Anatomic Pathology / MORPHOMETRY IN SMALL CELL LUNG CARCINOMA AND LARGE CELL NEUROENDOCRINE CARCINOMA
Morphometry Confirms the Presence of Considerable
Nuclear Size Overlap Between “Small Cells” and “Large
Cells” in High-Grade Pulmonary Neuroendocrine
Neoplasms
Alberto M. Marchevsky, MD,1 Anthony A. Gal, MD,2 Swati Shah, MD,1
and Michael N. Koss, MD3
Key Words: Small cell lung carcinoma; Large cell neuroendocrine carcinoma; Morphometry; Classification
Abstract
We morphometrically evaluated 5-µm H&E-stained
sections from 28 surgically resected high-grade
pulmonary neuroendocrine neoplasms, including 16
small cell lung carcinomas (SCLCs) and 12 large cell
neuroendocrine carcinomas (LCNECs). For each case,
200 tumor nuclei and 20 to 100 normal lymphocytes
were measured. The frequency distributions of tumor
cell/lymphocyte (TC/L) size ratios were plotted in bins
ranging from 1 to 6, classified into 6 histogram types
with TC/L size ratio peaks ranging from 2 to 6 (A-E)
and a histogram with a wide distribution (F). SCLCs fit
histograms A through E; LCNECs, A through F.
Morphometry demonstrated considerable nuclear size
overlap in high-grade neoplasms. Approximately one
third of SCLCs exhibited considerable numbers of
neoplastic cells that were larger than 3 normal
lymphocytes, while 4 of 12 LCNECs had a predominant
number of small cells. Ten tumors exhibited a B
histogram with a “borderline” peak TC/L of 3. The rule
that a TC/L size ratio larger than 3 helps distinguish
“large” from “small” neoplastic cells was confirmed in
only 9 of 28 cases. The use of more generic terminology
such as “high-grade neuroendocrine carcinoma” or
“grade III neuroendocrine carcinoma” for SCLC and
LCNEC is discussed.
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Am J Clin Pathol 2001;116:466-472
The World Health Organization and the International
Association for the Study of Lung Cancer (WHO/IASLC)
recently revised the diagnostic criteria for neuroendocrine
neoplasms of the lung.1 New criteria were adopted for the
distinction between typical and atypical carcinoid tumors,
and large cell neuroendocrine carcinoma (LCNEC) was
added as a new variant of large cell carcinoma. Both small
cell lung carcinoma (SCLC) and LCNEC can exhibit focal
areas with squamous, glandular, or large cell differentiation; these neoplasms are now designated as SCLC or
LCNEC, combined variant. Previous subtypes of SCLC
such as “oat” cell and “intermediate” cell carcinomas and
SCLC, mixed type are no longer included in classification
schema. 2 , 3 In addition, it has been recognized that
pulmonary adenocarcinomas, squamous cell carcinomas,
and large cell carcinomas can exhibit immunophenotypic
evidence of neuroendocrine differentiation when studied
with immunocytochemical methods and electron
microscopy. They are classified by the recent WHO/IASLC
scheme as non–small cell carcinoma-neuroendocrine.1
Mitotic densities and presence of necrosis are the most
important morphologic features to distinguish typical carcinoid tumors, atypical carcinoid tumors, and high-grade
neuroendocrine carcinomas such as SCLC and LCNEC.1-4
Typical carcinoid tumors have fewer than 2 mitoses per 10
high-power fields (HPF) and no necrosis. Atypical carcinoid tumors exhibit 2 to 10 mitoses per 10 HPF and
frequently show focal areas of punctate necrosis. LCNEC
and SCLC exhibit more than 11 mitoses per 10 HPF and
larger areas of necrosis than atypical carcinoid tumors.
Both LCNEC and SCLC are composed of round to oval
cells with hyperchromatic nuclei, inconspicuous nucleoli,
© American Society of Clinical Pathologists
Anatomic Pathology / ORIGINAL ARTICLE
and a high nuclear/cytoplasmic ratio, arranged in similar
histopathologic patterns, indicative of neuroendocrine
differentiation. The differential diagnosis between these
carcinomas is based on nuclear size and the identification
of certain cytologic features.5-10
The cell size of SCLC has been ambiguously defined
in various studies as ranging from 1.5 to 4 times the size
of normal lymphocytes. 9 Standard textbooks have
proposed the use of an arbitrary cutoff of 3 times the size
of lymphocytes to distinguish “small” from “large” cells,
based presumably on clinical experience.9 A morphometric
study by Lee and associates11 demonstrated that the cells
of SCLC are approximately twice the size of lymphocytes. This study also demonstrated that technical factors
such as specimen size and degree of tissue crushing had a
substantial impact on nuclear size.11 Cytologic features
are valuable for the distinction of SCLC from LCNEC.
Nucleoli and vesicular or fine chromatin are seen in the
nuclei of LCNEC, while the cells of SCLC exhibit absent
or faint nucleoli and finely granular nuclear chromatin. 1,8,9 However, reliance on the identification of
nucleoli or vesicular nuclear chromatin for the diagnosis
of LCNEC can be misleading in difficult cases, particularly in instances of SCLC or LCNEC, combined type.
Cell size is the most important diagnostic criterion to
distinguish SCLC from LCNEC.9 However, size can be
difficult to recognize with certainty as the cells of both
neoplasms usually exhibit a spectrum of nuclear sizes.
The subjective estimate by a pathologist of the relative
proportions of small and large cells has an important role
in the differential diagnosis of pulmonary neuroendocrine
neoplasms.
A study of interobserver variability by Travis and
associates6 raised questions about whether the distinction
between these high-grade neuroendocrine neoplasms of
the lung is truly reproducible. We report a study of SCLC
and LCNEC of the lung using a simple morphometric
method to test whether a cutoff of nuclear size based on
the size of 3 lymphocytes can objectively distinguish
SCLC from LCNEC.
Materials and Methods
Histologic slides from patients with surgically resected
SCLC and LCNEC of the lung were retrieved from the files
of the department of pathology, Cedars-Sinai Medical
Center, Los Angeles, CA, and Emory University, Atlanta,
GA. Sixteen SCLCs and 12 LCNECs that could be diagnosed by consensus by 3 experienced pulmonary pathologists (A.M.M., A.A.G., and M.N.K.) were studied. We evaluated 5-µm H&E-stained sections by morphometry.
© American Society of Clinical Pathologists
Morphometry
The nuclear area of 200 randomly selected tumor nuclei
and 20 to 100 normal lymphocytes was measured from each
case using a SAMBA 4000 image analysis system (IPI,
Trenton, NJ).12 The system segments the nuclei automatically from the background, and the investigator needs only to
edit manually adjacent nuclei that overlap with each other.
Tumor Cell/Lymphocyte Size Ratios
The average nuclear size of normal resting lymphocytes
was calculated for each tumor. Lymphocytes with a round
nucleus with regularly distributed granular chromatin were
selected. Lymphoid cells with irregular chromatin distribution, cleaved nuclei, and/or prominent nucleoli were
excluded from measurements. In each neoplasm, the nuclear
size of each tumor cell was divided by the average lymphocyte size for the case and a tumor cell/lymphocyte (TC/L)
size ratio was calculated. The tumor TC/L size ratios for all
cells of each case were plotted in a frequency distribution
histogram using bins ranging from 2 to 6 in peak TC/L.
Histogram Types
Histograms were classified into 6 types (A-F) according
to their predominant TC/L peak. Histogram type A was
defined as illustrating a frequency distribution with a peak at
a TC/L size ratio of 2. Histogram types B through E illustrated frequency distributions with TC/L size ratio peaks
ranging from 3 to 6. Histogram type F illustrated a frequency
distribution with a wide distribution of cells that exhibited no
predominant peak. We theorized that if the “3-times-lymphocyte-size” rule is valid to distinguish neoplastic small cells
from large cells, a majority of SCLCs ❚Image 1❚ should
exhibit type A histograms ❚Figure 1❚, and LCNECs ❚Image
2❚ should show type C through F histograms ❚Figure 2❚.
Histogram type B would illustrate “borderline” cases ❚Image
3❚ composed predominantly of cells with a peak at a TC/L
size ratio of 3 ❚Figure 3❚.
Results
Substantial overlap in the TC/L size ratio frequency
distribution was encountered in both variants of high-grade
neuroendocrine neoplasms. The frequency distribution of
nuclear sizes of SCLCs yielded type A through E histograms
(n = 4, 7, 2, 2, and 1, respectively) while LCNECs yielded
type A through F histograms (n = 1, 3, 2, 4, 1, and 1, respectively). Five of 16 SCLCs exhibited a predominant number
of neoplastic cells that were larger than 3 normal lymphocytes, while 4 of 12 LCNECs had a predominant number of
small cells. Ten neoplasms (SCLC, 7; LCNEC, 3) exhibited
borderline type B histograms.
Am J Clin Pathol 2001;116:466-472
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Marchevsky et al / MORPHOMETRY IN SMALL CELL LUNG CARCINOMA AND LARGE CELL NEUROENDOCRINE CARCINOMA
Percentage of Cells
100
50
0
1
2
3
4
5
6
7
TC/L Ratio
❚Image 1❚ High-grade neuroendocrine carcinoma of the lung
composed of neoplastic cells that are smaller than 3 lymphocytes (H&E, original magnification, ×400). The frequency
distribution of nuclear sizes of this tumor is shown in Figure 1.
❚Figure 1❚ The frequency distribution of nuclear sizes exhibits
a histogram type A with a peak at a tumor cell/lymphocyte
size ratio of 2. Most pathologists would probably classify this
lesion as a small cell carcinoma without difficulty.
Percentage of Cells
100
50
0
1
2
3
4
5
6
7
8
TC/L Ratio
❚Image 2❚ High-grade neuroendocrine carcinoma of the lung
composed of neoplastic cells that are clearly larger than 3
lymphocytes (H&E, original magnification, ×200). The 2
adjacent photomicrographs representing different areas of
the neoplasm illustrate the spectrum of nuclear sizes
present in this neoplasm. The frequency distribution of
nuclear sizes of this tumor is shown in Figure 2.
❚Figure 2❚ The frequency distribution of nuclear sizes exhibits
a histogram type F, without a clear tumor cell/lymphocyte
size ratio peak. Most pathologists would probably classify
this lesion as a large cell neuroendocrine carcinoma without
difficulty.
Discussion
graphic method the presence of considerable nuclear size
overlap in SCLC and LCNEC. Our results are similar to
those of older morphometric studies by Vollmer13 and Lee
and associates14,15 demonstrating a continuum of cell sizes
Morphometric analysis of high-grade pulmonary
neuroendocrine neoplasms confirms with an objective and
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© American Society of Clinical Pathologists
Percentage of Cells
Anatomic Pathology / ORIGINAL ARTICLE
TC/L Size Ratio
❚Image 3❚ High-grade neuroendocrine carcinoma showing
neoplastic cells with “intermediate nuclear sizes” larger than
those seen in the tumor shown in Image 1 (H&E, original
magnification, ×400). The frequency distribution of nuclear
sizes of this tumor is shown in Figure 3.
❚Figure 3❚ The frequency distribution of nuclear sizes exhibits
a histogram type B. This case would be difficult to diagnose
as either small cell carcinoma or large cell neuroendocrine
carcinoma using an arbitrary cutoff of tumor cell/lymphocyte
size ratio of 3.
from small cell to large cell undifferentiated carcinoma of
the lung. These studies demonstrated that the subclassification of small cell carcinomas into oat cell and intermediate
cell variants was spurious and that there was no clear size
cutoff between small cell and large cell carcinomas of the
lung. In our study, the rule that the identification of a
predominant neoplastic population composed of cells larger
than 3 lymphocytes permits the distinction between SCLC
and LCNEC was confirmed in only 9 of 28 neoplasms.
Moreover, 10 of 28 neoplasms exhibited a borderline spectrum of nuclear sizes centered on a TC/L size ratio of 3. Our
results provide an objective explanation for considerable
interobserver variability in the diagnosis of high-grade
pulmonary neoplasms and do not support the use of an arbitrary size cutoff for a reproducible distinction between SCLC
and LCNEC.6
In a study by Travis and associates,6 including two of
the present authors (A.A.G. and M.N.K.), a group of 40
surgically resected neuroendocrine tumors of the lung,
chosen from the files of the Armed Forces Institute of
Pathology, were reviewed independently by 5 experienced
pulmonary pathologists. Unanimous diagnostic agreement
occurred in 70% of SCLCs and 40% of LCNECs. The most
frequent disagreement fell between SCLC and LCNEC. The
study indicated a need for more careful definition and application of diagnostic criteria for the differential diagnosis of
SCLC vs LCNEC. Morphometric measurements of cell size
are unlikely to be useful for the differential diagnosis of
high-grade pulmonary neuroendocrine neoplasm. Indeed, if
we were to use a TC/L size ratio of 2, as supported by the
previous morphometric study of Lee et al,11 or any other
TC/L cutoff, there would still be considerable cell size
overlap between the cells of SCLC and LCNEC.
It is controversial whether the distinction between
SCLC and LCNEC has clinical value, as patients with both
neoplasms are being treated with similar therapeutic protocols.3,16-29 Surgery is advocated for the treatment of patients
with LCNEC and limited stage SCLC.21,22 Chemotherapy
has a limited value for patients with early-stage LCNEC; the
neoplasms pursue a very aggressive clinical course despite
therapy.21 In contrast, some SCLCs respond initially to
chemotherapy, but frequently relapse and metastasize. To
our knowledge, there are no retrospective or prospective
clinicopathologic studies demonstrating statistically significant differences in survival rates for patients with LCNEC
and patients with SCLC.25 A study of 200 patients with
pulmonary neuroendocrine tumors, using current diagnostic
criteria, suggested that patients with LCNEC may have a
slightly better prognosis (5-year survival, 27%; 10-year
survival, 9%) than people with SCLC (5-year survival, 9%;
10-year survival, 5%).10 However, the differences in survival
rates were not statistically significant. Dresler and
associates28 reported a 13% 5-year survival rate for patients
with LCNEC in stage I; adjuvant therapy did not improve
survival. It is difficult to collect at any institution a large
cohort of patients with well-staged LCNEC and limited-
© American Society of Clinical Pathologists
Am J Clin Pathol 2001;116:466-472
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Marchevsky et al / MORPHOMETRY IN SMALL CELL LUNG CARCINOMA AND LARGE CELL NEUROENDOCRINE CARCINOMA
stage SCLC to compare their clinical courses. The fact that
our data and previous observations question current diagnostic criteria for the distinction between the neoplasms
would make this task more difficult.
There has been recent support for the designation of
neuroendocrine carcinoma grades I through III similar to
updated terminology for the classification of epithelial
neuroendocrine neoplasms arising in other organs. 21,22
Wick22 reviewed these concepts in a recent editorial and
supported the use of the designation “grade III neuroendocrine carcinoma” for the classification of pulmonary
neuroendocrine neoplasms, as it “avoids the potential confusion surrounding the ‘baggage’ attached to the terms small
cell and large cell carcinoma of the lung.”
Studies with immunocytochemical and molecular
methods support the concept that high-grade neuroendocrine
lung tumors are a common group of neoplasms, distinct from
carcinoid tumor and atypical carcinoid tumor 25,30-61 (Z.K.
Arbiser, J.A. Arbiser, C.C. Cohen, et al. Neuroendocrine
lung tumors: grade correlates with proliferation but not
angiogenesis; written communication, 2001). SCLC and
LCNEC have similar genetic changes, cell cycle abnormalities, development of angiogenesis factors, and other molecular abnormalities. For example, Brambilla and associates59
described different incidences of p53 mutations and
Bcl2/bax ratios between low-grade (carcinoid and atypical
carcinoid tumors) and high-grade neuroendocrine carcinomas (SCLC and LCNEC). Debelenko and associates60
reported molecular changes in the gene responsible for the
multiple endocrine neoplasm 1 syndrome (MEN1) in
pulmonary neuroendocrine neoplasms, supporting the
hypothesis that SCLC and lung carcinoids develop via
distinct molecular pathways. Helpap and Kollermann61 used
double-labeling immunohistochemical methods to detect the
expression of MIB-1 and neuroendocrine markers, such as
chromogranin and synaptophysin, in high- and low-grade
neuroendocrine neoplasms arising from the lung and other
organs. Their findings suggest that high-grade and low-grade
neuroendocrine tumors might arise from different precursor
cell populations. Walch and associates27 described similar
complex cytogenetic changes in SCLC and LCNEC detected
by comparative genomic hybridization. Haruki and associates5 characterized mutations in the menin gene, which has a
role in the development of MEN1, and demonstrated that
loss of heterozygosity of the gene was more prevalent in
LCNEC (50%) than in SCLC (22%), suggesting a possible
distinction between these neoplasms.
Future studies of high-grade neuroendocrine neoplasms
of the lung probably need to include objective methods for
estimating the percentage of cells larger or smaller than a
particular cutoff and better descriptors of nuclear features to
differentiate SCLC and LCNEC with improved accuracy. A
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Am J Clin Pathol 2001;116:466-472
morphometric study by Jutting and associates 24 of
pulmonary neuroendocrine neoplasms demonstrated that
only chromatin features were independent predictors of
survival. The study included carcinoid tumors, well-differentiated neuroendocrine carcinomas (which would presumably
be classified as atypical carcinoid under current
WHO/IASLC guidelines), and SCLC, but not cases of
LCNEC. Future studies also would need to define more
precisely the cytologic features that would enable a pathologist to reliably distinguish large cells from an LCNEC from
those present in an SCLC, combined variant.
Our study reaffirms that there is considerable overlap in
nuclear sizes between SCLC and LCNEC, which contributes
to considerable difficulty in separating these variants of highgrade neuroendocrine lung tumors. Improved diagnostic
criteria and future prospective clinicopathologic studies are
needed to validate the concept that patients with LCNEC
have a different clinical course from that of those with
SCLC. Current evidence supports the use of the common
terminology of “high-grade neuroendocrine carcinoma” or
“grade III neuroendocrine carcinoma,” perhaps with a note
indicating whether the pathologist favors a small or large cell
subtype, for the diagnosis of both neoplasms in daily practice. This practice would avoid interobserver diagnostic
problems and would have no substantial negative impact on
clinical care.
From the Departments of Pathology, 1Cedars-Sinai Medical
Center and UCLA School of Medicine, Los Angeles, CA; 2Emory
University Hospital, Atlanta, GA; and 3University of Southern
California/Los Angeles County Hospital.
Presented at the Lung Cancer: Diagnosis and Staging MiniSymposium, American Thoracic Society, Toronto, Ontario, May
2000.
Address reprint requests to Dr Marchevsky: Dept of
Pathology and Laboratory Medicine, Cedars-Sinai Medical
Center, 8700 Beverly Blvd, Los Angeles, CA 90048.
References
1. Travis WD, Colby TV, Corrin B, et al. Histological Typing of
Lung and Pleural Tumours. Berlin, Germany: Springer Verlag;
1999.
2. Marchevsky AM. Neuroendocrine tumors of the lung.
Pathology. 1996;4:103-123.
3. Junker K, Wiethege T, Muller KM. Pathology of small-cell
lung cancer. J Cancer Res Clin Oncol. 2000;126:361-368.
4. Beasley MB, Thunnissen FB, Brambilla E, et al. Pulmonary
atypical carcinoid: predictors of survival in 106 cases. Hum
Pathol. 2000;31:1255-1265.
5. Haruki N, Yatabe Y, Travis WD, et al. Characterization of
high-grade neuroendocrine tumors of the lung in relation to
menin mutations. Jpn J Cancer Res. 2000;91:317-323.
6. Travis WD, Gal AA, Colby TV, et al. Reproducibility of
neuroendocrine lung tumor classification. Hum Pathol.
1998;29:272-279.
© American Society of Clinical Pathologists
Anatomic Pathology / ORIGINAL ARTICLE
7. Przygodzki RM, Finkelstein SD, Langer JC, et al. Analysis of
p53, K-ras-2, and C-raf-1 in pulmonary neuroendocrine
tumors: correlation with histological subtype and clinical
outcome. Am J Pathol. 1996;148:1531-1541.
8. Travis WD, Linnoila RI, Tsokos MG, et al. Neuroendocrine
tumors of the lung with proposed criteria for large-cell
neuroendocrine carcinoma: an ultrastructural,
immunohistochemical, and flow cytometric study of 35 cases.
Am J Surg Pathol. 1991;15:529-553.
9. Colby TV, Koss MN, Travis WD. Tumors of the Lower
Respiratory Tract. Washington, DC: Armed Forces Institute of
Pathology; 1995. Atlas of Tumor Pathology, Third Series,
Fascicle 13.
10. Travis WD, Rush W, Flieder DB, et al. Survival analysis of
200 pulmonary neuroendocrine tumors with clarification of
criteria for atypical carcinoid and its separation from typical
carcinoid. Am J Surg Pathol. 1998;22:934-944.
11. Lee T-W, Esinhart JD, Blackburn LD, et al. The size of small
cell lung carcinoma cells: ratio to lymphocytes and correlation
with specimen size and crush artifact. Anal Quant Cytol Histol.
1992;14:32-34.
12. Marchevsky AM, Afari A, Truong HM, et al. Image analysis
and multivariate statistics for the classification of nonHodgkin’s lymphomas: use of a commercially available
microcomputer-based image analysis system. J Surg Pathol.
1995;1:199-129.
13. Vollmer RT. The effect of cell size on the pathologic diagnosis
of small and large cell carcinomas of the lung. Cancer.
1982;50:1380-1383.
14. Lee T-W, Horner RD, Silverman JF, et al. Implications of
nuclear diameter in small cell lung carcinoma. Anal Quant
Cytol Histol. 1990;12:78-84.
15. Lee T-W, Silverman JF, Horner RD, et al. Overlap of nuclear
diameters in lung cancer cells. Anal Quant Cytol Histol.
1990;12:275-278.
16. Linnoila RI. Spectrum of neuroendocrine differentiation in
lung cancer cell lines featured by cytomorphology, markers,
and their corresponding tumors. J Cell Biochem Suppl.
1996;24:92-106.
17. Pahlman S, Hammerling U. src expression in small-cell lung
carcinoma and other neuroendocrine malignancies. Am Rev
Respir Dis. 1990;142(6 pt 2):S54-S56.
18. Ordonez NG. Value of thyroid transcription factor-1
immunostaining in distinguishing small cell lung carcinomas
from other small cell carcinomas. Am J Surg Pathol.
2000;24:1217-1223.
19. Anbazhagan R, Tihan T, Bornman DM, et al. Classification of
small cell lung cancer and pulmonary carcinoid by gene
expression profiles. Cancer Res. 1999;59:5119-5122.
20. Bunn PA, Linnoila I, Minna JD, et al. Small cell lung cancer,
endocrine cells of the fetal bronchus, and other
neuroendocrine cells express the Leu-7 antigenic determinant
present on natural killer cells. Blood. 1985;65:764-768.
21. Wick MR, Ritter JH. Neuroendocrine neoplasia of the lung.
Ann Thorac Surg. 2000;69:307-308.
22. Wick MR. Neuroendocrine neoplasia: current concepts. Am J
Clin Pathol. 2000;113:331-335.
23. Garcia-Yuste M, Matilla JM, Alvarez-Gago T, et al. Prognostic
factors in neuroendocrine lung tumors: a Spanish Multicenter
Study. Spanish Multicenter Study of Neuroendocrine Tumors
of the Lung of the Spanish Society of Pneumonology and
Thoracic Surgery (EMETNE-SEPAR). Ann Thorac Surg.
2000;70:258-263.
© American Society of Clinical Pathologists
24. Jutting U, Gais P, Rodenacker K, et al. Diagnosis and
prognosis of neuroendocrine tumours of the lung by means of
high resolution image analysis. Anal Cell Pathol. 1999;18:109119.
25. Ullmann R, Schwendel A, Klemen H, et al. Unbalanced
chromosomal aberrations in neuroendocrine lung tumors as
detected by comparative genomic hybridization. Hum Pathol.
1998;29:1145-1149.
26. Hammond ME, Sause WT. Large cell neuroendocrine tumors
of the lung: clinical significance and histopathologic
definition. Cancer. 1985;56:1624-1629.
27. Walch AK, Zitzelsberger HF, Aubele MM, et al. Typical and
atypical carcinoid tumors of the lung are characterized by 11q
deletions as detected by comparative genomic hybridization.
Am J Pathol. 1998;153:1089-1098.
28. Dresler CM, Ritter JH, Patterson A, et al. Clinical-pathologic
analysis of 40 patients with large cell neuroendocrine
carcinoma of the lung. Ann Thorac Surg. 1997;63:180-185.
29. Warren WH, Faber LP, Gould VE. Neuroendocrine neoplasms
of the lung: a clinicopathologic update. J Thorac Cardiovasc
Surg. 1989;98:321-332.
30. Carretta A, Ceresoli GL, Arrigoni G, et al. Diagnostic and
therapeutic management of neuroendocrine lung tumors: a
clinical study of 44 cases. Lung Cancer. 2000;29:217-225.
31. Langer P, Ernst M, Bartsch D, et al. Diagnosis and therapy of
well-differentiated neuroendocrine lung tumors. Chirurg.
2000;71:429-435.
32. Oliaro A, Donati G, Filosso PL, et al. Neuroendocrine tumors
of the lung. Minerva Chir. 2000;55:7-16.
33. Papotti M, Croce S, Macri L, et al. Correlative immunohistochemical and reverse transcriptase polymerase chain
reaction analysis of somatostatin receptor type 2 in
neuroendocrine tumors of the lung. Diagn Mol Pathol.
2000;9:47-57.
34. Dosaka-Akita H, Cagle PT, Hiroumi H, et al. Differential
retinoblastoma and p16(INK4A) protein expression in
neuroendocrine tumors of the lung. Cancer. 2000;88:550-556.
35. Michelland S, Gazzeri S, Brambilla E, et al. Comparison of
chromosomal imbalances in neuroendocrine and non–smallcell lung carcinomas. Cancer Genet Cytogenet. 1999;114:2230.
36. Couce ME, Bautista D, Costa J, et al. Analysis of K-ras, N-ras,
H-ras, and p53 in lung neuroendocrine neoplasms. Diagn Mol
Pathol. 1999;8:71-79.
37. Zhang PJ, Harris KR, Alobeid B, et al. Immunoexpression of
villin in neuroendocrine tumors and its diagnostic
implications. Arch Pathol Lab Med. 1999;123:812-816.
38. Sigl E, Behmel A, Henn T, et al. Cytogenetic and CGH
studies of four neuroendocrine tumors and tumor-derived cell
lines of a patient with multiple endocrine neoplasia type 1. Int
J Oncol. 1999;15:41-51.
39. Folpe AL, Gown AM, Lamps LW, et al. Thyroid transcription
factor-1: immunohistochemical evaluation in pulmonary
neuroendocrine tumors. Mod Pathol. 1999;12:5-8.
40. Mulligan LM, Timmer T, Ivanchuk SM, et al. Investigation of
the genes for RET and its ligand complex, GDNF/GFR alphaI, in small cell lung carcinoma. Genes Chromosomes Cancer.
1998;21:326-332.
41. Gouyer V, Gazzeri S, Bolon I, et al. Mechanism of
retinoblastoma gene inactivation in the spectrum of
neuroendocrine lung tumors. Am J Respir Cell Mol Biol.
1998;18:188-196.
Am J Clin Pathol 2001;116:466-472
471
Marchevsky et al / MORPHOMETRY IN SMALL CELL LUNG CARCINOMA AND LARGE CELL NEUROENDOCRINE CARCINOMA
42. DeLellis RA. Proliferation markers in neuroendocrine tumors:
useful or useless? a critical reappraisal. Verh Dtsch Ges Pathol.
1997;81:53-61.
43. Patriarca C, Pruneri G, Alfano RM, et al. Polysialylated NCAM, chromogranin A and B, and secretogranin II in
neuroendocrine tumours of the lung. Virchows Arch.
1997;430:455-460.
44. Senden NH, Timmer ED, de Bruine A, et al. A comparison of
NSP-reticulons with conventional neuroendocrine markers in
immunophenotyping of lung cancers. J Pathol. 1997;182:1321.
45. Carey FA, Save VE. Neuroendocrine differentiation in lung
cancer. J Pathol. 1997;182:9-10.
46. Cagle PT, el Naggar AK, Xu HJ, et al. Differential retinoblastoma protein expression in neuroendocrine tumors of the
lung: potential diagnostic implications. Am J Pathol.
1997;150:393-400.
47. Vuitch F, Sekido Y, Fong K, et al. Neuroendocrine tumors of
the lung: pathology and molecular biology. Chest Surg Clin N
Am. 1997;7:21-47.
48. Coppola D, Clarke M, Landreneau R, et al. Bcl-2, p53, CD44,
and CD44v6 isoform expression in neuroendocrine tumors of
the lung. Mod Pathol. 1996;9:484-490.
49. Loy TS, Darkow GV, Quesenberry JT. Immunostaining in the
diagnosis of pulmonary neuroendocrine carcinomas: an
immunohistochemical study with ultrastructural correlations.
Am J Surg Pathol. 1995;19:173-182.
50. Addis BJ. Neuroendocrine differentiation in lung carcinoma.
Thorax. 1995;50:113-115.
51. Senderovitz T, Skov BG, Hirsch FR. Neuroendocrine
characteristics in malignant lung tumors: implications for
diagnosis, treatment, and prognosis. Cancer Treat Res.
1995;72:143-154.
472
Am J Clin Pathol 2001;116:466-472
52. Linnoila RI, Piantadosi S, Ruckdeschel JC. Impact of
neuroendocrine differentiation in non–small cell lung cancer:
the LCSG experience. Chest. 1994;106(6 suppl):367S-371S.
53. Gouyer V, Gazzeri S, Brambilla E, et al. Loss of heterozygosity
at the RB locus correlates with loss of RB protein in primary
malignant neuro-endocrine lung carcinomas. Int J Cancer.
1994;58:818-824.
54. Michalides R, Kwa B, Springall D, et al. NCAM and lung
cancer. Int J Cancer Suppl. 1994;8:34-37.
55. Brambilla E, Veale D, Moro D, et al. Neuroendocrine
phenotype in lung cancers: comparison of immunohistochemistry with biochemical determination of enolase
isoenzymes. Am J Clin Pathol. 1992;98:88-97.
56. Roncalli M, Doglioni C, Springall DR, et al. Abnormal p53
expression in lung neuroendocrine tumors: diagnostic and
prognostic implications. Diagn Mol Pathol. 1992;1:129-135.
57. Komminoth P, Roth J, Lackie PM, et al. Polysialic acid of the
neural cell adhesion molecule distinguishes small cell lung
carcinoma from carcinoids. Am J Pathol. 1991;139:297-304.
58. Lantuejoul S, Moro D, Michalides RJ, et al. Neural cell
adhesion molecules (NCAM) and NCAM-PSA expression in
neuroendocrine lung tumors. Am J Surg Pathol. 1998;22:12671276.
59. Brambilla E, Negoescu A, Gazzeri S, et al. Apoptosis-related
factors p53, Bcl2, and Bax in neuroendocrine lung tumors.
Am J Pathol. 1996;149:1941-1952.
60. Debelenko LV, Swalwell JI, Kelley MJ, et al. MEN1 gene
mutation analysis of high-grade neuroendocrine lung
carcinoma. Genes Chromosomes Cancer. 2000;28:58-65.
61. Helpap B, Kollermann J. Immunohistochemical analysis of
the proliferative activity of neuroendocrine tumors from
various organs: are there indications for a neuroendocrine
tumor-carcinoma sequence? Virchows Arch. 2001;438:86-91.
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