Whether the 26mm*16mm cystic structure of the left ovary is serious or not depends on what causes it. Common ones such as inflammatory stimulation and benign tumors that can be controlled in time are not considered serious; if there are malignant changes, then it may be more serious.
If the left ovary is infected by bacteria, mycoplasma and other pathogens, then it is easy to lead to inflammatory lesions, resulting in an increase in inflammatory infiltrates, which may lead to the emergence of the left ovarian cysts, which may also show cystic structure.
In addition, if the left ovary has a teratoma (mature) or a mucinous tumor of the ovary, the left ovary may also have a cystic structure.
Most of the above two are benign lesions, so timely management is usually not serious. If there is a tendency of malignant transformation, such as ovarian mucinous carcinoma, ovarian teratoma (immature) and other malignant tumors, then it will also show cystic structure and more serious.
Therefore, if you find that you have cystic structure of the ovary, you need to further check what causes it, and consult the doctor in time so as not to delay your condition.