Clinical activity of pembrolizumab with or without chemotherapy in advanced pulmonary large-cell and large-cell neuroendocrine carcinomas: a multicenter retrospective cohort study

BACKGROUND

Immune checkpoint inhibitors (ICI)-based combination strategies have improved the survival outcomes in advanced non-small cell lung cancers; however, data regarding their efficacy remains limited for uncommon histological types, including large-cell carcinoma (LCC) and large-cell neuroendocrine carcinoma (LCNEC).

METHODS

We retrospectively analyzed a total of 60 patients with advanced LCC and LCNEC - 37 treatment-naïve and 23 pre-treated - who received pembrolizumab with or without chemotherapy. Treatment and survival outcomes were analyzed.

RESULTS

Of the 37 treatment-naïve patients who received first-line pembrolizumab combined with chemotherapy, the 27 patients with LCC had an overall response rate (ORR) of 44.4% (12/27) and a disease control rate (DCR) of 88.9% (24/27); whereas 10 patients with LCNEC had an ORR of 70% (7/10) and DCR of 90% (9/10). The median progression-free survival (mPFS) was 7.0 months (95% confidence intervals [CI]: 2.2-11.8) and median overall survival (mOS) was 24.0 months (95%CI: 0.0-50.1) for first-line pembrolizumab plus chemotherapy of LCC (n = 27), whereas mPFS was 5.5 months (95%CI: 2.3-8.7) and mOS was 13.0 months (95%CI: 11.0-15.0) for first-line pembrolizumab plus chemotherapy of LCNEC (n = 10). Of the 23 pre-treated patients who received subsequent-line pembrolizumab with or without chemotherapy, mPFS was 2.0 months (95% CI: 0.6-3.4) and mOS was 4.5 months (95% CI: 0.0-9.0) for LCC and mPFS was 3.8 months (95% CI: 0.0-7.6) and mOS was not reached for LCNEC.

CONCLUSION

Our study provides real-world clinical evidence of the anti-tumor activity of pembrolizumab plus chemotherapy in advanced LCC and LCNEC, indicating that this regimen could serve as a treatment option, particularly as first-line therapy, for improving the survival outcomes of patients with these rare histological subtypes of lung cancer.

TRIAL REGISTRATION

NCT05023837(ESPORTA, 27/08/2021).

Metastatic Neuroendocrine Neoplasms of Unknown Primary: Clues from Pathology Workup

Simple Summary

While most neuroendocrine neoplasms are indolent and slow-growing tumors, subsets of cases will spread beyond the tissue of origin. Given the rather slow progress, some lesions are incidentally discovered as metastatic deposits rather than primary masses. In these cases, a biopsy is often taken to allow the pathologist to identify the tumor type and possibly the primary tumor site via microscopic examination. In this review, the authors present a simplified guide on how to approach metastatic neuroendocrine tumors from a pathologist’s perspective.

Abstract

Neuroendocrine neoplasms (NENs) are diverse tumors arising in various anatomical locations and may therefore cause a variety of symptoms leading to their discovery. However, there are instances in which a NEN first presents clinically as a metastatic deposit, while the associated primary tumor is not easily identified using conventional imaging techniques because of small primary tumor sizes. In this setting (which is referred to as a “NEN of unknown primary”; NEN-UP), a tissue biopsy is often procured to allow the surgical pathologist to diagnose the metastatic lesion. If indeed a metastatic NEN-UP is found, several clues can be obtained from morphological assessment and immunohistochemical staining patterns that individually or in concert may help identify the primary tumor site. Herein, histological and auxiliary analyses of value in this context are discussed in order to aid the pathologist when encountering these lesions in clinical practice.

A case of large cell neuroendocrine carcinoma of the uterine cervix misdiagnosed as adenocarcinoma in Thinprep cytology test

Large cell neuroendocrine carcinoma (LCNEC) of uterine cervix is a rare malignancy with aggressive behavior and poor clinical outcome even in its early stage. Few cytopathologic features of cervical LCNEC have been reported previously. A 57-year-old postmenopausal African American female, presented to the local health department with a chief complaint of heavy vaginal bleeding. A 45-year-old female presented with 20 months of vaginal pruritus and foul odor. Cervical malignancy was suspected by pelvis magnetic resonance imaging. Thinprep cytology test demonstrated ball-like tumor cell clusters in a necrotic background. Cytologic diagnosis of adenocarcinoma was rendered. However, the histologic and immunohistochemical examination of cervical biopsy revealed the LCNEC of the uterine cervix. Due to its rarity, LCNEC may pose a diagnostic challenge in cervical cytology. Cytopathologists should pay attention to the cytological features of cervical LCNEC, such as rosettoid pattern, nuclear molding, and thin nuclear membrane for differentiation from other mimics.

Large cell neuroendocrine carcinoma of the maxillary sinus on fine needle aspiration cytology: Report of a rare case with a focus on pitfalls in diagnosis

Head and neck large cell neuroendocrine carcinoma (LCNEC) is a rare high-grade malignant tumor with neuroendocrine differentiation. We report a case of LCNEC causing difficulty in cytological diagnosis. A 60-year-old man with right-sided face pain presented with a swelling at the right cheek, and he complained of right nasal obstruction and lacrimation. Preoperative fine-needle aspiration cytology (FNAC) showed high cellularity, with a moderate number of clusters of tumor cells on an abundant necrotic background. The clusters were arranged in sheet structures with palisading, and were cohesive with overlapping. The tumor cells had comparatively abundant cytoplasm, with conspicuous large, irregular nucleoli with a fine granular chromatin pattern. Mitotic figures were observed easily. On immunocytochemistry using LBC smear, tumor cells were negative for p40. High-grade carcinoma other than non-keratinizing squamous cell carcinoma was suggested from these findings on FNAC. The pretreatment histological biopsy sample revealed tumor cells with solid growth pattern, necrotic materials and large polygonal cells with abundant cytoplasm, fine granular chromatin, and conspicuous nucleoli. Head and neck LCNEC with abundant cytoplasm, fine granular chromatin patterns, prominent nucleoli, and necrotic background were very characteristic of LCNEC. If considered carefully, these findings can enable us to exclude the majority of non-keratinizing squamous cell carcinomas, and FNAC using ancillary technique can be very useful for proper diagnosis.

Cytohistology of papillary carcinoid and emerging concept of pulmonary neuroendocrine neoplasms

This timely review starts by reporting the clinical, cytologic and histologic features of a morphologic variant of pulmonary carcinoid tumor forming exclusively of papillae. This growth pattern is so rare that it was not included in 2014 WHO classification of pulmonary neuroendocrine neoplasms. The current concept is reviewed, and example of spindle cell carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma, and small cell carcinoma are illustrated with fine needle aspiration cytology, surgical and clinical follow-up. Finally, the new findings in cell biology and molecular biology that led to the emerging concept that carcinoids and high-grade neuroendocrine lung carcinomas are separate biological entities are reviewed and summarized in a tumorigenic module.

High Grade (Large Cell) Neuroendocrine Carcinoma of the Nasopharynx: Novel Case Report with Touch Preparation Cytology and Positive EBV Encoded Early RNA

Fewer than five case reports of primary large cell neuroendocrine carcinoma of the nasopharynx are known to the authors. No previous reports have included examples of cytomorphology or have proven association with Epstein-Barr virus. We herein illustrate MRI findings, histopathologic features, immunohistochemical characterization, cytologic details, and in situ hybridization studies from a unique case of primary large cell neuroendocrine carcinoma of the nasopharynx in a 38-year-old Caucasian male patient. Recognition of rare tumor types of the nasopharynx allows for refinements in disease management and prognostication.

Respiratory Tract and Mediastinum

Normal cytology, abnormal and atypical cells, non-cellular components, and infectious cell changes are largely described together with benign, malignant, and neuroendocrine lesions regarding exfoliative and aspiration cytology of the lung. A separate section broadly addresses diagnostic findings and differential diagnoses in bronchoalveolar washings.

The section ‘Fine needle aspiration biopsy of mediastinal disorders’ covers in particular biopsy techniques, accuracy of liquid-based cytology, and the complex lesions of the thymus gland. Cytodiagnostic algorithms of the major benign and malignant pulmonary and mediastinal lesions and their respective differential diagnoses are additionally presented in synoptic setups.

Smear cytology findings of large cell neuroendocrine carcinoma of the uterine cervix

Large cell neuroendocrine carcinoma (LCNEC) of the uterine cervix is a rare tumor. Moreover, there are only three reports to date that have focused on the cytologic findings of cervical LCNEC. We report the case of a 59-year-old Japanese woman with cervical LCNEC combined with small cell carcinoma (SmCC). Cytologic specimens from the uterine cervix demonstrated large cells with coarse chromatin and prominent nucleoli. Frequent mitotic figures were also observed. Curettage of the uterine endometrium revealed an endometrioid adenocarcinoma with squamous differentiation; i.e., an adenoacanthoma. Histologic examination of surgically resected uterine cervical tissue revealed LCNEC with minor foci of SmCC. Neuroendocrine differentiation in LCNEC was confirmed by immunohistochemistry for synaptophysin and CD56. Cytotechnologists or pathologists need to consider a differential diagnosis of LCNEC while examining cervical cytologic specimens; therefore, it is important to correctly identify the cytologic characteristics of this tumor.

Diagnostic issues with cytopathologic interpretation of lung neoplasms displaying high-grade basaloid or neuroendocrine morphology

Basaloid squamous cell carcinoma (BSQCC) and high-grade neuroendocrine carcinomas (HGNEC) including small cell carcinoma (SMCC) and large cell neuroendocrine carcinoma (LCNEC) can be difficult to differentiate on lung cytology. This problem is particularly true in scant specimens where immunoperoxidase stains cannot be adequately performed. Sixty-six cases of BSQCC, LCNEC, and SMCC (22 cases of each) on lung or mediastinal cytology were retrospectively reviewed from the cytopathology archives of two hospitals. Common cytomorphologic characteristics were; hypercellularity, small to intermediate round blue (hyperchromatic) cells, lack of prominent nucleoli, lack of three dimensional architecture, karyorrhexis/necrosis, mitoses, naked nuclei, nuclear crush artifact, and nuclear molding. Distinctive features included: larger cell size with pleomorphism, more cohesive architecture, syncytial aggregation, slightly coarser chromatin texture, rare keratinized malignant cells, and a granular smear background seen more often in BSQCC as opposed to HGNEC. Larger cells with prominent nucleoli and more cytoplasm with focal rosette formation were helpful in distinguishing LCNEC from SMCC and BSQCC. Finally, SMCC displayed uniform small cells with extensive necrosis, and higher mitotic rate. Immunoperoxidase (IPOX) staining using p63, CK5, 6, neuroendocrine markers (chromogranin, synaptophysin and CD56) and TTF-1 were helpful. BSQCC showed p63 expression and was mostly negative for neuroendocrine markers and TTF-1. HGNEC showed immunoreactivity for neuroendocrine markers with variable immunoreactivity for TTF-1. BSQCC, SMCC, and LCNEC share overlapping cytomorphologic features and can be difficult to differentiate on limited cytology specimens. Careful consideration to subtle but definite cytomorphologic clues and attention to selective IPOX stains can lead to a definitive diagnosis.

Endoscopic ultrasound guided fine-needle aspiration diagnosis of duodenal high grade neuroendocrine carcinoma underlying a villous adenoma: report of a case

Endoscopic ultrasound guided fine-needle aspiration biopsy is a reliable and accurate method for the diagnosis of submucosal lesions of the gastrointestinal tract. We report the cytopathologic findings of a case of duodenal high-grade neuroendocrine carcinoma in a 68-year-old woman who presented with melena and marked anemia, 45 years after kidney transplantation. Imaging studies performed in the work-up of melena showed a duodenal mass, which on endoscopy proved to be an exophytic, villous duodenal lesion, 3 cm from the ampulla. Forceps biopsy of the exophytic lesion showed a villous adenoma. Endoscopic ultrasound additionally revealed an underlying submucosal lesion and EUS-guided fine needle aspiration of this submucosal mass and of the enlarged mesenteric lymph nodes was diagnostic of a high-grade neuroendocrine carcinoma. The aspirates showed abundant cellularity with tumor cells arranged in sheets and occasional loose clusters. The neoplastic cells had a moderate amount of pale cytoplasm and large round to oval hyperchromatic nuclei with focally prominent nucleoli. Mitoses, apoptotic bodies and necrotic debris were also present. The tumor cells were strongly and diffusely positive for cytokeratin AE1/AE3, synaptophysin and chromogranin and showed a very high proliferative fraction on Ki67 staining, supporting the diagnosis of a high-grade neuroendocrine carcinoma. This is to our knowledge the first case of high-grade neuroendocrine carcinoma of the duodenum diagnosed by EUS-FNA. This case also emphasizes the diagnostic value of EUS-FNA sampling of the submucosal and intramural component of villous tumors of the gastrointestinal tract when mucosal forceps biopsies show only benign findings.

Pulmonary neuroendocrine neoplasms: a review of clinicopathologic and cytologic features

Neuroendocrine tumors form a distinct group of lung neoplasms sharing characteristic cytohistologic, immunohistochemical, ultrastructural, and molecular features. The objective of this review article is to discuss the diagnostic classifications and the morphologic cytologic-histologic features for the different categories of neuroendocrine tumors of the lung. An accurate characterization of the neuroendocrine tumors of the lung requires knowledge of specific criteria separating the major categories, which is highly essential for determining prognosis and treatment options for these patients.