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.

Ki-67 Index of 55% Distinguishes Two Groups of Bronchopulmonary Pure and Composite Large Cell Neuroendocrine Carcinomas with Distinct Prognosis

BACKGROUND

Little information is available concerning prognostic factors for bronchopulmonary large cell neuroendocrine carcinomas (BP-LCNECs) and even less is known about combined LCNECs (Co-LCNECs). We investigated whether an integrated morphological, immunohistochemical, and molecular approach could be used for their prognostic evaluation.

METHODS

Morphological (including combined features), proliferative (mitotic count/Ki-67 index), immunohistochemical (napsin A, p40, TTF-1, CD44, OTP, SSTR2A, SSTR5, mASH1, p53, RB1, and MDM2), and genomic (TP53, RB1, ATM, JAK2, KRAS, and STK11) findings were analyzed in BP-LCNECs from 5 Italian centers, and correlated with overall survival (OS). The Ki-67 index was expressed as the percentage of positive cells in hot spots as indicated in the WHO 2019 Digestive System Tumors and, for Co-LCNECs, the Ki-67 index was evaluated only in the LCNEC component.

RESULTS

A total of 111 LCNECs were distinguished into 70 pure LCNECs, 35 Co-LCNECs (27 with adenocarcinoma [ADC] and 8 with squamous cell carcinoma [SqCC]), and 6 LCNECs with only napsin A immunoreactivity. The Ki-67 index cutoff at 55% evaluated in the neuroendocrine component was the most powerful predictor of OS (log-rank p = 0.0001) in all LCNECs; 34 cases had a Ki-67 index <55% (LCNEC-A) and 77 had a Ki-67 index ≥55% (LCNEC-B). Statistically significant differences in OS (log-rank p = 0.0001) were also observed between pure and Co-LCNECs. A significant difference in OS was found between pure LCNECs-A and Co-LCNECs-A (p < 0.05) but not between pure LCNECs-B and Co-LCNECs-B. Co-LCNEC-ADC and LCNEC napsin A+ cases had longer OS than pure LCNEC and Co-LCNEC-SqCC cases (log-rank p = 0.0001). On multivariable analysis, tumor location, pure versus combined features, and napsin A, but no single gene mutation, were significantly associated with OS after adjustment for Ki-67 index and study center (p < 0.05).

CONCLUSIONS

The Ki-67 proliferation index and the morphological characterization of combined features in LCNECs seem to be important tools for predicting clinical outcome in BP-LCNECs.

Disparity in clinical outcomes between pure and combined pulmonary large-cell neuroendocrine carcinoma: A multi-center retrospective study

OBJECTIVES

The 2015 World Health Organization classification defines pulmonary large-cell neuroendocrine carcinoma (LCNEC) as a high-grade neuroendocrine carcinoma. However, the clinical characteristics and prognostic factors of pure LCNEC and combined LCNEC remain unclear. Hence, we performed a multi-center retrospective study to compare the clinical outcomes of pure versus combined LCNEC.

MATERIALS AND METHODS

Data from 381 patients with pulmonary LCNEC admitted to 17 Chinese institutes between 2009 and 2016 were collected retrospectively. Clinical characteristics and prognosis were analyzed among patients receiving adjuvant (adjuvant group; n = 56) and first-line (first-line group; n = 146) chemotherapy, as well as among patients receiving small cell lung cancer (SCLC) and non-SCLC (NSCLC) chemotherapy regimens. The Kaplan-Meier method and multivariable Cox regression were used to identify clinicopathological variables that might influence patient outcomes.

RESULTS

Expression levels of neuroendocrine markers (synaptophysin, chromogranin-A, CD56) were associated with patients' prognosis in the total study cohort. In the adjuvant group, median disease-free survival was non-significantly longer for SCLC-based regimens than for NSCLC-based regimens (P = 0.112). In the first-line group, median progression-free survival was significantly longer for SCLC-based regimens than for NSCLC-based regimens (11.5 vs. 7.2 months, P = 0.003). Among patients with combined LCNEC, adenocarcinoma was the most common combined component, accounting for 70.0 % of cases. Additionally, median overall survival was non-significantly shorter for combined LCNEC than for pure LCNEC (P = 0.083).

CONCLUSION

The SCLC regimen is a more effective choice, as either first-line or adjuvant chemotherapy, when compared to the NSCLC regimen for LCNEC treatment. Further studies are needed to clarify the survival differences between patients with pure-, and combined LCNEC.