Presentation on theme: "D2-40 immunohistochemistry in the differential diagnosis of seminoma and embryonal carcinoma: a comparative immunohistochemical study with KIT (CD117)"— Presentation transcript:
D2-40 immunohistochemistry in the differential diagnosis of seminoma and embryonal carcinoma: a comparative immunohistochemical study with KIT (CD117) and CD30 Modern Pathology (2007) 20, 320–325 Sean K Lau, Lawrence M Weiss and Peiguo G Chu Department of Pathology, City of Hope National Medical Center, Duarte, CA, USA Intern 鄭詩燕
Germ Cell Tumors SeminomaNonseminomatous localized to the testisextension to the epididymis, spermatic cord, or scrotal sac StageI or IIII or III MetastasisLymphaticlymphatic Hematogenous to lung or liver TreatmentRadiotherapyChemotherapy PrognosisgoodDepend on the tumor type
Seminoma Age: 15-35y/o 50% of germ cell tumor Painless swelling Dysgerminoma in ovary
Seminoma Bulky masses, sometimes 10 times> the normal testis. Homogeneous, gray-white, lobulated cut surface, usually devoid of hemorrhage or necrosis Mostly the entire testis is replaced. Occasionally, extension to the epididymis, spermatic cord, or scrotal sac
Seminoma Cell: large and round to polyhedral and has a distinct cell membrane A clear or watery-appearing cytoplasm A large, central nucleus with one or two prominent nucleoli The cytoplasm contains varying amounts of glycogen. AFP(-) or HCG(-), placental alkaline phosphatase(+), 15%HCG(+)
Embryonal carcinoma 20- to 30-year age group. Grow faster than seminoma Painful More aggressive than seminomas
Embryonal carcinoma Size: smaller than seminoma Usually does not replace the entire testis. The mass is often variegated, poorly demarcated at the margins Punctuated by foci of hemorrhage or necrosis Extension through the tunica albuginea into the epididymis or cord is not infrequent.
The cells: alveolar or tubular patterns, sometimes with papillary convolutions Undifferentiated cells, epithelial appearance Hyperchromatic nuclei with prominent nucleoli. Indistinct cell border, variation in cell and nuclear size and shape, mitotic figures HCG(+), AFP (+)
Discussion D2-40 recognizes M2A antigen which present in fetal germ cells, lymphatic endothelium, and mesothelial cells. M2A antigen expression in all seminomas and seminomatous components of mixed germ cell tumors
Discussion Present study: -- D2-40 in pure or mixed seminoma: 100% (26/26), (mixed) embryonal carcinoma 29% (4/14) -- Seminoma: diffuse membrane staining -- Embryonal carcinomas: focal and confined to the apical or luminal surfaces. Marks et al study -- D2-40 in seminomas 98%, embryonal carcinomas 69%.
Discussion Distinction between seminoma and embryonal carcinoma can be made on a morphologic basis using conventional histologic methods. Studies addressing the impact of central histopathologic review of previously diagnosed testicular tumors have demonstrated major discrepancy rates of 4–11%
Discussion Immunohistochemical markers: keratins, KIT, and CD30. Antikeratin antibodies -- Embryonal carcinoma : keratin intermediate filaments -- Seminomas lacked Recent study -- Keratin positive in seminomas 4 to 45% KIT and CD30: more effective immunohistochemical markers
Discussion Previous study KIT expression in seminoma: 100% Present study KIT expression in seminoma: 92% none in embryonal carcinomas or non seminomatous germ cell tumors
Discussion CD30: as a sensitive as well as a specific maker for embryonal carcinoma (93%) Focal CD30 expression has been described in a subset of seminomas Leroy et al CD30 in combination with KIT -- seminoma: KIT(-), CD30(+) impossible -- embryonal carcinoma: KIT(+), CD30(-) impossible
Discussion Present study Sensitivity: D2-40 > KIT in seminomas Specific: D2-40 < KIT in seminomas (4/11 embryonal carcinomas +) D2-40 in seminomas: diffuse and membranous D2-40 in embryonal carcinomas: focal and limited to the apical or luminal surface of the cells.
Summary KIT and CD30: a useful markers that allows for seminoma to be distinguished from embryonal carcinoma. Although a highly sensitive marker of seminomas, focal D2-40 immunoreactivity can be seen in a subset of embryonal carcinomas, thus limiting the practical value of this marker for discriminating between these particular malignancies.