I dunno, if it's in an ovary I think the first question shouldn't be whether it's SCC or BCC, but whether it's some other type of CA, especially if there is no teratoma. If a carcinoma is poorly differentiated enough to not be able to tell BCC or SCC there is the potential it's just an endometrioid CA or something like that. Carcinomas arise from teratomas but it isn't that common.
Just saw this thread...looks like a pretty cool case! My first instinct was along the line of yaah's endometrioid thinking because I've been fooled by a rushed diagnosis of transitional cell carcinoma before. Upon first glance, my differential was a poorly differentiated endometrioid, a transitional cell, borderline vs. malignant brenner tumor, and a basaloid squamous cell CA (metastatic from a known primary or arising in the context of a mature teratoma).
I haven't read all the posts but it seems like a lot of us are on the same page. I just had a few questions/and thoughts will I'll project out loud:
1) Are there ANY areas of gland formation...especially if there was a focus of endometrioid type adenocarcinoma glands anywhere? I've been fooled by nests of solid endometrioid tumor that looks transitional in morphology but in both cases, that was due to necrosis, which is not seen here. That being said, based on looking at the histology, I wouldn't expect it. The wall of the cyst and nests of tumor look pretty clean.
2) Not really favoring a met at this point...I get the feeling that this patient has a dominant ovarian cystic mass. For instance, if the patient had a known cervical primary, you could throw on a p16 immunostain.
3) Are there any broad based papillae/fronds lined by transitional-type stratified epithelium along the inner cyst wall? Or is the one pic of the smooth cyst wall fairly representative?
4) Any teratomatous component to the ovary?
5) There are widely spaced somewhat complex looking nests of transitional type cells within stroma...are there confluent nests of transitional type cells?
6) Any Brenner tumor areas within the ovary?
7) Impox-I don't think impox will be terribly helpful. You could maybe try a p63 maybe to test the basaloid SCC hypothesis. TCCs of the ovary, unlike TCCs of the bladder/renal collecting system, is less likely to be CK20 postive. A positive CK7 doesn't help you. And I'm not a big fan of the uroplakin stain.
8) Completely random thought...granulosa cell tumors can exhibit a wide array of morphologies. But I'm not sure if they can have a transitional type look. And plus, the nuclei don't look right for GCT.
Good case...not an easy one...I'll mull over it and if I can come up with anything, I'll post again.
