Ciliated muconodular papillary tumors of the lung: a clinicopathologic analysis of 10 cases

So-called "non-classic" ciliated muconodular papillary tumors: a comprehensive comparison of the clinicopathological and molecular features with classic ciliated muconodular papillary tumors

Ciliated muconodular papillary tumors (CMPTs) are characterized by tripartite cellular components of ciliated columnar cells, mucinous cells, and basal cells with predominantly papillary architecture. Some peripheral lung nodules may not demonstrate papillary architecture and tripartite cells that show bronchiolar differentiation; these nodules are termed "CMPTs with non-classic morphology" by some authors. To validate the rationality of "non-classic" CMPTs and to analyze the clinicopathological features of CMPTs, we enrolled 21 cases of lung nodules, comprising classic CMPTs (n = 11) and so-called non-classic CMPTs (n = 10). The status of driver mutations, including those in EGFR, BRAF, ALK, and KRAS, was examined by molecular tests. Clinical and radiological follow-up was performed (3-27 months). Cilia as well as the mucinous and papillary components are usually present throughout classic CMPTs but may be absent in their non-classic counterparts. However, both entities present a bi-layer architecture with evidence of bronchiolar differentiation. Driver mutations involved the BRAF (n = 6), EGFR (n = 1) and ALK (n = 1), were identified in 8 of 11 (73%) classic CMPTs, whereas driver mutations, comprising BRAF (n = 2), EGFR (n = 1) and KRAS (n = 1), were identified in 4 of 10 (40%) non-classic lesions. Since it contains the largest series of Chinese patients with CMPTs, this study may expand the morphologic and molecular spectrum of CMPTs: a hallmark of CMPTs is bi-layer architecture with a continuous basal layer that can harbor high-frequency driver mutations. Recognition of the non-classic morphology of CMPTs may be helpful to avoid misdiagnosis and unnecessary treatment.

Ciliated muconodular papillary tumor of the lung harboring BRAF V600E mutation and p16INK4a overexpression without proliferative activity may represent an example of oncogene-induced senescence

Ciliated muconodular papillary tumor (CMPT) is a rare peripheral lung tumor that shows puzzling histologic features encompassing metaplastic and neoplastic nature. This type of tumor is occasionally misdiagnosed as lung adenocarcinoma clinically and pathologically, and its pathogenic mechanism has not been well characterized. We experienced a case of CMPT in a 73-year-old male and performed targeted deep sequencing to characterize its molecular features. The tumor was an ill-defined, subpleural, and non-endobronchial nodule showing glandular and papillary proliferation of mucous cells, ciliated columnar cells, and basal cells without any cytologic atypia. Abundant intra-alveolar mucin surrounded the main lesion. The patient was well without recurrence throughout 36 months of follow-up. Our case harbored BRAF V600E mutation and strongly expressed p16INK4a without proliferative activity, representing senescence and indolent biologic behavior. Overall, the results of this study indicate that BRAF V600E mutation might be the driver for tumorigenesis of CMPT and eventually leads to oncogene-induced senescence of this tumor.

Ciliated muconodular papillary tumors of the lung with KRAS/BRAF/AKT1 mutation

Background

Ciliated muconodular papillary tumors (CMPTs) are newly recognized rare peripheral lung nodules that are histologically characterized by ciliated columnar, goblet, and basal cells. Although recent studies have shown that CMPTs constitute a neoplastic disease, the complete histogenesis of CMPTs is not fully understood and molecular data are limited.

Methods

We reviewed four cases of CMPT and performed immunohistochemical and genomic analyses to establish CMPT profiles.

Results

All cases were positive for hepatocyte nuclear factor-4α and mucin 5B and negative for programmed death ligand 1 expression, as determined by immunohistochemistry. The genetic analysis revealed three pathogenic mutations (BRAF V600E, AKT1 E17K, and KRAS G12D), with the KRAS mutation reported here for the first time.

Conclusion

Histological and genetic profiles indicate that CMPTs are likely neoplastic and exhibit features similar to mucinous adenocarcinoma. This suggests that some CMPTs may be a precursor lesion of mucinous adenocarcinoma.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-017-0651-2) contains supplementary material, which is available to authorized users.

The Molecular Pathology of Lung Cancer

Advances in lung cancer genomics have revolutionized the diagnosis and treatment of this heterogeneous and clinically significant group of tumors. This article provides a broad overview of the most clinically relevant oncogenic alterations in common and rare lung tumors, with an emphasis on the pathologic correlates of the major oncogenic drivers, including EGFR, KRAS, ALK, and MET. Illustrations emphasize the morphologic diversity of lung adenocarcinoma, including genotype-phenotype correlations of genomic evolution in tumorigenesis. Molecular diagnostic approaches, including PCR-based testing, massively parallel sequencing, fluorescence in situ hybridization, and immunohistochemistry are reviewed.

Ciliated Muconodular Papillary Tumors of the Lung Can Occur in Western Patients and Show Mutations in BRAF and AKT1

Ciliated muconodular papillary tumors (CMPTs) are rare peripheral lung lesions, characterized by papillary architecture and ciliated columnar cells admixed with mucinous cells and basal cells. They often have prominent surrounding intra-alveolar mucin, which can lead to diagnostic confusion with mucinous adenocarcinoma. Recognition of the ciliated component is the key to diagnosis of CMPT. The literature contains few reported cases to date, all occurring in East-Asian patients. Although follow-up data are limited, CMPT seems to be an indolent tumor with very good prognosis, leading some to question whether it is a reactive or hamartomatous lesion. However, a very recent molecular study has identified BRAF (40%) and EGFR (30%) alterations in CMPT, supporting a truly neoplastic process. Here for the first time, we report 4 cases of morphologically typical CMPT in western patients, occurring in 1 man (60 y) and 3 women (71 to 83 y). Interestingly, 1 case occurred in background of pronounced small airway disease with necrotizing bronchiolitis and multiple carcinoid tumorlets. We further analyzed 1 tumor using a 50 gene next-generation sequencing oncology panel that identified 2 pathogenic mutations (BRAF V600E and AKT1 E17K). Our study is the first to describe that CMPT can occur in western (non-Asian) patients. Our data confirm BRAF V600E mutation as a probable driver in a subset of these tumors, along with AKT1 mutation, which further supports that CMPT are indolent pulmonary neoplasms.

A case of anaplastic lymphoma kinase (ALK)-positive ciliated muconodular papillary tumor (CMPT) of the lung

Ciliated muconodular papillary tumor (CMPT) is a rare papillary tumor that arises in the peripheral lung fields and is associated with the proliferation of ciliate d and goblet cells and increased mucin production. We report a case of CMPT involving the rearrangement of the anaplastic lymphoma kinase (ALK) gene. The patient was an 84-year-old Japanese female who had exhibited a small nodular shadow on chest computed tomography during a regular checkup 10 years ago. She underwent a partial resection of segment S10 of the right lung. The cut surface of the surgical specimen revealed a well-circumscribed, jelly-like mass measuring 8 × 8 × 10 mm. Histologically, the tumor was composed of a mixture of ciliated, goblet, and basal cells arranged in a papillary pattern together with pools of mucin. A diagnosis of CMPT was made. The lung tumor cells were subjected to fluorescent in situ hybridization and highly sensitive immunohistochemical staining for the ALK protein, both of which produced positive results. CMPT usually follows a favorable course, but the exact nature of this tumor; i.e., whether it is benign or malignant, has not been established. This is the first reported case of an ALK-positive CMPT.

Ciliated muconodular papillary tumor of the lung: A report of five cases

Ciliated muconodular papillary tumor (CMPT) of the lung is a newly defined and extremely rare tumor characterized by a papillary growth pattern, consisting of ciliated columnar cells, mucous cells, and basal cells with abundant mucin production. Tumor definitions and clinicopathological features continue to be debated. Herein, we report five surgical cases of CMPT to characterize its radiographic, gross, and microscopic features. The five cases involved three male patients aged 80, 67, and 66 years, and two female patients aged 73 and 70 years. Three cases were discovered during health care screenings, and two cases were found during follow-up for another synchronous cancer. Histopathological examination revealed that the tumor tissue was composed of ciliated columnar cells, mucous cells, and basal cells with abundant mucin production. Neither nuclear atypia nor mitotic figures were observed. All patients had good prognoses. The benign histological features and clinical courses in these five cases suggest that CMPT is an independent and benign tumor of the lung.

Ciliated muconodular papillary tumor of the lung: report of five cases

We report five serial cases of ciliated muconodular papillary tumor (CMPT) of the lung. CMPT is characterized as a low-grade malignant tumor with ciliated columnar epithelial cells combined with goblet cells, typically presenting as peripheral lung tumor and often causing diagnostic or therapeutic problems. In the cases described here, all patients presented with abnormal chest shadow but no definitive symptoms. Although all tumors were peripheral, computed tomography (CT) revealed various radiographic findings including small lung nodules, ground-grass opacity or irregular-shaped consolidation. All patients underwent complete surgical resection, and no recurrence has been noted over follow-up. In all cases, pathological findings included columnar ciliated cells with mucus lakes, consistent with the immunohistochemical staining. As there are few reports on this tumor entity, which has not yet received a WHO classification, we believe our case series may be of interest.

Frequent BRAF or EGFR Mutations in Ciliated Muconodular Papillary Tumors of the Lung

INTRODUCTION

Ciliated muconodular papillary tumors (CMPTs) are recently characterized, rare peripheral nodules of the lung. These small tumors are histologically comprised of a vaguely organized mixture of nonatypical ciliated columnar cells, mucous cells, and basal cells, and consistently follow a benign clinical course. However, the histogenesis of CMPTs remains uncertain.

METHODS

We performed detailed genomic analyses of 10 archived CMPT cases, using next-generation sequencing and high-resolution melting analysis.

RESULTS

Mutations were identified in eight of the 10 cases (80%); four cases harbored the BRAF-V600E mutation, one case harbored the BRAF-G606R mutation, and three cases harbored deletions in exon 19 of EGFR. All of the deletions in EGFR were of the E746-T751/S752V subtype.

CONCLUSIONS

The high prevalence of driver gene mutations in CMPTs supports the notion that these lesions are neoplastic rather than reactive or metaplastic.

Ciliated muconodular papillary tumor: a solitary peripheral lung nodule in a teenage girl

Papillary tumors of the peripheral lung containing ciliated cells and extracellular mucin include solitary peripheral ciliated glandular papilloma, ciliated muconodular papillary tumor, and well-differentiated papillary adenocarcinoma with cilia formation. We report the case of a 19-year-old woman who was a nonsmoker and presented with an incidental small peripheral lung nodule. The resection specimen showed a soft grayish nodule. Histologic examination further revealed a relatively circumscribed mucinous nodule featuring a tubulopapillary tumor composed of ciliated columnar cells and goblet cells, accompanied with abundant extracellular mucin. No lepidic growth pattern was evident. The tumor cells were immunoreactive for cytokeratin 7, thyroid transcription factor-1, and carcinoembryonic antigen, whereas p63 and cytokeratin 5/6 highlighted the presence of basal cells. Next-generation sequencing did not identify any genetic alterations in targeted regions and mutational hotspots of a panel of 22 genes commonly implicated in lung and colon cancers. Taken together, our case was most likely a ciliated muconodular papillary tumor.