Diagnosis
Diagnosis
Ciliated Muconodular Papillary tumor (CMPT)
Discussion
Ciliated muconodular papillary tumor is a rare lung tumor, typically found incidentally in older adults. Most of the cases have been reported from Eastern Asia. The most common location is the right lower lung. The tumors are usually less than 15 mm, with the largest reported being 45 mm.
Imaging findings are non-specific; CMPT is typically peripherally located. It appears solid, partially solid, or ground glass opacity. 25% of the cases have a component of central cavitation and irregular borders. Some cases were reported with concurrent primary lung cancer.
CMPTs are usually well-circumscribed, gray-white, solitary nodules with soft, gelatinous, or mucoid cut surfaces on gross examination.
Microscopically, CMPTs appear at lower power as a distinct nodule with predominantly glandular and papillary architecture. Adjacent alveolar spaces may contain mucin. Some cases have central mucin accumulation, which correlates to the imaging finding of central cavitation.
CMPT is characterized by a bilayered epithelium, including luminal cells surrounded by basal cells. The luminal cells may consist of ciliated columnar, and mucous cells. Some cases show a combination of ciliated and mucous cells. Mitotic figures are rare, and significant nuclear atypia is absent.
CMPT is positive for CK7. CEA and TTF-1 are expressed in most cases. The tumor shows a variable expression of MUC-1 and MUC5AC. CDX2 and CK20 are negative. P40 and P63 highlight the basal cells. In cases with the BRAF V600E mutation, cytoplasmic staining for BRAF V600E is present in all 3 cell components.
Differential Diagnosis
Adenocarcinoma – Can be distinguished by readily identifiable atypia, lack of basal cell layer, and cilia.
Mucoepidermoid carcinoma – Usually centrally located and associated with large airways.
Peribronchial metaplasia – Benign mimicker, typically a microscopic lesion and does not form a distinct tumor nodule.
Papilloma – Papillomas are characteristically central and endobronchial.
Molecular Alterations: BRAF driver mutation is the most common, with other mutually exclusive driver alterations, including
Prognosis: CMPT is a benign tumor. No recurrence or metastases has been reported in the literature.
References
Yen-Wen Lu, Yi-Chen Yeh; Ciliated Muconodular Papillary Tumors of the Lung. Arch Pathol Lab Med 1 January 2019; 143 (1): 135–139. doi: https://doi.org/10.5858/arpa.2017-0275-RS
Ishikawa Y. Ciliated muconodular papillary tumor of the peripheral lung: benign or malignant? Pathol Clin Med (Byouri-to-Rinsho). 2002;20:964–965.
Lau KW, Aubry MC, Tan GS, Lim CH, Takano AM. Ciliated muconodular papillary tumor: a solitary peripheral lung nodule in a teenage girl. Hum Pathol. 2016;49:22–26.
Taguchi R, Higuchi K, Sudo M, et al. A case of anaplastic lymphoma kinase (ALK)-positive ciliated muconodular papillary tumor (CMPT) of the lung. Pathol Int. 2017;67(2):99–104.
Liu L, Aesif SW, Kipp BR, et al. Ciliated muconodular papillary tumors of the lung can occur in Western patients and show mutations in BRAF and AKT1. Am J Surg Pathol. 2016;40(12):1631–1636.
Kamata T, Yoshida A, Kosuge T, Watanabe S, Asamura H, Tsuta K. Ciliated muconodular papillary tumors of the lung: a clinicopathologic analysis of 10 cases. Am J Surg Pathol. 2015;39(6):753–760.
Kon T, Baba Y, Fukai I, Watanabe G, Uchiyama T, Murata T. Ciliated muconodular papillary tumor of the lung: a report of five cases. Pathol Int. 2016;66(11):633–639.
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