Leiomyomas with unusual patterns of growth may be multinodular, multilobulated, or multifocal. They might exhibit an infiltrative pattern resembling malignant tumors at histological and macroscopic evaluation. Moreover multinodularity accompanied by perinodular hydropic degeneration might be also present. Dissecting leiomyoma is an unusual variant of uterine leiomyoma. This term defines the leiomyomas which causes myometrium dissection. If this tumor exceeds to extrauterine adnexial area with an exophytic pattern, then this lesion is defined as cotyledonoid dissecting leiomyoma because of its macroscopic appearance resembling placental cotyledons⁴. However, recently Roth et al had defined cotyledonoid leiomyoma as a new diagnostic term for benign smooth muscle tumors with an exophytic growth pattern which did not demonstrate myometrium dissection⁵.

Here we report an unusual leiomyoma variant with hydropic degeneration and extra uterine exophytic growth pattern without myometrium dissection.

At macroscopic examination uterus was 140x90x80 mm in dimensions and 200 grams in weight. In fundus of the uterus a serosal fleshy polypoid tumor mass was observed with soft consistency, irregular borders and 8x7 cm dimensions which was attached to the fundus of the uterus with a tiny stalk. Cut surface demonstrated cystic degeneration and partly multinodularity (Figure 1). Adnexes were found to be grossly normal. Histological examination revealed a neoplasm consisting of disorganized tumoreous nodules with prominent hydropic degeneration areas (Figures 2,3). Cellularity was variable through the tumor areas and nuclear atypia or mitotic activity was absent. Stroma contained vessel structures of different size but vascular invasion was not observed. Coagulation necrosis was absent either. Congested vascular structures which caused the purplish macroscopic appearance of the tumor were observed at peripheral areas (Figure 4A, B). Perinodular hydropic degeneration was prominent (Figure 4C). The exophytic bulbous processes apparently resulted from prominent hydropic degeneration between smooth muscle nodules. Immunohistochemical staining was performed in formaline-fixed and paraffin-embedded tissue sections. Avidin-biotin immunohistochemical technique was used for this purpose. Neoplastic cells were strongly positive for α-smooth muscle actin (1A4,Neomarkers) (Figure 4D), Desmin (D33, Neomarkers), and Vimentin (SP20, Neomarkers), but negative for CD10 (56C6, Novacastra) and S-100 protein (4C4.9, Neomarkers). CD34 (QBEnd/10, Neomarkers) was only positive in vessel endothelial cells. Ki-67 (MB67, Neomarkers) index was 1%. According to aforementioned pathological features a diagnosis of cotyledonoid leiomyoma was decided. Currently the patient is well and healthy following the sixth month of the operation.

Click Here to Zoom

Figure 1: In fundus of the uterus a serosal, purple colored, fleshy polypoid tumor mass was observed with multinodularity and cystic degeneration.

Click Here to Zoom

Figure 2: The slide obtained from the periphery of the tumor demonstrating congested and dilated vessels, smooth muscle nodules with irregular borders, and perinodular hydropic degeneration (H&E; x40).

Click Here to Zoom

Figure 3: The slide demonstrating perinodular hydropic degeneration around the irregular bordered smooth muscle nodules at high power field (H&E; x100).

Click Here to Zoom

Figure 4: A,B: Congested vascular structures apparent at the peripheral areas of tumor (H&E; x200-x40). C: Hydropic degeneration surrounding tumoreous nodules (H&E; x200). D: Immunohistochemically, tumoreous nodules stained positive with smooth muscle actin (x100).

However, this new case which showed a great macroscopic resemblance to those types of dissecting leiomyomas did not demonstrate intramural dissection so it was accepted as a new intermediate tumor other than intramural and cotyledonoid dissecting leiomyoma⁵. Both cotyledonoid dissecting and cotyledonoid leiomyomas demonstrate hydropic degeneration^4-6. As presented in our current case, hydropic degeneration may lead cystic degeneration.

According to our knowledge, our current cotyledonoid leiomyoma case which does not contain myometrium dissection is the third one following the original descriptive case of Roth et al and Gurbuz et al^5,11.

The differential diagnosis of cotyledonoid leiomyomas includes intravenous leiomyomatosis and leiomyomas with perinodular hydropic changes. Intravenous leiomyomatosis grossly demonstrates multinodularity however exophytic component of the tumor does not show congestion. In the current case, the apparent purple color of the tumor was the result of congested vessels which were more prominent at the periphery of the mass. Leiomyomas with perinodular hydropic degeneration and cotyledonoid leiomyomas both demonstrate hydropic degeneration. Nevertheless the placenta like gross appearance of cotyledonoid leiomyomas can be discriminative which was also observed in our current case. Myxoid leiomyosarcoma should also be included in the differential diagnosis. Although myxoid leiomyosarcoma demonstrate malignant biological behavior, they do not have atypical cytology and mitotic activity is low as 0-2 per ten high power fields. The main properties of the tumor which indicate the malignant potential are infiltrative growth pattern and high Ki-67 index (>60% of tumor cells positive for Ki-67). In our current case Ki-67 index was quite low (1%) and we could rule out myxoid leiomyosarcoma.

As a result, these types of exophytic smooth muscle tumors might demonstrate softer consistency and irregular borders in comparison with conventional leiomyomas. Grossly they might resemble malignant tumors and differential diagnosis might be problematic in microscopic evaluation. For this reason both gynecologic surgeons and pathologists should be well aware of these leiomyoma variants.

1) Clement PB: Pure mesenchymal tumors. In Clement PB, Young RH. (Eds): Tumors and tumor like lesions of the uterine corpus and cervix. New York, Churchill Livingstone, 1993, 265-274

2) Kim MJ, Park YK, Cho JH: Cotyledonoid dissecting leiomyoma of the uterus: A case report and review of the literature. J Korean Med Sci 2002, 17: 840-844 [ PubMed ]

3) Hendrickson MR, Kempson RL: Surgical pathology of the uterine corpus. Major Probl Pathol 1979, 12:1-580 [ PubMed ]

4) Roth LM, Reed RJ: Dissecting leiomyomas of the uterus other than cotyledonoid dissecting leiomyomas. Am J Surg Pathol 1999, 23:1032-1039 [ PubMed ]

5) Roth LM, Reed RJ: Cotyledonoid leiomyoma of the uterus: report of a case. Int J Gynecol Pathol 2000, 19:272-276 [ PubMed ]

6) Roth LM, Reed RJ, Sternberg WH: Cotyledonoid dissecting leiomyoma of the uterus: the Sternberg tumour. Am J Surg Pathol 1996, 20:1455-1461 [ PubMed ]

7) Saeed AS, Hanaa B, Faisal AS, Najla AM: Cotyledonoid dissecting leiomyoma of the uterus: a case report of a benign uterine tumor with sarcomalike gross appearance and review of literature. Int J Gynecol Pathol 2006, 25:262-267 [ PubMed ]

8) David MP, Homonnai TZ, Deligdish L, Lowenthal M: Grapelike leiomyomas of the uterus. Int Surg 1975, 60:238-239 [ PubMed ]

9) Payan H, Monges G, Jouve MP, Sudan N, Gamerre M: An unusual case of uterine leiomyoma: exophytic grape-like development in the pelvic peritoneum. Arch Anat Cytol Pathol 1980, 28:45-49 [ PubMed ]

10) Cheuk W, Chan JK, Liu JY: Cotyledonoid leiomyoma: a benign uterine tumor with alarming gross appearance. Arch Pathol Lab Med 2002, 126: 210-213 [ PubMed ]

11) Gurbuz A, Karateke A, Kabaca C, Arık H, Bilgic R: A case of cotyledonoid leiomyoma and review of the literature. Int J Gynecol Cancer 2005, 15:1218-1221 [ PubMed ]