Low-grade Müllerian adenosarcoma with prominent decidualization, involving bilateral ovaries against a background of endometriosis: A diagnostic and treatment challenge

A Shah¹, B Rekhi¹, A Maheshwari², NA Jambhekar¹,  
¹ Department of Pathology, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
² Department of Surgical Oncology (Gynecology), Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India

Correspondence Address:
B Rekhi
Department of Pathology, Tata Memorial Hospital, Parel, Mumbai, Maharashtra
India

Full Text

Müllerian adenosarcomas mostly arise from the endometrium. On histopathology, these tumors are characterized by a benign or atypical epithelial component and an invariably, low-grade, malignant stromal component. These tumors are not very commonly diagnosed in the ovary. In a large case series of 40 ovarian adenosarcomas, only a single patient had tumor involvement in both ovaries. [1] We present in this paper, a case of a young patient diagnosed with bilateral ovarian adenosarcomas.

A 29-year-old, nulliparous lady presented to us with complaints of lower abdominal pain and abnormal vaginal bleeding of 5-months duration. She gave a past surgical history of an endometriotic cyst excision 2.5 years prior as also medical therapy for endometriosis with Danazol. (200 mg twice daily for 6 days). She had also been using fertility stimulating drugs like clomiphene citrate, hydroxy progesterone, injectable human chorionic gonadotrophin, with progesterone and Gonadotrophin releasing hormone (GnRH) analogues. for 3 months. She underwent radiological imaging, followed by total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAHBSO), at our institution as described below.

On initial abdominal ultrasonography (USG), a cystic mass with internal echoes and fluid in the pouch of Douglas was seen and she underwent her first surgery for an endometrotic cyst excision After a year, a repeat USG revealed residual cyst with ascites. An abdominal computed tomography (CT) scan showed bilateral, heterogeneous, solid-cystic adnexal masses that measured 14.4 × 10.6 × 9.7 cm and 8.1 × 4 × 6 cm, respectively. In addition, there were bowel, bladder, and uterine adhesions. She underwent a second surgery at our Institution.During intraoperative frozen-section evaluation, a left-sided adnexal mass measuring 11 × 9 × 2 cm and a right-sided mass measuring 6 × 4 × 2 cm were received. Both the masses were ruptured, with adhesions between posterior uterine surface, bowel, and appendix [Figure 1]. At the second surgery a frozen-section histological assessment showed only one of the masses as an adenosarcoma. Thereafter, the patient underwent TAHBSO.{Figure 1}

On gross examination, bilateral adnexal masses showed grey-white cut surfaces. Microscopy from both the tumor masses revealed irregularly dilated endometrial glands with focal metaplasia, in a sarcomatous stroma, containing mitoses (2-3/10 high power field); exhibiting periglandular condensation and conspicuous decidualization [Figure 2]. Pigmented macrophages were noted in histological sections from one of the ovaries. Endometriosis with decidualization was also noted in the subserosal myometrium, bilateral parametria, and colonic serosal, the latter that also showed tumour foci. [Figure 3]. Focal decidualization was also noted in the endometrial stroma.{Figure 2}{Figure 3}

On immunohistochemistry (IHC), tumor cells were positively stained with vimentin (monoclonal V9, 1:400 dilution, Dako, Produkionsveg, Glostrup, Denmark) and progesterone receptor (PR) (Monoclonal Pgr636, dilution 1:100, Dako), focally with estrogen receptor (ER) (Monoclonal SP1, 1:100, Dako), Ki-67 (Monoclonal, MIB1, 1:200, Dako) (10% cells), CD10 (Monoclonal 56C6, 1:50, Biocare, PA, USA), and displayed cytoplasmic positivity with MIC2/CD99 (Monoclonal 12E7, 1:100, Dako) and nuclear positivity for calretinin (Monoclonal, 545, 1:50, Novacastra, UK) within stromal cells [Figure 4]. Post-operative USG abdomen, 12 months after the second surgery was normal.{Figure 4}

Adenosarcomas rarely occur in the ovary. In the largest documented series of 40 ovarian adenosarcomas, the observed age-range was 30-84 years (median = 54) and only a single patient had tumor involvement in bilateral ovaries. [1] The present case is one of a very young patient with bilateral ovarian adenosarcomas, wherein the tumor was identified on a background of multifocal pelvic endometriosis. On histopathological assessment, the tumor was characterized by conspicuous decidualization. [1],[2],[3],[4] In an earlier reported series, only 4/40 cases of adenosarcomas were associated with endometriosis. [1] The present case report exemplifies diagnostic challenges in such cases, especially during intraoperative frozen section evaluation, as also noted by previous authors. Whereas Chen et al., [5] underdiagnosed their case as a cyst adenoma at the time of intraoperative frozen section evaluation; one of the bilateral adenosarcomas in the present case was diagnosed as endometriosis, in view of clinical history. There is a definitive role for additional tissue sampling at the time of frozen section in such cases. Presence of discrete, bilateral adnexal masses, despite lack of normal ovarian tissue was indicative of an ovarian origin of the tumors in the present case. Within the histopathological spectrum of adenosarcomas that includes presence of various types of epithelia, sarcomatous stroma (with or without sarcomatous overgrowth), heterologous elements like skeletal muscle, cartilage, conspicuous decidualization, and sex-cord elements have been rarely identified. [1],[4] Stromal decidualization can occur as a result of progestational therapy, as noted in this case, as well as during pregnancy, in progesterone-secreting tumors, and in cases of surface-based ovarian tumors. Differential diagnosis of an adenofibroma and deciduoid polypoid endometriosis was ruled out in view of sarcomatous stroma in the present case. Lack of uterine tumour militated against metastasis from a uterine adenosarcoma. Endometrial stromal sarcoma was considered less likely, due to lack of arborizing vascular pattern and CD10 positivity. Absence of carcinomatous elements was against a malignant mixed Müllerian tumor. Lack of diffuse calretinin positivity and unremarkable omental sections, ruled out deciduoid mesothelioma. Focal calretinin and MIC2 positivity were indicative of sex-cord stromal components.

Malignancy is known to occur in 5% cases of ovarian endometriosis. [4],[5] Such cases are fraught with a poor prognosis due to lack of an anatomic barrier, large size, higher staging, and adhesions with adjacent structures that are difficult to remove and frequently rupture during surgery. Our patient underwent radical tumour resection and has been disease-free, 11 months post-surgery. In summary, young patients undergoing treatment for endometriosis should be followed-up for a rare possibility of developing an adenosarcoma. Diagnostic accuracy during evaluation of such tumors at the time of intraoperative frozen section can be enhanced with additional tissue sampling.

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