Ciliated Muconodular Papillary Tumor of the Lung: Thin-Section CT Findings of 16 Cases

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.

Ciliated muconodular papillary tumor of the lung: a case report and literature review

Background

Ciliated Muconodular Papillary Tumor (CMPT) was first reported in 2002, and fewer than 100 cases have since been reported. The prognosis after surgical resection is good, and recurrence has not been reported. However, it is easily misdiagnosed as adenocarcinoma. Summarizing the CT features of CMPT will help doctors better understand the disease.

Case presentation

Here, we report a rare and interesting case of ciliated muconodular papillary tumor. A 6-mm diameter solid nodule with slight lobulation, short spines, and subpleural indentation. Patients with clinical diagnosis of high-risk subpleural nodule in the left lung underwent thoracoscopic surgery. Most CMPT cases lack specific clinical manifestations and were found incidentally on physical examination or during a workup for other diseases. The disease was diagnosed through CT and biopsy, and it responded well to surgery.

Conclusions

This paper presents the detailed computed tomography features of CMPT to help prevent misdiagnosis. The typical manifestations of CMPT imaging as solid and partial nodules, nodules in subpleural or peripheral zones, and nodules contain cavities.

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.

CT Texture Analysis for Differentiating Bronchiolar Adenoma, Adenocarcinoma In Situ, and Minimally Invasive Adenocarcinoma of the Lung

Purpose: This study aimed to investigate the potential of computed tomography (CT) imaging features and texture analysis to distinguish bronchiolar adenoma (BA) from adenocarcinoma in situ (AIS)/minimally invasive adenocarcinoma (MIA).

Materials and Methods: Fifteen patients with BA, 38 patients with AIS, and 36 patients with MIA were included in this study. Clinical data and CT imaging features of the three lesions were evaluated. Texture features were extracted from the thin-section unenhanced CT images using Artificial Intelligence Kit software. Then, multivariate logistic regression analysis based on selected texture features was employed to distinguish BA from AIS/MIA. Receiver operating characteristics curves were performed to determine the diagnostic performance of the features.

Results: By comparison with AIS/MIA, significantly different CT imaging features of BA included nodule type, tumor size, and pseudo-cavitation sign. Among them, pseudo-cavitation sign had a moderate diagnostic value for distinguishing BA and AIS/MIA (AUC: 0.741 and 0.708, respectively). Further, a total of 396 quantitative texture features were extracted. After comparation, the top six texture features showing the most significant difference between BA and AIS or MIA were chosen. The ROC results showed that these key texture features had a high diagnostic value for differentiating BA from AIS or MIA, among which the value of a comprehensive model with six selected texture features was the highest (AUC: 0.977 or 0.976, respectively) for BA and AIS or MIA. These results indicated that texture analyses can effectively improve the efficacy of thin-section unenhanced CT for discriminating BA from AIS/MIA.

Conclusion: CT texture analysis can effectively improve the efficacy of thin-section unenhanced CT for discriminating BA from AIS/MIA, which has a potential clinical value and helps pathologist and clinicians to make diagnostic and therapeutic strategies.

Ciliated muconodular papillary tumor/bronchiolar adenoma of the lung

Ciliated muconodular papillary tumor (CMPT) is an uncommon tumor of the lung, usually detected incidentally in the peripheral lung fields on computed tomography. It is most commonly diagnosed in patients between the sixth and last decades of life. The canonical microscopic feature is a tripartite mixture of ciliated columnar, mucous, and basal cells with papillary architecture. However, studies have shown wide morphological variations in this tumor, such as a lack of ciliated columnar or mucous cells and flat instead of papillary architecture. Hence, a new umbrella term, bronchiolar adenoma (BA), has been proposed to encompass all tumors comprising a uniform layer of basal cells underneath the luminal epithelium displaying bronchiolar differentiation. Recent molecular studies on CMPT/BA discovered a high frequency of driver gene alterations, including mutations in the BRAF, EGFR, AKT1, KRAS, and HRAS genes, as well as ALK gene rearrangements. The tumor follows an indolent clinical course, as no recurrences or metastases have been reported in patients who underwent surgical resection. In this article we review the clinical, radiological, and pathological features, and molecular characteristics of CMPTs/BAs.

Mucinous adenocarcinoma caused by cancerization from a ciliated multinodular papilloma tumor: A case report

Ciliated multinodular papilloma tumor (CMPT), a subtype of proximal bronchiolar adenoma (BA), is a rare mucin‐producing papillary tumor arising in the peripheral lung. The nature of CMPT is so far controversial. The hypothesis that CMPT is a precancerous lesion that can lead to mucinous adenocarcinoma requires further research. A 61‐year‐old man with a ground‐glass opacity (GGO) suspected to be lung adenocarcinoma in the right lower lobe of his lung underwent surgical treatment. Postoperative pathology suggested that the patient had mucinous adenocarcinoma caused by cancerization from CMPT. Targeted next‐generation sequencing (NGS) was utilized to detect driver mutations in tumor DNA. Among the identified mutated genes, there were regrettably no high frequency mutations. This report describes a case of mucinous adenocarcinoma caused by cancerization from CMPT, indicating that CMPT may be a neoplasm rather than a metaplastic process and provides histological evidence for the hypothesis that CMPT is a precancerous lesion of mucinous adenocarcinoma.

Ciliated muconodular papillary tumor with a growing cavity shadow that mimicked colorectal metastasis to the lung: a case report

Background

Ciliated muconodular papillary tumor (CMPT) is a rare papillary nodule tumor with benign and malignant characteristics that occurs in the peripheral lung.

Case presentation

A 70-year-old woman who underwent right hemicolectomy for colorectal cancer (CRC; pT3N0M0, p-stage II) 2 years prior, presented with a sub-centimeter growing cavity shadow on chest computed tomography (CT), which was suspected to be a CRC metastasis. Because positron emission tomography CT suggested there was no other site suspicious of recurrence, thoracoscopic resection with preoperative pleural dye marking was planned to remove the small lesion, which seemed to be hardly palpable on CT. Immediately after pleural dye marking adjacent to the lesion using cone beam CT in the hybrid operating room, thoracoscopic wedge resection was performed and the tumor was finally diagnosed as CMPT, characterized by the papillary growth of mucus-producing cells in the alveoli.

Conclusion

We resected the non-palpable small lung lesions following preoperative marking using cone-beam CT in the hybrid operating room. This case highlights a rare cavitary CT image of a CMPT mimicking a metastatic lung tumor from colorectal cancer.