Cytokeratin profile and neuroendocrine cells in the glandular component of cardiac myxoma

Abstract

Glandular cardiac myxomas are very rare tumors of uncertain histogenesis that display glandular structures within otherwise typical myxomatous tissue. The origin of the glands has been attributed to epithelial differentiation of a totipotent cardiomyogenic precursor cell or to entrapped embryonal rests in the tumor. We studied four cases of glandular myxomas (three sporadic and one familial) to define the immunophenotypic profile of the glandular elements. The glands were either single and located within the myxoma cell islands (three cases) or in groups embedded in the myxomatous matrix. In the latter case, the glands featured villous projections, irregular profile, active inflammation or focal reactive cellular atypia (case 3) and had acidic and neutral mucins (mostly sialomucins). The cytokeratin expression profile (cytokeratin 7 and 20 co-expression) was similar to that of foregut derivatives. Scattered chromogranin-positive neuroendocrine cells were observed in case 3. Our findings indicate that the glandular component in cardiac myxoma is morphologically heterogeneous. In some cases, the scattered glands may derive from a divergent (epithelial) differentiation of myxoma cells; in others, entrapment of embryonic gastrointestinal rests (with mature neuroendocrine and mucous cell populations) could be the case.

A novel kind of tumor type-characteristic junction: plakophilin-2 as a major protein of adherens junctions in cardiac myxomata

“…Nonmuscle-type actin microfilaments are prevalent, but in a minor proportion of myxoma cells we have also detected a-smooth muscle-type actin filaments but no sarcomeric a-actins. All our general immunocytochemical observations in the 32 myxomata studied are grosso modo in agreement with most previous reports, indicating a derivation from cardiac mesenchymal cells [20][21][22][23][24][25][26][27][28][29] (for occasional claims of special cardiac myxoma tumor cells showing keratin reactions, mostly in glandular elements, see references 24,29,30).…”

Glandular cardiac myxoma

“…The incidence of glandular cardiac myxomas is very low and its histogenesis is unclear. Totipotent cardiomyogenic precursor cells and embryonal residues in the tumor have both been suggested as the origin of the glands [10,13] . Our case showed well-differentiated mucinous glandular structures.…”

“…They are also thought to arise from cardiomyocyte progenitor cells, subendothelial vasoformative reserve cells, or primitive cells that reside in the fossa ovalis and the surrounding endocardium or endocardial sensory nerve [5][6][7][8] . Occasionally, glandular epithelium may be present in cardiac myxomas (so-called glandular cardiac myxoma), which may represent rests of entrapped embryonic foregut [9,10] . Glandular cardiac myxomas are extremely rare as there had only been about 50 cases reported in the literature [11] .…”

Glandular cardiac myxoma: case report with literature review

“…The locations of the glandular structures were reported in 41 cases: 37 (90.2%) were at the base [1,8,30,37,40,44,56,60,65,73,75,79], 2 (5.4%) scattered [36,60], 1 (2.4%) central [72] and 1 (2.4%) central and at the base of pedicle [39]. The distributions of the glandular structures were expressed in [5,10,21,47,60,68,79], and 4 (7.7%) were widespread/ /extensive [15,24,48,64]. Development of the glandular structures were given in 28 patients: 25 (83.3%) were well-developed [8,12,14,17,21,24,27,36,38,40,43,53,64,65,73,75,79], 1 (3.3%) was very poorly formed [65], 2 (6.7%) had variable structures [22,56] and 2 (6.7%) were pseudo-glands …”

“…CM showed two patterns of glandular structures: glands separated from myxoma cell islands are termed as Pattern 1, and glands within the myxoma cell islands are termed as Pattern 2 [47]. Glandular structures were predominantly present at the base or the pedicle of the CM [1,14].…”