Lung tumor
Other tumors
Minute pulmonary meningothelial-like nodules

Editorial Board Member: Andrey Bychkov, M.D., Ph.D.
Editor-in-Chief: Debra Zynger, M.D.
Jian-Hua Qiao, M.D.

Topic Completed: 2 July 2019

Revised: 23 October 2019

Copyright: 2019, PathologyOutlines.com, Inc.

PubMed Search: Minute pulmonary meningothelial-like nodules

Jian-Hua Qiao, M.D.
Page views in 2019 to date: 1,384
Cite this page: Qiao JH. Minute pulmonary meningothelial-like nodules. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungtumormpmn.html. Accessed November 15th, 2019.
Definition / general
  • Uncommon incidental pulmonary nodules composed of interstitial nodular proliferation of small oval or spindle shaped cells arranged in a zellballen nesting pattern (J Thorac Imaging 2002;17:227)
Essential features
  • Generally detected incidentally in resected lung specimens (Hum Pathol 2009;40:678)
  • Occasionally detected on thin section computed tomography (Hum Pathol 2009;40:678)
  • More common in patients with malignant pulmonary tumors, especially lung adenocarcinoma, than benign disease (Hum Pathol 2009;40:678)
  • No significant difference in clinicopathologic factors between patients with single and multiple nodules, except for the size of each nodule (Hum Pathol 2009;40:678)
Terminology
  • Pulmonary chemodectomas were first described by Korn et al. in 1960 (Am J Pathol 1960;37:641)
  • In 1988, Gaffey et al. proposed to change the name of pulmonary chemodectomas to minute meningothelial-like nodules (Am J Surg Pathol 1988;12:167)
  • Terminology includes
    • Pulmonary meningothelial-like nodules (PMLNs)
    • Minute pulmonary meningothelial-like nodules (MPMNs)
    • Pulmonary chemodectoma
    • MPMN-omatosis syndrome
    • Diffuse pulmonary meningotheliomatosis (DPM)
ICD coding
  • ICD-10: R91.1 - solitary pulmonary nodule
Epidemiology
  • F > M (10.7% versus 4.5%) (Hum Pathol 2009;40:678)
  • Most frequent in the sixth decade
  • Absent in fetuses, infants and children, indicating that they do not represent congenital rests
  • Reported incidence is 0.3 to 9.5% at autopsy or in surgical specimens (Korean J Pathol 2012;46:87)
Sites
Pathophysiology
Etiology
Clinical features
Diagnosis
  • Often identified as incidental findings in histopathological lung sections or in high resolution CT scans conducted for unrelated causes (Korean J Pathol 2012;46:87)
Radiology description
  • Thin section chest CT reveals randomly distributed, well defined ground glass appearance micronodules, which may simulate metastatic disease (J Comput Assist Tomogr 2001;25:311)
Radiology images

Images hosted on other servers:

CT scan with
1 cm nodule

Positron emission tomography

Chest film shows bilateral diffuse nodules

CT scan shows nodules

Prognostic factors
Case reports
Treatment
Gross description
Microscopic (histologic) description
  • Characteristic nests of bland spindle cells with pale eosinophilic cytoplasm expand alveolar septa
  • Larger lesions connected by intervening collagen, often imparting a stellate configuration
  • Smaller lesions have closely apposed nests with mildly thickened alveolar septa (Am J Surg Pathol 1988;12:167)
Microscopic (histologic) images

Contributed by Jian-Hua Qiao, M.D.

Interstitial nests of spindle cells

CD56

EMA


PR

Vimentin

AE1 / AE3

CK5 / 6

Virtual slides

Images hosted on other servers:

Pulmonary meningothelial-like nodule

Cytology description
  • Single as well as clusters of bland spindle cells are present in aspirate smears
  • However, marked cellular atypia is often seen with cytology diagnosis of atypical / suspicious for malignancy / positive for malignancy
  • Immunohistochemistry of cell block will rule out the possibility of carcinoma or squamous cell carcinoma since the spindle cells are negative for pankeratin (AE1 / AE3), p63 and p40
Cytology images

Contributed by Jian-Hua Qiao, M.D.

Papanicolaou (Pap) stain

p63

p40

Electron microscopy description
  • Ultrastructural features include interdigitating cellular junctions, desmosomes and scattered intracytoplasmic filaments (Korean J Pathol 2012;46:87)
Electron microscopy images

Images hosted on other servers:

Interdigitating cells and desmosomes

Molecular / cytogenetics description
  • Mutational analyses were performed on microdissected tissue using 20 polymorphic microsatellite markers targeting 11 genomic regions in an effort to identify genetic similarities of MPMN and meningioma (Am J Surg Pathol 2004;28:207)
  • Loss of heterozygosity was identified in 25% of single MPMN affecting 3 genomic loci
    • No solitary MPMN had > 1 loss of heterozygosity event
    • Multiple loss of heterozygosity were seen only in diffuse pulmonary meningotheliomatosis (MPMN-omatosis syndrome), where 33.3% of MPMNs showed loss of heterozygosity affecting 7 genomic loci
    • Meningioma showed the highest frequency of loss of heterozygosity with major events seen at 22q (60%), 14q (42.8%) and 1p (44.4%) that were not shared by MPMN
    • MPMNs are different from meningioma based on the major molecular genetic events seen in their formation and progression
  • NF2 deletion similar to meningioma found in a limited series (Oncotarget 2018;9:36012)
Sample pathology report
  • Left lung, mass, CT guided needle core biopsy:
    • Minute pulmonary meningothelial-like nodule
    • Negative for malignancy
    • Adjacent lung parenchyma with mild interstitial fibrosis
Differential diagnosis
Additional references
Board review question #1
An 80 year old Caucasian woman had a thyroid mass and a 1 cm pulmonary lesion. CT guided transthoracic needle biopsy was performed to rule out metastatic tumor. Microscopic examination of core needle biopsy tissue reveals the following lesion. What is your diagnosis?



  1. Metastatic thyroid papillary carcinoma
  2. Minute pulmonary meningothelial-like nodule
  3. Pulmonary carcinoid tumor
  4. Pulmonary meningioma
  5. Pulmonary paraganglioma
Board review answer #1
B. Minute pulmonary meningothelial-like nodule. Microscopic lesion is classic of pulmonary meningothelial-like nodule, with irregular and uncircumscribed interstitial nests of spindle cells, morphologically similar to meningothelial cells.

Reference: Minute pulmonary meningothelial-like nodules

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Board review question #2
Sometimes, immunohistochemistry is necessary to work up this spindle cell lesion. Pulmonary meningothelial-like nodule is most likely positive for which of the following immunostains?

  1. CD56
  2. CK5 / 6
  3. ER
  4. Pankeratin (AE1 / AE3)
  5. Synaptophysin
Board review answer #2
A. CD56. Pulmonary meningothelial-like nodule is positive for CD56, EMA, progesterone receptor / PR and vimentin.

Reference: Minute pulmonary meningothelial-like nodules

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