The keratin markers (CK7, CAM 5.2, CK5/6, and 34bE12) and myoid/basal cell markers (calponin, SMA, SMMHC
, and p63) can be used to identify the cellular differentiation of most salivary gland tumors.
Abbreviations: ADH, atypical ductal hyperplasia; CK, cytokeratin; DCIS, ductal carcinoma in situ; HMWCK, high-molecular-weight cytokeratin; MEC, myoepithelial cells; SMMHC, smooth muscle myosin heavy chain.
Bcl2, B-cell chronic lymphocytic leukemia (CLL)/lymphoma; CD, cluster of differentiation; CK, cytokeratin; MEC, myoepithelial cells; SMMHC, smooth muscle myosin heavy chain.
They observed a reduced expression of CK5/6 in 32% of cases, SMMHC in 20%, CD10 in 15%, p63 in 10%, and calponin in 6%, compared to that of normal MECs.
In adenoid cystic carcinoma, the pattern is interesting: while p63 staining is positive in the basal-like cells, staining with calponin and SMMHC is negative.
Immunohistochemistry Panel in Cribriform Lesions of the Breast Marker CS ACC p63 Positive at the periphery Positive at the periphery and and surrounding lumens in the basaloid cells SMMHC Positive at the periphery Negative and surrounding lumens Calponin Positive at the periphery Negative and surrounding lumens c-KIT Negative Positive in the tumor cells Marker Cribriform DCIS ICC p63 Positive at the Negative periphery only SMMHC Positive at the Negative periphery only Calponin Positive at the Negative periphery only c-KIT Negative Negative Abbreviations: ACC, adenoid cystic carcinoma; CS, collagenous spherulosis; DCIS, ductal carcinoma in situ; ICC, invasive cribriform carcinoma; SMMHC, smooth muscle myosin heavy chain.
Markers SMA (Figure 4), MSA, calponin, p63 (Figures 3, C and 5), maspin, p75, and SMMHC (Figure 2, B) are probably largely comparable in their sensitivities for MECs for scenarios in which the question is invasive carcinoma versus an entirely benign process, with the important caveat that sclerosing lesions of the breast may show patchy or no staining in a significant subset.
As illustrated in Figure 2, B, the lack of myoepithelial layer (SMMHC) highlights invasive foci, which is otherwise not readily apparent.
(41) Calponin and SMMHC are expressed in collagenous spherulosis but not in adenoid cystic carcinoma.