DOI: 10.1055/s-0037-1604057 - volume 39 - Agosto 2017
Fatma Cavide Sonmez, Zeynep Tosuner, Ayse Filiz Gökmen Karasu, Dilek Sema Arıcı, Ramazan Dansuk
Cotyledonoid dissecting leiomyomas are a rare variant of leiomyomas with a disparate gross appearance. They generally arise from the myometrium and extend to the broad ligaments. This particular type of tumor typically incorporates various characteristics, including dissecting growth and perinodular hydropic degeneration.1 2 Mitoses, coagulative necrosis and atypical cells have not been reported in this variant. We report a case of a cotyledonoid dissecting leiomyoma in a 38-year-old woman who presented with abdominal pain and underwent myomectomy.
A 38-year-old multigravid woman presented with abdominal pain. An ultrasonography examination showed an irregularly contoured, subserous myoma with 95 mm x 93 mm dimensions arising from the uterine fundus. A cervicovaginal smear displaying normal cytology and endometrial sample demonstrating proliferative endometrium was obtained prior to the operation. A congested, multinodular mass was surgically resected by myomectomy, and the uterus was salvaged. Macroscopically, the mass was reddish brown colored and 135 mm x 105 mm x 90 mm in dimensions with a multinodular appearance (Fig. 1). Closely packed, variable-sized nodules were resembling cotyledons. The cut surface was gray-white and congested in some areas. Microscopically, the tumor showed smooth muscle fascicles and micronodules (Fig. 2A). Dilated and congested vessels were prominent at the peripheral areas of the nodules. Cellularity varied because of extensive hydropic degeneration (Fig. 2B). Mononuclear and multinuclear atypical, bizarre cells were detected (Fig. 2C). Coagulative necrosis was not observed. There were 2 mitoses per 10 high power fields, and the immunohistochemical Ki-67 index of was 2–3% (Fig. 2D). Intravascular involvement was not encountered.
Fig. 1
Gross appearance of the lesion reminiscence of placental cotyledons.
Fig. 2
(A) There are smooth muscle fascicles and nodules separated by vascularized and hydropic tissue (H&E stain, x 20). (B) Perinodular extensive hydropic degeneration is present (H&E stain, x 40). (C) There are mono and multinucleated atypical cells (H&E stain, x400). (D) The immunohistochemical Ki-67 index is of 2–3%.
The result of our macroscopic and microscopic examinations was ‘cotyledonoid leiomyoma with the presence of symplastic (atypical) features’. The patient was followed up with regular postoperative visits in the gynecology outpatient clinic, and was alive and well 36 months after surgery, with no evidence of recurrence.
Smooth muscle tumors are the most common neoplasms of the female genital tract, and they can demonstrate different growth patterns.1 2 3 4 Dissecting leiomyomas exhibit an unusual growth pattern, with apparent broad tongues infiltrating between myometrial muscle bundles. Cotyledonoid dissecting leiomyoma, or ‘Sternberg tumor,’ was first described in 1996 by Roth et al.2 Menolascino-Bratta et al5 coined the term ‘angionodular dissecting leiomyoma’. These tumors have been described in women from the third to the early sixth decade of life.1 The common clinical findings are pelvic masses and abnormal uterine bleeding.3 6 These tumors can be large with an average dimension of 15 cm (range 4–41 cm). Three potential types have been described. The first type is the cotyledonoid dissecting leiomyoma (Sternberg tumor), which comprises an exophytic mass of multinodular tissue resembling the placenta, and is often protruding from the lateral surface of the uterine corn in continuation with the myometrium. The second type is the intramural dissecting tumor, which is confined to the uterus. These two types are histologically similar. The last type is pure cotyledonoid leiomyoma, which is not associated with either a parent intramural mass or intramural dissection.7
Cotyledonoid dissecting leiomyoma is characterized by disorganized smooth muscle fascicles with extensive hydropic degeneration and marked vascularity.1 Histological features suggestive of malignancy, such as cytological atypia, necrosis and increased mitotic activity, are absent.8
The microscopic findings of our case were similar except for the atypical cells. Edema and congestion were prominent in some areas. Tumor cell necrosis, increased mitotic activity, and high immunohistochemical Ki-67 index were not detected, but a few mononuclear and multinuclear atypical, bizarre cells were observed, which makes our case unique. As an isolated finding, cytologic atypia, even when severe, is an unreliable criterion for the diagnosis of clinically malignant uterine smooth muscle tumor, as it may be observed in clinically benign neoplasms such as our case. These changes have been noted in leiomyomas excised from women taking progestin; however, there was no history of progestin use in our patient. A leiomyoma that exhibits moderate to severe cytologic atypia is designated as an atypical leiomyoma. By definition, mitotic figures cannot be present in numbers in excess of 10/10 high power fields. In atypical leiomyomas and tumor cells, necrosis must be absent.1
Intravenous leiomyomatosis, leiomyoma with perinodular hydropic degeneration, and myxoid leiomyosarcoma enter into the differential diagnosis.3 The tumor grows within the lumina in intravenous leiomyomatosis. Leiomyoma with perinodular hydropic changes does not have a gross appearance like placenta.4 Infiltrative growth pattern and high Ki-67 index are important to differentiate myxoid leiomyosarcoma from cotyledonoid dissecting leiomyoma.4 In our case, edematous areas resembled myxoid leiomyosarcoma, but were not infiltrative, and the Ki-67 index was of 2–3%.
Atypical cells are not features of cotyledonoid dissecting leiomyomas. Both atypical (symplastic) and dissecting leiomyomas are benign. Despite the macroscopic and microscopic aggressive appearance, no example of malignant behavior or recurrence has been reported in a dissecting leiomyoma.3 So, it is important that surgeons and pathologists are aware of this rare, unusual entity to prevent misdiagnosis and overtreatment.
The authors would like to thank Nurya Tatianya Buyuk Aleksanyan for the translation of the abstract.