Lung

Neuroendocrine tumors

Large cell neuroendocrine carcinoma



Last staff update: 12 November 2024 (update in progress)

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PubMed Search: Large cell neuroendocrine carcinoma

Kyriakos Chatzopoulos, M.D., Ph.D.
Cite this page: Chatzopoulos K. Large cell neuroendocrine carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungtumorlargecellNE.html. Accessed December 24th, 2024.
Definition / general
  • Aggressive, poorly differentiated carcinoma composed of large cells with neuroendocrine architecture, prominent nucleoli, high mitotic activity and necrosis
  • Grouped with other neuroendocrine tumors in the 2021 WHO classification of thoracic tumors (J Thorac Oncol 2022;17:362)
  • More likely to recur and has shorter patient survival than other types of non-small cell lung carcinoma, even in stage I disease (Cancer Control 2006;13:270)
  • May coexist with other lung cancers such as adenocarcinoma and squamous cell carcinoma
Essential features
  • High grade non-small cell carcinoma with neuroendocrine architecture and immunohistochemical markers, characterized by > 10 mitoses/2 mm2, prominent nucleoli and extensive necrosis (J Thorac Oncol 2022;17:362)
  • Poor overall prognosis
  • Should be distinguished from atypical carcinoid, basaloid squamous cell carcinoma and poorly differentiated adenocarcinoma, although diagnosis can be difficult on small biopsies or cytology specimens
Terminology
  • Large cell neuroendocrine carcinoma (LCNEC): proposed by Travis et al. in 1991 as distinct from small cell carcinoma (Am J Surg Pathol 1991;15:529)
  • Combined LCNEC: also has components of adenocarcinoma (most common), squamous cell carcinoma, giant cell carcinoma or spindle cell carcinoma (Thorac Surg Clin 2014;24:257)
ICD coding
  • ICD-O: 8013/3 - large cell neuroendocrine carcinoma
  • ICD-10: C34.90 - malignant neoplasm of unspecified part of unspecified bronchus or lung
  • ICD-11: 2C25.Y - other specified malignant neoplasms of bronchus or lung
Epidemiology
Pathophysiology
  • Proposed model of histogenesis of lung neuroendocrine carcinomas, in view of similarities in the expression of primitive neural / neuroendocrine cell specific transcription factors (Pathol Int 2015;65:277)
Etiology
Clinical features
Diagnosis
  • Difficult to make specific diagnosis on small biopsy and cytology specimens
  • Frequently recognized in cytology as non-small cell lung cancer (NSCLC), not otherwise specified or as adenocarcinoma
  • Neuroendocrine features by light microscopy and confirmation by immunohistochemical staining for neuroendocrine markers
Laboratory
Radiology description
  • Nonspecific findings, indistinguishable from other NSCLC
  • CT findings: peripherally located tumors, expansively growing with irregular margins, with or without calcification and infrequent cavitation (Clin Imaging 2007;31:379)
Prognostic factors
Case reports
Treatment
Gross description
Gross images

Contributed by Roseann Wu, M.D., M.P.H.
Peripheral LCNEC

Peripheral LCNEC

Frozen section description
  • Neuroendocrine organoid architecture, prominent nucleoli, abundant necrosis
Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Ioanna Abba Nteka, M.D., Aggeliki Cheva, M.D., Ph.D., Antonia Loukousia, M.D., Roseann Wu, M.D., M.P.H. and Kyriakos Chatzopoulos, M.D., Ph.D.
Nesting, peripheral palisading, necrosis

Nesting, peripheral palisading, necrosis

Nuclear pleomorphism, prominent nucleoli, mitosis

Nuclear pleomorphism, prominent nucleoli, mitosis

Solid and nested architecture

Solid and nested architecture

Vascular invasion

Vascular invasion


Cytokeratin

Cytokeratin

CD56

CD56

Synaptophysin

Synaptophysin

Chromogranin

Chromogranin

Cytology description
  • Hypercellular, with numerous, single medium to large cells
  • 3 dimensional and variably sized groups
  • Large, pleomorphic cells with irregular vesicular chromatin, prominent nucleoli, abundant cytoplasm, sharp cellular borders
  • Naked nuclei are abundant but with a variable subset of cells showing evident cytoplasm
  • Molding, mitoses, necrotic background
  • Peripheral nuclear palisading; rosette-like structures (Cancer 2008;114:180, Diagn Cytopathol 2001;24:58)
Cytology images

Images hosted on other servers:

Nuclear pleomorphism with prominent nucleoli (Pap)

Peripheral palisading
(Diff-Quik)

Rosette-like structure
(Diff-Quik)

Positive stains
Negative stains
Electron microscopy description
  • Neurosecretory granules, occasional evidence of granular differentiation and intercellular junctions suggestive of squamous differentiation (Am J Surg Pathol 1991;15:529)
Molecular / cytogenetics description
  • 3 molecular subsets identified by next generation sequencing; no statistically significant differences in clinicopathologic parameters or survival among subsets:
    • Small cell carcinoma-like: TP53 and RB1 comutation and MYCL amplification
    • Non-small cell carcinoma-like: STK11, KRAS, KEAP1 mutations, no TP53 / RB1 comutation, molecular profile resembling adenocarcinoma, with additional NOTCH family mutations
    • Carcinoid-like: MEN1 mutations, low mutation burden (Clin Cancer Res 2016;22:3618)
  • Other less commonly mutated genes: PIK3CA, PTEN, AKT2, FGFR1, KIT, ERBB2, HRAS, EGFR, NTRK2 and NTRK3 (Clin Cancer Res 2017;23:757, Hum Mutat 2008;29:609)
  • Case reports of tumors harboring an EML4::ALK fusion (Cold Spring Harb Mol Case Stud 2022;8:a00623, Front Oncol 2022;12:823813)
  • BRAF alterations including mutations, amplifications reported in small case series (JCO Precis Oncol 2018;2:1)
Sample pathology report
  • Lung, left upper lobe, CT guided needle core biopsy:
    • Large cell neuroendocrine carcinoma (see comment)
    • Comment: Multiple sections from the biopsy material reveal an infiltrative malignant tumor consisting of large cells with abundant amphophilic cytoplasm and large, ovoid or round nuclei with prominent nucleoli and increased mitotic activity. Tumor cells form solid nests with peripheral palisading and central necrosis. Immunostains performed on paraffin sections show diffuse and strong expression of keratins AE1 / AE3, synaptophysin, chromogranin, CD56 and nuclear expression of TTF1 and ISNM1. No expression of p40 or napsin A is seen. These findings support the diagnosis.
Differential diagnosis
Board review style question #1

A 76 year old man with a history of heavy smoking is diagnosed with a large pulmonary mass and undergoes lobectomy. The histologic features of the mass can be seen in the photograph above. Which initial panel of immunostains is more likely to be helpful in the differential diagnosis of this pulmonary malignancy from its most frequent counterparts?

  1. BRG1, INI1 and NUT
  2. Chromogranin, synaptophysin and cytokeratin 8/18
  3. ISNM1, p40 and napsin A
  4. p63, TTF1 and CD56
Board review style answer #1
C. ISNM1, p40 and napsin A. The differential diagnosis of this malignancy includes large cell neuroendocrine carcinoma, poorly differentiated adenocarcinoma and squamous cell carcinoma. In any case, additional immunostains will be needed to confirm the diagnosis. Answer D is incorrect because although CD56 can be expressed in LCNEC, it should be used in caution when alone, as it is not as specific as other neuroendocrine markers. TTF1 can be expressed in half of LCNECs. Although p63 is a marker of squamous differentiation, it is not as specific as its p40 isoform. Answer B is incorrect because although LCNEC is likely to express all these 3 markers, the panel will not help rule out poorly differentiated adenocarcinoma. Answer A is incorrect because BRG1 expression is lost in undifferentiated SMARCA4 deficient thoracic tumors. INI1 can be partially lost in poorly differentiated non-small cell carcinomas with rhabdoid features or totally lost in SMARCB1 deficient carcinomas. NUT immunopositivity would raise the possibility of NUT carcinoma. None of these markers will be helpful in differentiating LCNEC from its more frequent mimics. Answer C is correct because ISNM1 is a highly sensitive and specific marker of neuroendocrine differentiation . Similarly, p40 isoform of p63 is highly specific for squamous differentiation. Napsin A is most frequently expressed in lung adenocarcinomas. This panel of immunostains will be the most helpful, since ISNM1 positivity will point towards the diagnosis of LCNEC, while p40 and napsin A negativity will make the possibilities of squamous cell carcinoma and adenocarcinoma remote.

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Reference: Large cell neuroendocrine carcinoma
Board review style question #2
Which of the following histologic features is the most helpful in the differential diagnosis of large cell neuroendocrine carcinoma from small cell carcinoma?

  1. Extensive necrosis
  2. Mitotic count > 10/2 mm2
  3. Organoid nesting
  4. Prominent nucleoli
Board review style answer #2
D. Prominent nucleoli are a characteristic feature of LCNEC. In contrast, small cell carcinoma cells usually have hyperchromatic nuclei with salt and pepper chromatin distribution and indiscrete nucleoli. Answer B is incorrect because mitotic count is elevated both in LCNEC and small cell carcinoma. Answer A is incorrect because extensive geographic necrosis is a feature of both LCNEC and small cell carcinoma. Answer C is incorrect because although organoid nesting is very characteristic of LCNEC, in can be frequently seen in areas of small cell carcinoma as well.

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Reference: Large cell neuroendocrine carcinoma
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