Alveolar adenoma

Alveolar adenoma with a single cyst: A case report

Alveolar adenoma is a rare and benign pulmonary tumor, which originates from type II pneumocytes and is often incidentally identified on radiographic images. Alveolar adenoma presents as a peripleural, solitary and cystic nodule in the lung and may mimic other types of lung tumors, thus rendering its differential diagnosis difficult. Alveolar adenoma is diagnosed based on histopathological and immunohistochemical analyses. The present study describes the case of a 50-year-old male patient with alveolar adenoma. He visited a local doctor ~3 years prior due to left chest pain. A chest computed tomography scan revealed a cystic lesion in segment 8 of the left lung. A nodular shadow appeared in the cyst and gradually increased in size; the patient was thus referred to the authors' hospital. The nodule was well-defined, solitary and solid; thus, lung cancer or aspergilloma were suspected. Thoracoscopic wedge resection was performed as diagnostic therapy. The frozen sections were non-diagnostic, and a pathological examination revealed an alveolar adenoma with no evidence of malignancy and a negative culture. The patient had a good post-operative course, with no sign of recurrence at the follow-up evaluation 46 months later. On the whole, alveolar adenoma is a rare, benign pulmonary tumor that is difficult to diagnose pre-operatively.

What's new in benign lung tumours?

While lung cancer is one of the most common malignancies routinely encountered by pathologists, benign pulmonary neoplasms are quite rare. However, it is important for pathologists to be familiar with the typical diagnostic features of benign lung tumors to avoid confusing them with malignant morphological mimics. There have also been intriguing discoveries in the genetics of benign pulmonary neoplasms in the past decade. This review will cover several of the most common benign lung tumors, including the diagnostic categories of pulmonary adenomas, bronchial papillomas, and benign mesenchymal tumors, with discussion of the current classification, differential diagnosis, and current knowledge regarding genetic drivers.

Enlarging pulmonary cyst: a rare form of alveolar adenoma

BACKGROUND

Alveolar adenoma is a rare benign tumour, usually presenting as a peripherally located solid mass, sometimes mimicking malignancy.

CASE PRESENTATION

A 37-year-old woman presented with chronic intermittent vague chest discomfort. The chest x-ray showed a simple cyst in the left lower lung field, and serial computed tomography (CT) over the following 2-year period showed rapid growth of the cyst, from 3.5 to 9.0 cm in diameter. The CT scan suggested bronchiolar communication, which was suspected to be the cause of growth, via check-valve mechanism. Thoracoscopic surgery was performed, and we found a thin-walled cyst in the lingular segment. Wedge resection was performed and the pathology was an unexpected alveolar adenoma which had grown on the terminal bronchiole, causing the alveolus to rupture and the cyst to grow. In 48 months of follow-up, there was no evidence of recurrence and the patient's symptoms resolved.

CONCLUSIONS

Rapidly growing pulmonary cysts can lead to complications including rupture with pneumothorax and haemothorax, and surgery is always indicated. Abnormally rapid growth may indicate an underlying pathology such as alveolar adenoma. Surgical resection is the treatment of choice and there have been no reported cases of recurrence. Here we present a rare form of alveolar adenoma, which was a form of rapidly growing pulmonary cyst.

Alveolar Adenoma: A 20-Year Experience at a Western Balkan University Hospital and a Literature Review

Alveolar adenoma is a rare benign lung tumor. We report 5 patients within a 20-year period diagnosed with this rare tumor and its clinical and histopathological features, in order to emphasize its significance in differential diagnosis of other lung tumors. Alveolar adenoma was more frequently diagnosed in female patients (80%). The patients ranged in age from 52 to 68. Eighty percent of the patients had symptoms like dyspnea, and shoulder or back pain. Three patients underwent a video-assisted thoracoscopic surgery, while 2 patients underwent a thoracotomy in order to remove the tumor. The tumor was localized within the right upper lobe, right lower lobe, and left lower lobe in 40%, 40%, and 20% of patients, respectively. The tumor size ranged from 14 to 30 mm. A frozen section finding of all 5 tumors reported that the lesion was benign. In all analyzed tumors, immunohistochemical analysis showed positive expression of TTF-1 and pankeratin in surface epithelial cells, and Vimentin positivity and TTF-1 and pankeratin negativity in round stromal cells. Alveolar adenoma should be carefully considered in the differential diagnosis of solitary pulmonary nodules. Complete surgical removal of the lesion is widely used in its primary management.

Alveolar Adenoma With CD34 Diffusely Positive Stromal Cells: A Rare Case Report and Literature Review

Alveolar adenoma (AA) is a rare type of pulmonary neoplasm showing proliferation of alveolar epithelium and septal mesenchyme. Clinically, AA is asymptomatic, benign, and usually diagnosed incidentally. Surgical excision is curative. The etiology of AA is controversial and the pathogenesis is unknown, but it is thought to stem from type II pneumocytes and fibroblasts or fibroblast-like cells. The stromal cells in AA may show rare staining for CD34. Diffuse CD34 positivity of the interstitial stromal cells has rarely been described and reviewed. Here, we report a case of AA with strong and diffuse CD34 staining in the stromal cells.

Benign tumours of the bronchopulmonary system

The vast majority of tumours arising in the bronchopulmonary system are malignant in nature. Benign tumours of the lung are relatively rare and are often incidental findings during clinical investigations for unrelated conditions. These lesions can arise in the bronchial tree or the pulmonary parenchyma and may be of epithelial, mesenchymal, salivary gland-type or unknown differentiation. Although the spectrum of these lesions is wide, the clinical, pathological and immunohistochemical characteristics of the most relevant will be the subject of this review. In addition, the most important features allowing differentiation from malignant pulmonary neoplasms will be discussed.

Alveolar adenoma with poor imaging: a case report

Alveolar adenoma is an isolated, well-defined peripheral lung tumor that originates from type II alveolar cells. The tumor consists of a network of simple, low-cubic, epithelium-coated lacunae with varying amounts of fine and inconspicuous-to-thick spindle cells that sometimes contain mucus sample matrix. Few cases of alveolar adenoma have been reported. These tumors are usually detected by imaging examinations where the alveolar adenoma typically presents as a peripheral, solitary cystic nodule in the lung. The presentation may mimic that of other types of lung tumors, consequently leading to difficulties in the differential diagnosis of this condition. Thus, accurate diagnosis of alveolar adenoma is based on a combination of pathological sections and immunohistochemistry. This study describes an alveolar adenoma in a 59-year-old female patient. Chest X-ray imaging and chest computed tomography identified malignant lesions in the right upper lobe. The patient subsequently underwent a thoracoscopic right upper lobectomy. The diagnosis of alveolar adenoma was confirmed after pathological examination of the excised postoperative tissue. The disease course was stable, and there was no recurrence of pulmonary lesions during 3 years of postoperative patient follow-up. Herein, we report the case of a patient with benign alveolar adenoma with poor imaging and pathological results.

Rare Lung Tumors: Alveolar Adenoma-Four Case Reports

Alveolar adenoma is one of the rarely seen benign tumors of the lung, to date, one or two series have been reported. In this study, four rare alveolar adenoma cases were presented, thereby contributing to the existing scarce data.

Alveolar Adenoma of the Lung: A Clinicopathologic, Immunohistochemical, and Molecular Study of an Unusual Case

We describe an alveolar adenoma of the lung with 3 previously unreported findings, which expand both the clinical and the morphologic spectrum of this rare tumor: presentation as a cystic nodule, foci of mature adipocytes, and S-100 positivity of the mesenchymal cells. Furthermore, using a laser capture microdissection technique under microscope visualization, we analyzed multiple chromosomal loci in both the epithelial and mesenchymal components of the lesion, showing microsatellite alterations and loss of heterozygosity in the former but not in the latter.

Malignant transformation of alveolar adenoma to papillary adenocarcinoma: a case report

We present a case involving alveolar adenoma (AA) comprising a malignant component. An 83-year-old man was referred with a solitary pulmonary nodule, which was diagnosed as adenocarcinoma (AC) by transbronchial biopsy. Resected specimen after left S1+2 segmentectomy revealed that the tumor comprised two histologically distinct areas-a central multi-cystic area (AA) and a surrounding area (papillary AC). Careful examination clarified that the borderline lesion showed intermediate mindbomb homolog-1 index and cytological atypia with low papillary growth, suggesting the possibility of malignant transformation of the AA. The malignant potential and coexisting lung carcinoma should be considered in evaluating the tumor diagnosed as AA.

Coexistence of lung alveolar adenoma with cerebral arteriovenous malformations: A case report and literature review

Alveolar adenoma is an extremely rare benign tumor of the lung derived from type II pneumocytes. To date, only a limited number of alveolar adenoma cases have been reported in the literature. These tumors are usually discovered incidentally on radiographic images. However, other tumor types must be excluded when the characteristics of alveolar adenoma are not typical on the radiographic images. Therefore, diagnosis of alveolar adenomas is based on the combination of gross structural analysis and immunohistochemistry. The present study described a case of alveolar adenoma in a 47-year-old female patient. A chest X-ray revealed a pulmonary lesion in the right lower lobe and, subsequently, the patient underwent a right lower lobectomy. Pathological examination of the surgically resected tissue confirmed the initial diagnosis of alveolar adenoma. In addition, intracranial vascular malformations were detected on a computed tomography scan, but the patient did not experience any notable symptoms. Considering the benign nature of the malformations, as determined by digital subtraction angiography, the patient selected to undergo follow-up with observation only. The postoperative course was uneventful and no recurrence of pulmonary lesions was noted after >4 years, while the condition of the intracranial lesion was stable. In conclusion, the current study described a unique case of adenoma alveolar coexisting with intracranial vascular malformations. A literature review of previously-reported alveolar adenoma cases was also conducted.

Alveolar adenoma combined with multifocal cysts: case report and literature review

Alveolar adenoma is an extremely rare and benign pulmonary neoplasm; it is always asymptomatic and is usually detected incidentally on routine chest X-radiography. Typically on imaging examinations, alveolar adenoma exhibits as a peripheral, solitary, cystic nodule in the lung, which may easily imitate other lung lesions, consequently leading to difficulties in the differential diagnosis of this condition. Surgical resection is the primary treatment option. The diagnosis of alveolar adenoma is mainly based on postoperative histopathology, with features of proliferative type 2 alveolar epithelial cells and septal mesenchyme. The present case was a 60-year-old woman with alveolar adenoma, combined with systemic mutifocal cystic lesions. She underwent surgery following the obvious enlargement of this mass and a cystic nodule 7 cm in maximum diameter was resected. Postoperative histopathology confirmed a diagnosis of alveolar adenoma; her prognosis was favourable. In addition to reporting a rare case of alveolar adenoma coexisting with multifocal cysts, the English-language literature was reviewed for similar cases of alveolar adenoma.

Neoplastic and nonneoplastic benign mass lesions of the lung

While most lung neoplasms are malignant, a subset of true neoplasms are benign, the most common of which are pulmonary hamartomas. In addition, a substantial proportion of lung mass lesions are nonneoplastic; granulomas are among the commonly encountered nonneoplastic masses. There is also a group of relatively rare, mainly inflammatory and fibrous tumor-like lesions that are encountered on core biopsy and excisions of lung tissue.

CD34 Expression in the Stromal Cells of Alveolar Adenoma

The alveolar adenoma of the lung is a rare benign tumor characterized by a proliferation of both the alveolar epithelial cells and the mesenchymal septal cells. Immunohistochemically, the epithelial cells stain for cytokeratin (CK) AE1AE3, CK7, thyroid transcription factor 1 (TTF1), and surfactant apoprotein confirming the derivation by the type 2 pneumocytes. The stromal cells are negative for these markers but they show focally smooth muscle and muscle-specific actin positivity. We describe two cases that showed immunohistochemically a CD34 positivity of the mesenchymal septal cells. This aspect has been previously described in a two cases report, but not emphasized by the authors as a distinctive feature of the lesion. We consider this CD34 positivity as a marker of immaturity or stemness of the lesional septal spindle cells, that could be responsible of the different phenotypic and morphological profile of the interstitial cells, that could be, therefore, considered neoplastic and not reactive.

Alveolar adenoma of the lung: unusual diagnosis of a lesion positive on PET scan. A case report

The authors report a clinical case of alveolar adenoma presenting as a solitary pulmonary nodule which was positive to PET and deeply located in the lung. Few cases of alveolar adenomas have been reported in literature; these lesions are considered pulmonary neoplasms with benign behaviour, usually presenting as a peripheral or subpleural coin lesion; the PET activities of such neoplasms were unknown.

The present clinical case was singular for the deep location of the nodule and its tight adhesion to left inferior pulmonary vein requiring a lobectomy. In addition, alveolar adenoma PET behaviour has been reported as light positivity.

Alveolar adenoma: an extremely rare innocent coin lesion

Alveolar adenoma is an extremely rare benign tumour of the lung. Less than 30 cases have been reported in the English literature. A 42-year-old asymptomatic female who presented with a solitary peripheral pulmonary nodule on chest roentgenogram underwent thoracoscopic wedge resection and was diagnosed with this rare tumour. The indolent clinical progression and the absence of recurrence and metastasis after complete resection are the most important characteristics of this tumour. The classical solitary pulmonary nodule is a common and vexing problem. Nodules are extremely common in clinical practice and challenging to manage. Solitary pulmonary nodules can represent different specific lung diseases, focal non-specific inflammations, and primary and secondary malignant tumours. Identification of malignant nodules is important because they represent a potentially curable form of lung cancer.

Alveolar adenoma of the lung: a case report

Alveolar adenoma is a rare pulmonary neoplasm. This report describes a case of alveolar adenoma of the lung in a 61-year-old woman. A chest X-ray demonstrated a solitary round pulmonary nodule. After six years of observation, this lesion had increased in size. Thoracoscopic left upper segmentectomy was performed on account of a possible low-grade malignant tumor. Histologically, the neoplastic epithelial cells, which had the appearance of proliferative type II pneumocytes, revealed no evidence of malignancy. These findings indicated that the tumor is alveolar adenoma of the lung. The course of disease remains uneventful, one year after the resection.

An unusual case of a microscopic alveolar adenoma coexisting with lung carcinoma: a case report and review of the literature

Introduction

Alveolar adenomas are extremely rare, benign, primary lung tumors of unknown histogenesis that are characterized by proliferative type II alveolar epithelium and septal mesenchyma. Mostly incidental, they are clinically important as they can imitate benign primary and secondary malignant tumors and at times are difficult to differentiate from early-stage lung cancer. We describe the case of a 59-year-old man with an incidental microscopic alveolar adenoma coexisting with poorly differentiated lung carcinoma.

Case presentation

A 59-year-old Caucasian man with a medical history of smoking and chronic obstructive pulmonary disease was incidentally found to have a right upper lobe mass while undergoing a computed tomographic chest scan as part of a chronic obstructive pulmonary disease clinical trial. Our patient underwent a right upper lobectomy after a bronchoscopic biopsy of the mass revealed the mass to be a carcinoma. A pathological examination revealed an incidental, small, 0.2 cm, well circumscribed lesion on the staple line margin of the lobectomy in addition to the carcinoma. Histopathological and immunohistochemical examinations revealed the lesion to be an alveolar adenoma.

Conclusions

We report the rare presentation of a microscopic alveolar adenoma coexisting with lung carcinoma. Alveolar adenoma is an entirely benign incidental neoplasm that can be precisely diagnosed using immunohistochemical analysis in addition to its unique histopathological characteristics.

A small alveolar adenoma resected by thoracoscopic surgery

Alveolar adenoma (AA) is a rare lung benign tumor originated from type II pneumocytes. It presents as a well-defined nodule in clinical images, but is difficult to differentiate from early-stage lung cancer. We treated a 58-year-old woman with a small-sized AA measuring 8 x 6 mm in the upper lobe of the left lung by performing a thoracoscopic resection. The AA does not cause any symptoms and it is often incidentally detected as an abnormal shadow. There have been no reported cases of recurrence after a resection of AA, but a subsequent increase in such cases is expected, and we believe that it is necessary to understand the characteristics of this typical benign lung tumor.

Benign Tumors and Tumorlike Conditions of the Lung

Context.—Benign tumors and tumorlike conditions of the lung are encountered in the pathologic evaluation of asymptomatic and symptomatic lung nodules. Since many of these lesions are uncommon, they can be diagnostically challenging.

Objective.—To review the current classification of benign lung tumors, with emphasis on histopathology and useful ancillary studies.

Data Sources.—The current World Health Organization classification system for lung neoplasms and review of relevant publications.

Conclusions.—Despite improved imaging techniques, benign lung nodules are encountered in wedge biopsy and resection specimens. Histopathology, immunohistochemistry, and molecular techniques ensure accurate pathologic diagnosis and have shed light on the histogenesis of these unusual lesions.

Adenoma alveolar

O adenoma alveolar é uma neoplasia benigna rara dos pulmões, com poucos casos descritos na literatura. Freqüentemente, o paciente é assintomático e apresenta-se com um achado acidental em telerradiografias de tórax de um nódulo solitário e bem circunscrito. O diagnóstico definitivo é histológico e o tratamento consiste na ressecção cirúrgica do nódulo.

Alveolar adenoma of the lung: a clinicopathological description of a case of this very unusual tumour

Alveolar adenomas are extremely rare, and are probably benign lung tumours of unknown histogenesis. This report describes a case of alveolar adenoma in a 43 year old white man, who presented with pleuritic chest pain. A chest x ray and computerised tomography scan demonstrated a solitary left lower lobe lung nodule. Although a positron emission tomography scan seemed to document the benign nature of the lesion, a thoracoscopic wedge resection was performed to alleviate the symptoms and verify the diagnosis. Histologically, the lesion was well demarcated, dominated by large and small cysts with no normal lung parenchyma. The interstitial cellular component consisted of both epithelioid and vaguely spindle shaped cells. The cystic cell linings were mostly indistinct, although areas of cuboidal epithelial cells were seen. Multiple histochemical and immunohistochemical tests were performed. There were no histological signs of malignancy and the patient is doing well one and a half years postoperatively.

Alveolar Adenoma

Alveolar adenoma of the lung is a rare benign neoplasm with proliferation of alveolar epithelium and septal mesenchyme. This unusual neoplasm presents as a solitary mass on chest roentgenograms, especially in older, asymptomatic patients. We report a case of this unusual neoplasm and describe the histologic and radiographic features of this tumor, which should be included in the differential diagnosis of a solitary pulmonary mass.

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.

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.

Alveolar adenoma of the lung: computed tomography and magnetic resonance imaging findings

Alveolar adenoma of the lung is a rare benign neoplasm with distinctive gross and microscopic findings. Radiographically, alveolar adenoma usually presents as a well-circumscribed, peripheral, solitary nodule. The authors describe the contrast-enhanced computed tomography and magnetic resonance imaging features of alveolar adenoma of lung. Magnetic resonance imaging demonstrated the presence of a cystic space with central fluid and thin-rim enhancement. These findings are suggestive of a benign nodule, and alveolar adenoma of lung should be added to the differential diagnosis of nodules that demonstrate this pattern of enhancement and are probably benign.

Alveolar adenoma: a histochemical, immunohistochemical, and ultrastructural analysis of 17 cases

Alveolar adenoma of lung is a rare benign neoplasm of uncertain histogenesis. Its rarity hampers characterization of its epithelial and mesenchymal elements. Clinical and histopathologic features of 17 alveolar adenomas were reviewed. Histochemistry was performed on 10 cases, ultrastructural analysis on two, and immunohistochemistry on six cases for pneumocyte markers, thyroid transcription factor (TTF-1), surfactant protein markers pro-SP-B and pro-SP-C, and the Clara cell marker, CC10. Immunohistochemistry was performed in nine cases for desmin, smooth muscle actin, muscle-specific actin, cytokeratin, proliferating cell nuclear antigen (PCNA), factor VIII, and carcinoembryonic antigen. The mean age was 53 years. Seven cases occurred in men, and nine occurred in women. The age and sex were not known for one patient. The tumors were coin lesions on chest radiographs in asymptomatic patients except for one (cough). The mean size was 2.2 cm. The tumors were well demarcated with multiple cystic spaces containing granular material. Mostly type 2 pneumocytes lined the cystic spaces with fewer type 1 cells and no Clara cells. This was confirmed by staining for TTF-1, pro-SP-B, and pro-SP-C and by ultrastructure. CC10 was negative in all cases. The stroma varied from prominent spindle cells with a myxoid matrix to thin alveolar septa. The interstitial spindle cells resembled fibroblasts by immunohistochemistry and ultrastructure. Follow-up data available in five cases showed no recurrence at 2, 2, 5, 8, and 13 years. In summary, alveolar adenoma is a benign neoplasm consisting of an intimate admixture of alveolar epithelial and septal mesenchymal tissue. Most of the epithelial cells are type 2 pneumocytes, and the interstitial stromal cells are fibroblasts or fibroblast-like cells. Recognition of its characteristic morphological appearance allows for its distinction from other benign lesions of the lung.

Multifocal micronodular pneumocyte hyperplasia, lymphangiomyomatosis and clear cell micronodules of the lung in a Chinese female patient with tuberous sclerosis

Tuberous sclerosis is a rare genetic disease with protean clinical manifestations. The lesion most commonly described in the lung is lymphangiomyomatosis. There have been recent reports of multifocal micronodular pneumocyte hyperplasia, as well as a single case documentation of a clear cell tumor of the lung, in patients affected by the disease. We detail a case of a female Chinese patient with tuberous sclerosis who was incidentally discovered to have bilateral pneumothoraces. The open lung biopsy revealed combined histological features of multifocal micronodular pneumocyte hyperplasia, lymphangiomyomatosis and clear cell micronodules.

Pulmonary nodule caused by an alveolar adenoma of the lung

Alveolar adenomas of the lung may be a rare cause of solitary coin lesions on chest radiographs. We report a case of this neoplasm, describe its morphological and immunohistochemical characteristics and give further evidence that alveolar adenomas of the lung represent a benign proliferation of both the alveolar epithelium and the septal mesenchyme.

A nonbalanced translocation (10;16) demonstrated by FISH analysis in a case of alveolar adenoma of the lung

Short-term cultures from an alveolar adenoma of the lung were cytogenetically examined. Of the 54 metaphases studied, 44 were characterized by an apparently normal karyotype and 10 showed a pseudodiploid karyotype: 46,XX,add(16)(q24). Fluorescence in situ hybridization studies permitted identification of the add(16)(q24) as a der(16)t(10;16)(q23;q24). This is the first report of a chromosomal aberration in an alveolar adenoma of the lung.

Placentoid bullous lesion of the lung

Four adult patients presented with unilateral multicystic lung disease. The cysts had been detected years previously on chest radiographs in three patients. Two patients had histories of repeated childhood pneumonias. Preoperative diagnosis of bullous emphysema with rupture was made in three patients who presented with pneumothorax. Lobectomy was done in two patients and pneumonectomy in two patients. Macroscopically, each lung was spongy with cysts that contained gelatinous vesicular or grape-like structures resembling normal or molar placental tissue. Bullous emphysema was evident in one lung and marked panacinar emphysema in another. In one patient who had a lobectomy, the ipsilateral lobe of compressed lung re-expanded after surgery and proved to be cystic as well on subsequent radiographs. The vesicular and grape-like structures histopathologically are papillary structures with central edematous cores and a covering of cuboidal epithelial cells. Degenerate villi became either hydatidiform, fibrotic, or calcified. At low magnification the histology was similar to that of placenta with hydatidiform change. Emphysematous lung in which villiform structures appeared at the edges of bullae was found histologically in two patients. Lymphangiectasia was present in all patients. The placentoid bullous lesion has distinct macroscopic and microscopic features and is clinically unusual in that the cysts are unilateral and appear in otherwise healthy young adults. We do not know whether the lesion is a malformation or a peculiar devolution of localized bullous emphysema. We favor the latter interpretation. Torsion of lung may cause the lymphangiectasia and contribute to the unusual histology. Excision is curative.

Micronodular hyperplasia of type II pneumocytes--a new lung lesion associated with tuberous sclerosis

Open lung biopsy in a 38-year-old female with Pringle-Bourneville syndrome and recurrent pneumothorax revealed a micronodular pneumocyte II hyperplasia, a new entity probably associated with the tuberous sclerosis syndrome. The lesion caused an obstruction of the alveolar lymphatic vessels and alveolar ducts, resulting in an emphysema-like picture. This cystic dilation of alveoli and draining lymphatics followed by rupture caused the recurrent pneumothorax. The epithelial pneumocytic nature of the lesion was confirmed by immunohistochemistry and electronmicroscopy.

Breast carcinoma metastatic to the gallbladder

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Pulmonary adenoma: a variant of sclerosing haemangioma of lung?

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