Exuberant Vasculoconnective Component in Mediastinal Mixed Germ Cell Tumors

Abstract

We aimed to evaluate the histologic components of primary mediastinal mixed germ cell tumors. A total of 221 patients diagnosed with a mediastinal germ cell tumor (GCT) were retrospectively reviewed. Among them, 14 patients underwent surgical resection after chemotherapy and 8 patients were diagnosed with mixed GCT, who were then selected for further evaluation. Clinical chart review and histologic review of biopsy and surgical specimens of 8 patients were performed. All 8 patients were young males and showed a mature teratoma or a mature teratoma with a focal immature teratoma in the resected specimens. Serum alpha-feto protein was variably elevated. Seven patients experienced an increase in tumor size after the chemotherapy. In 5 patients, a variable amount of vasculoconnective tissue was found along with the mature teratoma occupying average 66.3% of resected mass, and 3 of them showed an identical vasculoconnective component on biopsy before chemotherapy. We suggest that vasculoconnective tissue might be the intrinsic component of primary mediastinal mixed GCT. When vasculoconnective tissue is obtained on small biopsy of an anterior mediastinal mass of a young male, the possibility of underlying mixed GCT should be considered and further clinical work up should be performed.Graphical Abstract

Primary germ cell tumours of the mediastinum: A review with emphasis on diagnostic challenges

“…Their cases of 55 patients were associated with yolk sac tumour components, and all specimens were analyzed after chemotherapy. A few similar cases have been published previously, associated with PMTERs independent of prior chemotherapy 142–145 . Recently, a case report also showed a VMT combined with a PMSEMs without prior chemotherapy 146 .…”

Vasoformative Lesions in Mediastinal Mixed Germ Cell Tumors: an Interesting Account of Two Cases Spanning the Benign to Malignant Spectrum

“…However, Cha et al could not reproduce the same pathogenesis in mediastinal GCT, since none of their five cases showed any neural components [10]. They therefore postulated that the benign vasculoconnective component is an intrinsic part of mediastinal mixed GCT [10]. Regardless of pathogenesis, differentiation of this florid benign vascular proliferation from an angiosarcoma is vital given the poor prognostic implications of the latter.…”

“…With respect to ovarian GCTs, it has been suggested that the expression of growth factors such as vascular endothelial growth factor by the neural component of the teratoma induces vascular proliferation [9]. However, Cha et al could not reproduce the same pathogenesis in mediastinal GCT, since none of their five cases showed any neural components [10]. They therefore postulated that the benign vasculoconnective component is an intrinsic part of mediastinal mixed GCT [10].…”

“…An extensive literature search revealed only few reported cases of florid/hemangiomatous vascular proliferation in a GCT, with most reports confined to ovarian teratomas [9]. Only a handful of mediastinal GCTs with this finding have been reported thus far [10]. Consequently, mediastinal lesions where the benign vasoformative component forms the bulk of a tumor pose a diagnostic challenge, especially in small biopsy samples.…”

“…Regardless of pathogenesis, differentiation of this florid benign vascular proliferation from an angiosarcoma is vital given the poor prognostic implications of the latter. Benign vascular proliferation is intermingled with the GCT, rather than forming a mass-like lesion that infiltrates into the surrounding tissue [3,10]. Furthermore, though a variable degree of cellular atypia may be encountered in benign vascular proliferations (possibly due to chemotherapy-induced changes), angiosarcoma cells show distinct anaplasia in the form of prominent cytologic atypia, brisk mitotic activity and an architecturally complex growth pattern.…”