Department of Pathology, St Jude Children's Research Hospital, Memphis, TN, USA.
Histopathology. 2013 Aug;63(2):250-62. doi: 10.1111/his.12152. Epub 2013 Jun 6.
Salivary duct carcinoma (SDC) often arises in pleomorphic adenoma (PA). Putative precursors, including low-grade cribriform cystadenocarcinoma (LGCCC) and ductal carcinoma in-situ (DCIS), are more controversial. Rearrangement of PLAG1 or HMGA2 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.
Forty-four SDCs were stained for smooth muscle actin, CK14, and p63, and examined with PLAG1 and HMGA2 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 'de-novo' SDCs. Ten cases had PLAG1 rearrangement/amplification (22.7%) and eight had HMGA2 (18.2%) rearrangement/amplification. The positive cases were four SDC ex-PAs, eight SDCs with an HN, and five 'de-novo' 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 'de-novo' SDCs. These cases represent 'cancerization' of ducts. Only six FISH-negative 'de-novo' SDCs showed DCIS.
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.
唾液腺癌（SDC）常起源于多形性腺瘤（PA）。有假说认为，低级别筛状囊腺癌（LGCCC）和导管原位癌（DCIS）为其潜在前体病变，但这一假说仍存在争议。PA 中约有 50-70%存在 PLAG1 或 HMGA2 的重排，但尚未在 SDC 中进行过研究。本研究通过荧光原位杂交（FISH）检测，对单一机构收集的大量 SDC 标本进行了这两种基因的研究，并将前体病变/导管内增生与基因改变相关联。
对 44 例 SDC 进行了平滑肌肌动蛋白、CK14 和 p63 染色，并进行了 PLAG1 和 HMGA2 FISH 检测。8 例为 SDC 源于 PA；10 例有透明样变性结节（HN），提示为 PA；6 例与 LGCCC 相关；20 例为“新发”SDC。10 例存在 PLAG1 重排/扩增（22.7%），8 例存在 HMGA2 重排/扩增（18.2%）。阳性病例包括 4 例源于 PA 的 SDC、8 例有 HN 的 SDC 和 5 例“新发”SDC。总共存在 23 例源于 PA 的 SDC（52.3%）。所有 6 例源于 LGCCC 的 SDC 均为 FISH 阴性。LGCCC 周围均有肌上皮染色，其中 17 例显示 DCIS。11 例 DCIS 病变位于源于 PA 的 SDC 或 FISH 阳性的“新发”SDC 中。这些病例代表导管的“癌变”。仅 6 例 FISH 阴性的“新发”SDC 出现 DCIS。
很大一部分 SDC 起源于 PA（有或无 PA 的残余证据）。一小部分 SDC 起源于 LGCCC。表现为 DCIS 的病例常代表癌变。
