Pulmonary meningothelial-like nodule
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Pulmonary meningothelial-like nodule, abbreviated MLN, is a common benign finding in the lung.
| Pulmonary meningothelial-like nodule | |
|---|---|
| Diagnosis in short | |
 Pulmonary meningothelial-like nodule. H&E stain. | |
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| |
| Synonyms | pulmonary chemodectoma |
|
| |
| LM | small cell nests (expanding alveolar septa) with whorled appearance/streaming; composed of bland cells with round/ovoid nuclei without appreciable nucleoli |
| LM DDx | lung tumourlet, poorly differentiated carcinoma, lobular breast carcinoma |
| IHC | PR +ve, vimentin +ve, EMA +ve, CD56 +ve, chromogranin A -ve, synaptophysin -ve, S-100 -ve |
| Gross | tan or yellow nodules - pleural or parenchymal, typically 1-3 mm |
| Site | lung |
|
| |
| Associated Dx | poorly understood association with lung tumours - esp. lung adenocarcinoma |
| Clinical history | typically an incidential finding |
| Prevalence | very common |
| Prognosis | benign |
| Treatment | none |
They are also referred to as minute pulmonary meningothelial-like nodules (abbreviated MPMN) and minute pulmonary chemodectoma.[1]
General
- Benign.[2]
- Very common - seen in almost half of well sampled lobectomies.[3]
- May be grouped with pulmonary meningioma in the larger category primary pleuropulmonary meningothelial proliferations.[4]
- Can mimic metastatic deposits.[2][5]
Associations:
Gross
- Tan or yellow nodules - pleural or parenchymal - typically 1-3 mm.[1]
Note:
Microscopic
Features:[1]
- Small cell nests - expanding alveolar septa.
- Whorled appearance/streaming.
- Composed of bland cells with round/ovoid nuclei without appreciable nucleoli.
DDx:
- Lung tumourlet - associated with airway.[citation needed]
- Poorly differentiated carcinoma.
- Lobular carcinoma.[5]
Images
Case 1
PMLN - very low mag. (WC)
PMLN - low mag. (WC)
PMLN - intermed. mag. (WC)
PMLN - intermed. mag. (WC)
PMLN - high mag. (WC)
PMLN - high mag. (WC)
PMLN - very high mag. (WC)
Case 2
MLN - very low mag. (WC/Nephron)
MLN - low mag. (WC/Nephron)
MLN - intermed. mag. (WC/Nephron)
MLN - high mag. (WC/Nephron)
MLN - very high mag. (WC/Nephron)
www
IHC
Features:
- CD56 +ve (18 of 18 cases[3]).
- EMA +ve (11 of 11 cases[3]).
- Vimentin +ve (10 of 14 cases[1]).
- PR (18 of 18 cases[3].
Others:[1]
- S-100 -ve.
- NSE -ve.
- Cytokeratin -ve.
- Actin -ve.
Images
PMLN - PR - intermed. mag. (WC)
PMLN - PR - high mag. (WC)
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Gaffey, MJ.; Mills, SE.; Askin, FB. (Mar 1988). "Minute pulmonary meningothelial-like nodules. A clinicopathologic study of so-called minute pulmonary chemodectoma.". Am J Surg Pathol 12 (3): 167-75. PMID 2830799.
- ↑ 2.0 2.1 2.2 Lee, SK.; Kim, GJ.; Kim, YJ.; Leem, AY.; Hwang, ED.; Kim, SK.; Chang, J.; Kang, YA. et al. (Aug 2013). "Minute pulmonary meningothelial-like nodules simulating hematogenous lung metastasis: a case report.". Tuberc Respir Dis (Seoul) 75 (2): 67-70. doi:10.4046/trd.2013.75.2.67. PMID 24023559.
- ↑ 3.0 3.1 3.2 3.3 Mukhopadhyay, S.; El-Zammar, OA.; Katzenstein, AL. (Apr 2009). "Pulmonary meningothelial-like nodules: new insights into a common but poorly understood entity.". Am J Surg Pathol 33 (4): 487-95. doi:10.1097/PAS.0b013e31818b1de7. PMID 19047895.
- ↑ Weissferdt, A.; Tang, X.; Suster, S.; Wistuba, II.; Moran, CA. (Aug 2015). "Pleuropulmonary Meningothelial Proliferations: Evidence for a Common Histogenesis.". Am J Surg Pathol. doi:10.1097/PAS.0000000000000489. PMID 26291511.
- ↑ 5.0 5.1 5.2 Kfoury, H.; Arafah, MA.; Arafah, MM.; Alnassar, S.; Hajjar, W. (Feb 2012). "Mimicry of Minute Pulmonary Meningothelial-like Nodules to Metastatic Deposits in a Patient with Infiltrating Lobular Carcinoma: A Case Report and Review of the Literature.". Korean J Pathol 46 (1): 87-91. doi:10.4132/KoreanJPathol.2012.46.1.87. PMID 23109985.
- ↑ 6.0 6.1 6.2 Mizutani, E.; Tsuta, K.; Maeshima, AM.; Asamura, H.; Matsuno, Y. (May 2009). "Minute pulmonary meningothelial-like nodules: clinicopathologic analysis of 121 patients.". Hum Pathol 40 (5): 678-82. doi:10.1016/j.humpath.2008.08.018. PMID 19144385.