An analysis of PLAG1 and HMGA2 rearrangements in salivary duct carcinoma and examination of the role of precursor lesions. Issue 2 (6th June 2013)

• Record Type: Journal Article
• Authors: Bahrami, Armita; Perez‐Ordonez, Bayardo; Dalton, James D; Weinreb, Ilan
• Is Part Of: Histopathology. Volume 63:Issue 2(2013)
• Page Start: 250
• Page End: 262
• Publication Date: 2013-06-06
• Subjects: Histology, Pathological -- Periodicals; 611.018
• DOI: 10.1111/his.12152
• Languages: English
• ISSNs: 0309-0167

Abstract

<abstract abstract-type="main" id="his12152-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="his12152-sec-0001" sec-type="section"> <title>Aims</title> <p>Salivary duct carcinoma (SDC) often arises in pleomorphic adenoma (PA). Putative precursors, including low‐grade cribriform cystadenocarcinoma (LGCCC) and ductal carcinoma <italic>in‐situ</italic> (DCIS), are more controversial. Rearrangement of <italic>PLAG1</italic> or <italic>HMGA2</italic> is seen in 50–70% of PAs, but this has not been investigated in SDC. Using a large collection of SDCs from a single institution, we aimed to study these genes by fluorescence in‐situ hybridization (FISH), and to correlate the presence of precursor lesions/intraductal proliferations with gene alterations.</p> </sec> <sec id="his12152-sec-0002" sec-type="section"> <title>Methods and results</title> <p>Forty‐four SDCs were stained for smooth muscle actin, CK14, and p63, and examined with <italic>PLAG1</italic> and <italic>HMGA2</italic> FISH. Eight cases were SDC ex‐PA; ten had a hyalinized nodule (HN), which is suspicious for PA; six arose in association with LGCCC; and twenty were '<italic>de‐novo</italic>' SDCs. Ten cases had <italic>PLAG1</italic> rearrangement/amplification (22.7%) and eight had <italic>HMGA2</italic> (18.2%) rearrangement/amplification. The positive cases were four SDC ex‐PAs, eight SDCs with an HN, and five '<italic>de‐novo</italic>' SDCs. Twenty‐three SDC ex‐PAs were present in total (52.3%). All six SDC ex‐LGCCCs were FISH‐negative. Myoepithelial staining surrounded all LGCCCs, and demonstrated DCIS in 17 cases. Eleven DCIS lesions were in SDC ex‐PAs or FISH‐positive '<italic>de‐novo</italic>' SDCs. These cases represent 'cancerization' of ducts. Only six FISH‐negative '<italic>de‐novo</italic>' SDCs showed DCIS.</p> </sec> <sec id="his12152-sec-0003" sec-type="section"> <title>Conclusions</title> <p>A large proportion of SDCs arise in PAs (with or without residual evidence of a PA). A small proportion of SDCs arise in LGCCCs. Cases showing DCIS often represent cancerization.</p> </sec> </abstract>