Stromal micropapillary pattern predominant lung adenocarcinoma - a report of two casesReport as inadecuate

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Diagnostic Pathology

, 6:92

First Online: 29 September 2011Received: 01 July 2011Accepted: 29 September 2011


Generally, adenocarcinomas with micropapillary pattern, featuring small papillary tufts lacking a central fibrovascular core, are thought to have poor prognosis. This pattern has been described in various organs. However, tumor cells with micropapillary pattern of lung adenocarcinoma are more often seen to float within alveolar spaces aerogenous micropapillary pattern, AMP than in fibrotic stroma like other organs stromal micropapillary pattern, SMP and SMP predominant lung adenocarcinoma SMPPLA has not been well described yet. We presented two cases of SMPPLA which were found in the last four years. Both the cases showed more than 50% of SMP in the tumor area. The majority of the stromal micropapillary clusters expressed MUC1 and epithelial membrane antigen along the outer surface of cell membrane. On the other hand, connective tissues surrounding stromal micropapillary clusters showed no reactivity for epithelial markers thyroid transcription factor-1 and cytokeratin or endothelial marker D2-40 and CD34. It means clusters of SMP do not exist within air space or lymphatic or vessel lumens. The tumors with SMP often presented lymphatic permeation and vessel invasion, and intriguingly, one of the two cases showed metastasis to the mediastinal lymph node. Additionally, both the cases showed EGFR point mutations of exon 21. These results suggest that SMPPLA might be associated with poor prognosis and effective for EGFR tyrosine kinase inhibitors.

Keywordslung adenocarcinoma micropapillary subtype stromal micropapillary pattern aerogeneous micropapillary pattern AbbreviationsAMPaerogenous micropapillary pattern

SMPstromal micropapillary pattern

SMPPLASMP predominant lung adenocarcinoma

MSLAthe micropapillary subtype of lung adenocarcinoma

Electronic supplementary materialThe online version of this article doi:10.1186-1746-1596-6-92 contains supplementary material, which is available to authorized users.

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Author: Miki Ohe - Tomoyuki Yokose - Yuji Sakuma - Sachie Osanai - Chikako Hasegawa - Kota Washimi - Kimitoshi Nawa - Tetsukan Woo


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