of sclerosing haemangioma of the lung (SHL) with prominent cystic changes.

METHODS AND RESULTS

The patients were three women, 27, 35, and 64 years of age. In two cases, the lesion was found on routine chest X-ray and in both instances the diagnosis of SHL was not entertained in the radiological differential diagnosis. In one case, the finding was discovered on post mortem examination. Grossly, the lesions were well-circumscribed and cystic. Histologically, the tumours were characterized by a dual population of small and large bland-appearing neoplastic cells growing in a predominantly cystic pattern. Immunohistochemical staining for epithelial membrane antigen by tumour cells was consistently positive in all three cases. All tumours were negative for keratin, CD34, factor VIII, and S100. The two patients in whom the lesion was identified ante-mortem are alive and free of disease 4 and 7 years after surgical excision.

CONCLUSIONS

The present cases indicate that sclerosing haemangioma may present as a cystic pulmonary neoplasm; such a presentation should be taken into consideration when assessing cystic pulmonary lesions.

Histopathological and CT features of pulmonary sclerosing haemangiomas

AIM

To demonstrate the computed tomography (CT) features of pulmonary sclerosing haemangiomas.

MATERIALS AND METHODS

Six pathologically proven sclerosing haemangiomas were included in this retrospective review. Patients consisted of five women and one man aged 20-54 years (mean, 34.5 years). Their CT features were recorded according to enhancement patterns and the presence of a tail sign, prominent pulmonary artery sign, air-trapping sign, presence of calcification or cystic spaces, consolidation, and interstitial infiltration. The predominant composition of an individual sclerosing haemangioma was documented by means of microscopy.

RESULTS

Inhomogeneous enhancement was frequently present and depended on the various compositions of the tumours, especially those in sclerotic and predominantly papillary predominant types. The presence of a tail sign, intra-tumoural cystic areas, and a prominent artery sign were the frequent features in our cases.

CONCLUSION

Sclerosing haemangioma should be considered in young or middle-aged female patients whose CT images show them having an inhomogeneous enhancing soft tissue mass with a smooth outline and with above the aforementioned features.

Pulmonary sclerosing hemangioma with lymph node metastases: report of 4 cases

CONTEXT

Sclerosing hemangioma is an unusual pulmonary tumor. Previously, 4 patients with pulmonary sclerosing hemangioma and lymph node metastases have been described in the literature.

OBJECTIVE

To report 4 additional cases of metastatic sclerosing hemangioma.

DESIGN

Retrospective review of the authors' consultation files and review of histologic sections of pulmonary tumors and lymph node metastases.

RESULTS

Four cases of a morphologically benign pulmonary sclerosing hemangioma with regional lymph node metastases (including hilar, peribronchial, and interlobar metastases) were identified. The patients (3 female, 1 male) had a mean age of 39 years (range, 10-56 years). The tumors ranged in size (greatest dimension) from 1.5 to 4.7 cm (mean, 3.1 cm). The pulmonary tumors were typical circumscribed sclerosing hemangiomas without mitotic activity, angiolymphatic invasion, or necrosis. One tumor had focal cytologic atypia. The metastases were identified in hilar lymph nodes that were removed at operation for the lung nodule. One patient received adjuvant chemotherapy for adenocarcinoma. All of the patients are alive. No recurrences or residual disease has been detected at a mean follow-up of 4.7 years (range, 2.3-10 years).

CONCLUSIONS

On the basis of case data from the 4 patients described here and the 4 patients described previously, metastases to regional lymph nodes from pulmonary sclerosing hemangioma may occur but are rare and do not appear to affect prognosis.

Epithelial plasma cell granuloma-like tumors of the lungs. A hitherto unrecognized tumor

We present two cases of benign pulmonary epithelial tumors located in the middle lobes of the lungs. The patients were women of 56 and 36 years of age. The tumors were morphologically similar to plasma cell granuloma. At the tumor periphery, the lesion cells formed thin organoid rows of cells and vague trabeculae, disclosing morphologically their epithelial nature. In addition, the tumors strongly stained immunohistochemically with antibodies to cytokeratins, TTF-1 and EMA, and they were negative for immunoglobulin kappa and lambda light chains. We are not aware of similar tumors described in the literature, and we suggest the name "epithelial plasma cell granuloma-like tumors" for these lesions.

Can pulmonary sclerosing haemangioma be accurately diagnosed by intra-operative frozen section?

AIMS

Pulmonary sclerosing haemangioma is a rare benign tumour with a characteristic variegated histological pattern. In this retrospective study we aimed to identify features that can aid in making a correct diagnosis and avoiding potential pitfalls at the time of intra-operative frozen section.

METHODS AND RESULTS

Twenty cases of pulmonary sclerosing haemangioma with intra-operative frozen section were reviewed. The four major histological patterns (solid, sclerotic, papillary and haemorrhagic) were found in various combinations in the frozen sections. In 17 cases, three or more patterns were present. There could be focal areas mimicking epithelioid haemangioendothelioma or carcinoid tumour. Intra-operative imprint/scrape cytology served as a helpful adjunct in confirming the cytological blandness, although occasional atypical cells could be present. An intra-operative frozen section diagnosis of 'sclerosing haemangioma' or 'benign tumour' was given in 14 cases; the diagnosis was deferred in six cases. Retrospective analysis of the deferred cases showed that a definitive intra-operative diagnosis could have been made in three, because three or more major histological patterns were present. One case showed a pure papillary pattern at frozen section, mimicking the appearance of papillary adenocarcinoma (primary or secondary), bronchioloalveolar carcinoma, epithelioid mesothelioma or papillary adenoma; two tumours from a patient with multicentric disease showed widespread significant cytological atypia in the tumours raising a serious consideration of malignancy.

CONCLUSION

A diagnosis of pulmonary sclerosing haemangioma can be made at intra-operative frozen sections in most cases based on the tumour circumscription and variegated histological patterns. When only a single histological pattern is identified or when there is significant cytological atypia, distinction from other tumours can be problematic, and the diagnosis is best deferred.

Unusual sclerosing haemangiomas and sclerosing haemangioma-like lesions, and the value of TTF-1 in making the diagnosis

AIMS

Sclerosing haemangiomas typically comprise a mixture of four architectural patterns (papillary, sclerotic, solid and haemorrhagic) and two cell types, eosinophilic cuboidal epithelial lining cells and sheets of rounded cells with either eosinophilic or clear cytoplasm. In most instances, recognition of these architectural and cytological features provides sufficient evidence for diagnosis. This study presents and discusses the histogenesis of four cases where difficulties in diagnosis were encountered, and reports the value of the antibody TTF-1 in making the diagnosis.

METHODS AND RESULTS

Four cases with focal areas reminiscent of sclerosing haemangioma were reviewed and immunostained with an antibody panel including antibodies to TTF-1 and surfactant apoprotein A. Of these, one case was classified as sclerosing haemangioma combined with typical carcinoid, in which there was a mediastinal lymph node metastasis solely comprising the solid component of sclerosing haemangioma. The second was classified as an alveolar adenoma with sclerosing haemangioma-like areas. In the remaining two cases, diagnosis was confounded by presentation with predominantly cystic masses, the largest 70 mm in diameter. Immunohistochemically, TTF-1 was of greater value than surfactant apoprotein, in particular in identifying the solid component of sclerosing haemangioma when this was solely present.

CONCLUSION

Sclerosing haemangiomas should be considered in the differential diagnosis of cystic pulmonary masses. They may also present histologically as combined tumours and metastasize to mediastinal nodes, indicating an, albeit low, malignant potential. TTF-1 is a valuable antibody in identifying the presence of a sclerosing haemangioma when typical features are absent.

Thyroid transcription factor-1: a review

Thyroid transcription factor-1 (TTF-1) is a 38-kd homeodomain containing DNA-binding protein originally identified in follicular cells of the thyroid and subsequently in pneumocytes. This review focuses on the utility of antisera in TTF-1 immunohistochemical staining in the diagnosis of neoplastic conditions. Based on published studies to date, anti-TTF-1 is a very useful reagent in distinguishing pulmonary adenocarcinoma from other primary carcinomas, identifying differentiated thyroid neoplasms, distinguishing mesothelioma from pulmonary adenocarcinoma, and distinguishing small cell carcinoma of the lung from Merkel cell carcinoma. It may also be useful in distinguishing neuroendocrine (NE) tumors of the lung from well-differentiated NE tumors from other sites, such as the intestine.

Cytopathologic diagnosis of pulmonary sclerosing hemangioma

There are many reports of sclerosing hemangioma from the perspective of its histopathologic features, but its cytopathologic characteristics are less well known. In this report we present the case of a patient in which the cytologic features firmly established a definitive diagnosis; surgical intervention was warranted only after the lesion had grown over the course of 7 yr of close observation. The cytologic diagnosis requires the identification of a dual cell population. Both populations of tumor cell nuclei are immunoreactive for thyroid transcription factor-1, but caution is warranted because this marker may be present in other tumors. Recognition of its distinctive cytologic features can lead to proper diagnosis and conservative management.

Sclerosing hemangioma with metastases to multiple nodal stations

We present a case of a large pulmonary sclerosing hemangioma with metastases to multiple lymph nodal stations and suspected contralateral pulmonary metastasis. Four cases (including the present) have been reported to have lymph node metastasis, and all had large tumors exceeding 3.5 cm in diameter. Accordingly, resection of sclerosing hemangioma is advisable while the tumor is small. Even in cases with a large sclerosing hemangioma, lymph node metastasis may be uncommon. However lymph node dissection may be necessary to detect lymph node metastasis in selected cases.

Thyroid transcription factor-1 is highly sensitive and specific in differentiating metastatic pulmonary from extrapulmonary adenocarcinoma in effusion fluid cytology specimens

BACKGROUND

Thyroid transcription factor-1 (TTF-1) is a homeodomain-containing transcription factor selectively expressed in thyroid, lung and diencephalon. It has been shown to label pulmonary adenocarcinoma, thyroid tumors, and small cell carcinoma (pulmonary and extrapulmonary) with relatively high sensitivity and specificity. The usefulness of this immunostain in cytology specimens has not been thoroughly discussed in the literature.

METHODS

The authors evaluated 36 effusion cytology cases (17 pleural effusion, 18 ascitic fluid, and 1 pericardial effusion) diagnosed as metastatic adenocarcinoma and with cell blocks prepared from the file of Pamela Youde Nethersole Eastern Hospital, Hong Kong, during a three-year period from 1998 to early 2001. The clinical, radiologic, cytologic, and histologic (if any) findings were reviewed. A provisional diagnosis of the primary site was deduced for each of the 36 cases by clinical, radiologic, and/or histologic correlation. Immunohistochemical study was performed on the cell block sections of the effusion cytology specimens using mouse monoclonal antibody against TTF-1, after microwave heat-antigen retrieval. The results were correlated with the primary origin of the metastatic adenocarcinoma.

RESULTS

Among the 17 cases of metastatic pulmonary adenocarcinoma, 15 cases showed nuclear staining for TTF-1 in most of the tumor cells (sensitivity, 88.2%). None of the 19 cases of metastatic extrapulmonary adenocarcinoma expressed TTF-1 (specificity, 100%).

CONCLUSIONS

The current study validates TTF-1 as a highly sensitive and specific immunomarker for distinguishing between metastatic pulmonary and extrapulmonary adenocarcinoma in effusion cytology specimens, which are known to be associated with intrinsic artifact due to less than ideal cellular preservation.

Sclerosing hemangioma of lung: A close cytologic mimicker of pulmonary adenocarcinoma

We report the fine-needle aspiration biopsy findings of sclerosing hemangioma of lung occurring in a 40-yr-old Chinese woman. Cytologically, there were hyalinized stromal tissue fragments admixed with clusters of nondescript mononuclear tumor cells. Scattered foamy macrophages and red blood cells were also noted in the background. Focal papillary and acinar configurations were seen. However, some of the epithelial cells show nuclear pleomorphism with nuclear hyperchromasia, prominent nucleoli, and occasional intranuclear inclusions. Mitotic activity was virtually absent. The cytologic atypia present may result in misdiagnosis of well-differentiated pulmonary adenocarcinoma, especially bronchioloalveolar carcinoma. Recognition of the subtle cytologic differences, together with cell block examination, immunocytochemistry, and proper clinicoradiologic correlation, is crucial for an accurate preoperative diagnosis.

Expression of thyroid transcription factor-1 and other markers in sclerosing hemangioma of the lung

CONTEXT

Sclerosing hemangioma of the lung is well characterized histologically, but the line of differentiation expressed by the tumor cells has been unclear. Despite the implication by its name of a vascular neoplasm, sclerosing hemangioma is considered by most authorities to be an epithelial tumor, possibly related to the pulmonary epithelium.

OBJECTIVES

To determine the line of differentiation of the tumor cells with immunohistochemistry and to review the related literature.

DESIGN

Nine cases of histologically typical pulmonary sclerosing hemangioma were studied with pan-epithelial (epithelial membrane antigen [EMA] and CAM 5.2), endothelial (CD31), neuroendocrine (chromogranin A), and pulmonary epithelial markers (thyroid transcription factor-1 and PE10). Staining intensity was separately evaluated in the pale cells of the solid areas and the cells lining the papillary structures.

RESULTS

Both cell types were positive for thyroid transcription factor-1 and EMA in all cases (100%). Thyroid transcription factor-1 showed diffuse strong staining, and EMA staining varied from focal weak to diffuse strong. The pale cells showed focal staining for keratin (CAM 5.2) in 2 (28%) of 7 cases, and for PE10 in 5 (62%) of 8 cases. The papillary lining cells were at least focally positive with CAM 5.2 and PE10 in all cases (100%). Reactions for chromogranin and CD31 were negative in both cell types in every case. The number of PE10- or CAM 5.2-positive papillary lining cells was less than the number of EMA-positive papillary lining cells.

CONCLUSION

The uniform positivity for EMA is consistent with the notion that the tumor cells of sclerosing hemangioma are epithelial, and the strong thyroid transcription factor-1 positivity suggests differentiation toward pulmonary epithelium. The papillary lining cells expressing EMA as well as PE10 or CAM 5.2 likely represent entrapped metaplastic alveolar epithelium, whereas the papillary lining cells expressing only EMA more likely constitute true neoplastic cells similar to those in the solid areas.