Ciliated muconodular papillary tumor/bronchiolar adenoma of the lung

Bronchial Sialadenoma Papilliferum in a 10-Year-Old Boy

Sialadenoma papilliferum (SP) is a rare salivary gland tumor mostly reported in the oral cavity. Here we describe a bronchial SP in the left upper lobe bronchus of a 10-year-old boy. At bronchoscopy, a well-circumscribed polypoid lesion protruding into the bronchial lumen was identified. The tumor was excised, but eventually, the patient had to undergo a sleeve resection after 2 recurrences. Pathology revealed a papillocystic lesion with exophytic and endophytic components. The cells lining the exophytic surface and papillary structures were columnar and squamous, and the cells lining endophytic cystic and papillary structures were cuboidal to columnar, all of which were diffusely reactive with antibodies to SOX10 protein. The presence of basal cells was demonstrated by p63 immunoreactivity. The cells failed to immunohistochemically express BRAF V600E. Fluorescence in situ hybridization analysis revealed no MAML2 or RET gene rearrangement. The patient is alive 24 years after resection with no additional recurrences. Bronchial SP needs to be recognized and distinguished from other benign and malignant salivary gland and pulmonary neoplasms so that patients can receive appropriate treatment and follow-up.

Pseudocavity on Thin-slice CT Can Be a Suggestion of Bronchiolar Adenoma: A Preliminary Study on 80 Cases With Bronchiolar Adenoma of the Lung

OBJECTIVES

At present, the study of bronchiolar adenoma (BA) mainly focuses on its pathologic characteristics, but there is limited understanding of its clinical manifestations and imaging signs. This article aims to summarize the clinical manifestations and imaging features of 80 cases of BA, with the goal of achieving a comprehensive and systematic understanding of BA.

MATERIALS AND METHODS

We retrospectively analyzed 80 patients with BA confirmed by surgical pathology in our hospital. All subjects underwent thin-slice CT examination. The basic information, tumor history, clinical manifestations, and CT imaging features of the lesions were collected. The subjects' age, maximum diameter of BA, and shortest distance from the pleura were analyzed by t-test or 1-way ANOVA, while other clinical and radiologic characteristics were compared for differences among different BA types by the χ2 test or Fisher exact probability method.

RESULTS

The majority of the 80 patients were female, with an average age of 59.08±10.16 years. The majority of them do not manifest any clinical symptoms. All lesions are located in the subpleural area, including 63 cases in the lower lobe of the lungs. The average size of the tumors was 10.31±5.01 mm. The majority of the lesions exhibited irregular morphology (53 cases, 66.25%) and predominantly comprised solid nodules (46 cases, 57.50%). There were statistically significant differences in lesion morphology, boundary, and pseudocavity among pure ground-glass nodular BA, mixed ground-glass nodular BA, and solid density nodular BA. Compared with pure ground-glass density BA (1 case, 1.25%) and mixed ground-glass density BA (7 cases, 8.75%), the boundary of solid nodules BA (42 cases, 52.50%) was significantly clearer (P<0.001). The presence of pseudocavity was found to be significantly higher in individuals with solid nodules compared with those with pure ground-glass nodules (P<0.0167). Compared with BA without pseudocavity, BA with pseudocavity exhibited a clearer lung interface (P<0.001), more abnormal vessel signs (P=0.007), and a higher incidence of malignant preoperative diagnosis (P=0.020).

CONCLUSIONS

BA mostly occurs in middle-aged and elderly women without any clinical symptoms. The imaging manifestations of BA are diverse, mainly presenting as irregular solid nodules. The interface between the tumor and lung is clear, and pseudocavity formation is common. In addition, BA with pseudocavity often exhibits abnormal vascular signs, which can lead to misdiagnosis as malignancy before surgery.

Uncommon Tumors of the Lung: Recently Described and Rediscovered Tumors

CONTEXT.—

The great majority of primary pulmonary neoplasms are represented by non-small cell carcinomas-adenocarcinoma and squamous cell carcinoma. In addition, there is another group of neoplasms such as those of neuroendocrine origin that also represent a meaningful subset of primary lung neoplasms. Basically, any other tumor that is not in these groups of tumors may represent an unusual lung neoplasm.

OBJECTIVE.—

To highlight more recently described unusual tumoral entities that may represent a challenge in diagnosis and that require awareness of their existence.

DATA SOURCES.—

This is a review of 3 different entities: bronchiolar adenoma, adenofibroma, and hemangioblastoma-like clear cell stromal tumor. These tumoral conditions are rare, and a review of the literature is presented. The most relevant morphologic, immunohistochemical, and molecular aspects of bronchiolar adenoma, adenofibroma, and hemangioblastoma-like clear cell stromal tumor are presented. The difficulty of arriving at an unequivocal diagnosis in small biopsies is highlighted.

CONCLUSIONS.—

The 3 entities represent uncommon tumors occurring primarily in the lung and a diagnostic challenge not only in biopsy specimens but also often in surgically resected specimens. The use of immunohistochemical stains and in some cases of molecular diagnostics is of aid in arriving at final interpretation.

Ciliated Muconodular Papillary Tumors of the Lung Harboring STRN::ALK Fusion: Case Report and Review of the Literature

Ciliated muconodular papillary tumor (CMPT) is a rare pulmonary tumor, typically occurring in middle-aged and elderly individuals. The molecular mutation spectrum of CMPT remains insufficiently explored. Commonly known driver gene alterations include KRAS, BRAF, EGFR, and ALK rearrangement. This report details the clinicopathological features of 2 patients presenting with CMPT as pulmonary nodules during clinical examinations. Microscopic analysis revealed tumors with glandular or papillary structures, consisting of mucinous cells, ciliated columnar cells, and basal cells. Notably, both patients exhibited STRN::ALK fusion, a finding not previously associated with CMPT. STRN::ALK fusion serves as a target for therapy in various tumors, including non-small cell lung cancer, thyroid cancer, and colon cancer. Consequently, we conducted a review of relevant literature, summarizing the clinicopathological and molecular characteristics of CMPT to facilitate further research. Our insights enhance the understanding of this uncommon tumor and contribute to the expansion of its molecular alteration spectrum.

Bronchiolar adenoma/ciliated muconodular papillary tumour: advancing clinical, pathological, and imaging insights for future perspectives

Bronchiolar adenoma/ciliated muconodular papillary tumour (BA/CMPT) is a benign peripheral lung tumour composed of bilayered bronchiolar-type epithelium containing a continuous basal cell layer; however, the similarities in imaging and tissue biopsy findings at histopathology between BA/CMPT and malignant tumours, including lung adenocarcinoma, pose significant challenges in accurately diagnosing BA/CMPT preoperatively. This difficulty in differentiation often results in misdiagnosis and unnecessary overtreatment. The objective of this article is to provide a comprehensive and systematic review of BA/CMPT, encompassing its clinical manifestations, pathological basis, imaging features, and differential diagnosis. By enhancing healthcare professionals' understanding of this disease, we aim to improve the accuracy of preoperative BA/CMPT diagnosis. This improvement is crucial for the development of appropriate therapeutic strategies and the overall improvement of patient prognosis.

Bronchiole adenoma/pulmonary ciliated mucinous nodular papillary tumor: Case series and literature review

OBJECTIVE

To analyze the clinical-pathological characteristics of 3 cases of bronchiolar adenoma/pulmonary ciliary mucinous nodular papillary tumors, and to improve the understanding of bronchiolar adenoma (BA)/ciliated muconodular papillary tumors (CMPT) (bronchiolar adenoma/ciliated muconodular papillary tumor).

METHODS

Retrospective analysis was done on the clinical information, diagnosis, and treatment of 3 instances of BA/CMPT at the Second People's Hospital of Weifang City. By scanning the CNKI, Wanfang, VIP database, and Pubmed database using the English key words "bronchiolar adenoma, ciliated muconodular papillary tumor," respectively patients with comprehensive clinical data were gathered, and studies from January 2002 to August 2021 that were relevant to the patients were examined.

RESULTS

A total of 35 articles and 71 instances were found, including 3 cases in our hospital, for a total of 74 cases. There were 31 males and 43 females among them, ranging in age from 18 to 84 years (average 63 years), and 15 cases had a smoking history. The majority of them were discovered by physical examination and had no clinical symptoms. The majority of the imaging revealed solid nodules with variable forms, with some ground-glass nodules displaying vacuole and bronchial inflation signs. BA/CMPT are generally gray-white, gray-brown solid nodules with obvious boundaries but no envelope with a maximum dimension of 4 to 45 mm (average 10.6 mm) on gross examination. Acinar, papillary, and lepidic formations can be seen under the microscope at high magnification; the majority of these structures are made up of tripartite epithelial components, including basal cells, mucous cells, ciliated columnar cells, and alveolar epithelial cells, demonstrating a variety of combinations. An important basis for diagnosis in immunohistochemistry is the continuous positive basal cell layer that is shown by p63, p40, and CK5/6. BRAF and epidermal growth factor receptor are the genes that are most frequently mutated. All of the patients showed no signs of metastasis or recurrence during follow-up period.

CONCLUSION

BA/CMPT is a rare benign tumor of lung epithelium. Because imaging and intraoperative cryosection diagnosis are easy to be misdiagnosed as malignant, it is necessary to further improve understanding and improve immunohistochemistry and genetic examination.

A case of bronchiolar adenoma/ciliated muconodular papillary tumor in the pulmonary center with high FDG accumulation on PET

BACKGROUND

Bronchiolar adenoma/ciliated muconodular papillary tumor (BA/CMPT) is listed in the World Health Organization (WHO) Classification 5th edition as a rare benign tumor with papillary growth of ciliary, goblet, and basal cells.

CASE PRESENTATION

The patient was a 67-year-old female in whom a nodular shadow of 20 mm in diameter in the right lower lobe S10 center was found in chest computed tomography (CT) for examination of dorsal pain. Positron emission tomography/computed tomography (PET-CT) showed the accumulation of 18F-fluorodeoxyglucose (FDG) with a standardized uptake value (SUV)max of 13.0. Primary lung cancer was suspected, and surgery was scheduled as a therapeutic strategy. Thoracoscopic resection of the right lower lobe was performed, and possible BA/CMPT or adenocarcinoma was suggested in the differential diagnosis by the intra-perioperative rapid pathologic diagnosis. The final diagnosis was BA/CMPT. Histological findings indicated that the cause of the high FDG-PET scan might be due to many inflammatory cell infiltration in the tumor.

CONCLUSIONS

We report a resected case of BA/CMPT with exceptionally high FDG accumulation in PET.

Bronchiolar adenoma-like tumour with monolayered component: Represent malignant transformation of bronchiolar adenoma? A series of five cases

Pulmonary bronchiolar adenoma (BA) is a rare lung tumour, it is unclear whether BA can develop into a malignancy. We presented five cases of BA-like tumour with monolayered components. This type of tumour may represent the malignant transformation of BA. Histologically, these tumours showed acinar and lepidic growth patterns. The acinar components were well-differentiated. The glandular tumour cells in these tumours contained cuboidal to columnar cells resembling type II pneumocytes or club (Clara) cells. A small number of mucinous cells were found in two cases. A few scattered ciliated cells were detected in three cases. The ciliated cells only existed in the bilayered components. The basal cells were highlighted by CK5/6 and p40 in a partial region of the tumour rather than in the entire tumour. The glandular tumour cells, including those in the bilayered component, were diffusely positive for TTF-1 and napsin-A. EGFR Exon19 deletions were found in four cases, and BRAF V600E mutation was found in one case. These BA-like tumours have biphasic morphological and molecular characteristics of BA and lung adenocarcinoma, suggesting distal-type BA may develop into a malignancy. More cases should be studied and especially cases with metastasis should be searched to further prove the malignant transformation.

Pulmonary Sialadenoma Papilliferum and Its Mimics: What You Need to Know

Pulmonary salivary gland-type tumors (SGT) represent a small but distinct group of primary lung neoplasms. These types of tumors originate from the submucosal bronchial glands of the tracheobronchial tree. Pulmonary SGTs differ greatly in the incidence of individual tumors from salivary gland tumors of the head and neck. Additionally, the vast majority of pulmonary SGT are malignant. Recently, pathologic diagnosis has significantly improved with the application of molecular diagnostic technologies. However, the current knowledge of benign SGTs is limited; moreover, tumor diversity and overlapping morphological features of SGT represent diagnostic challenges such as correct tumor categorization and their accurate differentiation from malignant lesions. Compounding this inherent difficulty has been the recent introduction of new variants, including sialadenoma papilliferum (SP). Pulmonary SP is very rare, with limited reports available, and most of the initial diagnoses rendered so far were incorrect, resulting in inappropriate treatment. Several cases of SP have recently been reported. This review will serve to update practicing pathologists on the morphology, immunophenotype, and molecular characteristics of SP and its mimics.

The 2021 WHO Classification of Lung Tumors: Impact of advances since 2015

The 2021 World Health Organisation (WHO) Classification of Thoracic Tumours was published earlier this year, with classification of lung tumors being one of the chapters. The principles remain those of using morphology first, supported by immunohistochemistry and then molecular techniques. In 2015, there was particular emphasis on using immunohistochemistry to make classification more accurate. In 2021, there is greater emphasis throughout the book on advances in molecular pathology across all tumor types. Major features within this edition are 1) broader emphasis on genetic testing than in the 2015 WHO Classification, 2) a chapter entirely dedicated to the classification of small diagnostic samples, 3) continued recommendation to document percentages of histological patterns in invasive non-mucinous adenocarcinomas, with utilization of these features to apply a formal grading system, as well as using only invasive size for T-factor size determination in part lepidic non-mucinous lung adenocarcinomas as recommended by the 8^th Edition TNM Classification, 4) recognition of spread through airspaces (STAS) as a histological feature with prognostic significance, 5) moving lymphoepithelial carcinoma to squamous cell carcinomas, 6) update on evolving concepts in lung neuroendocrine neoplasm classification, 7) recognition of bronchiolar adenoma/ciliated muconodular papillary tumor (BA/CMPT) as a new entity within the adenoma subgroup, 8) recognition of thoracic SMARCA4-deficient undifferentiated tumor, and 9) inclusion of essential and desirable diagnostic criteria for each tumor.

Bronchiolar adenomas (BA) - A detailed radio-pathologic analysis of six cases and review of literature

Bronchiolar adenomas (BAs)/ciliated muco-nodular papillary tumors (CMPTs), are small, peripheral lung nodules arising predominantly in the elderly that follow a benign course. They can be mistaken for adenocarcinomas on frozen section. Immunohistochemistry (IHC) for basal cell markers highlights the continuous layer of basal cells underlying the tumor cells in BAs. BAs are further subdivided into proximal-type and distal type. Six BAs were retrieved from the pathology archives. The cases were classified based on morphology into proximal and distal BAs. The clinical and radiological features were reviewed. Immunohistochemistry and special stains were performed. The most common radiological picture of BA/CMPT was of a solid nodule with SUV_max < 3 as seen in 60% cases. 40% cases showed cavitation on CT. On histological examination, four cases were morphologically classified as proximal BAs and two as distal BAs. In proximal BAs, TTF1 was focally positive only in the basal cells in three of four. The mucin stained acidic. In distal BAs, TTF1 was diffusely positive in both basal and luminal cells. There was scant intracellular neutral mucin. Both the distal BAs had concomitant neuroendocrine tumors in the same lobe. Though the number of cases evaluated in this study is too low to be statistically significant, this study provides additional evidence to the concept of BA classification based on site specific histology and supplementary immunohistochemistry and reiterates the radiological features that may help distinguish it from malignant lesions.