A 50-year-old woman presented with a several centimeter ovarian mass. An oophorectomy was performed. The resultant specimen demonstrated a solid, enlarged ovary with a yellow-brown mass noted on cut section. Microscopic images from the resection specimen are shown below.
The tumor had a somewhat variable appearance and consisted predominantly of nests and cords of bland, medium-sized epithelial cells with frequent central lumen or acinar formation. In other areas there were much larger gland-like lumina containing homogeneous eosinophilic material and lined by more attenuated cuboidal epithelial cells.
What is your diagnosis?
This is a straightforward example of an ovarian tumor comprised of a mixture of well-differentiated neuroendocrine carcinoma (typical carcinoid tumor) and mature follicular thyroid epithelium. The term, "strumal carcinoid" is frequently applied to this mixture. No other elements of teratoma were found in this case.
Stains for chromogranin and TTF-1 are shown below in that order.
In the chromogranin stain, the nests of neuroendocrine cells are strongly positive, but scattered chromogranin-positive cells can also be seen lining the thyroid-type follicles at the center and bottom of the image. Conversely, the TTF-1 stain shows more positive nuclei lining the thyroid-type follicles, but scattered positive cells are also seen in the more solid and acinar carcinoid nests. Stains for thyroglobulin (not shown) also strongly highlighted the areas of thyroid differentiation.
Ovaries are widely known to give rise independently to primary carcinoid tumors and mature thyroid-type tissue (struma ovarii), perhaps as monodermal elements of a teratoma. However, the tendency for these two elements to be intimately admixed, sometimes with multifocal "modulation" between the two components has always seemed curious to me. This mixture is virtually never seen in thyroid-based neoplasms or in neuroendocrine lesions arising elsewhere in the body, yet it is a well-recognized association in the ovary. Perhaps there is some greater meaning hidden here with regard to histogenetic associations... or maybe not.
Nonetheless, these are interesting biphasic tumors.