Comprehensive review of fetal adenocarcinoma of the lung

Prominent response to savolitinib monotherapy in high-grade fetal adenocarcinoma with MET amplification and concurrent brain metastasis: a case report

Background

Mesenchymal-epithelial transition (MET) represents a potential therapeutic target in various cancers, with amplification of the MET gene identified in a subset of patients with pulmonary adenocarcinomas. However, MET gene amplification is rarely observed in high-grade fetal adenocarcinoma (H-FLAC).

Case Description

Here we present a novel case of a patient diagnosed with stage IV H-FLAC harboring MET amplifications and treated with savolitinib. The 69-year-old male patient, who presented with a primary complaint of cough and white sputum, had a history of hypertension for over 10 years and a 45-year smoking history. The patient received savolitinib monotherapy treatment due to brain metastases. Despite the omission of radiotherapy for asymptomatic brain metastases, a notable response to savolitinib therapy was observed, with a partial response (PR) achieved after 4 weeks and a reduction in the brain tumor. At the time of the submission of this report, the patient received over 24 weeks of savolitinib treatment, and was maintained PR. The patient was still undergoing treatment. This highlights the potential clinical benefits of targeted therapy against MET amplification in H-FLAC.

Conclusions

H-FLAC harboring MET amplification and brain metastasis is rare. Treatment with savolitinib monotherapy resulted in a PR, providing preliminary insights to the efficacy of savolitinib for H-FLAC with MET amplification.

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.

Uniportal video-assisted thoracoscopic segmentectomy for fetal adenocarcinoma lung cancer with severe pulmonary emphysema: a case report

Background

Fetal adenocarcinoma is a very rare subtype of lung adenocarcinoma. Its incidence ranges from 0.1 to 0.87% among all primary lung neoplasms. Low-grade types tend to appear in the younger generation, and the age ranges from 20 to 50 years with a mean age of around 35 years. Surgical resection is currently the best way to treat fetal adenocarcinoma lung cancer without distant metastasis.

Case report

This is a 56-year-old female who underwent low-dose computer tomography (LDCT) screening during the health examination. She used to be a heavy smoker for more than 30 years, and the CT images revealed severe bronchiectasis and emphysema. There is a solitary nodule with a diameter of 18.9 x 17.8mm in the central area of the left upper lobe. We decided to conduct left upper lobe S1~S3 segmentectomy under uniportal VATS. The surgery was successful, and the patient was discharged within one week and recovered well. The final diagnosis was fetal adenocarcinoma, low-grade (pT1cN0Mx, stage IA3).

Conclusion

The first case reported as fetal adenocarcinoma lung cancer who underwent uniportal video-assisted thoracoscopic segmentectomy. We believe it is a safe and feasible procedure for low-grade types fetal adenocarcinoma patient with poor pulmonary function.

[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.

The prognostic value of histopathology in invasive lung adenocarcinoma: a comparative review of the main proposed grading systems

INTRODUCTION

An accurate histological evaluation of invasive lung adenocarcinoma is essential for a correct clinical and pathological definition of the tumour. Different grading systems have been proposed to predict the prognosis of invasive lung adenocarcinoma.

AREAS COVERED

Invasive non mucinous lung adenocarcinoma is often morphologically heterogeneous, consisting of complex combinations of architectural patterns with different proportions. Several grading systems for non-mucinous lung adenocarcinoma have been proposed, being the main based on architectural differentiation and the predominant growth pattern. Herein we perform a thorough review of the literature using PubMed, Scopus and Web of Science and we highlight the peculiarities and the differences between the main grading systems and compare the data about their prognostic value. In addition, we carried out an evaluation of the proposed grading systems for less common histological variants of lung adenocarcinoma, such as fetal adenocarcinoma and invasive mucinous adenocarcinoma.

EXPERT OPINION

The current IASLC grading system, based on the combined score of predominant growth pattern plus high-grade histological pattern, shows the stronger prognostic significance than the previous grading systems in invasive non mucinous lung adenocarcinoma.

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.

Combined large cell neuroendocrine carcinoma of the lung associated with low-grade fetal adenocarcinoma without β-catenin mutation: a case report

We report a case of combined large cell neuroendocrine carcinoma of the lung associated with low-grade fetal adenocarcinoma (L-FLAC) without β-catenin mutation in exon 3. A 33-year-old man presented at the hospital with a more than 5-month history of cough with no obvious cause. Computed tomography revealed a large, solid, round mass located in the upper lobe of the right lung. Microscopic examination showed two tumor components: large cell neuroendocrine carcinoma and low-grade fetal adenocarcinoma. Immunohistochemistry ofthe fetal adenocarcinoma showed abnormal nuclear/cytoplasmic expression of β-catenin, but no exon 3 mutation in β-catenin. Our findings provide further insight into the pathologic mechanism of FLAC.

Both the serum AFP test and AFP/GPC3/SALL4 immunohistochemistry are beneficial for predicting the prognosis of gastric adenocarcinoma

BACKGROUND

Both gastric adenocarcinoma with primitive enterocyte phenotype (GAPEP) (including hepatoid adenocarcinoma) and alpha-fetoprotein (AFP)-producing gastric adenocarcinoma have poor prognoses. However, the value of the serum AFP test and AFP/glypican-3 (GPC3)/spalt-like transcription factor 4 (SALL4) immunohistochemistry is still not clear, and these two methods have not yet been thoroughly compared.

METHODS

We collected 421 consecutive non-neoadjuvant surgically or endoscopically resected gastric adenocarcinoma patients with serum AFP results before surgery (group A). We divided these cases into serum AFP-high (sAFP-H) and serum AFP-normal (sAFP-N) by serum AFP levels, and into GAPEP (expressing AFP, GPC3, or SALL4) and non-GAPEP (nGAPEP) by AFP/GPC3/SALL4 immunohistochemistry results. We also collected 12 non-resected gastric adenocarcinoma patients with serum AFP ≥ 7 ng/mL before treatment (group B). We analyzed these patients' clinicopathological characteristics and prognoses.

RESULTS

Seventeen (4.04%) patients in group A were sAFP-H. These patients were younger and mainly had tubular adenocarcinoma with later pT (P = 0.014) and pN (P = 0.047) categories and more lymphovascular invasion (P < 0.001), perineural spread (P = 0.008), and metastases or recurrence (P < 0.001). For immunohistochemistry, 34 (8.08%) cases were GAPEP, and GAPEP cases also had later pT categories than nGAPEP cases (P = 0.001). Most group B patients with elevated serum AFP (especially > 1000 ng/mL) had simultaneous metastases, mainly liver metastases. Both the serological method and immunohistochemical method were useful for predicting prognosis (AUC _sAFP = 0.625, AUC _A/G/S-IHC = 0.723, z statistic = 1.726, P = 0.084). The serum AFP level (especially > 1000 ng/mL) is more specific (100%), and immunohistochemistry is more sensitive (50%).

CONCLUSION

Both the serum AFP level and immunohistochemical expression of AFP/GPC3/SALL4 can be used to indicate a poor prognosis for gastric adenocarcinoma.

Novel genetic characteristics in low-grade fetal adenocarcinoma of the lung

Background

Low‐grade fetal adenocarcinoma of the lung (L‐FLAC) is a rare subtype of lung adenocarcinoma with undetermined histological features and genetic abnormalities. In this study, we attempted to investigate the pathological characteristics and genomic profiles of L‐FLAC.

Methods

Among 9839 cases of primary lung adenocarcinoma resected at Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between January 2011 and June 2016, three cases diagnosed with L‐FLAC were selected. An immunohistochemical profile and whole exome sequencing (WES) using tumor and normal tissues was conducted. The last follow‐up date of patients was January 2021.

Results

Three cases diagnosed with L‐FLAC were finally screened, suggesting a percentage of 0.03%. All three patients were male and diagnosed as stage I following radical lobectomy. The missense variant was found to be the major gene mutation type using WES. CTNNB1 and DICER1 were the two most frequent gene mutations. All cases demonstrated positive TTF‐1 expression. In addition, two patients showed positive expression of β‐catenin (nuclear/cytoplasmic expression), CgA and Sny. Negative expression of PD‐L1 in tumor cells was observed in all three cases. One case with a relatively high tumor mutation burden (TMB) (2.18 mut/Mb) had an inferior overall survival of 11.5 months. However, the other two cases with a lower TMB (0.12 and 0.74 mut/Mb) still acquired disease‐free status up to the last follow‐up date.

Conclusions

L‐FLAC has a specific molecular background which is different from lung adenocarcinoma. Furthermore, gene heterogeneity was found and might be the reason for a dramatically different prognosis in these L‐FLAC patients.

Coexistence of Low-Grade Fetal Adenocarcinoma and Adenocarcinoma in situ of the Lung Harboring Different Genetic Mutations: A Case Report and Review of Literature

Low-grade fetal lung adenocarcinoma (L-FLAC) is an exceptionally rare pulmonary tumor, presenting with unclear histological and molecular features. In particular, the potential driver genes of L-FLAC remain elusive. To date, only five reports have documented genetic aberrations in L-FLAC. In the current study, we describe an unusual case of L-FLAC coexisting with adenocarcinoma in situ (AIS) of the lung, harboring different genetic mutations. A 39-year-old non-smoker female patient was referred to our hospital with the chief complaint of dyspnea for 20 days. Chest computed tomography (CT) revealed a 2.5×1.5×1.5 cm nodule in the right middle lobe, with no mediastinal lymph node enlargement or distant metastases. Thoracoscopic surgery was performed to remove the nodules. Histopathological analysis of the tissue sections, based on findings from immunohistochemical staining, confirmed a diagnosis of L-FLAC coexisting with AIS of the lung. Next-generation sequencing revealed L-FLAC-based mutations in DICER1 and CTNNB1, and AIS harboring KRAS mutations. Currently, the patient remains recurrence-free 17 months after the initial diagnosis. This report presents the first case demonstrating the coexistence of L-FLAC and AIS in the same pulmonary nodule, harboring different genetic mutations. Based on the literature review, this is the second reported case of L-FLAC bearing DICER1 mutations.

Co-existence of well-differentiated fetal adenocarcinoma of the lung with tuberculosis in a young female: A rare case report

RATIONALE

Fetal adenocarcinoma of the lung (FLAC) with fetal lung-like morphology is a rare entity of pulmonary adenocarcinoma. Well-differentiated fetal adenocarcinoma (WDFA) belongs to its the low-grade form, which possesses a relatively favorable prognosis. Tuberculosis (TB) is an aggressive infectious disease that has been ranked as one of the top 10 causes of death worldwide. There may be a connection between the 2 and attention should be paid to the differential diagnosis.

PATIENT CONCERNS

A 28-year-old non-smoking female was admitted with signs of hemoptysis, and she had been coughing up phlegm for 5 years. The patient was previously diagnosed with TB in another hospital, and underwent an anti-TB regimen.

DIAGNOSIS

The co-existence of WDFA and TB was confirmed via histopathological evaluation of postoperative samples.

INTERVENTIONS

The patient was subjected to a right lower lobectomy together with a wedge resection of the right upper lobe using video-assisted thoracoscopic surgery, with systemic lymphadenectomy.

OUTCOMES

The patient tolerated the surgical procedure well and underwent an uneventful postoperative course.

LESSONS

To our knowledge, no previous reports exist of cases with WDFA accompanied by TB. The present case indicated that a prior diagnosis of TB might predispose to lung cancer regardless of smoking history. It is also essential to distinguish WDFA from TB because of the similarity in clinical features and sites of pathological changes. Patients with WDFA usually have a better prognosis and surgery is the preferred treatment.