Ovarian Leiomyosarcoma in a Young Woman

Abstract

Background: Leiomyosarcomas are extremely rare primary ovarian smooth muscle tumors accounting for <1% of ovarian malignancies. Case: A 30-year-old woman presented with complaints of pain and heaviness in the right iliac region. Abdominal examination revealed a pelvic mass, 18 weeks of gestation in size, with restricted mobility, palpable in the right iliac region. Ultrasonography (USG) revealed a large mass of 14.3×13.2×12.5 cm, occupying the whole of the pelvis just superficial to fundus, but not arising from the uterus. Magnetic resonance imaging (MRI) revealed a large oval well-defined mass in the right lower abdomen and pelvis. An excised right ovarian mass measuring 15×12×11 cm was sent for histopathologic examination. The cut surface of the mass was variegated, with areas of hemorrhage and necrosis. Results: On histopathologic examination, a diagnosis of leiomyosarcoma was made on morphologic and immunohistochemical grounds. Based on the diagnosis, the patient was given chemotherapy and has been followed-up since then. As of this writing, she is doing well. Conclusions: This case of ovarian leiomyosarcoma in a 30-year-old woman is extremely rare. In such cases, postoperative radiotherapy and chemotherapy for large tumor volumes may help control local disease and avoid metastatic recurrences. (J GYNECOL SURG 30:297)

Introduction

Ovarian leiomyosarcomas are extremely rare primary ovarian smooth muscle tumors. These tumors account for <1% of ovarian malignancies. The majority of the cases are seen in peri- and postmenopausal women. Here, a rare presentation of ovarian leiomyosarcoma in a 30-year-old woman is presented. Grossly, these tumors attain a large size, with a tendency for hemorrhage and necrosis. Histopathology and immunohistochemistry play a major role in the diagnosis of these ovarian masses. Microscopically, these masses are usually characterized by the presence of fascicles of spindle-shaped cells with marked pleomorphism, brisk mitotic activity, and necrosis. The prognosis is invariably poor, and patients die with multiple widespread distant metastases.¹ Most patients die within 1 year.² No standard treatment protocols are set, because of the rarity of cases. Surgery is the main mode of treatment. This case of ovarian leiomyosarcoma in a 30-year-old woman is reported because of its extreme rarity, to add to the literature.

Case

A 30-year-old woman presented with complaints of pain and heaviness in the right iliac region. Abdominal examination revealed a pelvic mass, 18 weeks of gestation in size, with restricted mobility, palpable in the right iliac region. On vaginal examination, a mass was felt in the right fornix with restricted mobility and tenderness. Ultrasonography (USG) revealed a large mass of 14.3×13.2×12.5 cm, occupying whole of the pelvis just superficial to the fundus, but not arising from the uterus (Fig. 1).

FIG. 1.

Ultrasonography shows a large heterogeneous echoic mass occupying the whole of the pelvis, just superficial to the fundus, but not arising from the uterus.

Magnetic resonance imaging (MRI) revealed a large oval well- defined altered signal intensity mass of 14.7×14.6×10 cm in the right lower abdomen and pelvis, with a moderate amount of fluid signals in the abdomen and pelvis (Fig. 2). Her preoperative routine test results were normal except for mild anemia, with hemoglobin (Hb) 9.0 gm%. CA-125 value was 69.9 international units (IU)/mL.

FIG. 2.

Magnetic resonance imaging shows a large well-defined altered signal intensity mass in the right lower abdomen and pelvis. (A) Transverse view. (B) Sagittal view.

An excised right ovarian mass measuring 15×12×11 cm was sent for histopathologic examination along with an attached Fallopian tube measuring 3.5×0.6 cm. An omental biopsy was also sent, to rule out metastatic deposits. The cut surface of the mass was variegated, with areas of hemorrhage and necrosis (Fig. 3). Histopathologic examination showed a tumor composed of oval to spindle shaped cells revealing mild-to- moderate nuclear pleomorphism, which was mitotically active with >10 mitoses per 10 high-power fields (HPF) (Fig. 4). The structure of a normal ovary was identified in sections taken from the periphery of the mass. On immunohistochemistry, the tumor cells were noted to be positive for desmin, vimentin, and smooth muscle actin, and negative for inhibin (Fig. 5). The result of an omental biopsy was found to be negative for metastatic tumor deposits.

FIG. 3.

(A) Ovarian tumor mass with attached Fallopian tube. (B) Cut surface of the tumor, revealing areas of hemorrhage and necrosis.

FIG. 4.

Oval-to–spindle-shaped cells revealing mild-to-moderate nuclear pleomorphism and high mitotic activity. (A) 200×; (B) 400×; hematoxylin and eosin (H&E). (C) Periphery of the tumor area showing structure of a normal ovary with hemorrhagic areas.

FIG. 5.

Photomicrograph showing immunohistochemical expression of tumor cells. The tumor cells show intense cytoplasmic positivity for vimentin (A), desmin (B), and smooth muscle actin (C), and negativity for inhibin (D).

Results

Taking into account morphology and immunohistochemistry, a diagnosis of ovarian leiomyosarcoma was made. Subsequently, the patient was given chemotherapy, and has been on follow-up for 4 months, which have been uneventful to date.

Discussion

Primary smooth muscle ovarian tumors are rare, and account for <3% of ovarian tumors. The most common smooth muscle tumors are rhabdomyosarcoma, fibrosarcoma, and leiomyosarcoma, which is the rarest, and accounts for <1% of all cases. Only 55 cases have been reported so far. The majority of cases occur in women in the peri- and postmenopausal age group: between 45 and 65 years of age. There is little information on their origin, etiology, histologic features, clinical behavior, and treatment.³

Pathogenesis is uncertain, with many theories, including: malignant degeneration of an ovarian leiomyoma, or of the smooth muscle present in the wall of the blood vessels in the cortical stroma and corpus luteum; muscular attachments of the ovarian ligament; Wolffian duct remnants; or totipotential ovarian mesenchyme, or arising in a teratoma.⁴ These tumors are usually well-circumscribed and have a tendency to reach a very large size. These sarcomas also tend to have features of necrosis, hemorrhage, and cystic degeneration.

Ovarian leiomyosarcomas generally are highly malignant and present with local, hematogenous, or lymphatic spread. Distant metastasis has been seen, mainly in the lungs and liver in the cases diagnosed so far. On histopathologic examination, markedly pleomorphic spindle-shaped cells intersecting each other at wide angles are seen. Nuclei of the cells are vesicular and ovoid or cigar shaped. The tumors show immunoreactivity for smooth-muscle actin, desmin, and caldesmon. Often, these tumors present with brisk mitotic activity. Generally, malignant potential behavior of smooth-muscle tumors is associated with any two of the following features: coagulative necrosis; cellular atypia; and a mitotic index >10/10 HPF.⁵

The majority of cases have a poor prognosis, with death ensuing within 1 year of diagnosis. The International Federation of Gynecology & Obstetrics (FIGO) staging and treatment of ovarian leiomyosarcoma have been the same as those for ovarian carcinoma.⁶ Prognosis depends upon the tumor stage, tumor size, and mitotic index.

Conclusions

There is no established treatment for these sarcomas other than surgery.⁷ Most of these tumors are radioresistant. Dixit et al. have suggested postoperative radiotherapy and chemotherapy in large tumor volumes, to control local disease and avoid metastatic recurrence.⁸

Footnotes

Disclosure Statement

No financial conflicts of interest exist.

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