Clinicopathological characteristics and molecular analysis of lung cancer associated with ciliated muconodular papillary tumor/bronchiolar adenoma.

Ciliated muconodular papillary tumor/bronchiolar adenoma (CMPT/BA) is a recently introduced benign lung tumor. It remains unclear whether CMPT/BA is associated with a specific type of lung cancer (LC). We studied the clinicopathological characteristics and genetic profiles of the coexisting primary LC and CMPT/BA (LCCM) cases. We identified eight LCCM (0.4%) from the resected Stage 0-III primary LC (n = 1945). The LCCM cohort was male-dominant (n = 8), elderly (median 72 years old), and most were smokers (n = 6). In addition to the adenocarcinoma (n = 8), we detected two squamous cell carcinomas and one small cell carcinoma-in some cases, multiple cancer. The target sequence/whole exome sequence (WES) revealed no shared mutations between CMPT/BA and LC. One exceptional case was invasive mucinous adenocarcinoma harboring an HRAS mutation (I46N, c.137T>A), but it was likely to be a single nucleotide polymorphism based on variant allele frequency (VAF). Other driver mutations in LC included EGFR (InDel, n = 2), BRAF(V600E) (n = 1), KRAS (n = 2), GNAS (n = 1), and TP53 (n = 2). BRAF(V600E) was the most frequent mutation in CMPT/BA (60%). In contrast, LC showed no specific trend in driver gene mutations. In conclusion, our study revealed differences in the gene mutation profiles of CMPT/BA and LC in coexisting cases, suggesting mostly independent clonal tumorigenesis of CMPT/BA from LC.

Invasive Mucinous Adenocarcinoma of the Lung With a Mural Nodule-like Lesion.

Invasive mucinous adenocarcinoma (IMA) of the lung shares some clinicopathological features with mucinous carcinoma of other organs, such as the ovary. Sarcoma-like lesions, called mural nodules, have been reported in the cystic walls of ovarian mucinous tumors. In this study, we analyzed 213 surgically resected cases of IMA of the lung to determine whether similar mural nodule-like lesions were present. We considered abrupt discrete lesions composed of dedifferentiated tumor cells as mural nodule-like lesions. Of 213 IMAs, we identified 11 tumors with mural nodule-like lesions that were histologically categorized into three subtypes similar to those in the ovary. The sarcomatoid and anaplastic carcinoma-like nodules were composed of spindle cell proliferations and polygonal undifferentiated carcinoma, respectively. Sarcoma-like lesions mimicked sarcomatoid nodules, but the spindle cell proliferations were considered a fibroblastic reaction to the scattered, isolated clusters of tumor cells. Molecular analysis of the components of differentiated IMAs and mural nodule-like lesions revealed a clonal relationship, suggesting a spectrum of tumors with different histology. Clinicopathologically, an older age, the male sex, and smokers were significantly associated with IMAs with mural nodule-like lesions. Notably, patient outcomes were unaffected by the presence or absence of these lesions. Our findings demonstrated that IMA of the lung rarely develops mural nodule-like lesions (11 of 213, 5%). Despite a histological impression of clinical aggressiveness, there was no clear trend in patient outcomes, suggesting that pathologists should avoid overstating this mural nodule-like lesion.

Nodular-type central squamous cell lung carcinoma cured by intraluminal bronchoscopic treatment: A case report.

Primary squamous cell carcinoma (SqCC) often occurs in the trachea and bronchi. Recently, intraluminal bronchoscopic treatment (IBT) has emerged as an option for curative treatment, not just surgery, in patients with central early-stage SqCC (CES-SqCC). However, patients that can be cured by IBT are limited. We report a rare case of CES-SqCC that was surgically confirmed to be cured by IBT alone. A 72-year-old woman had a nodular bronchial tumor at the bifurcation of right upper and intermediate bronchi. For histological diagnosis, the tumor was resected and incinerated using high-frequency snare (HFS). Obtained specimens were diagnosed as SqCC; wedge resection of the bifurcation was performed to remove the residual lesion. However, no malignant findings were found in the excised specimens. Some patients with CES-SqCC may be cured by aggressive diagnostic bronchoscopy. The risk of postoperative complications cannot be ignored because the surgery requires bronchoplasty in patients with CES-SqCC. For patients with CES-SqCC, surgical resection may be avoided by detailed assessment of residual lesion with radial probe endobronchial ultrasonography (RP-EBUS).