Ovarian Sertoli-Leydig cell tumors (SLCTs) are uncommon neoplasms that are 
occasionally associated with an elevated level of serum alpha fetoprotein (AFP), 
a marker of germ cell neoplasms, particularly yolk sac tumor (YST). We report 7 
cases of ovarian SLCT (3 moderately differentiated, 2 poorly differentiated, 2 
retiform) with heterologous intestinal-type glands, 6 of which were associated 
with elevated serum AFP. The intestinal-type mucinous glands were immunoreactive 
for SALL4 (4 cases), AFP (4 cases), glypican 3 (1 case), CDX2 (6 cases), and 
villin (7 cases), markers that are commonly expressed in YSTs, although the 
latter 2 markers would be expected to be positive in intestinal-type glands. We 
show that heterologous intestinal-type glands in ovarian SLCTs often have an 
endodermal sinus-like (YST-like) immunophenotype and stress that these should 
not be misinterpreted as microscopic foci of endodermal-type YST. Cases of 
ovarian SLCT with elevated serum AFP should be sampled extensively to look for 
foci of intestinal-type glands, the likely source of the AFP elevation in some 
of these neoplasms.