Comprehensive molecular analysis of genomic profiles and PD-L1 expression in lung adenocarcinoma with a high-grade fetal adenocarcinoma component

Clinical and Pathological Characteristics and Prognosis of Lung Adenocarcinoma With High-Grade Fetal Features: A Retrospective Analysis

Fetal adenocarcinoma of the lung is a rare tumor. The clinical and pathological characteristics, treatment, and prognosis of patients with lung adenocarcinoma with fetal lung-like morphology were retrospectively investigated. The tumors of 9 patients with lung adenocarcinoma contained fetal lung-like morphology. One patient had pure-type high-grade fetal adenocarcinoma. Two patients had more than 50% high-grade fetal adenocarcinoma. Six specimens accounted for < 50% of the high-grade fetal features. It occurred in 7 men and 2 women. The median age at diagnosis was 62.0 years. Thyroid transcription factor-1 was frequently expressed in 8 specimens. All 9 specimens showed high rates of immunopositivity for β-catenin and E-cadherin. Three specimens showed nuclear β-catenin staining. Some patients showed immune expression of CDX2, α-fetoprotein (AFP), SALL4, and Glypican-3. Three of these specimens were diffusely strongly positive for p53, including 1 mixed-type high-grade fetal adenocarcinoma and 2 lung adenocarcinomas with high-grade fetal features. However, the other 6 patients had wild-type p53, including 1 pure-type high-grade fetal adenocarcinoma. PD-L1 was not expressed in all patients. Epidermal growth factor receptor mutations were detected in 1 patient. All patients were diagnosed using surgical samples. During the follow-up period of 36 months (range: 1-92 months), 3 patients received chemotherapy. One patient underwent radiotherapy. Two patients experienced recurrences. No patient died. PD-L1 expression status suggests a poor response to immune checkpoint therapy. The prognosis of the patient was relatively good.

[High-grade Fetal Adenocarcinoma of the Lung with Scalp Metastasis: A Case Report]

Fetal adenocarcinoma of the lung (FLAC) is a rare tumor. Due to its different clinicopathological features, biological behavior and clinical outcome, FLAC is classified into low-grade FLAC (L-FLAC) and high-grade FLAC (H-FLAC). Most patients with H-FLAC are middle-aged heavy smokers. Here, we describe an extremely rare case of a young male patient who denies smoking and initially presents with a mass on the top of the head and is eventually diagnosed with H-FLAC. The aim of this article is to improve the understanding and awareness of FLAC, and increase the attention to the disease, so as to prevent the underdiagnosis and misdiagnosis of the disease, strengthen early identification and accurate diagnosis, and promote subsequent effective treatment and improve prognosis.
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High-grade fetal adenocarcinoma of the lung misdiagnosed as male breast carcinoma: a case report and literature review

Background and aim

High-grade fetal adenocarcinoma of the lung (HG-FLAC) is a specific subtype of lung adenocarcinoma with a poor prognosis. A lack of understanding exists because of the rarity of this disease. This study aimed to present a case of HG-FLAC with multiple metastases misdiagnosed as male breast carcinoma at the initial diagnosis.

Case presentation

The patient visited our hospital due to a month-long cough. The chest computed tomography (CT) scan revealed a mass in the left lung and chest wall, accompanied by enlargement of mediastinal lymph nodes. The magnetic resonance imaging indicated potential metastatic lesions in the brain and adrenal glands. The patient underwent a biopsy of the lesion in the right chest wall. The pathological and immunohistochemical findings indicated a high possibility of male breast cancer. However, the clinical features did not support this diagnosis. Therefore, a CT-guided percutaneous lung biopsy was performed, and the pathological examination finally indicated HG-FLAC.

Conclusions

We presented a complex yet interesting case in which HG-FLAC was misdiagnosed as male breast cancer. Our interesting case may stimulate discussions about the methods to manage patients with HG-FLAC.

KMT2C expression and DNA homologous recombination repair factors in lung cancers with a high-grade fetal adenocarcinoma component

Background

High-grade fetal adenocarcinoma of the lung (H-FLAC) is a rare variant of pulmonary adenocarcinoma. Our previous study showed a high frequency of KMT2C mutations in lung cancers with an H-FLAC component, showing that KMT2C dysfunction may be associated with the biological features of H-FLACs.

Methods

In this study, we performed RNA sequencing and immunohistochemical analysis to identify the differentially expressed genes and corresponding pathways associated with H-FLACs, compared with common adenocarcinomas.

Results

Ingenuity pathway analysis based on RNA sequencing data revealed that DNA homologous recombination repair (HRR) pathways were significantly inactivated in H-FLAC. Expression of KMT2C, ATM, ATR, and BRCA2 was significantly lower in H-FLACs than in common adenocarcinomas, and BRCA1 expression showed a decreasing trend. Pearson correlation analyses for all cases revealed that KMT2C expression showed a strong positive correlation (R>0.7) with the expression of ATR, BRCA1, and BRCA2 genes and a moderately positive correlation with ATM expression (R=0.47). Immunohistochemical analysis showed significantly lower levels of KMT2C, ATM, ATR, and BRCA2 expression in H-FLACs than in common adenocarcinomas, and a trend of lower BRCA1 levels. Additionally, KMT2C expression showed a weak to moderate correlation with that of ATM, ATR, BRCA1, and BRCA2.

Conclusions

Cancers containing H-FLAC components showed lower levels of KMT2C and HRR factors than common lung adenocarcinomas, and their levels exhibited a positive correlation. These results support the hypothesis that loss of KMT2C function decreases the expression of the HRR factors in H-FLACs. H-FLACs with low KMT2C expression may be a good indication for poly (ADP-ribose) polymerase (PARP) inhibitor-based therapy.

Yolk Sac Tumor Originating From Cervical Adenocarcinoma: A Case Predominated by Enteroblastic Differentiation

The fetal gut-like phenotype can be found in yolk sac tumors and adenocarcinomas with enteroblastic differentiation (AEBDs). We report a cervical yolk sac tumor in a 44-yr-old woman. The tumor has similar morphology, immunophenotype, and molecular features to the AEBD of the digestive system. The tumor showed a glandular-predominant growth pattern, composed of columnar cells with clear glycogen-rich cytoplasm. The microcystic/reticular architecture or Schiller-Duval bodies were not found in the tumor. Immunohistochemically, the tumor cells were positive for p16, glypican-3 (GPC3), spalt-like transcription factor 4 (SALL4), CDX-2, and p53. TP53 mutation was identified by next-generation sequencing, and human papillomavirus (HPV) 35 was detected by HPV DNA polymerase chain reaction. In the present case, the adenocarcinoma cells in the superficial cervical glandular epithelium and the nonclear glandular components proved the existence of somatic components. The positivity of p16 and HPV also supports that the present case originates from an HPV-associated adenocarcinoma. The yolk sac tumor should be thought of as "germ cell differentiation" from a somatic carcinoma. This kind of yolk sac tumor arising from somatic-type adenocarcinoma in the female genital tract may be the counterpart of AEBD in the digestive tracts and adenocarcinomas with fetal gut-like morphology in other organs. The tumor might be more aggressive than conventional adenocarcinoma, pathologists should highlight the existence of the enteroblastic component in the pathologic report.

Morphological and Molecular Characteristics in Low Grade Fetal Adenocarcinoma of the Lung: Two Case Reports and Literature Review

Background: Low-grade fetal adenocarcinoma of the lung is a rare pulmonary tumor resembling fetal lung histologically. Due to its rarity, there is limited information regarding the pathogenesis and biological characteristics of low-grade fetal adenocarcinoma of the lung. Here, we describe two cases of low-grade fetal adenocarcinoma of the lung treated at our hospital and summarize cases of low-grade fetal adenocarcinoma of the lung reported in the literature. Case presentation: We examined two cases (one woman and one man; 30 and 67 years old, respectively). Histologically, tumor tissues from both cases had a complex glandular component with clear cuboidal and columnar cells that resembled the histological features of fetal lung. In some areas, squamous morules were prominent. Immunohistochemically, nuclear/cytoplasmic expression of β-catenin was detected in both cases. Mutation analysis revealed a CTNNB1 mutation in both cases and a DICER1 mutation in 1 case. No mutations in EGFR, BRAF, KRAS, or PIK3CA were found. Conclusions: Low-grade fetal adenocarcinoma of the lung showed a high frequency of CTNNB1 mutations and low frequencies of EGFR, KRAS, BRAF, and PIK3CA mutations in our examined cases and in previous studies. This rare tumor has unique clinicopathological characteristics with specific genetic aberrations involving the Wnt pathway. These results provide a molecular basis for development of new therapies to treat these tumors.

α-Fetoprotein-Producing Endometrial Carcinoma Is Associated With Fetal Gut-Like and/or Hepatoid Morphology, Lymphovascular Infiltration, TP53 Abnormalities, and Poor Prognosis: Five Cases and Literature Review

The clinicopathological, immunohistochemical, and molecular characteristics of α-fetoprotein (AFP)-producing endometrial carcinoma (AFP+ EC) are poorly understood. From 284 cases of endometrial carcinoma in our pathology archive, we identified five cases (1.8%) of AFP+ EC with fetal gut–like (4/5) and/or hepatoid (2/5) morphology. All cases exhibited lymphovascular infiltration. In addition, 24 cases of endometrial carcinoma with elevated serum AFP levels were retrieved from the literature. The patient age ranged from 44 to 86 years (median: 63). Of 26 cases whose FIGO (International Federation of Gynecology and Obstetrics) stage and follow-up information was available (mean follow-up 24 months), 15 were stage I or II and 11 were stage III or IV. Even in stage I or II disease, death or relapse occurred in more than half of the patients (8/15). Detailed analysis of our five cases revealed that, on immunohistochemistry, AFP+ EC was positive for SALL4 (4/5), AFP (3/5), and HNF1β (4/5) in >50% of neoplastic cells and negative for estrogen and progesterone receptors (5/5), PAX8 (4/5), and napsin A (5/5). Four cases exhibited aberrant p53 immunohistochemistry and were confirmed to harbor TP53 mutations by direct sequencing. No mutation was found in POLE, CTNNB1, or KRAS. In conclusion, AFP+ EC merits recognition as a distinct subtype of endometrial carcinoma, which occurs in 1.8% of endometrial carcinoma cases, are associated with TP53 abnormalities, exhibit lymphovascular infiltration, and can show distant metastasis even when treated in early stage.

Distinct properties of pure- and mixed-type high-grade fetal lung adenocarcinomas by genetic profiling and transcription factor expression

The clinicopathological differences among high-grade fetal lung adenocarcinomas completely comprising tumor cells that resemble fetal lung epithelium (pure type) and those with fetal lung-like components admixed with conventional adenocarcinoma cells (mixed type) remain undetermined. Here, we examined the clinicopathological, immunohistochemical, and molecular features of 11 lung adenocarcinomas with fetal lung-like morphology among 3895 consecutive cases of primary lung cancer based on the expression pattern of transcription factors. According to the current WHO classification, two cases (0.05%) were categorized as low-grade fetal adenocarcinoma, two cases (0.05%) were pure-type high-grade fetal adenocarcinoma, five cases (0.1%) were mixed-type high-grade fetal adenocarcinoma, and the remaining two cases (0.05%) were lung adenocarcinoma with high-grade fetal features (fetal lung-like morphology occupied less than 50%). CTNNB1 mutations were exclusively identified in low-grade fetal adenocarcinomas. In contrast, mixed-type high-grade fetal adenocarcinoma or lung adenocarcinoma with high-grade fetal features frequently harbored mitogenic drivers including EGFR mutations. Furthermore, almost all tumor cells expressed CDX2 and HNF4α in both cases of pure-type high-grade fetal lung adenocarcinoma, but lacked TTF-1 positivity. In contrast, TTF-1 was frequently expressed in mixed-type high-grade fetal lung adenocarcinoma and in lung adenocarcinoma with high-grade fetal features. Our data suggest similar prevalence of low-grade fetal lung adenocarcinoma and pure-type high-grade fetal lung adenocarcinoma, and indicate that pure- and mixed-type high-grade fetal lung adenocarcinomas are distinct, with the former akin to low-grade fetal adenocarcinoma with respect to purely embryonic morphology and absence of common lung adenocarcinoma mitogenic drivers, and the latter being genetically and transcriptionally related to conventional lung adenocarcinoma.