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1.2.5 Ovarian tumors and cysts

The ułtrasonic images of ovarian neoplasms can vary considerably. Among the most commonly encountered granulosa celi tumors the predominant form is charac-terized by a multicystic partitioning of the tumor (White and Allen 1985, Kahn and Leidl 1987 b, Leidl and Kahn 1989). Morę vesicular structures can usually be counted in such tumors than would be expec-ted in normal, intact ovaries. On a normal ovary 5 to 10 ; follicles with a diameter of morę than 10 mm each will physiologicaUy be found during an estrous cycle (Pier-son and Ginther 1987). In cases of ultrasonically ex-amined granulosa celi tumors and in excised specimens many morę cystic structures were found. In single ova-ries 50 to 60 cystic structures were identified.

The diameters of indmdual vesicles in granulosa celi tumors vary from a few millimeters to several centime-ters. A normal ovary is characterized by the presence of many follicles of differing sizes in the same organ. It is rare to find morę than 2 to 3 follicles with a diameter of 30 to 50 mm on a normal ovaiy, the majority of visible follicles ranging in size between 5 and 20 mm. The ul-trasonic images of granulosa celi tumors usually differ from this pattem. Sometimes single, extremely large vesicles are seen within a tumor or the entire image of

the tumor consists of numerous smali, tightly packed vesicles (Fig. 1.37 and 1.38). On cross sectional image of GC tumors the proportion taken up by vesicular structures is mostly greater than that occupied by solid tumor tissue.

Apart from the multicystic granulosa celi tumors there are also those that are virtually solid on cross section (Fig. 1.39 and 1.40). Their ultrasonograms depict a relatively homogenous image free of hypo-echoic vesicles. In some tumors there were areas of hyperechogenicity which were interpreted as areas of mineralized tumor tissue, which produced sound shadows beyond these foci.

Ovarian tumors consisting of a single large vesicle with moderately echoic contents have also been found. Their walls showed histopathological changes consistent with those seen in granulosa celi tumors.

The taking of accurate measurements of an ovaiy is an important application of ultrasonography during the examination of ovarian neoplasms. Measurements of the ovary taken at regular time intervals make it pos-sible to calculate the growth ratę of the tumor, and to confirm the diagnosis. In addition, knowledge of the ovary’s exact size aid in the decision whether the ovari-ectomy should be performed by laparotomy or trans-yaginally.