. The
gross examination usually shows a two to three centimetre pale grey, poorly defined tumour with associated
haemorrhage and
necrosis. The microscopic features include: indistinct cell borders, mitoses, a variable architecture (tubulopapillary, glandular, solid, embryoid bodies – ball of cells surrounded by empty space on three sides), nuclear overlap, and necrosis. Solid (55%), glandular (17%), and papillary (11%) are the most common primary patterns (predominant architectural pattern occupying at least 50%). Other less common primary patterns included nested (3%), micropapillary (2%), anastomosing glandular (1%), sieve-like glandular (<1%), pseudopapillary (<1%), and blastocyst-like (<1%). Testicular embryonal carcinoma occurs mostly (84%) as a component of a
mixed germ cell tumor, but 16% are pure. Occasionally, embryonal carcinoma develops predominantly in the context of
polyembryoma-like (6%) and diffuse
embryoma-like ("necklace" pattern) (3%) proliferations. There may be elevations in serum
human chorionic gonadotropin (hCG) and
alpha fetoprotein (AFP) levels but it would be in association with other tumors, (e.g. yolk sac tumor) because they themselves do not produce the serum markers. At surgery, there is extension of the tumour beyond the ovary in forty percent of cases. They are generally large, unilateral tumours, with a median diameter of 17 centimetres. Long-term survival has improved following the advent of chemotherapy. == References ==